中国水螅属一新种(水螅虫纲:螅形目)  

A NEW SPECIES OF THE GENUS HYDRA FROM CHINA (HYDROZOA :HYDRIDA)

作　　者：范学铭[1] 史新柏[1] 

机构地区：[1]哈尔滨师范大学生物学系,哈尔滨150080

出　　处：《动物分类学报》1999年第4期372-379,共8页Acta Zootaxonomica Sinica

基　　金：蔡火石生命科学基金;国家自然科学基金部分资助

摘　　要：报道采自黑龙江省漠河地区北极村水螅１新种，即漠河水螅Ｈｙｄｒａ ｍｏｈｅｎｓｉｓ ｓｐ．ｎｏｖ．，模式标本保存于哈尔滨师范大学生物学系无脊椎动物教学研究室。Hydramohensissp .nov . (Figs.1 9) Bodysmallsize ,oftenwithacolumnlengthof8mm .Nodifferentiationofbodyandstalk . Tentaclesusuallysixinnumber ,alwaysshorterthanthecolumn . Thestenotelespear formedand (1 2 6 1 6 9) μm× (1 0 5 1 5 5) μminsize .Theholotrichous isorhizasbroadlyovaland (8 8 1 1 1 ) μm× (6 5 8 4) μminsize ;theirpointedendshowingdis tinctbeak likeprojection ;thenematocystthreadusuallyarrangedin 4.5transversecoils.Theatrichousisorhizas (6.4 7 9) μm× (4 0 4 5) μminsizeandellipsoidsharp ,withanirregularlycoiledthread .Thedesmonemescomma shaped ,withasizeof (7 3 7 8) μm× (5 3 5 5) μm;its threadtheshortestoneamongthefournematocysts,showingacrossspiralshape .Thisspeciesishermaphroditic .Sexualreproductiontakesplaceunder 1 2℃ ,buttheagedin dividualscanalsoundergosexualreproductionatthetemperatureashighas 2 0℃ .Thetestesareroughlybluntcone shapedandusuallyoccuras 3to 5justunderthetentacles.Frequentlytwoeggsdevelopsimultaneouslyintheprovisionalovariesbehindthetestes.Maturedeggsrupturetheovarywallandadheretothecolumnforashorttime .whentheyfertilizedandcleftforseveral timestheembryoisdepositedbytheparent.Itbecomesattachedtothesubstratumandgeneratestheembryonicthecawhichiscomposedofshallowcup shapedspines.ThenewspeciesissimilartoHydrahymanaeHadley&Forrest,1 949.But,thedifferencesbe tweenbothspeciesabouttheformcharacteristcsofthenematocystsandembryonicthecaareex tremelyevident:(1 )Holotrichousisorhiza :thenematocystthreadisusuallyarrangedinfourtransversecoilsinH .Hymanae,anditisinfourpointfivetransversecoilsinthenewspecies.(2 )Desmoneme:thedesmonemeandholotrichousisorhizaofH .hymanaearenearlyequalinsize,theyarepredominantly1 0 5μminlength ,andinthenewspeciesthedesmonemeismuchsmaller thantheformer’s,theyarepredominaltly7 5μminlegth .Moreover,themajorityofthethreadinthedesmonemesofthenewspeciesarecrossspiral shaped ,whileitspiralsintoaringinthefor merspecies.(3 )Embryonictheca :thesurfaceoftheouterlayerofthethecaissetwithsmallsharp pointedspinesinH .hymanae,anditiscomposedofshallo

关 键 词：水螅虫纲 螅形目 水螅属 新种 

分 类 号：Q959.131.1[生物学—动物学]