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Keywords:

  • Campos Basin;
  • cladistic analysis;
  • Corophiidea;
  • deep sea;
  • Ischyroceridae;
  • new species

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Systematics
  7. Acknowledgements
  8. References

The family Ischyroceridae is analysed herein by cladistic methods based on morphological characters, using both PAUP 4.0b and TNT. The data matrix of 41 characters × 32 terminal taxa was constructed using DELTA. Based on the results, we comment on the phylogenetic relationships of certain genera and their synapomorphic characters, also discussing the phylogenetic position of Myersius gen. nov., which appeared as the sister group of Bathyphotis. In addition, Pseudischyrocerus crenatipes is removed to Bathyphotis, for which a new diagnosis is provided. A taxonomic study with the Ischyroceridae collected on the continental slope (depth, 700–2000 m) in the Campos Basin (20.5–24°S, 40–41°W) was also performed. Samples were collected in November–December 2002 and July–August 2003 using a box core device. As a result, a new genus and eight new species are described: Bonnierella campensis sp. nov., Bonnierella laurensi sp. nov., Myersius denticaudatus gen. et sp. nov., Notopoma lowryi sp. nov., Notopoma teresae sp. nov., Pseudericthonius bousfieldi sp. nov., Pseudericthonius concavus sp. nov., and Pseudischyrocerus caecus sp. nov. The genus Bonnierella is recorded for the first time from Brazilian waters, and the subspecies Bonnierella linearis linearis and Bonnierella linearis californica are elevated to species rank. Keys to the genera of Ischyroceridae used in the cladistic analysis and the world species of Notopoma are given. © 2014 The Linnean Society of London


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Systematics
  7. Acknowledgements
  8. References

The taxonomic and phylogenetic relationships among some groups of Corophioidea are controversial, and have been much discussed, including the position of this superfamily within the suborder Gammaridea. J.L. Barnard (1973) erected the superfamily Corophioidea including the families Ampithoidae, Cheluridae, Corophiidae, Ischyroceridae, and Podoceridae, all of which were well defined except for Corophiidae. In the same work, Barnard synonymized the families Photidae, Aoridae, and Isaeidae with Corophiidae, but recognized no subfamilies. Other authors have proposed a more restricted concept of the family Corophiidae. Bousfield (1978) recognized the superfamily Corophioidea including nine families, among which Aoridae, Corophiidae, Photidae, and Isaeidae were considered distinct families. Later on, Myers (1981) erected the family Neomegamphopidae, and retained a separate status for Aoridae and Corophiidae, whereas Photidae and Isaeidae were merged with Isaeidae. Just (1983) erected the subfamily Siphonoecetinae within Corophiidae (sensu Myers, 1981). Despite these proposals, J.L. Barnard & Karaman (1991) followed J.L. Barnard's (1973) classification and submerged Ischyroceridae and Neomegamphopidae within Corophiidae, but maintained the subfamily Siphonoecetinae. Nevertheless, Bousfield & Hoover (1997) continued giving separate recognition to Aoridae, Isaeidae, and Ischyroceridae within the superfamily Corophioidea, and considered the family Corophiidae to have two subfamilies, Corophiinae and Siphonoecetinae.

Currently, the family Ischyroceridae comprises 254 species distributed in 40 genera, with a worldwide distribution. This family is mainly characterized by the uropod 3 with the peduncle broad proximally and narrow distally, and its rami with tiny apical setae and the outer ramus with recurved apical spines; these spines are lost in siphonoecetids (Myers & Lowry, 2003). Studies dealing with the evolution of the Ischyroceridae include that of Lowry & Berents (1996), who presented a cladistic analysis for the Ericthonius group, which included the Cerapus clade, Ericthonius, Pseudericthonius, Pseudischyrocerus, and the Siphonocetid clade. Myers & Lowry (2003) proposed a new classification for the corophioideans based on a morphological cladistic analysis, where the suborder Corophiidea was erected. This suborder comprised two infraorders: the Corophiida, earlier placed within the suborder Gammaridea, and the Caprellida, previously treated as a separate suborder. This classification supported the previous hypothesis where the Caprellida share a common ancestor with podocerids (Laubitz, 1979). Myers & Lowry (2003) also used feeding strategies to separate these groups, where Corophiida were considered as derived from bottom-feeding detritivores, whereas members of the Caprellida were derived from ancestors that fed on material suspended in the water column. The work of Myers & Lowry (2003) clarified the relationship among most families of Corophioidea, and provided a restricted diagnosis of most of the families discussed above. For example, the Ericthonius group was found to be monophyletic, as observed by Lowry & Berents (1996), although it appeared as a Siphonoecetine within the Ischyroceridae. Also, Photidae and Isaeidae were found to be separate families. The relationships among genera of these families were not discussed, however. Recently, Lowry & Myers (2013) erected the suborder Senticaudata, defined as a monophyletic clade that shares robust setae on the apices of uropods 1 and 2. The Senticaudata included 95 families that were previously assigned to the suborder Gammaridea, and all members of the suborder Corophiidea, which is now considered as the infraorder Corophiida.

The first Brazilian deep-sea amphipod, Parandania boecki, was recorded by Stebbing (1888; as Andania boecki), and was collected by the ‘Challenger Expedition – 1873’ at a depth of 1234 m off the state of Pernambuco. More than a century later, new deep-sea amphipod records off the Brazilian coast began to be reported. Fifteen studies have recorded a total of 35 amphipod species from off the Brazilian coast in waters below 200 m (Table 1). Despite these efforts, the Brazilian deep-sea amphipod fauna is still little known, and many more species await description.

Table 1. List of deep-sea species of the order Amphipoda recorded in Brazilian waters
SpeciesLocality and depthReference
Amathillopsis atlantica Chevreux, 190823°54′S, 42°10′W, 830 mWakabara & Serejo (1999)
Ampelisca anae Valério-Berardo, 200822°27′31.62″S, 40°09′23.19″W, 750 mValério-Berardo (2008)
Ampelisca campensis Valério-Berardo, 200822°41′10.8″S, 40°2′20.3″W, 1650 mValério-Berardo (2008)
Ampelisca minuta Valério-Berardo, 200822°31′12.47″S, 40°15′11.08″W, 750 mValério-Berardo (2008)
Ampelisca wakabarae Valério-Berardo, 200822°04′33.9″–22°27′31.62″S, 39°52′05.1″–40°09′23.19″W, 750–1050 mValério-Berardo (2008)
Bathybirubius margaretae Senna, 201022°02′31″S, 39°52′14″W, 1050 mSenna (2010)
Byblis bjornbergae Valério-Berardo, 200822°10′43.278″S, 39°54′46.036″W, 750–1050 mValério-Berardo (2008)
Caprella ungulina Mayer, 190314°36.579′S, 038°49.544′W 1067 mSittrop & Serejo (2009)
Coxophoxus alonso Senna, 201022°02′31″S, 39°52′13″W, 1050–1350 mSenna (2010)
Epimeria bathyalis Wakabara & Serejo, 199919°01′S, 37°47′W, 1500–1575 mWakabara & Serejo (1999)
Epimeria rotunda Wakabara & Serejo, 199921°36′S, 39°58′W, 1190–1205 mWakabara & Serejo (1999)
Epimeria ultraspinosa Wakabara & Serejo, 199923°54′S, 42°10′W, 830 mWakabara & Serejo (1999)
Eurythenes gryllus (Lichtenstein in Mandt, 1822)13° 19′.944″S, 38 19′.654″W and 20° 26′.850″S, 39 41′.636″W, 1089–1730 mSerejo et al. (2007)
Eurythenes obesus (Chevreux, 1905) 22°15.49′S, 39°47.450′W, 1300–1608 mSenna & Serejo (2008)
Haploops meloi Valério-Berardo, 200822°02′50.811″S, 39°52′24.1″W, 1050 mValério-Berardo (2008)
Lepechinella campensis Sittrop & Serejo, 200922°10′54.4″S, 39°52′19.4″W, 1050 mSittrop & Serejo (2009)
Lepechinella hirsuta Sittrop & Serejo, 200921°52′50.5′′S, 39°51′42.6′′W, 1050 mSittrop & Serejo (2009)
Lepechinella laurensi Sittrop & Serejo, 200921°57′26.8″S, 39°40′34.0″W, 1950 mSittrop & Serejo (2009)
Leptophoxoides marina Senna, 201021°52′36″S, 39°55′18″W, 750–1950 mSenna (2010)
Liljeborgia quinquedentata Schellenberg, 193119°02′S, 33°47′W, 790 mWakabara et al. (1991)
Liropus nelsonae Guerra-García, 20037°50′–7°58′S, 34°17′W, 943–1007 mGuerra-García (2003)
Megamphopus robustisetae Souza-Filho & Senna, 201222°41.928′S, 40°16.506′W, 1045–1350 mSouza-Filho & Senna (2012)
Notopoma fluminense Valério-Berardo, Souza & Rodrigues, 200822°41′S, 40°20′W, 730 mValério-Berardo et al. (2008)
Parandania boecki (Stebbing, 1888)off Pernambuco State, 1234 mStebbing (1888)
Parvipalpus colemani Guerra-García, 20037°50′–7°58′S, 34°17′W, 943–1007 mGuerra-García (2003)
Pseudharpinia berardo Senna, 201022°35′25″S, 40°15′31″W, 900 mSenna (2010)
Pseudharpinia ovata Senna, 201022°02′31″–22°41′08″S, 39°52′13″–40°14′06″W, 1050–1100 mSenna (2010)
Stephonyx uncinatus Senna & Serejo, 200714°27′654″S, 38°51′130″W, 730–739 mSenna & Serejo (2007)
Tectovalopsis ruffoi (Serejo & Wakabara, 2003)19°01′S, 37°47′W, 1500–1575 mSerejo & Wakabara (2003)
Trischizostoma costai Freire & Serejo, 200421°12.293′S, 40°00.884′W, 1364 m,Freire & Serejo (2004)
Trischizostoma denticulatum Ledoyer, 197821°07.780′S, 39°49.106′W to 21°04.783′S, 39°48.698′W, 1642 mFreire & Serejo (2004)
Trischizostoma longirostrum Chevreux, 191915°47.725′–19°58.936′S, 38°24.839′–39°38.657′W, 1002–2076 mFreire & Serejo (2004)
Trischizostoma raschi Boeck, 186115°08.595′–19°59.936′S, 38°40.638′–39°38.657′W, 922–1026 mFreire & Serejo (2004)
Trischizostoma richeri Lowry & Stoddart, 199415°48.503′S, 38°36.265′W, 599 mFreire & Serejo (2004)
Valettiopsis macrodactyla Chevreux, 190921°36′S, 39°58′W, 1190–1295 mSerejo & Wakabara (2003)

In recent decades, deep-water drilling exploration activities off the Brazilian coast intensified with the discovery of giant oil reserves, such as the Albacora, Marlin, and Barracuda banks in the Campos Basin. Consequently, in order to maintain sustainable deep-water exploration, the Petrobras Research Center or Cenpes/Petrobras (Petróleo do Brasil SA) initiated the Campos Basin Deep Sea Environmental Project (OCEANPROF). The main objective of this project was to characterize the oceanic region of the Campos Basin according to the physical, chemical, and biological properties of the water and the bottom between the depths of 700 and 2000 m (Lavrado et al., 2010). As a result of this project, two books were published in which 144 crustaceans were listed (Serejo et al., 2010). Several taxonomic studies with Decapoda, Isopoda, and Tanaidacea from the OCEANPROF have been published (e.g. Cardoso & Serejo, 2007; Albuquerque & Costa, 2008; Larsen, Silva & Coelho, 2009).

Among the amphipods collected by the OCEANPROF project, the corophiideans were one of the most important groups. The family Ischyroceridae Stebbing, 1899 was represented by five genera and eight species, distributed in two subfamilies: Bonnierellinae Myers & Lowry, 2003 and Ischyrocerinae Stebbing, 1899. Currently, 11 ischyrocerids are known from Brazilian waters (Wakabara & Serejo, 1998; Valério-Berardo, 2001; Valério-Berardo, Souza & Rodrigues, 2008), but the present study raised this number to 19. Taking this material into account, we performed a cladistic analysis based on morphological characters, to better understand the phylogenetic relationships among certain genera of the family Ischyroceridae, including the position of Myersius gen. nov. described herein. Based on this analysis, some minor taxonomic changes within the family are also proposed.

Material and Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Systematics
  7. Acknowledgements
  8. References

Phylogenetic analysis

In order to classify the material observed from the Campos Basin, we decided to run a cladistic analysis of the family Ischyroceridae, including the genera Bathyphotis, Bathypoma, Bonnierella, Cerapus, Ericthonius, Notopoma, Paracerapus, Pseudischyrocerus, Pseudericthonius, and Runanga, plus Myersius gen. nov. and the Siphonoecetes clade (Australoecetes, Borneoecetes, Bubocorophium, Caribboecetes, Concholestes, Corocubanus, Rhinoecetes, and Siphonoecetes).

Considering that we did not include all genera of Ischyroceridae, the monophyly of the family was based on the cladistic analysis proposed by Myers & Lowry (2003). The family Photidae is considered as a sister clade of Ischyroceridae within the superfamily Photoidea (sensu Myers & Lowry, 2003). Thus, two species of this family, Gammaropsis sp. and Photis sp., were chosen as out-groups.

The in-group was composed of 32 terminal taxa of the family Ischyroceridae (Table 2). Within the subfamily Bonnierellinae, the genus Bogenfelsia J.L. Barnard, 1962 was briefly described based only on Bogenfelsia incisa J.L. Barnard, 1962. Taking this into account, and considering that this taxon would have many gaps in the character matrix, it was not included in the analysis.

Table 2. List of 32 taxa used in the cladistic analysis with reference information used for each species, and catalogue number when the material was available for study
TaxonReferenceCollection number
Gammaropsis sp. MNRJ 21546
Photis sp. MNRJ 21573
Bonnierella linearis J.L. Barnard, 1964J.L. Barnard (1964)AMNH 12348
Bonnierella campensis sp. nov.Present studyMNRJ 21218
Bonnierella laurensi sp. nov.Present studyMNRJ 21231
Myersius denticaudatus gen. et sp. nov.Present studyMNRJ 21424
Bathyphotis tridentata Stephensen, 1944Stephensen (1944); Griffiths (1977) 
Bathyphotis crenatipes (Bellan-Santini & Ledoyer, 1986)Bellan-Santini & Ledoyer (1986) 
Pseudischyrocerus besnardi Valério-Berardo, 2001Valério-Berardo (2001) 
Pseudischyrocerus caecus sp. nov.Present study 
Pseudischyrocerus denticauda Schellenberg, 1931Schellenberg (1931) 
Pseudericthonius concavus sp. nov.Present study 
Pseudericthonius hesperidesi Rauschert, 1997Rauschert (1997) 
Pseudericthonius gaussi (Schellenberg, 1926)Schellenberg (1926); Bellan-Santini & Ledoyer (1986) 
Ericthonius brasiliensis (Dana, 1853)Present studyMNRJ 6117
Ericthonius pugnax (Dana, 1853)Myers (1995) 
Paracerapus polutovi (Gurjanova, 1951)Lowry & Berents (1996) 
Cerapus tubularis Say, 1817Lowry & Berents (1996) 
Cerapus jonsoni Valério-Berardo, Souza & Rodrigues, 2008Valério-Berardo et al. (2008) 
Runanga coxalis J.L. Barnard, 1962J.L. Barnard (1962) 
Bathypoma enigma Lowry & Berents, 1996Lowry & Berents (1996) 
Notopoma teresae sp. nov.Present studyMNRJ 21239
Notopoma stoddartae Lowry & Berents, 1996Lowry & Berents (1996) 
Notopoma lowryi sp. nov.Present study 
Notopoma cidaridis Berge, Vader & Lockhart, 2004Berge et al. (2004) 
Australoecetes australis (Stebbing, 1910)Just (1985) 
Borneoecetes wongi Barnard & Thomas, 1984J.L. Barnard & Thomas (1984) 
Bubocorophium macropalpus Just, 2004Just (2004) 
Caribboecetes barbadensis Just, 1983Just (1983) 
Concholestes dentalii Giles, 1888Just (1984) 
Rhinoecetes robustus Just, 1983Just (1983) 
Siphonoecetes (Siphonoecetes) arabicus Barnard & Thomas, 1984J.L. Barnard & Thomas (1984)

The data matrix of 41 characters × 32 terminal taxa (Tables 3 and 4) was constructed using DELTA (Dallwitz, 2005). Some character states (Figs 1-6) were scored according to Lowry & Berents (1996) and Myers & Lowry (2003), but most of them have been verified by personal observation by the authors, including photomicrographs in SEM for character 33 (Fig. 6). Also, other characters not previously considered by Lowry & Berents (1996) were included or re-defined based on new personal observations. Continuous characters, such as the number of articles on the accessory flagellum of antenna 1 and the size of the inner ramus of the uropods, were not included. Myers (1981) pointed out that these characters have doubtful phylogenetic significance in Amphipoda. The gradual reduction of a biramous appendage to a uniramous condition and the reduction of the accessory flagellum are phenomena that are repeated again and again throughout the Crustacea, and therefore there is no reason to assume that they are a synapomorphy in Amphipoda (Myers, 1981, 1986).

Table 3. Morphological characters used in the analyses
Characters
 1. Head anteroventral margin: (1) moderately recessed; (2) strongly recessed.
 2. Antenna 1, length in relation to antenna 2: (1) subequal to antenna 2; (2) shorter than antenna 2.
 3. Antenna 1, peduncular article 1: (1) long and rectangular; (2) produced anterodistally and medially.
 4. Antenna 1, peduncular article 3: (1) subequal or shorter than article 2; (2) longer than article 2.
 5. Antennae 1, article 1 posterior margin: (1) without swelling; (2) with swelling.
 6. Mandibular palp: (1) well developed, 3-articulate; (2) reduced, 2-articulate; (3) very reduced, 1-articulate.
 7. Maxilla 1, outer margin of inner plate: (1) with a row of setae; (2) without a row of setae.
 8. Gnathopod 1, carpus: (1) shorter than propodus; (2) longer than propodus.
 9. Gnathopod 2 male: (1) subchelate; (2) carpochelate; (3) simple.
10. Gnathopod 2 male, carpus: (1) shorter than propodus; (2) longer than propodus; (3) subequal to propodus.
11. Gnathopod 2 female, carpus: (1) shorter than propodus; (2) longer than propodus; (3) subequal to propodus.
12. Coxae 1–7, relative lengths: (1) coxae 1–5 longer than wide and coxae 6 and 7 wider than long; (2) coxae 1–7 wider than long; (3) coxae 1–4 longer than wide and coxae 5–7 wider than long.
13. Coxa 4, margin: (1) smooth; (2) serrate.
14. Coxa 4, posterior margin: (1) not excavated; (2) excavated.
15. Coxa 5: (1) with posterodorsal lobe; (2) without posterodorsal lobe.
16. Pereopods 3–7 basis: (1) ovate; (2) rectilinear.
17. Pereopod 4, merus: (1) equal to merus of pereopod 3; (2) longer than merus of pereopod 3.
18. Pereopod 5, carpus: (1) subrectangular; (2) lunate or reniform.
19. Pereopods 5, shape: (1) pereopod 5 similar to pereopods 6 and 7; (2) pereopod 5 dissimilar to pereopods 6 and 7; (3) pereopod 5 similar to pereopod 6 and dissimilar to pereopod 7.
20. Pereopods 5–7, dactylus: (1) without accessory spines; (2) with accessory spines.
21. Pereopod 5, carpus: (1) without denticles or robust setae on posteroventral margin; (2) with denticles on posteroventral margin; (3) with denticles and short robust setae on posteroventral margin.
22. Pereopod 5: (1) distal part (at least the propodus and dactylus) directed anteriorly; (2) distal part directed posteriorly.
23. Pereopod 6: (1) distal part (at least the propodus and dactylus) directed anteriorly; (2) distal part directed posteriorly.
24. Pereopod 7: (1) distal part (at least the propodus and dactylus) directed anteriorly; (2) distal part directed posteriorly.
25. Pleosomite: (1) without lateral ridges; (2) with lateral ridges.
26. Pleopods peduncle: (1) slender, not expanded; (2) broad, expanded.
27. Pleopod 2, inner ramus: (1) present, as long as outer ramus; (2) reduced or absent.
28. Urosomite 1: (1) without dorsal spines; (2) with dorsal spines.
29. Uropod 1, peduncle: (1) with interamal process; (2) with distoventral corona; (3) without distoventral corona or process.
30. Uropod 1, outer margin of outer ramus: (1) smooth; (2) dentate.
31. Uropod 2: (1) biramous; (2) uniramous; (3) rami absent.
32. Uropod 2, outer margin of rami: (1) smooth and with robust setae; (2) dentate and without robust setae.
33. Uropod 3, tip of outer ramus: (1) without spines; (2) with spines; (3) with plate bearing spines.
34. Uropod 3, peduncle: (1) parallel sided; (2) broad proximally and narrow distally.
35. Uropod 3: (1) biramous; (2) uniramous; (3) absent.
36. Uropod 3, rami or ramus: (1) longer than peduncle; (2) shorter than peduncle.
37. Uropod 3, outer ramus: (1) 2-articulate, second one rudimentary; (2) 1-articulate.
38. Telson: (1) longer than wide; (2) wider than long.
39. Telson: (1) entire; (2) cleft.
40. Telson, dorsal margin: (1) without recurved spines; (2) with recurved spines in patches; (3) with recurved spines in rows.
41. Telson, tip: (1) without distolateral spines; (2) with 2 distolateral spines.
Table 4. Character matrix with 32 terminal taxa and 41 morphological characters used in the analysis
Species1234567891011121314151617181920212223242526272829303132333435363738394041
  1. Numerals 1–3 represent the character states listed and discussed in the results; ?, missing data; –, no applicable character.

Gammaropsis sp.11111111111111111111111111111111111111111
Photis sp.21111121111111111112111111111111111211111
Bonnierella linearis21111121111211221111111111111111221221111
Bonnierella campensis sp. nov.21111121111211221111111111111111221221111
Bonnierella laurensi sp. nov.21111121111211221111111111111111221221111
Bathyphotis crenatipes comb. nov.2111112311111221112111111??21111221221111
Bathyphotis tridentata21111123111112211121111111121111221221111
Pseudischyrocerus besnardi21111123111111111121111111111111321221111
Pseudischyrocerus denticauda21111123111111111121111111111111321221111
Pseudericthonius hesperidesi21111113222211111222111111112111222222121
Pseudericthonius gaussi21111113222211111222111111112111222222121
Pseudericthonius concavus sp. nov.21111113222211111222111111112111222222121
Ericthonius brasiliensis21111113221211111222111111112111222222121
Ericthonius pugnax21111113221211111222111111112111222222121
Bathypoma enigma21211121111211112222222221212222222222231
Cerapus jonsoni21112121221211112222222221212222222222231
Notopoma stoddartae21211121231211112222222221212222222222231
Notopoma cidaridis21211121231211112222222221212222222222231
Runanga coxalis21121121233211112222222221212222222222231
Myersius denticaudatus gen. et sp. nov.211111221111122111?1111111111111221221112
Pseudischyrocerus caecus sp. nov.21111123111111111121111111111111321221111
Cerapus tubularis21112121221211112222222221212222222222231
Notopoma teresae sp. nov.21211121231211112222222221212222222222231
Notopoma lowryi sp. nov.21211121231211112222222221212222222222231
Paracerapus polutovi21111121221211111222221111112222322222231
Borneoecetes wongi22111223111311111232322212112222122222111
Caribboecetes barbadensis2211122331132111123132221211223-123222121
Rhinoecetes robustus22111223111311111231322112113222122222121
Australoecetes australis22111221311311111232322212112222122222121
Bubocorophium macropalpus22111323111321111232322212112222122222121
Concholestes dentalii2211122311132111123132221211323123222121
Siphonoecetes arabicus22111223311311111231322212112212122222121
figure

Figure 1. Characters 1–8. Head anteroventral margin moderately recessed (1.1), strongly recessed (1.2). Antenna 1 subequal to antenna 2 (2.1), shorter than antenna 2 (2.2). Antenna 1, peduncular article 1 long and rectangular (3.1), produced anterodistally and medially (3.2). Antenna 1 peduncular article 3 subequal or shorter than article 2 (4.1); longer than article 2 (4.2). Antenna 1 article 1 posterior margin without swelling (5.1), with swelling (5.2). Species: (1.1) Gammaropsis sp.; (1.2, 8.1) Bonnierella laurensi sp. nov.; (2.1, 3.2, 4.1) Notopoma teresae sp. nov.; (2.2, 3.1, 4.1, 5.1, 6.2) Caribboecetes barbadensis Just, 1983 (redrawn from Just, 1984); (4.2) Runanga coxalis J.L. Barnard, 1961 (redrawn from J.L. Barnard, 1962); (5.2) Cerapus tubularis Say, 1818 (redrawn from Lowry & Berents, 1996); (6.1, 7.1, 8.2) Pseudericthonius bousfieldi sp. nov.; (7.2) Bonnierella campensis sp. nov.

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Figure 2. Characters 9–15. Gnathopod 2 male subchelate (9.1), carpochelate (9.2), (simple 9.3). Gnathopod 2 male, carpus shorter than propodus (10.1), longer than propodus (10.2), subequal to propodus (10.3). Gnathopod 2 female, carpus shorter than propodus (11.1), longer than propodus (11.2), subequal to propodus (11.3). Coxae 1–7. Coxae 1–5 longer than wide and coxae 6 and 7 wider than long (12.1); coxae 1–7 wider than long (12.2), coxae 1–4 longer than wide and coxae 5–7 wider than long (12.3). Coxa 4 margin smooth (13.1), serrate (13.2). Coxa 4 posterior margin not excavated (14.1), excavated (14.2). Coxa 5 with posterodorsal lobe (15.1), without posterodorsal lobe (15.2). Species: (9.1, 12.2, 13.1, 14.1) Bonnierella laurensi sp. nov.; (9.2, 10.3) Notopoma teresae sp. nov.; (12.3) Caribboecetes barbadensis Just, 1983 (redrawn from Just, 1984); (11.3) Runanga coxalis J.L. Barnard, 1961 (redrawn from J.L. Barnard, 1962); (9.3, 10.2, 11.2, 12.1, 15.2) Pseudericthonius bousfieldi sp. nov.; (10.1, 11.1, 14.2) Myersius spinicaudatusgen. et sp. nov. (12.1, 15.1) Pseudischyrocerus caecus sp. nov.

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Figure 3. Characters 16–20. Pereopods 3–7 basis ovate (16.1), rectilinear (16.2). Pereopod 4 merus equal to merus of pereopod 3 (17.1), longer than merus of pereopod 3 (17.2). Pereopod 5 carpus subrectangular (18.1); lunate or reniform (18.2). Pereopods 5 similar to pereopods 6 and 7 (19.1); pereopod 5 dissimilar to pereopods 6 and 7 (19.2), pereopod 5 similar to pereopod 6 and dissimilar to pereopod 7 (19.3). Pereopods 5–7 dactylus without accessory spines (20.1), with accessory spines (20.2). Species: (16.1, 17.2, 18.2, 19.2, 20.2) Notopoma teresae sp. nov.; (19.3) Caribboecetes barbadensis Just, 1983 (redrawn from Just, 1984); (16.2, 17.1, 19.1, 20.1) Bonnierella linearis; (18.1) Bonnierella campensis sp. nov.

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Figure 4. Characters 21–33. Pereopod 5 carpus without denticles or robust setae on posteroventral margin (21.1); with denticles on posteroventral margin (21.2); with denticles and short robust setae on posteroventral margin (21.3). Pereopod 5 distal part (at least the propodus and dactylus) directed anteriorly (22.1); distal part directed posteriorly (22.2). Pereopod 6 distal part (at least the propodus and dactylus) directed anteriorly (23.1); distal part directed posteriorly (23.2). Pereopod 7 distal part (at least the propodus and dactylus) directed anteriorly (24.1); distal part directed posteriorly (24.2). Pleosomite without lateral ridges (25.1); with lateral ridges (25.2). Pleopods peduncle slender, not expanded (26.1); broad, expanded (26.2). Pleopod 2 inner ramus present, as long as outer ramus (27.1); reduced or absent (27.2). Urosomite 1 without dorsal spines (28.1); with dorsal spines (28.2). Uropod 1 peduncle with interamal process (29.1); with distoventral corona (29.2); without distoventral corona or process (29.3). Uropod 1 outer margin of outer ramus smooth (30.1); dentate (30.2). Uropod 2 biramous (31.1); uniramous (31.2); rami absent (31.3). Uropod 2, outer margin of rami smooth and with robust setae (32.1); dentate and without robust setae (32.2). Uropod 3, tip of outer ramus without spines (33.1); with spines (33.2); with plate bearing spines (33.3). Species: (27.1, 33.1) Gammaropsis sp.; (22.1, 23.1, 24.1, 25.1, 29.1, 30.2) Bonnierella laurensi sp. nov.; (21.2, 25.2, 26.1, 27.2, 30.1, 31.2, 32.2) Notopoma teresae sp. nov.; (21.3, 22.2, 23.2, 24.2, 26.2, 29.3, 31.3) Caribboecetes barbadensis Just, 1983 (redrawn from Just, 1984); (29.2, 31.1, 32.2, 33.2) Pseudericthonius bousfieldi sp. nov.; (21.1) Bonnierella campensis sp. nov.; (28.1) Myersius spinicaudatusgen. et sp. nov.; (33.3) Pseudischyrocerus caecus sp. nov.; (28.2) Bathyphotis tridentata.

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Figure 5. Characters 34–40. Uropod 3, peduncle parallel-sided (34.1); broad proximally and narrow distally (34.2). Uropod 3 biramous (35.1), uniramous (35.2), absent (35.3). Uropod 3 rami or ramus longer than peduncle (36.1), shorter than peduncle (36.2). Uropod 3, outer ramus 2-articulate, second one rudimentary (37.1), 1-articulate (37.2). Telson longer than wide (38.1), wider than long (38.2). Telson entire (39.1), cleft (39.2). Telson dorsal margin without recurved spines (40.1); with recurved spines in patches (40.2); with recurved spines in rows (40.3). Telson tip without distolateral spines (41.1); with two distolateral spines (41.2). Species: (34.1, 36.1) Gammaropsis sp.; (40.1, 41.1) Bonnierella laurensi sp. nov.; (39.2, 40.3) Notopoma teresae sp. nov.; (35.3) Caribboecetes barbadensis Just, 1983 (redrawn from Just, 1984); (35.38.2, 39.1, 40.3) Pseudericthonius bousfieldi sp. nov.; (40.1, 41.1) Bonnierella campensis sp. nov.; (34.2, 38.1, 41.2) Myersius spinicaudatusgen. et sp. nov.; (35.3, 37.1) Pseudischyrocerus caecus sp. nov.; (37.2) Photis sarae.

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Figure 6. Detail of outer ramus tip of Bonnierella campensis sp. nov.

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A total of 40 unordered characters were used in the analysis (listed below), of which 39 were parsimony informative and one defined the out-group (Figs 1-6; Table 3). When appropriate, characters were combined into multistate groupings to avoid overly dependent characters. This resulted in 28 binary characters and 12 multistate characters. The data matrix was analysed using the parsimony criterion available in PAUP* 4.0b-10 (Swofford, 2002) and TNT 1.1 (Goloboff et al., 2008). Heuristic searches (additional sequence) with 1000 replications, with one tree held in PAUP and ten trees held in TNT at each step during stepwise addition, were performed on the data matrix. The branch-swapping algorithm used was tree, bisection and reconnection (TBR). The characters were analysed as unweighted; multistate taxa were treated as polymorphisms. Bremer support (Bremer, 1994) was evaluated with TNT using a 20-step suboptimal tree search, and the values are given in absolute numbers.

Taxonomic study

The study area included the Campos Basin, which extends from the states of Espírito Santo to Rio de Janeiro (20.5–24°S, 40–41°W) on the south-eastern Brazilian coast. The Campos Basin measures some 100 000 km2 and has enormous economic importance, as it currently accounts for nearly 80% of Brazil's oil production and is the largest oil reserve in Brazilian waters (Lavrado et al., 2010).

The samples analysed herein were collected on board the N/RB Astro Garoupa, on the continental slope (depth 700–2000 m) of the Campos Basin in cruises carried out in November–December 2002 (OCEANPROF I) and July–August 2003 (OCEANPROF II). These samples were collected according to the framework of the Campos Basin Deep Sea Environmental Project (OCEANPROF) coordinated by CENPES/PETROBRAS (Leopoldo Américo Miguez de Mello Center for Research and Development/Petróleo Brasileiro SA). All samples were obtained using a box corer (50 cm3) and the sediment was sieved in a 0.5-mm net. An overview of the Campos Basin area, together with a map, the sampling methodology, and the general results for the macrobenthic fauna resulting from the OCEANPROF I–II project can be found in Lavrado et al. (2010). Additional material of the species Pseudischyrocerus caecus sp. nov. was collected by a remotely operated vehicle (ROV) as part of the project ECOPROF-Deep-Sea Ecosystems in the Campos Basin (21–23°S), also coordinated by CENPES/PETROBRAS.

Type material of Bonnierella linearis J.L. Barnard, 1964 from the American Museum of Natural History, New Your, USA (AMNH) was redescribed for comparison with local species. The observations on Bonnierella linearis californica J.L. Barnard, 1966 and Bathyphotis crenatipes comb. nov. (Bellan-Santini & Ledoyer, 1986) were based on the literature, as attempts to borrow the original material of the two species were unsuccessful.

Treatment of specimens

Specimens were preserved in 70% ethanol. Appendages and mouthparts of dissected specimens were mounted on glass slides and sealed with CMC-10 or glycerol gelatin. For photomicrography in a scanning electron microscope (SEM; JEOL 6390 series) the specimens were treated according to Felgenhauer's (1987) method. In order to minimize the modification of structures, a smooth alcohol gradient (5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100%) was used. The type material is housed at the Crustacean Collection of the Museu Nacional, Rio de Janeiro (MNRJ).

Abbreviations used: Ant, antenna; AF, accessory flagellum; Cx, coxa; EP, epistome; Gn, gnathopod; Hb, habitus; Hd, head; LL, lower lip; Md, mandible; Mx, maxilla; Mxp, maxilliped; P, pereopod; Pl, pleopod; Pr, pereonite; T, telson; UL, upper lip; Ur, uropod; f, female; l, left; m, male; r, right.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Systematics
  7. Acknowledgements
  8. References

Phylogenetic analysis

Heuristic searches under equal weights resulted in two trees of length 90 steps (consistency index, CI = 0.622; homoplasy index, HI = 0.379; retention index, RI = 0.904; and rescaled consistency index, RC = 0.563; Fig. 7). Clade 1 (family Ischyroceridae) is monophyletic, and is well supported by five synapomorphies: head with anteroventral margin strongly recessed (1.2); coxae 1–7 wider than long (12.2); uropod 3 with recurved spines (33.2), this character state has also undergone reversal in the Siphonoecetes group, and has changed in Paracerapus and Pseudischyrocerus (clade 13); peduncle of uropod 3 broad proximally and narrow distally (34.2); and outer ramus of uropod 3 1-articulate (37.2).

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Figure 7. Strict consensus cladogram (tree length = 90; consistency index, CI = 0.622; homoplasy index, HI = 0.379; retention index, RI = 0.904; rescaled consistency index, RC = 0.563), calculated from the four fundamental trees. Numbers of nodes are included in bold under each branch, weith the Bremer support set in italics below.

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Clade 1 divides into two monophyletic groups, clades 2 and 17, considered subfamilies Ischyrocerinae and Bonnierellinae, respectively. The Bonnierellinae (clade 17) is defined by coxa 5 with posterodorsal lobe absent (14.2) and pereopods 3–7 with rectangular basis (16.2). Ischyrocerinae (clade 2) is defined by: gnathopod 1 carpus longer than propodus (8.2) – this character state reverts in Myersius gen. nov., within clade 15, and in clade 6; and pereopod 5 dissimilar to pereopods 6 and 7 in shape and length (19.2) – this character changes within the Siphonoecetes clade (19.3).

Clade 2 splits into two monophyletic groups, clades 3 and 13, tribes Ischyrocerini and Siphonoecetini, respectively. The Siphonoecetini (clade 13) is defined by coxae 1–5 longer than wide and coxae 6 and 7 wider than long (12.3). Within this clade we found three monophyletic genera. The first is Pseudischyrocerus (clade 14), which is defined by the tip of the outer ramus of uropod 3 with a plate bearing spines (33.3). Then, we have clade 15 comprising Myersius gen. nov. and Bathyphotis (clade 15), which are defined by coxa 4 with the posterior margin excavate (14.2) and coxa 5 lacking a posterodorsal lobe (15.2). Myersius denticaudatus gen. et sp. nov. can be defined by the telson with two subdistal spines (41.2), and gnathopod 1 with the carpus shorter than the propodus (8.1); this character state appeared independently in clade 6.

Tribe Siphonoecetini (clade 3, Fig. 7) is defined by eight synapomorphies: gnathopod 2 of the male carpochelate (9.2) and with the carpus longer than the propodus (10.2) – these characters change in clade 5 (9.3, 10.1), and are reversed in Bathypoma (9.1, 10.1); pereopod 5 carpus short, lunate, or reniform (18.2); pereopods 5–7 dactylus with accessory spines (20.2); peduncle of uropod 1 with a distal corona (29.2); uropod 3 uniramous (35.2); and telson wider than long (38.2), with recurved spines in patches on the dorsum (40.2) – this character changes in clade 6 (40.3). Siphonoecetini is divided into two groups. Clade 4 (Cerapus-like genera + Siphonoecetes group) is defined by four synapomorphies: pereopod 5 with the distal part directed posteriorly (22.2); uropod 1 with the outer margin of the ramus dentate (30.2); uropod 2 outer margin of the ramus dentate, without robust setae (31.2); and uropod 2 uniramous (32.2). Clade 11 consists of a basal trichotomy, defined by outer margin of the inner plate of maxilla 1 with a row of setae (7.2): Ericthonius brasiliensis (Dana, 1853) + Ericthonius pugnax (Dana, 1853) + clade 13 (genus Pseudericthonius). Clade 13 was defined by the female gnathopod 2 with the carpus longer than the propodus (11.2).

Clade 6 is defined by the telson cleft (39.2) and with recurved dorsal rows of spines (40.3, homoplasy). Within this clade, the most basal group is the genus Paracerapus, which is defined by three reversal characters: pereopods 6 and 7 with the distal part directed anteriorly (23.1, 24.1); and with the tip of the outer ramus of uropod 3 with a plate bearing spines (33.3) – this last character also occurred in Pseudischyrocerus (clade 14).

Clade 7 comprises four closely related genera (Cerapus, Runanga, Bathypoma, and Notopoma), sharing four synapomorphies: merus of pereopod 4 longer than merus of pereopod 3 (17.2); pereopod 7 with the distal part directed posteriorly (24.2); pleosomite with lateral ridges (25.2); and pleopod 2 with the inner ramus reduced or absent (28.2). The genus Cerapus (clade 10) is defined by one synapomorphy, antenna 1 posterior margin with a swelling (5.2). Clade 8 is defined by gnathopod 2 of the male subequal to the propodus (10.3), and is divided in two sister groups: Runanga and clade 9. The genus Runanga is defined by the peduncular article 3 of antenna 1 longer than article 3 (4.2) and the carpus of pereopod 5 without denticles or spines on the posteroventral margin (21.1, homoplasy). Clade 9 (Notopoma + Bathypoma) shares one character state: peduncular article 1 of antenna 1 produced anterodistally and medially (3.2). The genus Bathypoma, represented by Bathypoma enigma Lowry & Berents, 1996, is defined by two reversal characters, gnathopod 2 of the male subchelate (9.1), with the carpus shorter than the propodus (10.3). Notopoma, on the other hand, seems to have no clear synapomorphy and appeared as an unresolved clade.

Clade 5 (Siphonoecetes group) is defined by: antenna 1 shorter and often more slender than antenna 2 (2.2); mandibular palp 1-articulate (6.3); gnathopod 2 of the male simple (11.3, it changes in some genera); coxae 1–4 longer than wide and coxae 5–7 wider than long (12.3, homoplasy); pereopod 5 similar to pereopod 6, but dissimilar to pereopod 7 (19.3); peduncle of the pleopod broad and expanded (26.2); and uropod 3 without recurved spines (33.1, reversal). The Siphonoecetes clade appeared as a single branch in the strict consensus tree and will not be discussed further here. For discussions of this group, see Just (1983) and Lowry & Berents (1996).

Tree discussion

The hypothesis of the family Ischyroceridae as a monophyletic group is herein corroborated. Myers & Lowry (2003), who conducted a wider evolutionary treatment of the corophioideans, defined the Ischyroceridae based on two characters: the peduncle of uropod 3 long, broad proximally, and narrow distally; and the rami of uropod 3 with tiny apical setae. The classical character of the presence of recurved spines on the outer ramus of uropod 3, which has been used to define the Ischyroceridae, was used to characterize only the Ischyrocerinae, as the basal subfamily Bonnierellinae was defined as lacking these spines. However, in our analysis, this character state was found to define the family Ischyroceridae (clade 1) rather than just the subfamily Ischyrocerinae (clade 2). This was possible because we noted that species of Bonnierella do have recurved spines on uropod 3, as observed herein (Fig. 6), and also in some other studies on Bonnierella (e.g. J.L. Barnard, 1964: fig. 33m; J.L. Barnard, 1966: fig. 11h; J.L. Barnard, 1967: fig. 13l). Thus, we assume that the ancestor of ischyrocerids had spines on the outer ramus of uropod 3, with the loss of these spines occurring only in clade 5 (Siphonoecetes group). Also, in our analysis, we found five synapomorphies for the Ischyroceridae (Fig. 7), but only one of these was used by Myers & Lowry (2003) (character 33.2).

Within the Tribe Ischyrocerini (clade 13), Pseudischyrocerus crenatipes Bellan-Santini & Ledoyer, 1987 appeared as the sister taxon of Bathyphotis tridentata Stephensen, 1944, forming clade 16, and is herein transferred to the genus Bathyphotis, which is defined by the presence of two dorsal spines on urosomite 1 (28.2). The genera Bathyphotis and Myersius gen. nov. (clade 15) are sister groups, sharing the posterior margin of coxa 4 excavated, a character state unique among both Corophiidae and Ischyroceridae. Moreover, Myersius gen. nov. was confirmed as a well-defined genus based on two synapomorphies: gnathopod 1 carpus longer than the propodus (8.2) and the telson with two distolateral spines (41.2).

Clade 11 formed a trichotomy with species of Ericthonius and Pseudericthonius. Pseudericthonius was erected by Schellenberg (1926) based on Pseudericthonius gaussi (Schellenberg, 1926), and it was distinguished from Ericthonius by two characters: female gnathopod 2 almost carpochelate; and with a much-reduced inner rami of uropods 1 and 2. For almost 70 years, only the type species of Pseudericthonius was known. Presently, with five described species, it was possible to re-evaluate the characters used to define this genus. The first character also occurs in females of Ericthonius, which have a strongly lobate carpus in gnathopod 1. The second is a continuous character that varies within the genus, for example: the inner rami of uropods 1 and 2 can be longer than the outer ramus in E. pugnax (Dana, 1853); three-quarters of the outer ramus in Pseudericthonius stephenseni Myers & McGrath, 1984; two-thirds of the outer ramus in Pseudericthonius concavus sp. nov.; and one-quarter of the outer ramus in Pseudericthonius bousfieldi sp. nov. and P. gaussi. The same continuous character is observed in the genera Cerapus and Notopoma, and should be used at the species level. In the analysis of Lowry & Berents (1996), Ericthonius and Pseudericthonius appeared in a trichotomy together with a group formed with the Cerapus clade + siphonocetid clade. Thus, Ericthonius and Pseudericthonius would be synonymized (Lowry & Berents, 1996). In our analysis, we found Ericthonius and Pseudericthonius forming clade 11, supported by maxilla 1 outer margin of the inner plate with a row of setae (7.2), and separated from clade 6 (Paracerapus, Cerapus, Runanga, Bathypoma, Notopoma, and the siphonocetid clade). No synapomorphies for the genus Ericthonius were found, however, which appeared as unresolved in the analysis, whereas the species of Pseudericthonius (clade 12) formed a monophyletic group sharing female gnathopod 2 with the carpus longer than the propodus (11.2). To reach a better solution, a wider analysis should be performed, including all species of these two genera.

Concerning clade 6 (Cerapus clade), we found some differences from the topology described by Lowry & Berents (1996). In their analysis, the genus Runanga, characterized by having a rudimentary accessory flagellum, was derived early in the Cerapus group. Then, the Paracerapus + Cerapus clade was defined by having the carpus longer than the propodus in the male gnathopod 2, and formed a sister group with the Notopoma + Bathypoma clade, which was defined by the medial and distal expanded peduncle of antenna 1. Nevertheless, the present analysis showed that Paracerapus diverged earlier in the evolution of the group as the basal genus within clade 6, and it did not form a separate group with Cerapus. Also, the presence of the carpus longer than the propodus in the male gnathopod 2 appeared earlier as a synapomorphy of clade 3 (tribe Ischyrocerini), and cannot be used to characterize Paracerapus + Cerapus. The next branch in our analysis corresponds to the genus Cerapus (clade 10), which appeared to be monophyletic and is herein characterized by the posterior margin of article 1 of antenna 1 with a swelling. The genus Runanga is the sister group of Notopoma and Bathypoma (clade 9). Lowry & Berents (1996) showed that the presence of an accessory flagellum on antenna 1 was a synapomorphy of Runanga, and its absence characterized the Ericthonius group; however, an accessory flagellum is also found in other genera within the tribe Ischyrocerini, including all species of Ericthonius and some species of Notopoma (Notopoma cidaridis Berge, Vader & Lockhart, 2004 and Notopoma lowryi sp. nov.), and its presence or absence should be checked in future studies. Clade 9 showed that Notopoma shares a common ancestor with Bathypoma, as noted by Lowry & Berents (1996); however, Notopoma did not appear as a monophyletic group. Even examining almost all descriptions available in the literature, including the new species described herein, we could not find a synapomorphy for Notopoma. Bathypoma can be distinguished from Notopoma by the subchelate male gnathopod 2 (9.1), whereas the carpochelate male gnathopod 2 (9.2) appeared as a synapomorphy for the tribe Siphonoecetini (clade 3). Nevertheless, our present opinion is that Notopoma and Bathypoma should be maintained separately, as we did not have all species of these genera to compare. Moreover, we are aware of some species of Notopoma from the south-western Atlantic Ocean that await description, which should provide new insights into this problem.

Key to the genera of Ischyroceridae used in this analysis

  • 1. 
    Pereopods 5–7 with accessory spines; uropods 1 and 2 peduncle with distoventral corona of spines; uropod 3 uniramous; telson rectangular, wider than long, with rows or patches of recurved spines   2
  • – 
    Pereopods 5–7 without accessory spines; uropods 1 and 2 peduncle with acute interamal process; uropod 3 biramous; telson triangular, longer than wide, without rows or patches of recurved spines   9
  • 2. 
    Telson with two patches of recurved spines on each side   3
  • – 
    Telson with rows of recurved spines on distal margin   5
  • 3. 
    Antenna 1 shorter and often more slender than antenna 2   Siphonoecetes group
  • – 
    Antenna 1 subequal to antenna 2   4
  • 4. 
    Gnathopod 2 carpus shorter than propodus in female   Ericthonius
  • – 
    Gnathopod 2 carpus longer than propodus in female   Pseudericthonius
  • 5. 
    Antenna 1 article 1 with anterior margin medially and distally expanded   6
  • – 
    Antenna 1 article 1 with anterior margin not medially and distally expanded   7
  • 6. 
    Gnathopod 2 subchelate in both male and female   Bathypoma
  • – 
    Gnathopod 2 carpochelate in male and subchelate in female   Notopoma
  • 7. 
    Pereopods 5–7, distal part directed posteriorly   Paracerapus
  • – 
    Pereopods 5–7, at least the propodus and dactylus directed anteriorly   8
  • 8. 
    Antenna 1, posterior margin of peduncular article 1 lacking swelling, peduncular article 3 longer than article 2, accessory flagellum vestigial   Runanga
  • – 
    Antenna 1, posterior margin of peduncular article 1 with swelling, peduncular article 3 shorter than article 2, accessory flagellum absent   Cerapus
  • 9. 
    Gnathopod 1 carpus longer than propodus; coxa 5 with posterior lobe; tip of outer ramus of uropod 3 with a plate bearing spines   Pseudischyrocerus
  • – 
    Gnathopod 1 carpus shorter than or subequal to propodus; coxa 5 without posterior lobe; outer ramus of uropod 3 without accessory spines near apex, but with recurved spines   10
  • 10. 
    Coxa 4 not excavated posteriorly, basis of pereopods 3–7 rectangular   Bonnierella
  • – 
    Coxa 4 excavated posteriorly; basis of pereopods 3–7 not rectangular   11
  • 11. 
    Urosomite 1 with two dorsal teeth; telson without subapical spines   Bathyphotis
  • – 
    Urosomite 1 without dorsal teeth; telson with a pair of subapical spines   Myersius gen. nov.

Systematics

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Systematics
  7. Acknowledgements
  8. References

Order Amphipoda Latreille, 1816

Suborder Senticaudata Lowry & Myers, 2013

Infraorder Corophiida Leach, 1814

Family Ischyroceridae Stebbing, 1899

Diagnosis

Head lateral cephalic lobe not or only weakly extended, eye, if present, situated proximal to lobe; anteroventral margin moderately to strongly recessed and moderately excavated. Mandible palp, if present, article 3 symmetrical, distally rounded, setae extending along most of posterodistal margin, posterior margin with setae of variable length. Gnathopod 1 not enlarged in males or females. Gnathopod 2 enlarged in males. Pereopods 5–7 not subchelate. Urosomites usually not coalesced. Uropod 3 peduncle broad proximally and narrow distally; rami with tiny apical setae, outer ramus 1-articulate, with or without recurved apical spines. Telson with or without rows of recurved hooks, with or without patches of short denticles (modified from Myers & Lowry, 2003).

Subfamily Bonnierellinae Myers & Lowry, 2003

Diagnosis

Pereopods 3–7 with basis rectangular. Pereopods 5–7 dactyli without accessory spines on anterior margin. Coxa 5 with posterodorsal lobe absent. Uropods 1 and 2, peduncle with acute inter-ramal process. Uropod 3 outer ramus with recurved spines (only visible with high magnification). Telson without hooks or denticles (modified from Myers & Lowry, 2003).

Included genera

Bonnierella Chevreux, 1900 and Bogenfelsia J.L. Barnard, 1962.

Genus Bonnierella Chevreux, 1900

Bonnierella Chevreux, 1900: 97. – Stebbing, 1906: 737. – J.L. Barnard, 1962: 70. – J.L. Barnard, 1964: 42. – J.L. Barnard, 1969. – J.L. Barnard, 1973. – Ledoyer, 1982: 184. – J.L. Barnard & Karaman, 1991: 176.

Type species

Podoceropsis abyssi Chevreux, 1887.

Diagnosis

Antenna 1 subequal to antenna 2; peduncular article 1 long and rectangular; article 1 longer than article 2. Eyes absent. Mandibular palp well developed and 3-articulate. Gnathopod 1 carpus shorter than propodus. Gnathopod 2 subchelate in both sexes; carpus shorter than propodus. Coxae 1–7 wider than long. Coxa 4 posterior margin not excavated. Pereopods 3–7 basis rectangular. Pereopod 4 merus equal to merus of pereopod 3. Pereopod 5 similar to pereopods 6 and 7; carpus long, subrectangular, and without denticles or spines on posteroventral margin. Pleosomite without lateral ridges. Peduncle of pleopods slender and not expanded. Pleopod 2 inner ramus present, as long as outer ramus. Urosomite 1 without dorsal spines. Uropod 1 peduncle with acute interamal process; outer margin of outer ramus smooth. Uropod 2 biramous; outer margin of rami smooth, with robust setae. Uropod 3, outer ramus with recurved spines (only visible with high magnification). Telson without hooks or denticles.

Included species

Bonnierella abyssi (Chevreux, 1887); Bonnierella abyssorum (Bonnier, 1896); Bonnierella angolae J.L. Barnard, 1962; Bonnierella californica J.L. Barnard, 1966; Bonnierella campensis sp. nov.; Bonnierella compar Myers & Cunha, 2004; Bonnierella dimorpha Ledoyer, 1982; Bonnierella lapisi (J.L. Barnard, 1962); Bonnierella laurensi sp. nov.; Bonnierella linearis J.L. Barnard, 1964; Bonnierella palenquia J.L. Barnard, 1967.

Excluded species

Bonnierella longiramus Ledoyer, 1982, incertae sedis.

General remarks

The genus Bonnierella was erected by Chevreux (1900) in the family Photidae based on the species Podoceropsis abyssi Chevreux, 1887, differing from other genera by: the shape of male gnathopod 2; rectangular basis of pereopods 3–7; and telson triangular. Later, J.L. Barnard (1964) transferred Bonnierella to the family Ischyroceridae based on the presence of spines on the outer ramus of uropod 3 and the rami of uropod 3 shorter than the peduncle. The spines on the outer ramus of uropod 3 in Bonnierella are visible only at high magnification. Subsequently, Myers & Lowry (2003) erected the subfamily Bonnierellinae in their phylogenetic study of the suborder Corophiidea. These authors showed that this subfamily, composed of Bonnierella and Bogenfelsia Barnard, 1964, is the basal branch of the family Ischyroceridae.

The genus Bonnierella has been, until the present study, composed of ten species, and this number is now raised to 11 (Table 5). The reason is that B. longiramus Ledoyer, 1982 shows some characters outside the diagnosis of Bonnierella, and should be removed from the genus. This species has the anteroventral margin of the head moderately excavated, gnathopod 1 with the carpus longer than the propodus, coxae 1–4 longer than wide, uropod 3 with the rami longer than the peduncle, the outer ramus with a rudimentary second article, and the telson trapezoid with two subdistal crests (Ledoyer, 1982: fig. 64). Considering that the last two characters do not fit the diagnosis of the family Ischyroceridae, the position of this species is still unclear.

Table 5. Comparative morphological characters of all species of the genus Bonnierella
SpeciesMaxilliped outer plate reachingGnathopod 1 propodus palmSexual dimorphismMale gnathopod 2 palm of propodus withMale gnathopod 2 palmar corner withFemale gnathopod 2 palm of propodusUropod 1 peduncleUropod 3 outer rami × peduncle lengthTelson tip
  1. Information from the literature and from observed material.

B. abyssi (Chevreux, 1887)1/3 of palp article 2Ornamented?3 simple blunt processesgroup of setae?1 large distoventral acute process0.7×Rounded
B. abyssorum (Bonnier, 1896)?Ornamented???????
B. angolae J.L. Barnard, 19621/3 of palp article 2Ornamented?2 simple blunt processesA short process?1 large distoventral acute process0.6×Rounded
B. californica J.L. Barnard, 19661/3 of palp article 2UnornamentedWeak2 blunt processes, the first bifidA short processwith U-shaped excavation1 large distoventral acute process0.45×Rounded
B. campensis sp. nov.2/3 of palp article 2UnornamentedStrong2 simple blunt processesA short processlacks excavation1 large distoventral acute process0.7×Acute
B. compar Myers & Cunha, 20041/3 of palp article 2UnornamentedWeak2 blunt processes, the first crenulateA short processwith U-shaped excavation1 large distoventral acute process0.3×Rounded
B. dimorpha Ledoyer, 19821/3 of palp article 2UnornamentedWeakgroups of robust setaeA group of robust setaewith U-shaped excavation1 large distoventral acute process0.7×Rounded
B. lapisi (J.L. Barnard, 1962)1/3 of palp article 2UnornamentedStrong2 blunt processes, the first crenulateA large acute processwith V-shaped excavation1 large distoventral acute process0.6×Truncated
B. laurensi sp. nov.1/3 of palp article 2UnornamentedStrong2 blunt processes, the first crenulateA large acute processwith triangular process1 large distoventral acute process0.8×Acute
B. linearis J.L. Barnard, 19641/3 of palp article 2UnornamentedWeak2 blunt processes, the first crenulateA large acute processwith U-shaped excavation1 large distoventral acute process0.5×Acute
B. palenquia J.L. Barnard, 19671/3 of palp article 2UnornamentedWeak??with V-shaped excavation2 large distal acute processes0.5×Acute
Geographic distribution

Cosmopolite, deep sea.

Bonnierella campensis sp. nov. (Figs 9, 10, 8)

figure

Figure 8. Bonnierella campensis sp. nov. Holotype: male (3.7 mm), OCEANPROF I, BC-SUL, #79, 775 m, 21 November 2002, MNRJ 21218. Scale bars: 0.1 mm.

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figure

Figure 9. Bonnierella campensis sp. nov. Holotype: male (3.7 mm), OCEANPROF I, BC-SUL, #79, 775 m, 21 November 2002, MNRJ 21218. Paratype: female (3.3 mm) OCEANPROF I, BC-SUL, #79, 775 m, 26 November 2002, MNRJ 21484. Scale bars: 0.1 mm.

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figure

Figure 10. Bonnierella campensis sp. nov. Holotype: male (3.7 mm), OCEANPROF I, BC-SUL, #79, 775 m, 21 November 2002, MNRJ 21218. Paratype: female (3.3 mm) OCEANPROF I, BC-SUL, #79, 775 m, 26 November 2002, MNRJ 21484. Scale bars: 0.1 mm.

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Bonnierella sp. Souza-Filho & Serejo, 2010a: 180.

Material examined
Holotype

male (3.7 mm), OCEANPROF I, BC-SUL, #79, Campos Basin, Rio de Janeiro, Brazil, 22°20′44.82″S, 40°01′24.72″W, 775 m, 21 November 2002, MNRJ 21218.

Paratypes

One female (3.3 mm) (dissected and drawn), OCEANPROF I, BC-SUL, #79, Campos Basin, Rio de Janeiro, Brazil, 22°20′44.82″S, 40°01′24.72″W, 775 m, 26 November 2002, MNRJ 21484. One female, OCEANPROF I, BC-SUL, #74, Campos Basin, Rio de Janeiro, Brazil, 22°28′3.24″S, 40°09′23.22″W, 750 m, 12 December 2002, MNRJ 21215. One female, OCEANPROF I, BC-NORTE, #59, Campos Basin, Rio de Janeiro, Brazil, 21°53′59.22″S, 39°55′30,66″W, 750 m, 1 July 2003, MNRJ 21216. One female, OCEANPROF II, BC #44, BC-NORTE, Campos Basin, Rio de Janeiro, Brazil, 22°11′27″S, 39°54′45″W, 749 m, 26 November 2002, MNRJ 21217. One male, OCEANPROF I, BC-NORTE, #59, Campos Basin, Rio de Janeiro, Brazil, 21°53′59.22″S, 39°55′30.66″W, 750 m, 12 December 2002, MNRJ 21219. One male, OCEANPROF II, BC-NORTE, #54, Campos Basin, Rio de Janeiro, Brazil, 21°57′23.58″S, 39°56′0.42″W, 750 m, 29 July 2003, MNRJ 21220. One male and one female, OCEANPROF II, BC-SUL, #79, Campos Basin, Rio de Janeiro, Brazil, 22°20′44.82″S, 40°01′24.72″W, 750 m, 21 June 2003, MNRJ 21221. One female, OCEANPROF I, BC-NORTE, #60, Campos Basin, Rio de Janeiro, Brazil, 21°53′40.92″S, 39°51′42.60″W, 1050 m, 12 December 2002, MNRJ 21228. One female, OCEANPROF II, BC-SUL, #59, Campos Basin, Rio de Janeiro, Brazil, 21°52′59.2″S, 39°55′32.2″W, 750 m, 29 June 2003, MNRJ 19049. One male and one female, OCEANPROF II, BC-SUL, #74, Campos Basin, Rio de Janeiro, Brazil, 22°28′02.22″S 40°09′23.52″W, 750 m, 18 June 2003, MNRJ 21230. One male, OCEANPROF I, BC-SUL, #84, Campos Basin, Rio de Janeiro, Brazil, 22°26′41.4″ S 39°58′53.28″ W, 1050 m, 20 June 2003, MNRJ 21232.

Etymology

The name campensis refers to the type locality, Campos Basin, Rio de Janeiro, Brazil.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Maxilliped outer plate ovate, extending to two-thirds of palp article 2; palp 4-articulate, article 4 longer than article 3, with apical nail. Gnathopod 2 carpus triangular and short; propodus massive, 2.6 × carpus length, palm shorter than posterior margin with two processes, first process proximal and tridentate and second process truncate, separated by a U-shaped excavation followed by a concave crenulated portion, palmar corner defined by a short acute spine, facial margin with two pairs of robust setae; dactylus stout with a spine on inner margin. Uropod 1 peduncle interamal process about one-fifth of peduncle length; rami with one apical seta. Uropod 2 interamal process rudimentary; rami with one apical seta. Uropod 3 peduncle 1.4 × outer ramus length, outer ramus with four subapical tiny spines. Telson triangular with two short subapical setae.

Description

Based on holotype male (3.7 mm), MNRJ 21218. Head as long as pereonites 1 and 2 together; lateral cephalic lobe acute; eyes absent; anteroventral margin strongly recessed. Antennae 1 and 2 missing. Epistome acute and turned upwards. Mandible lacinia mobilis asymmetrical; palp article 2 longer than article 3, with 11 slender setae; article 3 spatulate, with long facial and long setae. Maxilla 1 inner plate with one long seta; outer plate with ten robust setae; palp longer than outer plate, with four robust apical setae and one slender facial seta. Maxilliped inner plate rectangular, with three apical short robust setae; outer plate ovate, extending to two-thirds of palp article 2; palp 4-articulate, article 4 longer than article 3 with apical nail. Upper lip, lower lip, and maxilla 2 with basic characters for the genus.

Coxae 1–7 wider than long. Coxa 2 wider than other coxae, with seven short setae on distal margin. Coxae 5 and 6 excavate distally. Gnathopod 1 basis slender, without setae; propodus subovoid, slightly longer than carpus, palm evenly rounded and crenulated; dactylus fitting propodus. Gnathopod 2 basis, anterior margin with some sparse setae, anterodistal angle with a short process, posterior margin weakly convex; carpus triangular and short; propodus massive, 2.6 × carpus length, palm shorter than posterior margin, with two processes, first process proximal and tridentate and second process truncate, both separated by a U-shaped excavation followed by a concave crenulated portion, palmar corner defined by a short acute spine, facial margin with two pairs of robust setae; dactylus stout, with a spine on inner margin. Pereopods 3 and 4 similar in shape and length; basis long and slender, as long as merus and carpus together, both anterior and posterior margins without setae; merus with anterior margin produced; propodus longer than carpus; dactylus slightly shorter than propodus. Pereopods 5–7 missing.

Epimera 1–3 rounded. Uropods 1 and 2 reaching equally apex of uropod 3. Uropod 1 peduncle inner margin with four short robust marginal setae and one distal seta, outer margin with only one marginal seta; interamal process about one-fifth peduncle length; rami with one apical seta; inner ramus longer than outer ramus, with one short robust seta about midlength of ramus; outer ramus naked. Uropod 2, inner margin with one short robust marginal seta and one robust apical seta; interamal process rudimentary; rami with one apical seta; inner ramus longer than outer ramus, with one single short robust seta about midlength of ramus. Uropod 3 peduncle 1.4 × length of outer ramus, with three robust marginal setae; inner ramus longer than outer ramus, naked; outer ramus with four tiny subapical spines. Telson triangular, with two short subapical setae.

Sexually dimorphic characters

Females differ from males by the more-inflated body, and in the shape of gnathopod 2, in which the propodus is 1.9 × length of the carpus, and the palm is evenly rounded, with two crenulated portions separated by a shallow oblique excavation with a small spine.

Additional description

Based on female paratype (3.3 mm), MNRJ 21484. Pereopod 5, basis subrectangular; merus longer than carpus, with posterior margin produced; carpus 0.37 × propodus length; propodus long; dactylus about one-quarter of propodus length. Pereopod 6, basis rectangular; merus shorter than basis, with posterior margin produced; carpus 0.57 × propodus length; propodus long; dactylus more than one-thrid propodus length. Pereopod 7, basis rectangular, posterior margin with three slender setae; merus longer than basis; propodus long; dactylus more than one-third propodus length.

Remarks

Bonnierella campensis sp. nov. shows some similarities with B. lapisi, such as the shape of gnathopods 1 and 2 in the male, and the basis of pereopods 5 and 6 rectangular; however, B. campensis sp. nov. has the palm of gnathopod 2 with two blunt processes, and the palmar corner is defined by a short process in the male, whereas B. lapisi has two acute processes and the palmar corner is defined by a large acute process. Also, B. campensis sp. nov. has less setose rami of uropods 1 and 2, and the outer rami of uropod 3 measures 0.7 × the peduncle length. Moreover, the female gnathopod 2 of B. campensis sp. nov. lacks an excavation on the palm.

Bonnierella campensis sp. nov. is also closely related to B. californica, in the shape of gnathopods 1 and 2, basis of pereopods 5 and 6, and uropods 1 and 3. Nevertheless, B. campensis sp. nov. has gnathopod 1 sparsely setose, with the dactylus short, both margins of the basis of pereopod 3 sparsely setose, the tip of the telson acute, and the rami of uropod 3 elongate. Additionally, B. campensis sp. nov. differs from all other species of the genus in having an elongate and ovate outer plate of the maxilliped (Table 5).

Geographic distribution

South-western Atlantic: Campos Basin, Rio de Janeiro, Brazil.

Bonnierella laurensi sp. nov. (Figs 12, 13, 11)

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Figure 11. Bonnierella laurensi sp. nov. Holotype: male (3.1 mm), OCEANPROF II, BC-SUL, #84, 1050 m, 20 June 2003, MNRJ 21231.

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figure

Figure 12. Bonnierella laurensi sp. nov. Holotype: male (3.1 mm), OCEANPROF II, BC-SUL, #84, 1050 m, 20 June 2003, MNRJ 21231.

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Figure 13. Bonnierella laurensi sp. nov. Holotype: male (3.1 mm), OCEANPROF II, BC-SUL, #84, 1050 m, 20 June 2003, MNRJ 21231. Paratype: female (3.2 mm), OCEANPROF II, BC-SUL, #84, 1050 m, 20 June 2003, MNRJ 21422.

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Type material
Holotype

Male (3.1 mm; dissected and drawn), OCEANPROF II, BC-SUL, #84, Campos Basin, Rio de Janeiro, Brazil, 22°26′41.4″S. 39°58′53.28″W, 1050 m, 20 June 2003, MNRJ 21231.

Paratypes

Two females (one female dissected and drawn, 3.2 mm), OCEANPROF II, BC-SUL, #84, Campos Basin, Rio de Janeiro, Brazil, 22°26′57.6″S, 39°58′53.28″W, 1050 m, 20 June 2003, MNRJ 21422. Two males, OCEANPROF I, BC-SUL, #71, Campos Basin, Rio de Janeiro, Brazil, 22°39′47.22″S, 40°04′14.22″W, 1350 m, 23 November 2002, MNRJ 21207. One female, OCEANPROF II, BC-NORTE, #44, Campos Basin, Rio de Janeiro, Brazil, 22°11′27″S, 39°54′45″W, 749 m, 1 July 2003, MNRJ 21210. One female, OCEANPROF I, BC-SUL, #66, Campos Basin, Rio de Janeiro, Brazil, 22°45′37.2″S, 40°10′12″W, 1350 m, 22 November 2002, MNRJ 21485.

Etymology

Bonnierella laurensi sp. nov. is named in honour of Dr Jerry Laurens Barnard (1928–1992), one of the most important amphipodologists in the last century, who made important contributions to the systematics of this genus.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Maxilliped outer plate ovate, reaching more than half of palp article 2; palp 4-articulate, article 4 slightly shorter than article 3, with apical nail. Gnathopod 1 propodus triangular, setose, and longer than carpus, palm acute and crenulated; dactylus fitting palm. Gnathopod 2 carpus triangular and short; propodus massive, 2.6 × carpus length, palm shorter than posterior margin with two processes, first one proximal and triangular, dentate on anterior part, second one blunt, both separated by a deep U-shaped excavation followed by a concave crenulate portion, palmar corner defined by a well-developed acute process, facial margin with one pair of short and long robust setae, inner surface with two robust setae; dactylus stout with a spine about two-thirds its length. Pereopod 6, basis with posterior margin sinuous. Uropod 1 peduncle interamal process about one-fifth of peduncle length; rami with one apical seta. Uropod 2 interamal process short and blunt. Uropod 3 peduncle 1.2 × outer ramus length; outer ramus with five subapical tiny spines. Telson triangular, longer than wide with two dorsal slender setae and three pairs of pappose setae, tip acute.

Description

Based on holotype male (3.1 mm). Head longer than pereonites 1 and 2 together; lateral cephalic lobe acute; eyes absent; anteroventral margin strongly recessed. Antennae 1 and 2 missing. Epistome acute and turned upwards. Mandible lacinia mobilis asymmetric; palp article 2 longer than article 3, with many slender setae; article 3 spatulate with long sub to apical setae and a row of facial setae. Maxilla 1 inner plate with one long seta; outer plate with nine robust setae; palp longer than outer plate with four apical robust setae and two facial slender setae. Maxilliped inner plate rectangular with two apical short robust setae; outer plate ovate, reaching more than one-half of palp article 2; palp 4-articulate, article 4 slightly shorter than article 3 with apical nail. Upper lip, lower lip, and maxilla 2 with basic characters for the genus.

Coxae 1–7 wider than long. Coxae 5–6 excavate distally. Gnathopod 1 basis slender; propodus triangular, setose, and longer than carpus, palm acute and crenulated; dactylus fitting palm. Gnathopod 2 basis with five setae on posterior margin, anterodistal angle with a short process; carpus triangular and short; propodus massive, 2.6 × carpus length, palm shorter than posterior margin with two processes, first one proximal and triangular dentate on anterior part, second one blunt, both separated by a deep U-shaped excavation followed by a concave crenulate portion, palmar corner defined by well-developed acute process, facial margin with one pair of one short seta and one long robust seta, inner face with two robust setae; dactylus stout with a spine about two-thirds its length. Pereopod 3 basis rectangular and slender, longer than merus and carpus together; merus with anterior margin produced; propodus longer than carpus; dactylus shorter than propodus. Pereopods 4 and 5 missing. Pereopod 6, basis with posterior margin sinuous; merus longer than carpus with posterior margin produced; carpus 0.7 × propodus length; propodus long; dactylus about two-thirds propodus length. Pereopod 7 missing.

Epimera 1–3 rounded. Uropods 1 and 2 reaching apex of uropod 3 equally. Uropod 1 peduncle inner margin with three marginal and one distolateral robust setae, outer margin with five marginal and one distolateral setae; interamal process about one-fifth of peduncle length; rami with one apical setae; inner ramus longer than outer ramus, with two short robust setae about halfway along ramus length; outer ramus with three short robust setae about halfway along ramus length. Uropod 2 inner margin longer than outer ramus, both with two marginal robust setae and one apical seta; interamal process short and blunt. Uropod 3 peduncle 1.2 × outer ramus length, with one marginal and one distolateral robust setae; inner ramus longer than outer ramus, naked; outer ramus with five subapical tiny spines. Telson triangular, longer than wide, with two dorsal slender setae and three pairs of pappose setae, tip acute.

Sexually dimorphic characters

Females differs from males in two ways: first by a more inflated body; and second in the shape of gnathopod 2, which has the basis slender with setae on both anterior and posterior margins, propodus 1.6 × carpus length, and palm acute with two crenulate portions separated by a triangular process followed by a shallow oblique excavation, and palmar corner with two robust setae.

Remarks

Bonnierella laurensi sp. nov. is closely related to B. campensis sp. nov. in having pereopod 6 with a sinuous basis and uropod 3 with elongate rami; however, it differs from B. campensis sp. nov. by the gnathopod 1 with a triangular propodus, the shape of the palmar processes of gnathopod 2, setose uropods 1 and 2, the peduncle of uropod 3 with one robust seta on the anterior margin, the outer ramus 1.2 × peduncle length, and the more setose telson. Also, the female of B. laurensi sp. nov. has gnathopod 1 with the basis setose, the palmar margin with a well-developed triangular process, and only two robust setae on the palmar corner.

Bonnierella laurensi sp. nov. also resembles B. lapisi in the shape of gnathopods 1 and 2, and the maxilliped. Nevertheless, it is quite different in the less setose gnathopods, the U-shaped excavation in the palm of the male gnathopod 2, more elongate rami of uropods 1–3, and the setose telson. Females of B. laurensi have a triangular process on the palm of gnathopod 2, whereas B. lapisi has a deep V-shaped excavation.

The shape of the male gnathopod 2 of B. laurensi sp. nov. and B. californica, as well as the basis of pereopod 6, are very similar. On the other hand, B. laurensi sp. nov. shows pronounced sexual dimorphism, less setose gnathopods, a triangular propodus, and a short dactylus of gnathopod 1, as well as the telson with an acute tip (Table 5).

Geographic distribution

South Atlantic: Campos Basin, Rio de Janeiro, Brazil.

Bonnierella linearis J.L. Barnard, 1964 (Figs 14, 15)

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Figure 14. Bonnierella linearis J.L. Barnard, 1964. Holotype: male (4 mm), station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, AMNH 12348. Habitus redrawn from Barnard (1964), with permission from the American Museum of Natural History.

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figure

Figure 15. Bonnierella linearis J.L. Barnard, 1964. Holotype: male (4 mm), station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, AMNH 12348. Paratype: female (3.8 mm), station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, RV Vema col., AMNH 12351.

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Bonnierella linearis J.L. Barnard, 1964: 43, fig. 33.

Bonnierella linearis linearis J.L. Barnard, 1966: 63.

Material examined
Holotype

Male (4 mm), station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, AMNH 12348.

Paratypes

Eighteen males and 13 females, station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, RV Vema col., AMNH 12351.

Type locality

Off Peru, 10°13′S, 80°05′W.

Description

Based on holotype male (4 mm). Head, lateral cephalic lobe acute; eyes absent; anteroventral margin strongly recessed. Antennae 1 and 2 missing. Epistome acute and turned upwards. Mandible palp article 1 with marginal setae; article 2 shorter than article 3, with marginal and facial setae; article 3 spatulate, with long sub to apical row of setae. Maxilla 1 inner plate with one distal seta. Maxilliped inner plate rectangular, with three apical short robust setae; outer plate ovate, extending to about one-third of palp article 2; palp 4-articulate, article 4 longer than article 3 without apical nail. Upper lip, lower lip, and maxilla 2 with basic characters for the genus.

Coxae 1–7 wider than long. Coxa 5 excavate distally. Gnathopod 1 basis slender; propodus subovoid, slightly longer than carpus, both weakly setose; palm evenly rounded and crenulated; dactylus fitting propodus. Gnathopod 2 basis anterior margin without setules, anterodistal angle produced, posterior margin almost straight; carpus triangular and short; propodus massive, 3.2 × carpus length, palm longer than posterior margin, with two processes separated by a U-shaped excavation, first process proximal and crenulate, and second process acute; palmar corner defined by a well-developed spine; dactylus stout, reaching palmar corner. Pereopods 3 and 4 similar in shape and length; basis rectangular, long, and slender, longer than merus and carpus together, anterior margin with some slender setae; merus with anterior margin slightly produced; propodus longer than carpus; dactylus shorter than propodus. Pereopod 5, basis rectangular, posterior margin straight; merus longer than carpus; carpus 0.56 × propodus length; propodus long; dactylus about one-half propodus length. Pereopod 6 basis rectangular, posterior margin straight; merus 1.5 × carpus length; carpus 0.54 × propodus length; propodus long; dactylus more than one-half propodus length. Pereopod 7 basis rectangular, posterior margin straight; merus 1.5 × carpus length; carpus 0.6 × propodus length; propodus long; dactylus about one-thrid propodus length.

Epimera 1–3 rounded. Uropods 1 and 2 reaching equally apex of uropod 3. Uropod 1 peduncle inner margin with three marginal robust setae and one distal robust seta, outer margin with two marginal setae; interamal process about one-sixth peduncle length; rami lacking apical setae; inner ramus shorter than outer ramus, without setae; outer ramus with two robust setae. Uropod 2 peduncle inner margin with one marginal robust setae and two distolateral robust setae; interamal process little developed; rami with one apical setae; inner ramus longer than outer ramus, with two robust setae; outer ramus with one robust setae. Uropod 3 peduncle 2 × outer ramus length, with two distal robust setae; inner ramus longer than outer ramus, with two marginal setae; outer ramus with subapical tiny spines. Telson triangular, with four subapical and four lateral setae, tip acute.

Sexually dimorphic characters

Female with pronouced sexual dimorphism. Differs from male by less robust gnathopod 2, which lacks the palmar corner, and the two palmar processes are subacute, instead of crenulate.

Additional description

Based on paratype female (3.8 mm), AMNH 12351. Antenna 1 article 1 about 0.5 × article 2 length; article 3 longer than article 2; accessory flagellum 2-articulate, first article long and second article rudimentary; primary flagellum longer than peduncle, with eight articles. Antenna 2 article 4 shorter than article 5; flagellum shorter than peduncle, with seven articles.

Remarks

Bonnierella linearis J.L. Barnard, 1964 was described from off Peru. Later on, J.L. Barnard (1966) described B. californica from the Tanner Basin of southern California as a subspecies of B. linearis. Nevertheless, the distinctive character states detailed by J.L. Barnard seem to be sufficient to warrant specific rank for these taxa.

Indeed, B. linearis is very close to B. californica, but these species are quite different from each other in a number of character states. As a whole, B. californica is distinguished from B. linearis by: article 1 of mandibular palp lacking setae and about 0.15 × length of article 2; male gnathopod 2 with a lobate process near the hinge of the dactylus (versus a multicrenulate process); gnathopod 1 of both males and females more setose; basis of pereopods 3 with several setae along both anterior and posterior margins; outer ramus of uropod 1 0.7 × peduncle length (versus 0.3×); outer ramus of uropod 3 0.6 × peduncle length (versus 0.5×); and telson with a rounded tip (versus acute tip).

Also, the female of B. californica can be separated from B. linearis by gnathopod 2 with a well-developed palmar corner. Although J.L. Barnard (1966) considered this character a matter of age difference, the paratype female of B. linearis (3.4 mm) is larger than that of B. californica (2.75 mm). Therefore, we considered these characters as valid in separating these species from each other. For comparison with other species, see Table 5.

Geographic distribution

Known only from the type locality.

Subfamily Ischyrocerinae Stebbing, 1899

Tribe Ischyrocerini Stebbing, 1899

Diagnosis

Pereopod 5 carpus long, subrectangular. Pereopods 5–7 dactyli lacking accessory spines on anterior margin. Uropods 1 and 2 peduncle with acute interamal process, without distoventral corona of cuticular spines. Uropod 3 peduncle long, broad proximally, narrow distally. Telson entire, without rows of hooks or patches of denticles (Myers & Lowry, 2003).

Included genera

Bathyphotis Stephensen, 1944; Coxischyrocerus Just, 2009; Isaeopsis K.H. Barnard, 1916; Ischyrocerus Krøyer, 1838; Jassa Leach, 1814; Microjassa Stebbing, 1899; Myersius gen. nov.; Neoischyrocerus Conlan, 1995; Paradryope Stebbing, 1888; Parajassa Stebbing, 1899; Pseudischyrocerus Schellenberg, 1931; Ruffojassa Vader & Myers, 1996; Scutischyrocerus Myers, 1995; Tropischyrocerus Just, 2009; Ventojassa J.L. Barnard, 1970; Veronajassa Vader & Myers, 1996.

Genus Bathyphotis Stephensen, 1944

Bathyphotis Stephensen, 1944: 25.

Pseudischyrocerus – Bellan-Santini & Ledoyer, 1986: 397 (partim) (not Schellenberg, 1931).

Type species

Bathyphotis tridentata Stephensen, 1944.

Diagnosis

Antenna 1 subequal to antenna 2; peduncular article 1 long and rectangular; accessory flagellum with between three and six articles. Eyes present. Mandibular palp well developed and 3-articulate. Gnathopod 1 carpus shorter than propodus. Gnathopod 2 male subchelate; carpus longer than propodus. Coxae 1–4 longer than wide and coxae 5–7 wider than long. Coxa 4 posterior margin excavated. Coxa 5 with posterodorsal lobe absent. Pereopods 3 and 4 with merus equal in size. Pereopods 5–7 dactylus distal part (at least the propodus and dactylus) directed anteriorly; dactylus without accessory spines. Pereopod 5 carpus expanded, longer than propodus, without denticles or spines on a posteroventral margin. Pleosomite without lateral ridges. Pleopods peduncle slender and not expanded. Urosomite 1 with dorsal spines.

Included species

Bathyphotis crenatipes comb. nov. (Bellan-Santini & Ledoyer, 1986) and B. tridentata Stephensen, 1944.

Remarks

The cladistic analysis showed that Bathyphotis and Myersius gen. nov. are sister groups (clade 14), sharing the posterior margin of coxa 4 excavated and coxae 1–4 longer than wide as synapomorphies. Bathyphotis can be distinguished from Myersius gen. nov. by urosomite 1 with two dorsal teeth, outer ramus of uropod 3 with a recurved and weakly dentate tip, and telson without subapical spines.

Geographic distribution

Arctic Ocean; Atlantic Ocean, west of Cape Point, South Africa; Prince Edward Island, subantarctic region.

Genus Myersius gen. nov.

Type species

Myersius denticaudatus sp. nov., by monotypy.

Etymology

Named in honour of Dr Alan A. Myers, in recognition of his immense contributions to the systematics of the Corophioidea.

Diagnosis

Antenna 1 subequal to antenna 2; peduncular article 1 long and rectangular; accessory flagellum 2-articulate, article 1 longer than article 2. Mandibular palp well developed and 3-articulate. Eyes absent. Gnathopod 1 carpus shorter than propodus. Gnathopod 2 male subchelate; carpus shorter than propodus. Coxae 1–5 longer than wide and coxae 6 and 7 wider than long. Coxa 4 posterior margin excavated. Coxa 5 with posterodorsal lobe absent. Pereopods 3 and 4 with merus equal in size. Pereopods 5–7 with at least the propodus and dactylus directed anteriorly; dactylus without accessory spines. Pereopod 5 carpus long, subrectangular, and without denticles or spines on a posteroventral margin. Pleosomite without lateral ridges. Pleopods peduncle slender and not expanded. Pleopod 2 inner ramus present, as long as outer ramus. Urosomite 1 without dorsal spines. Uropod 1 peduncle with acute interamal process; outer margin of outer ramus smooth. Uropod 2 biramous; outer margin of ramus smooth with robust setae. Telson longer than wide (triangular), entire and with two subapical spines.

Geographic distribution

South-western Atlantic: Campos Basin, Rio de Janeiro, Brazil.

Remarks

See remarks on Bathyphotis.

Myersius denticaudatus sp. nov. (Figs 17, 18, 16)

figure

Figure 16. Myersius denticaudatus sp. nov. Holotype: male (2.5 mm), OCEANPROF II, BC-SUL, #59, 29 June 2003, 750 m, MNRJ 21424.

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figure

Figure 17. Myersius denticaudatus sp. nov. Holotype: male (2.5 mm), OCEANPROF II, BC-SUL, #59, 29 June 2003, 750 m, MNRJ 21424.

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figure

Figure 18. Myersius denticaudatus sp. nov. Paratype: female (3.2 mm), OCEANPROF I, BC-NORTE, #59, 12 December 2002, 750 m, MNRJ 21227.

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Etymology

The specific name denticaudatus is derived from the Latin ‘denti’ (= teeth) and ‘cauda’ (= tail, telson), and refers to the subdistal spines on the telson.

Material examined
Holotype

Male (2.5 mm), OCEANPROF II, BC-SUL, #59, Campos Basin, Rio de Janeiro, Brazil, 21°53′58.38″S, 39°55′32.22″W, 29 June 2003, 750 m, MNRJ 21424.

Paratype

One female (3.2 mm) (dissected and illustrated), OCEANPROF I, BC-NORTE, #59, Campos Basin, Rio de Janeiro, Brazil, 21°53′59.22″S, 39°55′30.36″W, 12 December 2002, 750 m, MNRJ 21227.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Gnathopod 1 basis moderately stout, posterior margin convex, smooth; propodus palm acute, with two portions serrate, separated by a shallow dentate excavation, without palmar corner. Gnathopod 2 propodus ovate, massive; palm shorter than posterior margin, with one proximal triangular process followed by a large blunt process, palm corner defined by a short spine with three robust setae; dactylus slender, inner margin with three spines. Epimeron 3 rectangular. Uropod 1 peduncle interamal process 0.3 × peduncle length; outer margin with three marginal robust setae and one distal robust seta. Uropod 2 peduncle interamal process 0.16 × peduncle length. Uropod 3 outer ramus robust and shorter than inner ramus, with a subapical row of spines. Telson with three pairs of dorsomarginal pappose setae, one pair of dorsal slender setae, and two subapical spines.

Description

Based on holotype male (2.5 mm), MNRJ 21424. Head longer than pereonites 1 and 2 together; anteroventral margin strongly recessed; lateral cephalic lobe acute; eyes absent. Antennae missing. Epistome acute and turned upwards. Mandible, palp article 3 spatulate, shorter than article 2, both with long pappose setae. Maxilla 1, inner plate with a single setae; outer plate with four bifid robust setae and six simple robust setae; palp 2-articulate and extended beyond outer plate, apex with four robust setae, and three slender facial setae. Maxilla 2 outer plate longer and wider than inner plate; both plates with marginal and submarginal pappose setae. Lower lip inner lobes well developed; mandibular process acute. Maxilliped, inner plate rectangular, with four distal robust setae and one subdistal seta; outer plate ovate, reaching about two-thirds the length of palp article 2, with three subdistal to distal robust setae, one slender seta, and one pappose robust seta; palp slender, 5-articulate; article 3 wider distally; articles 4 and 5 with a distal seta.

Coxae 1–4 rectangular, slightly wider distally. Coxa 4 excavated posteriorly. Coxae 5–7 wider than long. Coxae 6 and 7 almost the same size, and shorter than coxa 5. Gnathopod 1 basis moderately stout, posterior margin convex, smooth; merus excavate; carpus slightly shorter than propodus, weakly lobate, posterior margin with many pappose setae; propodus palm acute, with two portions serrate separated by a shallow dentate excavation, without palmar corner; dactylus slender and long with medial serration. Gnathopod 2 basis moderately stout, posterior margin smooth, convex, inner margin slightly concave; merus longer than ischium; carpus triangulate, 0.54 × propodus length; propodus ovate, massive; palm shorter than posterior margin, with one proximal triangular process follow by a large blunt process, palm corner defined by a short spine with three robust setae; dactylus slender, inner margin with three spines. Pereopods 3 and 4 similar, basis moderately inflated; merus anterior margin expanded; propodus longer than carpus; dactylus slender and shorter than propodus.

Epimeron 3 rectangular. Uropod 1 peduncle inner margin with two marginal robust setae and one distal robust seta; interamal process 0.3 × peduncle length; outer margin with three marginal robust setae and one distal robust seta. Uropod 2 peduncle shorter than inner ramus, with three marginal to apicolateral robust setae; interamal process 0.16 × peduncle length; inner ramus longer than outer ramus, with three marginal robust setae; outer ramus bearing two marginal robust setae. Uropod 3 peduncle with two marginal robust setae and two apical robust setae; outer ramus robust and shorter than inner ramus, with a subapical row of spines; inner ramus naked, with only one apical setule. Telson with three pairs of dorsomarginal pappose setae, one pair of dorsal slender setae, and two subapical spines.

Variations

Paratype female (3.2 mm), MNRJ 21227. Antenna 1 setose, article 1 shorter than article 3; article 2 longer than article 3; accessory flagellum 2-articulate, article 1 longer than article 2.

Sexually dimorphic characters

Overall, the females of M. denticaudatus sp. nov. differ from males by: gnathopod 1 basis slender, posterior margin straight with two long setae; merus moderately excavate; carpus as long as propodus, posterior margin densely setose; propodus setose, palm serrate and acute, with one robust seta defining palmar corner; dactylus long, slender, inner margin serrate. Gnathopod 2 basis slender; carpus triangular and shorter than propodus, palm acute with one dentate triangular process near insertion of dactylus, followed by a large U-shaped excavation; palmar corner acute, with two pairs of facial robust setae.

Geographic distribution

South-western Atlantic: Campos Basin, Rio de Janeiro, Brazil.

Genus Pseudischyrocerus Schellenberg, 1931

Pseudischyrocerus Schellenberg, 1931: 234. – J.L. Barnard, 1973: 26. – J.L. Barnard & Karaman, 1991: 229. – Valério-Berardo, 2001: 65.

Type species

Pseudischyrocerus denticauda Schellenberg, 1931.

Diagnosis

Antenna 1 subequal to antenna 2, peduncular article 1 long and rectangular; accessory flagellum 2-articulate, article 1 longer than article 2. Eyes present or absent. Mandibular palp well developed and 3-articulate. Gnathopod 1 carpus longer than propodus. Gnathopod 2 male subchelate; carpus shorter than propodus. Coxae 1–5 longer than wide, and coxae 6 and 7 wider than long. Coxa 4 posterior margin not excavated. Coxa 5 with posterodorsal lobe. Pereopods 3 and 4 merus equal in size. Pereopods 5–7 with at least the propodus and dactylus directed anteriorly, and without accessory spines. Pereopod 5 dissimilar to pereopods 6 and 7 in shape and length; carpus long, subrectangular, and without denticles or spines on a posteroventral margin. Pleosomite without lateral ridges. Pleopods peduncle slender and not expanded. Pleopod 2 inner ramus present, as long as outer ramus. Urosomite 1 without dorsal spines. Uropod 2 biramous; outer margin of outer ramus smooth, with robust setae.

Included species

Pseudischyrocerus besnardi Valério-Berardo, 2001; Pseudischyrocerus caecus sp. nov.; Pseudischyrocerus denticauda Schellenberg, 1931; and Pseudischyrocerus distichon (K.H. Barnard, 1930).

Excluded species: 

Pseudischyrocerus crenatipes Bellan-Santini & Ledoyer, 1986 is herein removed to the genus Bathyphotis Stephensen, 1944.

Pseudischyrocerus caecus sp. nov. (Figs 17-19)

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Figure 19. Pseudischyrocerus caecus sp. nov. Paratype: male (2.5 mm), OCEANPROF II, BC-SUL, #59, 29 June 2003, 750 m, MNRJ 21225. lAF and rAF from holotype male (6.2 mm), Campos Basin, 11 March 2006, 1058 m, ECOPROF, MNRJ 21604. Scale bars: 0.1 mm.

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figure

Figure 20. Pseudischyrocerus caecus sp. nov. Paratype: male (2.5 mm), OCEANPROF II, BC-SUL, #59, 29 June 2003, 750 m, MNRJ 21225. Holotype: hyperadult male (6.2 mm), Campos Basin, 11 March 2006, 1058 m, ECOPROF, MNRJ 21604. Paratype: female, Campos Basin, 11 March 2006, 1058 m, ECOPROF, MNRJ 21604. Paratype: adult male OCEANPROF II, BC-SUL, #59, 29 June 2003, 750 m, MNRJ 21225. Scale bars: 0.1 mm.

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Figure 21. Pseudischyrocerus caecus sp. nov. Paratype: male (2.5 mm), OCEANPROF II, BC-SUL, #59, 29 June 2003, 750 m, MNRJ 21225. Holotype: hyperadult male, Campos Basin, 11 March 2006, 1058 m, ECOPROF, MNRJ 21604. Paratype: female, Campos Basin, 11 March 2006, 1058 m, ECOPROF, MNRJ 21604. Scale bars: 0.1 mm.

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Etymology

The specific name is derived from the Latin caecus, meaning blind, referring to a unique character within the genus.

Type material
Holotype

One male, Campos Basin, 11 March 2006, 1058 m, ECOPROF, MNRJ 21604.

Paratypes

One female, Campos Basin, 11 March 2006, 1058 m, ECOPROF, MNRJ 21604. One male (2.5 mm, dissected and drawn) OCEANPROF II, BC-SUL, #59 (0–2 CM), Campos Basin, Rio de Janeiro, Brazil, 21°52′59″S, 39°55′32″W, 29 June 2003, 750 m, MNRJ 21225. One female, OCEANPROF I, BC-NORTE, #44, Campos Basin, Rio de Janeiro,Brazil, 22°11′44″S, 39°54′46″W, 12 December 2002, 750 m, MNRJ 21226.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Eyes absent. Antennae 1 accessory flagellum 2- or 3-articulate. Coxa 1, shorter than coxae 2–4, anterodistal angle slightly produced. Gnathopod 1 basis slender; carpus longer than propodus. Gnathopod 2 basis moderately stout, posterior margin with two or three long setae; carpus triangular, shallowly lobate, one-third of propodus length; propodus massive, ovate, palm acute, serrate with a rounded and serrate process near hinge of dactylus bearing one facial robust seta; palmar corner defining by a subacute spine and one facial robust setae; dactylus curved, not reaching end of palm. Pereopod 5 basis broad, ovoid, posterior margin excavate, posteroventral corner rounded and produced. Uropod 1 peduncle interamal process one-third of inner ramus length. Uropod 2 peduncle interamal process one-quarter of outer ramus length. Uropod 3 peduncle with two robust setae and two slender setae on distolateral angle, ventral margin with four robust setae; inner ramus with two marginal and one apical setae; outer ramus with two middle robust setae, tip with one subdistal robust seta, and a plate bearing three recurved spines. Telson triangular, wider than long; tip rounded; lateral margins with two pairs of pappose setae and two groups of three robust setae; dorsal margin with two pairs of robust and pappose setae.

Description

Based on holotype male. Head anteroventral margin strongly recessed; lateral cephalic lobe acute; eyes absent. Antennae 1 accessory flagellum 2- or 3-articulate. Epistome acute and upturned. Mandibular palp strong, article 3 spatulate, shorter than article 2. Maxilla 1, inner plate with a single seta; outer plate with seven robust setae; palp article 2 with four robust setae, and three slender facial setae. Maxilla 2, plates with almost the same width and apically setose; inner plate without row of facial setae. Lower lip with developed inner lobes; mandibular process acute. Maxilliped, inner plate rectangular; outer plate reaching one-third of palp article 2, with four medial to distal robust setae; palp 4-articulate; article 3 wider distally than proximally; article 4 with a long distal seta.

Coxa 1, shorter than coxae 2–4, anterodistal angle slightly produced. Coxae 2–4, similar in size, anterior and posterior margins straight, angles rounded and distally with some setules. Coxa 5 with posterior lobe. Coxa 6 wider than long; slightly excavate distally. Coxa 7 shorter than coxa 6, subovate. Gnathopod 1 basis slender; carpus longer than propodus; posterior margin with long pappose setae; propodus setose; palm acute, with some marginal and facial setae; dactylus long, slender, inner margin serrate, outer margin with one plumose seta. Gnathopod 2 basis moderately stout, posterior margin with two or three long setae; carpus triangular, shallowly lobate, one-third of propodus length; propodus massive, ovate, palm acute, serrate with one facial robust seta and a rounded and serrated process near dactylus hinge; palmar corner defined by a subacute spine and one facial robust seta; dactylus curved, not reaching end of palm. Pereopods 3 and 4 similar in shape and size; basis subrectangular; merus, anterodistal angle slightly produced; dactylus slender and shorter than propodus. Pereopod 5 basis broad, ovate, posterior margin excavate, posteroventral corner rounded and produced; merus anterior and posterior distal angles produced, propodus longer than carpus and merus together, with one very long robust seta and one short robust seta. Pereopods 6 and 7 slender, similar; basis subrectangular, posterior margin sinuous; merus and carpus with antero- and posterodistal angle produced; propodus long, three times longer than merus; dactylus about one-third length of propodus, posterior margin with one plumose setae. Pereopod 6 propodus anterior margin with one robust seta and three robust setae on anterodistal angle, posterodistal angle with a tuft of long setae. Pereopod 7 propodus anterior margin with one robust seta on anterodistal angle, posterodistal angle with a tuft of long setae.

Epimera 1 and 2 posteroventral corner rounded. Epimeron 3 posteroventral corner acute, with posterior margin excavated. Uropod 1 not exceeding apex of uropod 2, peduncle longer than rami, inner margin with three robust setae, outer margin with four robust setae; interamal process one-third of inner ramus length; outer ramus with one marginal and four distal robust setae; inner ramus shorter than outer ramus, with four distal setae. Uropod 2 peduncle with one distolateral robust setae; interamal process one-quarter of outer ramus length; inner ramus longer than outer ramus, with two marginal robust setae and three distal robust setae; outer ramus with one marginal robust seta and four distal robust setae. Uropod 3 peduncle longer than rami, broad proximally and narrow distally, with two robust setae and two slender setae on distolateral angle, ventral margin with four robust setae; inner ramus more slender than outer ramus, with two marginal and one apical seta; outer ramus slightly recurved, with two middle robust setae, tip with one subdistal robust seta and a plate bearing three recurved spines. Telson triangular, wider than long; tip rounded; lateral margins with two pairs of pappose setae and two groups of three robust setae; dorsal margin with two pairs of robust and pappose setae.

Sexually dimorphic characters

Pseudischyrocerus caecus sp. nov. presents a weak sexual dimorphism. The female differs mainly in gnathopod 2 less setose and propodal palm lacking process.

Variation

The males of P. caecus sp. nov. show extensive ontogenetic modification in some structures, including the number of articles in the accessory flagellum, gnathopods 1 and 2, basis of pereopod 5, and uropod 3. In juvenile and adult specimens the number of articles in the accessory flagellum varies from two to three; also, one female showed a difference between the right and left side. In juvenile specimens the carpus of gnathopod 1 is about as long as the propodus, the basis of pereopod 5 is slightly concave, and uropod 3 has the peduncle with only one robust distal seta and the rami are naked; however, in adults and hyperadults the carpus of gnathopod 1 is about 1.5 × propodus length, the basis of pereopod 5 is strongly concave, and the uropod 3 peduncle bears four robust setae on the ventral margin, and both rami have two robust setae. The most important modification is observed in gnathopod 2, as in juveniles the propodus is sparsely setose, the palm is serrate and without a palmar corner, whereas in adults it becomes densely setose with a rounded crenulate process near the dactylus hinge. Moreover, in hyperadults a palmar corner is developed and the dactylus is strongly curved, reaching three-quarters of the palm.

Remarks

As a whole, P. caecus sp. nov. differs from the other three species of the genus by the following combination of characters: eyes absent; palm of the male gnathopod 2 with two robust facial setae; and a distinctly more setose telson.

Geographic distribution

South-western Atlantic: Campos Basin, Rio de Janeiro, Brazil.

Tribe Siphonoecetini Just, 1983

Genus Notopoma Lowry & Berents, 1996

Notopoma Lowry & Berents, 1996: 85. – Berge, Vader & Lockhart, 2004: 1725. – Alonso de Pina, 2005: 528. – Valério-Berardo, Souza & Rodrigues, 2008: 60.

Type species

Notopoma stoddartae Lowry & Berents, 1996.

Diagnosis

Antenna 1 subequal to antenna 2, peduncular article 1 produced anterodistally and medially; accessory flagellum absent or present, if present 1-articulate, rudimentary. Eyes present or absent. Mandibular palp well developed and 3-articulate. Gnathopod 1 carpus shorter than propodus. Gnathopod 2 male carpochelate. Carpus subequal to the propodus. Coxae 1–7 wider than long, with margin smooth. Coxa 4 posterior margin not excavated. Coxae 5–7 with posterodorsal lobe. Pereopod 4 merus longer than merus of pereopod 3. Pereopods 5–7 dactylus distal part directed posteriorly and with accessory spines. Pereopod 5 dissimilar to pereopods 6 and 7 (in shape and length), with carpus short, lunate, or reniform, with denticles on a posteroventral margin. Pleosomite with lateral ridges. Pleopods peduncle slender and not expanded. Pleopod 2 inner ramus present, reduced, or absent. Urosomite 1 without dorsal spines. Uropod 1 peduncle with distoventral corona; outer margin of outer ramus dentate. Uropod 2 uniramous; outer margin of ramus dentate, without robust setae. Uropod 3 uniramous with recurved spines. Telson cleft with recurved rows of spines on the dorsum.

Included species

Notopoma argentina Alonso de Pina, 2005; Notopoma africana Lowry & Berents, 1996; Notopoma cidaridis Berge, Vader & Lockhart, 2004; Notopoma crassicornis (Bate, 1857); Notopoma fallohideus (Lowry, 1981); Notopoma fluminense Valério-Berardo, Souza & Rodrigues 2008; Notopoma harfoota (Lowry, 1981); Notopoma lutkini (Tzvetkova, 1990); Notopoma lowryi sp. nov.; Notopoma moorea Lowry & Berents, 1996; Notopoma opposita (K.H. Barnard, 1931); Notopoma sismithi (Stebbing, 1888); Notopoma stoddartae Lowry & Berents, 1996; Notopoma stoora (Lowry, 1981); Notopoma teresae sp. nov.

Notopoma lowryi sp. nov. (Figs 22-24)

figure

Figure 22. Notopoma lowryi sp. nov. Holotype: male (3 mm), OCEANPROF I, #59, 12 December 2002, 750 m, MNRJ 21244. Scale bars: 0.1 mm.

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figure

Figure 23. Notopoma lowryi sp. nov. Holotype: male (3 mm), OCEANPROF I, #59, 12 December 2002, 750 m, MNRJ 21244. Scale bars: 0.1 mm.

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figure

Figure 24. Notopoma lowryi sp. nov. Holotype: male (3 mm), OCEANPROF I, #59, 12 December 2002, 750 m, MNRJ 21244. Scale bars: 0.1 mm.

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Notopoma sp. Souza-Filho & Serejo, 2010b: 182.

Type material
Holotype

Male (3 mm), OCEANPROF I, #59, Campos Basin, Rio de Janeiro, Brazil, 21°53′59.22″S, 39°55′30.66″ W, 12 December 2002, 750 m, MNRJ 21244.

Etymology

Named in honour of Dr James K. Lowry, in recognition of his contributions to Amphipoda systematics.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Head eyes absent; rostrum extended slightly beyond lateral lobes. Antenna 1 stout, setose, longer than pereonites 1–6 together; article 2 slightly shorter than article 3; flagellum with three articles; flagellum article 1 with dense aesthetascs; accessory flagellum rudimentary, 1-articulate. Gnathopod 1 propodus palm acute and serrate, with short and long pappose setae; dactylus extended beyond end of palm. Gnathopod 2 carpochelate; basis anterior margin convex and crenulate; carpus enlarged, with one large posterodistal bidentate process, little produced anteriorly, with distal U-shaped excavation; propodus 2.2 times as long as wide, posterior margin excavate; dactylus as long as propodus and with one marginal tooth. Pleopod 3 uniramous very reduced, as long as inner ramus of pleopod 2. Telson broader than long; cleft almost one-half of its length.

Description

Based on holotype male (3 mm), MNRJ 21244. Head anteroventral margin strongly recessed; eyes absent; rostrum extended slightly beyond lateral lobes. Antenna 1 stout, setose, longer than pereonites 1–6 together; article 2 slightly shorter than article 3; flagellum with three articles; flagellum article 1 with dense aesthetascs; accessory flagellum rudimentary, 1-articulate. Antenna 2 peduncle article 4 setose, 1.2 times as long as article 5; flagellum with three articles. Mandible molar triturative; right mandible, incisor with four teeth; lacinia mobilis minutely serrate, accessory setal row with three pappose robust setae; palp article 3 shorter than article 2, spatulate, with long setae medially and distally. Maxilla 1 inner plate short and with a distal single seta; outer plate with six robust setae; palp with four distal robust setae and one facial pappose seta. Maxilla 2 outer plate slightly longer than inner plate; with a row of pappose medial and distal setae. Lower lip inner lobes present; mandibular process well developed. Maxilliped inner plate subquadrate, with three short and robust setae on distal margin and one subdistal short and robust seta; outer plate ovate, with three medial to distal robust setae and one distal robust pappose seta; palp articles 1–3 with long pappose setae along inner margin; palp article 2 2.5 × length of article 1; palp article 4 with one very long distal robust seta.

Coxae 1–7 wider than long. Gnathopod 1 subchelate, carpus lobate and shorter than propodus; palm acute and serrate, with short and long pappose setae; dactylus extended beyond end of palm. Gnathopod 2 carpochelate; basis 1.3 times longer than broad; anterior margin convex and crenulate; carpus enlarged, with one large ventrodistal bidentate process weakly produced anteriorly, with distal U-shaped excavation; propodus 2.2 times as long as wide, posterior margin excavate; dactylus as long as propodus, and with one marginal tooth. Pereopod 3 basis subovate; merus anterodistal angle produced and shorter than propodus; dactylus acute and shorter than propodus. Pereopod 4 similar to pereopod 3, but merus as long as propodus. Pereopod 5 basis ovate; merus with anterior and posterior margin produced; propodus triangular and short; carpus longer than merus; dactylus with three accessory spines. Pereopod 6 thin, basis slender and subrectangular; merus and carpus with anterior and posterior margin produced; dactylus with two accessory spines. Pereopod 7 similar to pereopod 6, except for basis broad with posterior margin rounded.

Pleonites with lateral ridges. Pleopod 1 large and biramous. Pleopod 2 biramous, inner ramus 1-articulate, half the length of article 1 of outer ramus. Pleopod 3 uniramous, much reduced, as long as inner ramus of pleopod 2. Uropod 1 peduncle 1.1 times longer than outer ramus; rami denticulate distally, with one pappose seta; inner ramus shorter than outer ramus, with one distal robust and pappose seta; outer margin of outer ramus denticulate, with a row of short robust setae. Uropod 2 uniramous; outer margin of ramus denticulate, with one long seta distally and one seta subdistally. Uropod 3 uniramous, short, almost as long as length of ramus of uropod 2; peduncle broad, with one seta distally; ramus very reduced, with two short upturned spines. Telson broader than long; cleft almost one-half of its length.

Tube

Unknown.

Remarks

Notopoma lowryi sp. nov. is similar to N. cidaridis, from Elephant Island, Antarctica, in having antenna 1 with the accessory flagellum rudimentary and 1-articulate, eyes absent, and pleopod 3 uniramous; however, N. lowryi sp. nov. differs from N. cidaridis by the flagellum of antennae 1 and 2 with three articles instead of four articles, the rostrum slightly longer than the lateral cephalic lobes (versus much longer), gnathopod 2 with the posterior margin of the propodus smooth (versus crenulate) and the carpus with the posterodistal process weakly produced anteriorly (versus strongly produced anteriorly), and the basis of pereopods 6 and 7 more slender and subrectangular.

Notopoma teresae sp. nov. (Figs 25-27)

figure

Figure 25. Notopoma teresae sp. nov. Holotype: male (1.77 mm), OCEANPROF II, #44, 1 July 2003, 749 m, MNRJ 21239. Scale bars: 0.05 mm.

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figure

Figure 26. Notopoma teresae sp. nov. Holotype: male (1.77 mm), OCEANPROF II, #44, 1 July 2003, 749 m, MNRJ 21239. Scale bars: 0.1 mm.

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figure

Figure 27. Notopoma teresae sp. nov. Holotype: male (1.77 mm), OCEANPROF II, #44, 1 July 2003, 749 m, MNRJ 21239. Paratype: female (1.9 mm), 1 July 2003, 749 m, MNRJ 21239. Scale bars: 0.1 mm.

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Material examined
Holotype

Male (1.77 mm), OCEANPROF II, #44, Campos Basin, Rio de Janeiro, Brazil, 22°11′32.4″S, 39°54′45″W, 1 July 2003, 749 m, MNRJ 21239.

Paratypes

One male, OCEANPROF I, #79, Campos Basin, Rio de Janeiro, Brazil, 22°20′40.26″S, 40°00′35.1″W, 26 December 2002, 775 m, MNRJ 21238. One female (dissected and drawn), Campos Basin, Rio de Janeiro, Brazil, 22°11′32.4″S, 39°54′45″W, 1 July 2003, 749 m, MNRJ 21239.

Etymology

Named in honour of Dr Maria Teresa Valério-Berardo, in recognition of her contribution to the taxonomy of Brazilian Amphipoda.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Head eyes present; rostrum subequal to lateral cephalic lobes. Antenna 1 stout, setose, longer than pereonites 1–6 together; article 2 slightly shorter than article 3; flagellum with two articles; flagellum article 1 with few aesthetascs; accessory flagellum absent. Gnathopod 1 propodus palm acute, serrate, and with short and long pappose setae; dactylus not reaching end of palm. Gnathopod 2 carpochelate; basis anterior margin slightly concave and smooth; carpus enlarged, with one large posterodistal process very produced forward, with a middle tooth; propodus 1.9 times as long as wide; propodus posterior margin straight; dactylus slightly shorter than propodus, with one marginal tooth. Pleopod 3 absent. Telson wider than long and weakly cleft.

Description

Based on holotype male (1.77 mm), MNRJ 21239. Head, anteroventral margin strongly recessed; eyes present; rostrum subequal to lateral cephalic lobes. Antenna 1 stout, setose, longer than pereonites 1–6 together; article 2 slightly shorter than article 3; flagellum with two articles; flagellum article 1 with few aesthetascs; accessory flagellum absent. Antenna 2 peduncle article 4 setose, 1.3 times as long as article 5; flagellum with three articles. Mandible palp article 3 shorter than article 2, spatulate, with long setae medially and distally; molar triturative; lacinia mobilis present; right mandible, incisor with six teeth; setal row with two setae; left mandible incisor with five teeth; setal row with four setae. Maxilla 1 inner plate short, with many long marginal setae; outer plate with seven robust setae; palp with four distal robust setae; palp with one facial pappose seta. Maxilla 2 outer plate longer than inner plate; with a row of pappose medial and distal setae. Lower lip inner lobes present; mandibular process well developed. Maxilliped inner plate suquadrate, with two short and robust setae along distal margin and one subdistal short and robust seta; outer plate ovate, with three medial to distal robust setae and two distal robust pappose setae; palp articles 1–3 with long pappose setae along inner margin; palp article 2 2 × length of article 1; palp article 4 with one distal robust seta as long as article 4 length.

Coxae wider than long. Gnathopod 1 subchelate, carpus lobate and shorter than propodus; palm acute, serrate, and with short and long pappose setae; dactylus not reaching end of palm. Gnathopod 2 carpochelate; basis 1.3 times longer than broad; basis anterior margin slightly concave and smooth; carpus enlarged, with one large ventrodistal process very produced forward, with a middle tooth; propodus 1.9 times as long as wide; propodus posterior margin straight; dactylus slightly shorter than propodus, with one marginal tooth. Pereopod 3 basis subovate; merus 1.1 times as long as wide, with anterodistal angle produced; dactylus acute and shorter than propodus. Pereopod 4 similar to pereopod 3, but merus 1.6 times as long as wide. Pereopod 5 basis ovate; merus with anterior and posterior margin produced; propodus triangular, short; carpus longer than merus; dactylus with two accessory spines. Pereopod 6 thin, basis subrectangular; merus and carpus with anterior and posterior margin produced; dactylus with two accessory spines. Pereopod 7 similar to pereopod 6, except for basis broad with posterior margin rounded.

Pleonites with lateral ridges. Pleopod 1 large and biramous. Pleopod 2 biramous, inner ramus 1-articulate, about 1.5 times the length of article 1 of outer ramus. Pleopod 3 absent. Uropod 1 peduncle 1.3 times longer than outer ramus; rami denticulate distally, with one robust seta and one pappose seta; inner ramus with one distal robust and pappose seta; outer margin of outer ramus denticulate, with a row of short robust setae. Uropod 2 uniramous; ramus outer margin denticulate, with one long seta distally. Uropod 3 uniramous, almost as long as ramus of uropod 2; peduncle broad; ramus short with two short upturned spines. Telson wider than long and weakly cleft.

Sexually dimorphic characters

Based on paratype female (1.9 mm), MNRJ 21238. Very similar to male, but with gnathopod 2 subchelate, basis stout, 2 times longer than wide, with a few long setae on the anterior margin; merus triangulate, produced; propodus ovate, longer than carpus, with long setae along the palm. Pereonite 5 is wider than others.

Tube

Unknown.

Remarks

Notopoma teresae sp. nov. is similar to N. africana Lowry & Berents, 1996 and N. fallohidea (Lowry, 1981) in the long thin antennae, about half the body length, and the dactylus of gnathopod 2 more than half the propodus length. It also resembles N. africana in having a slender palp of the mandible and seven robust setae on the outer plate of maxilla 1; however, N. teresae sp. nov. can be distinguished from both species by the 2-articulate flagellum of antenna 1, the distoventral process of gnathopod 2 more produced anteriorly, and a more inflated propodus. Furthermore, N. teresae sp. nov. differs from N. africana by the presence of eyes, absence of pleopod 3, the inner ramus of uropod 3 about two-thirds the outer ramus length, and the telson weakly cleft.

Geographic distribution

South-western Atlantic: Campos Basin, Rio de Janeiro, Brazil.

Key to world species of the genus Notopoma Lowry & Berents, 1996

  • 1. 
    Antenna 1 with accessory flagellum present (minute)   2
  • – 
    Antenna 1 with accessory flagellum absent   3
  • 2. 
    Gnathopod 2 male propodus with posterior margin undulate   Notopoma cidaridis
  • – 
    Gnathopod 2 male propodus with posterior margin not undulate   Notopoma lowryi sp. nov.
  • 3. 
    Antenna 1 flagellum bearing four or five articles, subequal to peduncle articles 2 and 3 combined (with the exception of Notopoma fluminense)   4
  • – 
    Antenna 1 flagellum bearing two or three articles, shorter than peduncle articles 2 and 3 combined   7
  • 4. 
    Mandible palp slender, long; uropod 1 inner ramus 0.8 × outer ramus   Notopoma africana
  • – 
    Mandible palp robust, short; uropod 1 inner ramus 0.5–0.6 × outer ramus   5
  • 5. 
    Gnathopod 2 male carpus with two distal spines   Notopoma fallohidea
  • – 
    Gnathopod 2 male carpus with one distal spine   6
  • 6. 
    Antenna 1 flagellum subequal than peduncle articles 2 and 3 combined; gnathopod 2 male propodus slender and longer than carpus; carpus with convex palm   Notopoma sismithi
  • – 
    Antenna 1 flagellum shorter than peduncle articles 2 and 3 combined; gnathopod 2 male propodus broad and subequal to carpus; carpus with oblique palm   Notopoma fluminense
  • 7. 
    Gnathopod 2 male carpus with a spine midway along posterior margin   8
  • – 
    Gnathopod 2 male carpus without a spine midway along posterior margin   9
  • 8. 
    Gnathopod 2 male propodus with rectangular process on posterior margin   Notopoma lutkini
  • – 
    Gnathopod 2 male propodus without process on posterior margin   Notopoma crassicornis
  • 9. 
    Gnathopod 2 male dactylus short, subequal to propodus, distally bifid   10
  • – 
    Gnathopod 2 male dactylus normal, clearly longer than propodus, distally acute   12
  • 10. Pleopod 3 present, uniramous   Notopoma moorea

  • – 
    Pleopod 3 absent   11
  • 11. 
    Antenna 1 0.3 × body length; pleopod 2 biramous, inner ramus vestigial   Notopoma teresae sp. nov.
  • – 
    Antenna 1 0.7 × body length; pleopod 2 uniramous   Notopoma stoddartae
  • 12. 
    Gnathopod 2 female propodus linear; antenna 1 peduncle article 1 only slightly produced distally   Notopoma harfoota
  • – 
    Gnathopod 2 female propodus broadly rectangular or oval; antenna 1 peduncle article 1 strongly produced distally   13
  • 13. 
    Telson deeply cleft   Notopoma stoora
  • – 
    Telson emarginate   Notopoma opposita

Genus Pseudericthonius Schellenberg, 1926

Pseudericthonius Schellenberg, 1926: 385. – J.L. Barnard, 1969: 196. – J.L. Barnard, 1973: 26. J.L. Barnard & Karaman, 1991: 228. – Rauschert, 1997: 28.

Diagnosis

Antenna 1 subequal to antenna 2; peduncular article 1 long and rectangular; accessory flagellum 1-articulate, rudimentary. Eyes present or absent. Mandibular palp well developed and 3-articulate. Maxilla 1 outer margin of inner plate with a row of setae. Gnathopod 1 carpus longer than propodus. Gnathopod 2 male carpochelate; carpus longer and larger than propodus. Gnathopod 2 female carpus longer than propodus. Coxae 1–7 wider than long. Coxa 4 margin smooth; posterior margin not excavated. Coxa 5 with posterodorsal lobe. Pereopods 3 and 4 merus equal in size. Pereopods 5–7 dactylus distal part (at least the propodus and dactylus) directed anteriorly, and with accessory spines. Pereopod 5 dissimilar to pereopods 6 and 7 (in shape and length); carpus short, lunate or reniform, and without denticles or spines on posteroventral margin. Pleosomite without lateral ridges. Pleopods peduncle slender and not expanded. Pleopod 2 inner ramus present, as long as outer ramus. Urosomite 1 without dorsal spines. Uropod 1 peduncle with distoventral corona; inner ramus reduced; outer margin of outer ramus smooth. Uropod 2 biramous; inner ramus reduced; outer margin of outer ramus smooth with robust setae. Uropod 3 uniramous, with recurved spines. Telson wider than long, rectangular, entire, and with spines in patches on the dorsum.

Included species

Pseudericthonius bousfieldi sp. nov.; Pseudericthonius concavus sp. nov.; Pseudericthonius gaussi Schellenberg, 1926; Pseudericthonius hesperidesi Rauschert, 1997; Pseudericthonius inflatus Ren, 1991.

Pseudericthonius bousfieldi sp. nov. (Figs 28-30)

figure

Figure 28. Pseudericthonius bousfieldi sp. nov. Holotype, male (3.8 mm), OCEANPROF II – BC -NORTE #44, 01 July 2003, 749 m, MNRJ 21257.

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figure

Figure 29. Pseudericthonius bousfieldi sp. nov. Holotype, male (3.8 mm), OCEANPROF II – BC -NORTE #44, 01 July 2003, 749 m, MNRJ 21257.

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figure

Figure 30. Pseudericthonius bousfieldi sp. nov. Paratype female (3.5 mm), OCEANPROF II (BC SUL) #75, 18 June 2003, 1050 m, MNRJ 21250.

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Pseudericthonius sp. 2 Souza-Filho & Serejo, 2010c: 186.

Type material
Holotype

Male (3.8 mm) (dissected and drawn), OCEANPROF II, BC–NORTE, #44, Campos Basin, Rio de Janeiro, Brazil, 22°10′43.5″S, 39°54′45″W, 1 July 2003, 749 m, MNRJ 21257.

Paratypes

One male and two females (one dissected and drawn), OCEANPROF II, BC-SUL, #75, Campos Basin, Rio de Janeiro, Brazil, 22°31′28.3″S, 40°03′49.3″W, 18 June 2003, 1050 m, MNRJ 21250. One female, OCEANPROF II, BC-SUL, #84, Campos Basin, Rio de Janeiro, Brazil, 22°26′28.8″S, 39°58′53.3″W, 20 June 2003, 1050 m, MNRJ 21246. One male and one female, OCEANPROF II, BC-SUL, #79, Campos Basin, Rio de Janeiro, Brazil, 22°20′22.4″S, 40°01′24.7″W, 21 June 2003, 750 m, MNRJ 21247. Two females, #RONCADOR, Campos Basin, Rio de Janeiro, Brazil, 21°58′32.2″S, 39°51′52.66″W, 24 September 2001, 1700 m, MNRJ 21249. One female, OCEANPROF I, BC-SUL, #84, Campos Basin, Rio de Janeiro, Brazil, 22°26′27.75″S, 39°58′51.65″W, 20 November 2002, 1050 m, MNRJ 21264.

Etymology

The name bousfieldi is given in honour of Dr Edward Lloyd Bousfield (Canadian Museum of Nature) for his great contributions to amphipod taxonomy.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Eyes absent. Mandibular palp very long, 5.5 times length of mandibular body. Gnathopod 1 carpus longer than propodus (1.2×), posterior margin densely setose, with posterodistal angle acute and slightly produced; propodus subtriangular, with both anterior and posterior margins setose. Gnathopod 2 strongly carpochelate; carpus massive, posterior margin setose, posterodistal angle produced into a long and acute process; propodus about two-thirds length of carpus, posterior margin setose, with a shallow middle excavation; dactylus as long as propodus, with a long seta on posterior margin. Uropod 1 long, peduncle with distoventral corona of spines, outer ramus with eight robust setae on both outer and inner margins, and one long robust apical seta; inner ramus one-quarter as long as outer ramus, with a single apical robust seta. Uropod 2 peduncle with distoventral corona of spines; outer ramus with two robust setae on outer margin, five robust setae on inner margin, and three distal robust setae; inner ramus one-third the length of outer ramus, with one distal robust seta. Uropod 3 peduncle with a distolateral tuft of setae; ramus without marginal robust setae, tip recurved with four spines and two setae. Telson subrectangular, wider than long, with acute process in middle of distal margin.

Description

Based on holotype male (3.8 mm), MNRJ 21257. Antennae missing. Head shorter than pereonites 1 and 2 together; anteroventral margin strongly recessed; eyes absent; lateral cephalic lobe acute. Epistome acute and turned upwards. Upper lip without distal notch. Mandibular palp very long, 5.5 times length of mandibular body, article 2 longer than article 3, with facial and marginal setae, article 3 with marginal and distal long setae. Maxilla 1 palp article 2 with four apical robust setae and four facial setae. Maxilla 2 outer plate broader than inner plate; inner plate with a row of facial setae. Maxilliped inner plate not extending beyond end of palp article 1; outer plate reaching one-third along palp article 2; article 4 with a long apical robust seta.

Coxae 1–7 wider than long, mostly discontinuous. Coxae 1 and 2 anteroventral angle rounded and not produced. Coxae 3 and 4 similar in shape to each other, and shorter than coxae 1 and 2. Coxa 5 longer than coxae 1–4, with ten long setae on distal margin. Coxae 6 and 7 short, similar in shape to each other, shorter than the others. Gnathopod 1 basis moderately stout, posterior margin slightly convex, with four short setae; carpus longer than propodus (1.2×), posterior margin densely setose, with posterodistal angle acute and slightly produced; propodus subtriangular, with antero and postero margins setose; palm acute and minutely serrate; dactylus moderately stout, reaching end of palm. Gnathopod 2 strongly carpochelate; basis stout, posterior margin with five short setae; ischium and merus with a tuft of setae on posterodistal angle; carpus massive, posterior margin setose, posterodistal angle produced into a long acute process; propodus about two-thirds the length of carpus, posterior margin setose, with a shallow middle excavation; dactylus as long as propodus, with a long setae on posterior margin. Pereopods 3–7 missing.

Epimera 1–3 posteroventral margin rounded. Epimeron 3 posterior margin smooth. Uropod 1 long, peduncle with distoventral corona of spines, with two robust setae on outer margin; outer ramus with eight robust setae on both outer and inner margins, and one long robust apical seta; inner ramus one-quarter as long as outer ramus, with a single apical robust seta. Uropod 2 peduncle with distoventral corona of spines, with two robust setae on outer margin; outer ramus with two robust setae on outer margin, five robust setae on inner margin, and three distal robust setae; inner ramus one-third length of outer ramus, with one distal robust seta. Uropod 3 peduncle with a distolateral tuft of setae; ramus without marginal robust setae, tip recurved with four spines and two setae. Telson subrectangular, wider than long, with acute process in middle of distal margin.

Sexually dimorphic characters

The female differs from the male in having gnathopod 2 subchelate.

Tube

Unknown.

Remarks

Pseudericthonius bousfieldi sp. nov. is closely related to P. gaussi and P. hesperidesi in having the eyes absent, the carpus of gnathopod 2 of the male with the posterodistal process acute, the very reduced inner ramus of uropods 1 and 2, and the telson with a medial distal process. Nevertheless, P. bousfieldi sp. nov. has the peduncle of uropod 1 with two robust marginal setae; the inner ramus is one-quarter as long as the outer ramus, with a single robust distal seta; and the peduncle of uropod 3 has a subdistal tuft of setae. In addition, P. bousfieldi sp. nov. has the mandibular palp very long, about 5.5 times length of mandibular body; article 2 of the palp of maxilla 1 with four robust setae; article 2 of the maxilliped palp 4.2 times longer than wide; and the ramus of uropod 3 without robust setae and its tip recurved, with four spines.

Geographic distribution

South-western Atlantic: Campos Basin, Rio de Janeiro, Brazil.

Pseudericthonius concavus sp. nov. (Figs 31-33)

figure

Figure 31. Pseudericthonius concavus sp. nov. Holotype, female (2.7 mm), OCEANPROF II BC, #50, 30 June 2003, 1050 m, MNRJ 21423.

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figure

Figure 32. Pseudericthonius concavus sp. nov. Holotype, female (2.7 mm), OCEANPROF II BC, #50, 30 June 2003, 1050 m, MNRJ 21423.

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figure

Figure 33. Pseudericthonius concavus sp. nov. Holotype, female (2.7 mm), OCEANPROF II BC, #50, 30 June 2003, 1050 m, MNRJ 21423.

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Pseudericthonius sp. 1 Souza-Filho & Serejo, 2010d: 184.

Type material
Holotype

One female (2.7 mm) (dissected and drawn), OCEANPROF II, BC, #50, Campos Basin, Rio de Janeiro, Brazil, 22°04′33.9″S, 39°52′05.1W, 30 June 2003, 1050 m, MNRJ 21423.

Paratypes

Two females, BARRACUDA-CARATINGA, #35, Campos Basin, Rio de Janeiro, Brazil, 22°35′10.8″S, 40°10′54.8″W, 19 May 2002, 1000 m, MNRJ 18142. One female, BARRACUDA-CARATINGA, #38, Campos Basin, Rio de Janeiro, Brazil, 22°41′12.5″S, 40°14′10.7″W, 19 May 2002, 1100 m, MNRJ 19008. Two females, BARRACUDA-CARATINGA, #32, Campos Basin, Rio de Janeiro, Brazil, 22°37′54.9″S, 40°17′31.34″W, 18 May 2002, 900 m, MNRJ 19199. One female, BARRACUDA-CARATINGA, #33, Campos Basin, Rio de Janeiro, Brazil, 22°35′40.99″S, 40°15′5.12″W, 19 May 2002, 900 m, MNRJ 19202. One female, OCEANPROF I, BC-SUL, #67, Campos Basin, Rio de Janeiro, Brazil, 22°46′59.0″S, 40°7′49.44″W, 22 November 2002, 1650 m, MNRJ 21248. One female, OCEANPROF II, BC-SUL, #79, Campos Basin, Rio de Janeiro, Brazil, 22°20′22.7″S, 40°01′24.7″W, 21 June 2003, 750 m, MNRJ 21251. Three females, OCEANPROF I, BC-SUL, #79, Campos Basin, Rio de Janeiro, Brazil, 22°20′40.26″S, 40°00′35.1″W, 26 November 2002, 775 m, MNRJ 21253. One female, OCEANPROF I, BC-SUL, #64, Campos Basin, Rio de Janeiro, Brazil, 22°36′30″S, 40°21′45.36″W, 22 November 2002, 750 m, MNRJ 21254. One female, OCEANPROF II, BC-NORTE, #44, Campos Basin, Rio de Janeiro, Brazil, 22°11′43.5″S, 39°54′45″W, 1 July 2003, 749 m, MNRJ 21255. Two females, OCEANPROF I, BC-SUL, #69, Campos Basin, Rio de Janeiro, Brazil, 22°31′12.47″S, 40°1511.08″W, 22 November 2002, 750 m, MNRJ 21256. One female, OCEANPROF II, BC-SUL, #74, Campos Basin, Rio de Janeiro, Brazil, 22°28′31.1″S, 40°09′23.5″W, 18 June 2003, 750 m, MNRJ 21258. One female, OCEANPROF I, #50, Campos Basin, Rio de Janeiro, Brazil, 22°04′33.99″S, 39°52′04.97″W, 24 November 2002, 1050 m, MNRJ 21259. One female, OCEANPROF I, BC-SUL, #74, Campos Basin, Rio de Janeiro, Brazil, 22°27′31.62″S, 40°09′23.19″W, 21 November 2002, 750 m, MNRJ 21260. One female, OCEANPROF II, BC-SUL, #59, Campos Basin, Rio de Janeiro, Brazil, 21°53′59.2″S, 39°55′32.2″W, 29 June 2003, 750 m, MNRJ 21261. Two females, OCEANPROF II, BC-SUL, #70, Campos Basin, Rio de Janeiro, Brazil, 22°35′03.7″S, 40°08′52.5″W, 15 June 2003, 1050 m, MNRJ 21262. One female, OCEANPROF II, BC, #50, Campos Basin, Rio de Janeiro, Brazil, 22°04′33.9″S, 39°52′05.1″W, 30 June 2003, 1050 m, MNRJ 21263. Two females, OCEANPROF I, BC-SUL, #84, Campos Basin, Rio de Janeiro, Brazil, 22°26′27.7″S, 39°58′51.65″W, 20 November 2002, 1050 m, MNRJ 21265. One female, OCEANPROF I, BC-SUL, #65, Campos Basin, Rio de Janeiro, Brazil, 22°41′55.68″S, 40°16′30.36″W, 22 November 2002, 1050 m, MNRJ 21266.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Antenna 1 accessory flagellum present, rudimentary, 1-articulate. Eyes absent. Mandibular palp very long, 3.4 times length of mandibular body, article 2 longer than article 3. Gnathopod 1 carpus longer than propodus (1.4×), posterior margin densely setose, posterodistal angle oblique. Gnathopod 2 weakly carporchelate; basis moderately stout, enlarged distally; carpus triangular and massive, posterior margin with long setae, posterodistal angle produced into a subacute process; propodus subequal to carpus, anterior margin with long setae; palm rounded and minutely serrate, with long facial setae. Pereopod 5 basis subrectangular, three times longer than wide; dactylus with one accessory spine. Pereopods 6 and 7 dactylus with one accessory spine. Uropod 1 outer ramus with one long and robust apical seta, about 0.8 × ramus length, and one short apical robust seta; inner ramus half as long as outer ramus, with a short apical seta. Uropod 2 inner ramus half as long as outer ramus; inner ramus naked. Uropod 3 ramus without marginal robust setae, tip recurved with two spines and two setae. Telson subrectangular; wider than long, with shallow excavation distally and two patches of spines on both sides of telson.

Description

Based on holotype female (2.7 mm), MNRJ 21423. Antenna 1 article 3 longer than article 1; flagellum with five articles, accessory flagellum present, rudimentary, 1-articulate. Head longer than pereonites 1 and 2 together; anteroventral margin strongly recessed; eyes absent; lateral cephalic lobe acute. Epistome acute and curved upwards. Upper lip with distal notch. Mandibular palp very long, 3.4 times length of mandibular body, article 2 longer than article 3, with facial and marginal setae, article 3 marginal and distal long setae. Lower lip, mandibular process acute. Maxilla 1 inner plate with a row of marginal setae; outer plate with seven robust setae; palp with four apical robust setae and two facial setae. Maxilla 2 outer plate broader than inner plate; inner plate with a row of facial setae. Maxilliped inner plate extending beyond end of palp article 1; outer plate reaching about two-thirds along palp article 2; article 4 with a long apical robust setae.

Coxae 1–7 wider than long, mostly discontinuous. Coxae 1 and 2 anteroventral angle rounded and not produced. Coxae 3 and 4 similar in shape, and as deep as coxae 1 and 2. Coxa 5 as long as coxae 1–4, with a few long setae on distal margin. Coxae 6 and 7 short, similar in shape, shorter than others. Gnathopod 1 basis slender, posterior margin convex; carpus longer than propodus (1.4×), posterior margin densely setose, posterodistal angle oblique; propodus suboval, with long setae on antero, postero, and facial margin; palm evenly rounded and minutely serrate, without palmar corner; dactylus moderately stout, reaching end of palm. Gnathopod 2 weakly carporchelate; basis moderately stout, enlarged distally; carpus triangular and massive, posterior margin with long setae, posterodistal angle produced into a subacute process; propodus subequal to carpus, anterior margin with long setae; palm rounded and minutely serrate, with long facial setae. Pereopods 3 and 4 similar in shape and length, basis suboval, moderately inflated; merus, anterior margin well produced; dactylus longer than propodus. Pereopod 5 basis subrectangular, three times longer than wide; merus three times longer than wide; propodus long, 5 × carpus length; dactylus with one accessory spine. Pereopods 6 and 7 similar in shape, basis subrectangular, 2.1 times longer than wide; merus long, about 1.25 × propodus length; propodus a tuft of setae on posterodistal angle; dactylus with one accessory spine.

Epimera 1–3 distoventral margin rounded. Epimeron 3 posterior margin smooth. Uropod 1 long, peduncle with distoventral corona of spines, without robust setae on outer margin; outer ramus with outer and inner margins naked, with one long and robust apical seta about 0.8 × ramus length and one short apical robust seta; inner ramus half as long as outer ramus, with a short apical seta. Uropod 2 peduncle with distoventral corona of spines, without robust setae along outer margin; outer ramus without setae; inner ramus half as long as outer ramus; inner ramus naked. Uropod 3 peduncle without subapical setae; ramus without marginal robust setae, tip recurved, with two spines and two setae. Telson subrectangular; wider than long, with shallow excavation distally and two patches of spines on both sides of telson.

Tube

Composed of fine detritus and short sand grains.

Etymology

The specific name is derived from the Latin concavus, meaning concave. It refers to the excavation on the telson tip, which is unique within the genus.

Remarks

Pseudericthonius concavus sp. nov. is distinguished from all its congeners in having a sparsely setose coxa 5, the basis of pereopod 5 subrectangular, uropods 1 and 2 with the inner ramus reaching about midlength of the outer ramus, and lacking robust marginal setae. Also, both rami of uropod 2 lack distal setae, and the distal margin of the telson is concave, without an acute middle process.

Geographic distribution

South-western Atlantic: Campos Basin, Rio de Janeiro, Brazil.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Systematics
  7. Acknowledgements
  8. References

We thank Drs Kim Larsen and Carolina Tavares for their comments and useful advice on the article. We thank Dr Janet Reid for English revision. Thanks are also due to Cenpes-Petrobras for making available the material studied. The first author thanks CAPES (Fundação Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) and FACEPE (Fundação de Amparo à Ciência e Tecnologia) for a postdoctoral fellowship. The second author thanks CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for a productivity grant, process number 310752/2011–6. We are grateful to Dr Mark E. Siddall and Christine LeBeau from the American Museum of Natural History for the loan of the type series of Bonnierella linearis J.L. Barnard, 1964. The figures of Bonnierella linearis californica from J.L. Barnard, 1966 were used with the permission of Jean E. Crampon (Associate University Librarian, University of Southern California). The figures of Bonnierella linearis J.L. Barnard, 1964 were used with the permission of Mai Qaraman (Research Services Librarian, American Museum of Natural History).

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  3. Introduction
  4. Material and Methods
  5. Results
  6. Systematics
  7. Acknowledgements
  8. References
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