Comatulid Crinoids from R/V Eltanin Cruises in the Southern Ocean
- Louis S. Kornicker
Published Online: 16 MAR 2013
Copyright 1983 by the American Geophysical Union.
Biology of the Antarctic Seas XIII
How to Cite
Speel, J. A. and Dearborn, J. H. (1983) Comatulid Crinoids from R/V Eltanin Cruises in the Southern Ocean, in Biology of the Antarctic Seas XIII (ed L. S. Kornicker), American Geophysical Union, Washington, D. C.. doi: 10.1029/AR038p0001
- Published Online: 16 MAR 2013
- Published Print: 1 JAN 1983
Print ISBN: 9780875901862
Online ISBN: 9781118666722
- Marine biology—Antarctic regions—Collected works
Collections of comatulid crinoids obtained in the Southern Ocean are described and discussed. One hundred forty-two Eltanin stations occupied in 70—5043 m, yielded comatulids. Over half these stations (78) sampled depths greater than 500 m, 16 were occupied below 1000 m, 18 below 2000 m, and 6 below 4000 m. The study material includes 27 of the 45 known Southern Ocean species and about 2450 individuals, 1451 of which are Promachocrinus kerguelensis, the largest and most abundant crinoid on the Antarctic shelf. Twelve other species are represented by more than 15 individuals each. Thirteen Antarctic species are, however, still known only from five or fewer individuals. Two species are known from more than five but less than 10 Eltanin stations, and a further 12 species remain known only from five or fewer stations from all expeditions. Nineteen of the present 27 species are in the family Antedonidae, two each in the Comasteridae, Thalassometridae, and Notocrinidae, and one each in the Charitometridae and Pentametrocrinidae. For 13 species, the present material represents the first specimens obtained since the original records. Geographic or bathymetric ranges are extended for 21 species. Eighteen species previously reported from the Southern Ocean are not represented in the Eltanin collections. A table listing Antarctic comatulids taken by all major expeditions and another summarizing the geographic and bathymetric ranges of all Eltanin specimens are presented. Descriptions, geographic and bathymetric ranges, taxonomic discussions, and biological notes are provided for most species. A new key to the species of Isometra is presented. The distribution patterns of comatulids taken by the Eltanin support earlier work, which demonstrated that the major affinity of the Antarctic comatulid fauna is with South America through the Magellanic Region and the Scotia Arc. The notable presence in the Eltanin collections of several species and genera taken south of 47°S, previously known only from the Indo-West Pacific or New Zealand or both, suggests a link may also exist between the Southern Ocean fauna and the Indo-West Pacific through the New Zealand-Antarctic region. Measurements of axillary and brachial angles are used herein and are proposed as a method of quantifying the development of synarthrial tubercles. Examination of the present material has shown that with increasing animal size, substantial changes may occur in the form and numbers of structures currently used in taxonomy. Characters of this sort, which require careful interpretation, are: IBrl-Br9; width at first syzygy, number of columns of cirri, number of cirri, and BD:VH. Two other characters, number of arms and position of syzygies, are probably related in part to regeneration and must be interpreted with care.