The oldest named New Zealand species is the Early Paleocene (Danian) age (Text-fig. 2) L. (Limopsista) micropsFinlay and Marwick, 1937 from the Wangaloa Formation at Wangaloa and Boulder Hill, South Island, which was a shallow water deposit (Finlay and Marwick 1937; Beu and Maxwell 1990). The species is now referred to L. microps (Text-fig. 3A) as Beu (2006) did not consider the subgenus Limopsista to be valid. However, there are several records of unpublished and unnamed specimens of Limopsis recorded in New Zealand, from the Piripauan–Haumurian local stages (Santonian–Maastrichtian; FRED – The Fossil Record Electronic Database –http://www.fred.org.nz/index.jsp) and also some unnamed older occurrences in the Early Cretaceous (Speden 1975; Moore and Speden 1984), so it is clear that Limopsis had a much longer and more extensive fossil record in New Zealand than the published literature of described species shows. The Maastrichtian species L. antarcticaWilckens, 1910 (Text-figs 2, 4A) from the shallow-water López de Bertodano Formation of Seymour and Snow Hill islands (Text-fig. 1), is the oldest species of Limopsis to have been identified in Antarctica (Wilckens 1910; Zinsmeister and Macellari 1988). The oldest Australian species, of Late Paleocene age, is L. rupestrisDarragh, 1994 (Text-figs 2, 5A) from the Pebble Point Formation, Otway Basin, Victoria, which was interpreted as a high-energy, shallow water deposit (Darragh 1994).
Figure TEXT-FIG. 3.. A–Q, Fossil Limopsis species found in New Zealand in order of first appearance in the fossil record, oldest to youngest. Unless otherwise stated, images were taken from the original descriptions. A, L. micropsFinlay and Marwick, 1937. B, L. campaAllan, 1926. C, L. waihaoensisAllan, 1926, picture from Beu and Maxwell (1990). D, L. parvicostata (Maxwell, 1992). E, L. parmaMarwick, 1929. F, L. catenataSuter, 1917; picture from Beu and Maxwell (1990). G, L. zealandicaHutton, 1873; picture from Beu and Maxwell (1990). H, L. propeinvalidaLaws, 1939. I, L. gisbornensis (Maxwell, 1978) originally described and illustrated as L. retifera by Marwick (1931). J, L. productaFinlay and McDowall, 1923. K, L. lawsiKing, 1933. L, L. aoteana (Vella, 1954). M, L. cookiMarwick, 1931. N, L. invalidaMarwick, 1928. O, L. marwickiPowell, 1938, picture from Beu (2006). P, L. peteriBeu, 1969; picture from Beu (2006). Q, L. turnbulliBeu, 2006. Scale bars represent 5 mm.
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Figure TEXT-FIG. 4.. A–D, Fossil Limopsis species found in Antarctica. A, L. antarcticaWilckens, 1910. B, L. antarcticominutaStilwell, 2000. C, L. psimolisAnelli et al., 2006. D, L. infericola sp. nov. DSDP and ODP specimens ?Limopsis sp., L. aff. marionenesis and Limopsis sp. are not illustrated in the original literature and thus could not be included in this figure. The Cape Melville specimens assigned to Limopsis sp. are not illustrated because of the poor preservation of the material. Scale bars represent 5 mm.
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Figure TEXT-FIG. 5.. A–F, Fossil Limopsis species (not subspecies) found in Australia in order of first appearance in the fossil record, oldest to youngest. Unless otherwise stated, images were taken from the original descriptions. A, L. rupestrisDarragh, 1994. B, L. chapmaniSingleton, 1932. C, L. multiradiataTate, 1886. D, L. morningtonensisPritchard, 1901. E, L. beaumariensisChapman, 1911, external view from Ludbrook (1955). F, L. maccoyiChapman, 1911. G, L. affinitalisChapman and Crespin, 1928. H, L. werrikooensisSingleton, 1941. I, L. forteradiataCotton, 1930 picture from Lamprell and Healy (1998). J, L. tensioni (Tenison-Woods, 1878) picture from Lamprell and Healy (1998). Scale bars represent 5 mm.
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Three Limopsis species have been documented from the Eocene in New Zealand. The Bortonian (Lutetian–Bartonian: Middle Eocene) species L. campaAllan, 1926 (Text-figs 2, 3B) was found in the Waihao Greensand, Waihao Downs, South Island, a unit deposited in a deeper water, shelf environment (Beu and Maxwell 1990). The Kaiatan (Priabonian: Late Eocene) species L. waihaoensisAllan, 1926 (Text-figs 2, 3C; which ranged to the Runangan) and L. parvicostata (Maxwell, 1992; Text-fig. 2) were both found towards the top of the Waihao Greensand in the Tahu Member at McCulloch’s Bridge, South Island (Beu and Maxwell 1990), which was deposited in outer shelf to the uppermost bathyal waters (Maxwell 1992). The species L. parvicostata was originally assigned to the genus Pectunculina because of the presence of marginal crenulations (Text-fig. 3D). Maxwell (1992) considered that these crenulations made the species distinct from the smooth margined genus Limopsis. Pectunculina is a taxon which has a contentious taxonomic history. Although considered as a subgenus of Limopsis at the time, Vella (1954) also believed Pectunculina should be regarded as a separate genus because of its crenulated margin. However, Beu (2006) stated that the significance of a crenulate margin as a distinguishing character is unclear as the degree of crenulations can vary, meaning that there are intermediate species that cannot be placed in Pectunculina or Limopsis (Beu 2006; A. G. Beu, pers. comm. 2010). He also placed several New Zealand species previously assigned to Pectunculina into the genus Limopsis. Also, Lamprell and Healy (1998) placed Pectunculina as a subgenus of Limopsis, and Oliver (1981) referred all species previously named as Pectunculina to Limopsis (s.l.), but suggested that cladistics need to be employed to resolve this matter (Oliver, pers. comm. 2010).
The Eocene species L. antarcticominutaStilwell, 2000 (Text-figs 2, 4B) was restricted to erratics at McMurdo Sound in East Antarctica (Text-fig. 1), which were considered by Stilwell (2000) to be from shallow water facies. The age of the erratics was not accurately constrained, but the fauna present in the unit placed it around the late Early Eocene to Late Eocene (Stilwell 2000). The species L. chapmaniSingleton, 1932 (Text-figs 2, 5B) first occurred in an unnamed Middle–Late Eocene sandstone unit in the Carnarvon Basin of Western Australia (Darragh and Kendrick 2008). The unit was thought to have been deposited in a middle-shelf environment, although the fossils appeared broken, so transport may have occurred (Darragh and Kendrick 2008). The species also has other records from the Late Eocene, Oligocene and Early Miocene (Darragh and Kendrick 1980; Darragh 1985; Darragh and Kendrick 2008). The subspecies L. chapmani validaSingleton, 1932 was described from Birregurra, Victoria. Singleton (1932) stated that they differed slightly from L. chapmani in morphology, such as being more tumid; the specimens were tentatively dated as Miocene, but no geological information was given about the locality. The Aldingan (Bartonian–Priabonian: Late Eocene) species L. multiradiataTate, 1886 (Text-figs 2, 5C) was found in the shallow-water Blanche Point Formation of the St Vincent Basin at Kent Town and Aldinga Bay, South Australia (Ludbrook 1973).
Early Oligocene specimens tentatively identified as ?Limopsis sp. (Text-fig. 2) were found in the CRP-3 drillhole in the Victoria Land Basin, Antarctica (Taviani and Beu 2001; Text-fig. 1). The stratigraphic units on either side of the unit in which the fossils were found were interpreted as having been deposited in inner- to middle-shelf environments (Taviani and Beu 2001). The identification was based on two fragments of a single valve of a specimen on which some shell sculpture and a small area of the hinge were preserved; the shell had a symmetrical, sub-circular shape, and the shell material was thick (Taviani and Beu 2001).
Four new species of Limopsis first appeared in the Early Miocene of Antarctica (Text-fig. 2). Several specimens identified as Limopsis aff. marionensis by Dell and Fleming (1975) were collected from mudstone and diamictite sediments from Deep Sea Drilling Project site 270 in the Ross Sea (Dell and Fleming 1975; Text-fig. 1). The identification was based on shell morphology, which was thought to resemble that of the Recent species L. marionensisSmith, 1885 (Dell and Fleming 1975). It was suggested that they had been transported to the deeper water depositional setting, without the separation of valves, by gravity slide or turbidity current (Dell and Fleming 1975). This assessment was based on the Recent distribution of L. marionensis; the possibility that the fossil specimens inhabited this depth was not considered. The oldest specimen from the drilling site, a broken juvenile, occurred just above the Oligocene/Miocene boundary (identified from microfossils in the core). Younger Miocene specimens included a left valve and fragments of an articulated pair of valves (Dell and Fleming 1975). Dell and Fleming (1975) suggested that the continuous occurrence of sea ice was unlikely, but the presence of diamictites in the samples indicated at least periodic glacial conditions.
Early Miocene limopsids also occurred in the Cape Melville Formation, King George Island (South Shetland Islands; Text-fig. 6). This outer shelf to upper slope glacial unit was dated using Sr isotopes from bivalve specimens at 22.6 ± 0.4 Ma (Early Miocene; Dingle and Lavelle 1998). Five specimens of Limopsis psimolis Anelli, Rocha-Campos, Dos Santos, Perinotto and Quaglio, 2006 were identified; this species was characterized by large, thick shells and strongly anisomyarian muscle scars (Text-figs 4C, 7A). Two additional specimens from the BAS collections (P. 2702.696 right and left valve preserved and P. 2702.25, internal mould of both valves, hinge region missing) have been assigned to L. psimolis based on shell shape, shell thickness and shape of the muscle scars (Text-figs 4D, 7B). Three specimens from the BAS collections have been identified as Limopsis sp. (P. 2702.226, P. 2702.170 and P. 2702.735); species designation is not possible because of abrasion and preservation as internal moulds. Finally, four specimens have been assigned to a new species of Limopsis (L. infericola sp. nov. see systematic palaeontology below; Text-figs 4E, 7C).
Figure TEXT-FIG. 6.. A, Location of the South Shetland Islands in relation to the Antarctic Peninsula. B, King George Island, showing the location of Cape Melville. A, B, from: Birkenmajer (1987). C, Cape Melville geology and site localities (P. 2702 and P. 2707) for Limopsis infericola n. sp. specimens. (From Feldmann and Crame 1998).
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Figure TEXT-FIG. 7.. A–D. Limopsis specimens from the Cape Melville Formation, King George Island, South Shetland Islands, Antarctica. A, L. psimolisAnelli et al., 2006. B, L. psimolis P. 2702.696 from British Antarctic Survey collection. C, L. infericola sp. nov, holotype P. 2702.736. D, Specimen GP/1T 2177, previously identified as a paratype of L. psimolis by Anelli et al. (2006), is re-assigned to L. infericola sp. nov. Scale bars represent 10 mm.
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Limopsis insolita (Sowerby, 1846; Text-figs 2, 8) was a long-ranging species known from Patagonia. It was common throughout the tertiary shallow marine molluscan assemblages of Argentina, which ranged from the Oligocene to Middle Miocene (Del Río 2004). The species was found at several localities, in three geological units – the San Julian, Monte León and Chenque Formations (Zinsmeister 1981; Griffin and Nielsen 2008; Casadío and Griffin 2009; Parras and Griffin 2009). L. insolita was also identified from the Late Oligocene to Early Miocene Guadal Formation, Pampa Castillo, Región de Aisén in Chile (Frassinetti and Covacevich 1999). Two specimens of an undescribed Miocene species of Limopsis were found in the Navidad Formation of Chile (see GSA Data Repository item 2010262 of Kiel and Nielsen 2010); however, they have not yet been described or figured. The species L. modestaDoello Jurado, 1915 (Text-figs 2, 8B) was found in rocks deposited in shallow water from the Late Miocene Arroyo Pescado borehole in the Buenos Aires Province (Del Río and Martínez 1998).
Several Early Miocene Limopsis species have been recorded from Australia (Text-fig. 2). L. morningtonensisPritchard, 1901 (Text-fig. 5D) first occurred in the Fishing Point Marl, Horden Vale, Victoria, which was a shallow water deposit (Darragh 1985). L. beaumariensisChapman, 1911 (Text-fig. 5E) (Ludbrook 1955) is associated with the Gellibrand Marl Formation at Lake Bullenmerri in the Otway Basin, Victoria (Chapman 1911; Bock and Cook 2001); this was thought to be a cool, deep water deposit (Nicolaides 1995). Chapman (1911) also stated that the variant L. beaumariensis var. depressaChapman, 1911 could be distinguished from L. beaumariensis by its thin, depressed form, apiculate umbo and stronger concentric striae. Finally, L. maccoyiChapman, 1911 (Text-fig. 5F) also occurred in the Gellibrand Marl Formation from Brown’s Creek, Victoria (Nicolaides 1995).
Limopsis species were common throughout the Oligocene and Miocene (Text-fig. 2) in New Zealand in a variety of different environments. The Duntroonian (Chattian: Late Oligocene) species L. parmaMarwick, 1929 from the Chatton Formation, Shell Gully, Chatton, South Island was preserved in a shallow water assemblage (Beu and Maxwell 1990; Text-fig. 3E). During the Duntroonian (Chattian: Late Oligocene), the first specimens of L. catenataSuter, 1917 (Text-fig. 3F) were found from the upper part of the Wharekuri Greensand, Lake Waitaki, South Island in a mid-shelf depth assemblage. The species also occurred in shallow water assemblages until the Waiauan (Serravallian: Middle Miocene; Beu and Maxwell 1990). Waitakian (Aquitanian: Early Miocene) aged examples of L. zealandicaHutton, 1873 (Text-fig. 3G) were identified from two localities on South Island: first, from the Mount Harris Formation in the Tengawai River near Trap Creek and second, in the Otekaike Limestone Formation at Trig Z, Otiake. At both of these localities, deeper water assemblages were preserved (Beu and Maxwell 1990). L. zealandica was a long-ranging species, with records until the Altonian (Burdigalian–Langhian: Early–Middle Miocene) and possibly younger (Burdigalian–Serravallian; A. G. Beu, pers. comm. 2010). The Otaian (Aquitanian: Early Miocene) L. propeinvalidaLaws, 1939 (Text-fig. 3H), from the Pakaurangi Formation, Pakaurangi Point, Kaipara Harbour, North Island was preserved within an outer shelf assemblage (Laws 1939; Beu and Maxwell 1990). This species ranged until the Altonian (Burdigalian–Langhian: Early–Middle Miocene; Beu and Maxwell 1990). The Lillburnian (Serravallian: Middle Miocene) species L. gisbornensisMaxwell, 1978 (Text-fig. 3I) occurred in the Tutamoe Conglomerate, Pangopango Stream, Gisborne District, North Island (Maxwell 1978). The Tutamoe Conglomerate was a deeper water unit that also contained shallow water molluscs, suggesting a degree of transport for some aspects of the fauna (Beu and Maxwell 1990). L. gisbornensis was previously designated as L. retiferaMarwick, 1931; however, the name L. retifera had already been assigned to another specimen (Maxwell 1978; Beu and Maxwell 1990). The Waiauan (Serravallian: Middle Miocene) L. productaFinlay and McDowall, 1923 (Text-fig. 3J) was found in the Dowling Bay Limestone, Dowling Bay, Dunedin, South Island (Beu and Maxwell 1990); the unit was thought to represent an outer shelf depositional setting (Finlay and McDowall 1923). However, this specimen came from a highly tectonised locality and was possibly a distorted specimen of other common species at the locality such as L. zealandica or L. gisbornensis (Beu, pers. comm. 2010). The early Tongaporutuan (Tortonian: Late Miocene) L. lawsiKing, 1933 (Text-fig. 3K), from the Hurupi Series, Hurupi Creek, Palliser Bay, Southern Wairarapa, North Island and Blind River, Malborough, north South Island, was described as a shelf dwelling species (Beu 2006). The Middle Tongaporutuan (Tortonian: Late Miocene) species L. aoteana (Vella, 1954) (Text-fig. 3L) from bathyal mudstones at Bell’s Creek, Southern Wairarapa, North Island (Vella 1954; Beu and Maxwell 1990) was originally assigned to the genus Pectunculina. Late Miocene specimens of L. cookiMarwick, 1931 (Text-fig. 3M) were described from the Ormond Formation, Gisborne District, North Island, which has been interpreted as a shallow water deposit (Marwick 1931). Beu (pers. comm. 2010) suggested that there are probably many unidentified specimens of Limopsis in New Zealand fossil collections, including several unnamed new species in the richly diverse, shelf depth successions at Clifden, Southland from the Altonian–Waiauan (Burdigalian–early Tortonian: Early–Late Miocene).
Several species first appeared in the Late Pliocene to Early Pleistocene fossil record of New Zealand (Text-fig. 2). The Waipipian–Mangapanian (Piacenzian–Gelasian: Late Pliocene) species L. invalidaMarwick, 1928 (Text-fig. 3N) from the Whenuataru Tuff, Pitt Island, Chatham Islands probably inhabited deep, cold waters (Marwick 1928; Beu and Maxwell 1990). The Nukumaruan (Gelasian: Late Pliocene) L. marwickiPowell, 1938 (Text-fig. 3O) occurred in the Castlepoint Formation, Castlepoint, East Wairarapa, North Island, which was originally considered to be a mixed shelf and upper bathyal fauna, but Beu (2006) considered it to be entirely bathyal. Another Nukumaruan (Gelasian: Late Pliocene) species was L. peteriBeu, 1969 (Text-fig. 3P), from a mudstone stratigraphically lower than the Pukenui Limestone, from Palliser Bay as well as from the Ruakokopatuna and Mangaopari valleys in South Wairarapa, North Island; this was deposited in deep, cold waters (Beu 2006). Finally, the Castlecliffian (Pleistocene) species L. turnbulliBeu, 2006 (Text-fig. 3Q) occurred in a Pleistocene mudstone, Wilson River, SW Fiordland, South Island, which was also interpreted as a deep, cold water deposit (Beu 2006; Turnbull et al. 2007). The shallower water Limopsis species were absent in New Zealand from the Late Pleistocene (Beu 2006); Beu stated that bathyal species (assigned to Pectunculina, which he placed in Limopsis) are present in waters around New Zealand at the present day and suggested that the genus retreated to deep water around New Zealand as temperatures fell during the late Neogene (Beu 2006).
A Pliocene occurrence of L. marionensis (Text-fig. 2) was recorded from an unnamed sandstone horizon at Marine Plain in the Vestfold Hills, East Antarctica (Pickard et al. 1988; Text-fig. 1). The depositional setting was thought to have been shallow water, less than 50 m deep, in an interglacial period, warmer than at present (Pickard et al. 1988). Unfortunately, there was no description or illustrations of the specimens. In Australia, the Pliocene species L. affinitalisChapman and Crespin, 1928 (Text-figs 2, 5G) was recorded from a borehole on the Mornington Peninsula, Victoria, in sandy sediments thought to have been deposited in shallow waters (Chapman 1928). The Late Pliocene species L. werrikooensisSingleton, 1941 (Text-figs 2, 5H) occurred in the Werrikoo Limestone, Glenelg River, Victoria, Australia, a unit that was deposited in very shallow water (Singleton 1941; Darragh 1985). In Australia, two of the species that arose during the Miocene, L. beaumariensis and L. maccoyi, had a continuing record into the Pliocene (Chapman 1911; Ludbrook 1955). Chapman (1911) also stated that in the Pliocene, L. maccoyi was ‘moderately rare; passing into L. tenisoni (living)’ suggesting that there was a continuous record of some species of Limopsis in Australia. This is also shown by L. forteradiataCotton, 1930 (Text-figs 2, 5I) and L. tensioni (Tenison-Woods, 1878; Text-figs 2, 5J), which were both recorded in the Early Pleistocene in the east of Western Australia, in the shallow water Roe Calcarenite (Ludbrook 1978). These two species both range until the present (Lamprell and Healy 1998).
A Middle Pleistocene record of Limopsis (Text-fig. 2) was found in an unnamed carbonate-rich unit in the CRP-1 drillhole, Cape Roberts, Victoria Land Basin, Antarctica (Taviani et al. 1998; Text-fig. 1). However, the age of this unit was not precise, and there was no description or image of the Limopsis specimen. Taviani et al. (1998) estimated water depth at the time of deposition to have been approximately within the range of 100–200 m. There are currently no published records of Limopsis from southern South America in the Pliocene–Pleistocene.
Oliver (1981) divided Recent Limopsis species into three major groups (limopsiform, glycymeriform and abyssate) and thirteen morphological classes based on shell characters and anatomical features. In Antarctica, there is a diversity of Limopsis species at the present day in comparison with other genera (Text-fig. 9), with current circum-Antarctic and Magellan Region species belonging to three of the morphological classes (I, V and XIII) described by Oliver (1981). Classes I and V belong in Oliver’s limopsiform group and class XIII belongs to the abyssate group. There are no members of glycymeriform group in Antarctica, this class being present in the Indo-Pacific and Australia (Oliver 1981). Oliver (1981) stated that class I limopsids are cosmopolitan, except for the Arctic Ocean, and are typically ploughing forms living semi-infaunally in soft sediments. They are represented by L. marionensis (Text-fig. 9A) and L. tenella dalliLamy, 1912 (Text-fig. 9B), which are found in Antarctic waters and the Magellan Region, and L. tenella tenellaJeffreys, 1879 (Text-fig. 9C) from Antarctic waters (Text-fig. 1). Class V limopsids are cosmopolitan, except for the Arctic Ocean; they are more sedentary and have an infaunal habit. Representatives from Antarctic waters are L. longipilosaPelseneer, 1903 (Text-fig. 9D) and L. scabraThiele, 1912 (Text-fig. 9E); L. mabillianaDall, 1908 (Text-fig. 9F) is found both in Antarctic waters and in the Magellan Region (Text-fig. 1). Class XIII limopsids are only found in the Antarctic Ocean and are thought to have a shallow burrowing mode of life (Oliver 1981). The Antarctic species L. enderbyensisPowell, 1958 (Text-fig. 9G), L. lillieiSmith, 1915 (Text-fig. 9H), and L. scotianaDell, 1964 (Text-fig. 9I) belong to this group, and Oliver (1981) also included L. hirtella Mabille and Rochebrune, 1911 (inRochebrune and Mabille 1889; Text-fig. 9J), which is found in Antarctic waters and the Magellan Region (Text-fig. 1). Finally, Recent Southern Ocean species that have not been assigned to a morphological group include Limopsis sp. 1 (Text-fig. 9K) and Limopsis sp. 2 (Text-fig. 9L), which have been identified by K. Linse from Antarctic waters (unpublished data) and L. knudseniDell, 1990 (Text-fig. 9M), known from the Antarctic and Magellan Region (Text-fig. 1).
Figure TEXT-FIG. 9.. A–M, Recent Limopsis species from waters around Antarctica and the Magellan region. Images were used from the original descriptions, unless otherwise stated. A, L. marionensisSmith, 1885 (specimen MR 597 from the BAS marine collection). B, L. tenella dalliLamy, 1912 (image from Dell 1990). C, L. tenella tenellaJeffreys, 1879 (image from Dell 1990). D, L. longipilosaPelseneer, 1903. E, L. scabraThiele, 1912 (image from Dell 1990). F, L. mabillianaDall, 1908 (image from Dell 1990). G, L. enderbyensisPowell, 1958. H, L. lillieiSmith, 1915. I, L. scotianaDell, 1964. J, L. hirtella Mabille and Rochebrune, 1889 inRochebrune and Mabille (1889) (image from Lamy 1911). K, Limopsis undescribed sp. 1 BAS marine collection. L, Limopsis undescribed sp. 2 BAS marine collection. M, L. knudseniDell, 1990. Scale bars represent 5 mm.
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Modern Limopsis species are also found in South African and Australian waters in depths of up to 600 m (Oliver 1981; Lamprell and Healy 1998). Several species have been described from bathyal depths around New Zealand; however, they were originally assigned to Pectunculina as they possess crenulate inner ventral margins. Beu (2006) included L. lata (Smith, 1885; placed in morphological class VII, limopsiform group by Oliver, 1981), L. proceritas (Crozier, 1966) and L. tasmani (Dell, 1956; placed in morphological class V, limopsiform group by Oliver (1981)) in Limopsis. Therefore, several deep-water Limopsis species are present in New Zealand waters.