Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.sevin.ru/laboratories/Marine_Invertebrates/dgebuadze/Dgebuadze_Kantor_2009_Ruthenica.pdf Дата изменения: Tue Feb 1 16:53:56 2011 Дата индексирования: Mon Feb 4 05:09:00 2013 Кодировка:

Ruthenica, 2009, vol. 19, No. 2: 73-75, Published December 17, 2009.

©Ruthenica, 2009 http://www.ruthenica.com

On the finding of free-living population of parasitic gastropod Amamibalcis yessoensis in Peter the Great Bay (Japan Sea)
Polina Yu. DGEBUADZE, Yuri I. KANTOR
A.N. Severtzov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninski prospect 33, Moscow 119071, RUSSIA; p.dgebuadze@gmail.com
ABSTRACT. Parasitic gastropod Amamibalcis yessoensis (Eulimidae) was described from holothurians Cucumaria japonica and Eupentacta fraudatrix from Peter the Great Bay of the Japan Sea. Numerous specimens of this species were found in free living state in Peter the Great Bay for the first time. Presence of mass aggregation of mollusks without their hosts shows the case of facultative parasitism of the gastropod species and recorded for the first time within the family Eulimidae.

Results and discussion
The aggregation of Amamibalcis yessoensis (Fig. 1) were found near Islands of Alekseev (42°33'22,44"N; 131°10'58,71"E) and at the Andreev's cape (42°38'06,28"N; 131°07'21,14"E) in Peter the Great Bay using scuba diving in October, 2009 (Fig. 2). More than 40 free-living mollusks were found at 10-15 meters depth under the rock. Specimens of Amamibalcis yessoensis parasitizing on Cucumaria japonica were observed also but far from the location of aggregation. The average shell length of mollusks from the holothurians was 6.55 mm (from 5.2 to 7.7 mm); that of free-living -- 5.38 mm (from 3.4 to 7.1 mm) (Fig. 1). Obviously, such mass aggregation of mollusks without their hosts may indicate that this parasitic species can exist both in association with holothurians, and free-living. Thus, we observed the case of facultative parasitism of gastropod species. It should be noted that many species of symbiotic polychaetes and crustaceans, can be found both associated with marine invertebrates, and free-living [Martin, Britayev, 1998]. For instance, many shrimps species from the north seas are recorded as symbionts of anemones and at the same time in free-living state [e.g. Stevens, Anderson, 2000]. Although eulimids are symbiotic (parasitic) organisms, WarИn [1983] recorded their ability to survive being detached from the hosts (it was shown for Melanella spp., Vitreolina philippii, Pelseneeria stylifer, Peasistilifer nitidula, Pulicicochlea spp.). However we did not found any information in literature about free aggregations of parasitic gastropods. The average size of the free-living specimens is smaller, than that of the specimens from holothurians (5.38 vis 6.55), but there is significant overlap and it is too preliminary to conclude that the free-living specimens represent the earlier stage of the life cycle comparing to the parasitizing one. Further research should be done for identification of details of Amamibalcis yessoensis life history.

Peter the Great Bay of the Japan Sea is situated near the boundary of boreal and subtropical waters of the Pacific Ocean and is characterized by a complex hydrological regime which is subjected to the effect of the northern cold Primorsky Current as well as the warm Korean Current from the south and southeast. The Bay is characterized by numerous shallow lagoons, which warm up well in summer and freeze in winter. Stable low temperatures are observed near the bottom at the Bay's mouth, where the depth reaches 1000 m. As a result, the fauna of the Bay is characterized by high species diversity, and coexistence of boreal-arctic and subtropical species [Gulbin, 2004]. The family Eulimidae is rather poorly investigated family of symbiotic gastropods. These mollusks are exclusively parasites of echinoderms, more or less permanently attached to the host. About 1250 species of this family have been described. Many eulimids are not specific for one host. Moreover, hosts are unknown for many of them. Most species of the family were found in tropical waters [WarИn, 1983]. Eight species of eulimids are recorded in the Sea of Japan. One of them -- Amamibalcis yessoensis Rybakov et Yakovlev, 1993 is described from holothurians Eupentacta fraudatrix Djakanov et Baranova, 1958 and Cucumaria japonica Semper, 1868 from Peter the Great Bay [Rybakov, Yakovlev, 1993; Kantor, Sysoev, 2006].


P.Yu. Dgebuadze, Yu.I. Kantor

74

FIG. 1. Shells of Amamibalcis yessoensis from Peter the Great Bay. A -- shell length 6.4 mm, specimen from Cucumaria japonica near Alekseev Islands; B -- shell length 6.6 mm, free-living individual, near Andreev cape (photo by A. Semenov). . 1. Amamibalcis yessoensis . -- 6,4 mm, Cucumaria japonica ; B -- 6,6 mm, , ( . ).

Acknowledgements
The authors want to express their thanks to dive club Bosfor East (http://bosfor.org) which organized the trips where the material was collected; Ivan N. Marin, Elena S. Mekhova (A.N. Severtzov Institute of Ecology and Evolution) for assistance in material collecting and to Alexander A. Semenov (White Sea Biological Station, Moscow State University) for making a photograph of mollusks. Anders WarИn provided comments on the manuscript.

References
Gulbin V.V. 2004. Fauna of prosobranch gastropods of Peter the Great Bay, Sea of Japan, and the biogeographical composition. Russian Journal of Marine Biology, 30(1): 20-29. Kantor Yu.I., Sysoev A.V. 2006. Marine and brackish-water Gastropoda of Russia and adjacent

countries: an illustrated catalogue. KMK Scientific Press Ltd., 371 pp., 140 col. plates. Martin D., Britayev T.A. 1998. Symbiotic polychaetes: review of known species. Oceanography and Marine Biology, An Annual Review, 36: 217340. Rybakov A.V., Yakovlev Yu.M. 1993. Amamibalcis yessoensis n. sp. (Gastropoda: Eulimidae) -- a parasite of holothurians from the Sea of Japan. Venus, 52(1): 47-49. Stevens B.G., Anderson P.J. 2000. An association between the anemone, Cribrinopsis fernaldi, and shrimps of the families Hippolytidae and Pandalidae. Journal of Northwest Atlantic Fishery Science, 27: 77-82. WarИn A. 1983. A generic revision of the family Eulimidae (Gastropoda, Prosobranchia). The Journal of Molluscan Studies, suppl.13: 1-96.


Free-living population of parasitic Eulimidae

75

Amamibalcis yessoensis ( )
.. , ..
. .. , 33, , 119071; p.dgebuadze@gmail.com

FIG. 2. Sampling sites in Peter the Great Bay. Circle -- finding of Amamibalcis yessoensis on holothurians Cucumaria japonica near Alekseevs' Islands. Square -- finding of free-living mollusks aggregation near Andreev's cape (Google Earth). . 2. Amamibalcis yessoensis . -- Cucumaria japonica . -- (Google Earth).

. Amamibalcis yessoensis Rybakov et Yakovlev, 1993 (. Eulimidae), , . . , .

This paper is published on a CD-ROM to comply with the Article 8.6 of the International Code of Zoological Nomenclature. The copies of the CD-ROM were mailed on the date mentioned on the front page to: Department of biological literature of the Library on Natural Sciences of Russian Ac. Sci., Library of Zoological Institution of Russian Ac. Sci., Malacology library of MusИum National d'Histoire Naturelle (Paris, France), Malacology library of the Natural History Museum (London, UK), Library of the National Museum of Natural History, Smithsonian Institution (Washington, DC, USA); Thomson Reuters (publishers of Zoological Record). CD-ROM, 8.6 . CD-ROM , : (), ( ); ; MusИum National d'Histoire Naturelle (, ); Natural History Museum (London, UK), National Museum of Natural History, Smithsonian Institution (Washington, DC, USA); Thomson Reuters ( Zoological Record).