SOME DATA ON THE SYSTEMATICS OF THE FAMILY LIMNORIIDAE () FROM NORTHERN AND FAR-EASTERN SEAS OF THE U.S.S.R.

BY

O. G. KUSSAKIN Biological Faculty, Leningrad State University, U.S.S.R.

Study on marine borers of the family Limnoriidae in Russian northern and far- eastern seas was started rather long ago. In 1880 N. Grebnitski collected specimens of in eastern Kamchatka and at the Komandorski Islands. In 1908 K. Derjugin discovered Limnol'ia on the Murman coast; the was determined by him as L. lignorum (Rathke). Some collections of various expeditions were partially examined by Gurjanova (1932, 1936). Data on distribution and biology of Limnoria in Soviet seas were gathered and summarized by Ryabchicov (1957) in his paper on marine borers of the U.S.S.R., but the author mentioned only L. lignorum. However, the study of Limnoriidae in the U.S.S.R. was essentially retarded by the absence of satisfactory descriptions of boreal species of Linanoria, particularly of L. lignorum (Rathke ) and L. japonica Richardson. Because of this, exact iden- tification of Russian specimens was impossible. The situation changed definitely when a revision of this family with redescriptions of previously described species, after a first contribution by Holthuis (1949), was successfully undertaken by Men- zies (1957, 1959). Unfortunately Menzies had no materials from Soviet seas with the exception of one sample from the Komandorski Islands. In 1961 Jesakova described a new species of Limnoria, L. ?na???danen.ri.? from the Okhotsk Sea. At our disposal were collections of the Zoological Institute of the Academy of Sciences of the U.S.S.R. from the White, Barents, Bering, Okhotsk and Japan Seas including some syntypes of L. magadanera.ri.r which were transmitted by Jesakova to the Zoological Institute. In all the author examined 27 samples of Limnoria containing more than 2180 specimens. In these collections 4 species of the family Limnoriidae were determined: Limnoria lignorum (Rathke), L. magadanensis Jesakova, and two new species, L. boreali.r and Phycolimnoria zinovae. The subgenus Phycolimnoria Menzies is considered by the writer a distinct genus that is essentially distinguished from the genus Linanoria (s. str.) by the structure of the mandibles and by its habitat.

Phycolimnoria zinovae new species (figs. la, 2) Material examined. Ascold Island near the mainland coast of the Japan Sea, depth 20 m, July 1949, K. Gordeeva 282

Holotype 9, length 3.7 mm, width of pleotelson 1.0 mm; allotype 8, length 2.2 mm, width of pleotelson 0.6 mm. Known only from the locality. The types are deposited in the Zoological Institute of the Academy of Sciences,U.S.S.R., with the catalogue number N 1/44160. The species is named in honour of the well-known Soviet algologist Anna D. Zinova.

Fig. 1. Pleotelson and fifth pleonal somite. a, Phycolimi7oriazinovae sp. n., female holotype, Japan Sea; b, Limnoria lignorum (Rathke), specimen from the southern Kuriles; c, Limnoria magadanensis Jesakova, syntype, Okhotsk Sea; d, Limnoria boreali.rsp. n., specimen from the Soviet coast of the Japan Sea; e, Limnoria boreali.rsp. n., specimen from western Kamchatka; f, Limnoria boreali.rsp. n.. male holotype, White Sea.