海南岛多毛类锥头虫科(Orbiniidae)-新种

A NEW SPECIES OF ORBINIIDAE (POLYCHAETA) FROM HAINAN ISLAND

1984年7月中澳海洋科学家在海南岛合作进行生态考察时。我们采到了锥头虫科截锥虫属一新种,现描述如下。海南截锥虫Nainereis hainanensis sp. nov.

A new species of Nainereis was found by us during the ecology expedi-tion of Sino-Australia marine scientists on waters around the Hainan Island China in July,1984.The new species is named as Nainereis hainanensis(sp.nov.).Altogether,three specimens of the species were collected in the intertidalzone of medium sand mixed with coral detritus in Luhuitou,Hainan Island.The specimen measures 50-60mm in length for 80-100 segments and1-2mm in width including parapodia and bristles.Description:Prostomium flattened and truncated at its frontal margin.Region of body not clearly demarkated.First segment without parapodia.The thorax consists of 21 segments followed by transitional regions of 6 seg-ments;therefter the change to abdominal neuropodia is complete.Branchiaedevelop from the seventh segment and already so large as to extend distallyto the postsetal notopodical lobe of the same segment;they are simple throu-ghout.All the parapodia are biramous and each with a digitiform ligule.All setae are simple.There are three kinds of them as follows,(1)Denticulate and hooded hooks,present to neuropodia of thorax nearthe reverse side;(2)Acicular setae,present to neuropodia of abdomin and;(3)Denticulate and capillate setae,present to all neuropodia and noto-podia of parapodia.The most obvious character of this new species is as follows:only the first sogment without parapodia and the prostomium is truncated atits front margin,with the same basic characteristics as that of NainereisBlainville.According to the report of Fauchald,(1977),up to now thereare eighteen species of Nainereis Blainville.The species resemble tothis new one are N.grubei(Gravier,1909),N.grubei australis Hartman,1957 and N.bicornis Hartman.1951.The former two species are more simi-lar to this new one,but they have obvious characteristics different fromthose of the new species:the branchial of our specimens develop from theseventh segment,and 21 segments of thorax and the transition from thoraxto abdomen is at segment 22-27;while N.grubei(Gravier)with 18segments of thorax and without segment of transition;the N.grubei austalis hasthe branchia from the 6th segment,28 segments of thorax and 10 transitionalsegments from thorax to abdomen.In terms of the geographical distribu-tion,N.grubei(Gravier)and its subspecies axe spotted in the South Pacificwaters only and they are not found in the Indian-West Pacific Ocean,sothe new species is not the stem species of N.grubei(Gravier).The author is greatly in debt to Professor Wu Baolin for his guide inthe taxonomical and ecological work and the critical reading of the manu-seript.