Study On Classification Of Free-living Nematodes From The Hainan Island

Sediment samples collected from intertidal zone to subtidal zone of Hainan Island in September of 2016 and March 2017 were studied.Taxanomy of free living nematodes are studied,1821 specimens are sorted out,146 species(or taxa),belonging to 58 genera,25 families,3 orders,1 class,are identified.Ten new species were identified and described,14 new record species are also described.Catalogues of the free living nematode of Hainan Island are also given.Thalassironus longicaudatus nov.sp.is similar to Thalassironus lynnae Keppner,1987 in having long tail and segmented midventral precloacal seta.The new species can be differentiated from T.lynnae in having longer tail(780 vs 300-506 ?m);longer spicules(68 vs 35–40 ?m);shorter cephalic setae(8 vs 14-16 ?m)and smaller value of de Man ratio a(66 vs 99.7-102).Minolaimus multisupplementus sp.nov.differs from similar species,Minolaimus lineatus Vitiello,1970 by larger body size(3305 ?m vs 1752-1833 ?m)and much more numbers of precloacal supplements(29 vs 20).Diplopeltoides brevicaudatus sp.nov.differs from the most closely related species D.linkei and the other 19 species of the genus by its very short cephalic setae and tail,lack of amphids sclerotized plate,longer spicules(41vs29?m)and small gubernaculum apophyses.Cervonema longispicula sp.nov.is easily difference from other 18 recorded species of this genus by having the stout cephalic setae;long spicules with hooked proximal end;small gubernaculum with hooked dorsal apophysis.Desmoscolex longispiculatus sp.nov.is small,with only 17 oval desmens and differs from other 123 known species in having unique long spicules,longer than 2.5 abd.The spicules of other species not longer than 2 abd.Desmodorella zhangi sp.nov.differs from other thirteen species recorded in genus Desmodorella by multispiral amphideal fovea with 4 turns;filiform spicules 98 ?m i.e.3.5abd long,with funnel-shaped proximal end,curved and pointed distal end;slenderrod-shaped gubernaculum slightly curved without apophyses,17 ?m long,tail conico-cylindrical with a long non-annulated posterior end(29 ?m long).Rhinema longispicula sp.nov.differs from the other two recorded species of this genus in having shorter cephalic setae and much longer spicules.Daptonema contortspicula sp.nov.differs from the smillar species Daptonema paraoxyuroides Tu,Gagarin & Thanh,2014 by absence of gubernaculum,cervical setae and tail terminal setae.In having short body length and waved spicules,the new species is similar to Daptonema microspiculum Gerlach,1953,but differs from the latter by having very shorter cephalic setae(0.18 hd vs 1 hd)and much anterior position of amphidial fovea(0.6 hd vs 2.5 hd from anterior end).Parasphaerolaimus minor sp.nov.is closely related to Parasphaerolaimus pilosus Julia et al,2007 in having lateral alae and long cervical setae.The new species is distinguished from P.pilosus by a smaller body size(906 vs 1380–1800 ?m)and shorter spicules(25 vs 54–56 ?m).Paramonohystera hainanensis sp.nov.differs from other three recorded species of this genus by having shorter cervical setae,longer spicules with cuticularized cephalate proximal end,foot-shaped gubernaculum with a proximal caudal apophysis and presence of three papilliform precloacal supplements.Fourteen new record species of China Sea were discorved and described.There are Filoncholaimus ditlevceni Kreis,1934;Diplopeltoides bulbosus(Vitiello,1972)Holovachov & Bostr?m,2017;Cheironchus paravorax Castillo-Fernandez & Decraemer,1993;Synonchiella minuta Vitiello,1970;Didelta scutata Wieser,1956;Halalaimus luticolus Timm,1961;Halalaimus lineatoides Timm,1961;Sabatieria conicauda Vitiello,1970;Sabatieria migrans Jensen & Gerlach 1977;Catanema macintyrei Platt & Zhang,1982;Draconema cephalatum Cobb,1913;Dorylaimopsis brevispiculata Gagarin,2013;Paralinhomoeus buculentus(Wieser,1956)Gerlach,1963;Elzalia kimae Castillo-Fernandez and Lambshead,1990.