On New and Little Known Species of Archiconchoecia (Mydocopa, Halocyprididae) from the Sargasso and Caribbean Seas, with Descriptions of Seven New Species

Abstract

Except for two relatively well-known species, specimens of the oceanic, planktonic, primarily bathypelagic ostracod genus Archiconchoecia have been rarely noted. Four species were described by 1908, and none since then until the past year. Now 14 species are known, including the 7 new species described herein, and also a specimen previously ascribed to a known species which is renamed as a new species. The male of a known species is described for the first time. A key to the 14 species is included. Six of the new species were collected in the Sargasso Sea off Bermuda between 500 and 2000 m-depths. One species was found in the western Caribbean Sea. Quantitatively, species of Archiconchoecia constitute only a small proportion of the total numbers of planktonic ostracods in the Sargasso Sea, but their relative importance rises with depth, from 1.2% of the total ostracods in surface waters to 10% over 1500-2000 m-depths. For the 2000 m water column a mean figure of 115 Archiconchoecia per square meter of sea surface was obtained from 2 years of monthly sampling in the Sargasso Sea.