Integrative Identification And Description Of Four Species In The Genus Paratylenchus(Nematoda:Paratylenchidae)

The genus Paratylenchus Micoletzky,1922 is an important group of obligate ectoparasites with typical looped esophagus.Pin nematode species are widely distributed all over the world and known to be associated with a variety of plants that reported as shrubs,grasses,fruit and flowering trees.Some species were reported as plant pathogens.In this study,four species of Paratylenchus were found in 332 soil samples from Henan province and Zhejiang province,China.Integrative taxonomical approaches including molecular and ultra-structure observations were used to describe the species.The main results obtained in this study are as follows:1.Description of Paratylenchus sinensis n.sp.from Haining,Zhejiang,China.A pin nematode population in the rhizosphere of mulberry,Morus alba,from Haining,Zhejiang,China was described as Paratylenchus sinensis n.sp.based on morphological and rDNA characters.The new species characterized by having swollen and slender females,four incisures in the lateral field,advulval flap present and lip region conoid with anterior end flattened,submedian lobes absent.The slender females have stylet 56.2(50-62)μm long;tail conoid gradually tapering to a finely pointed terminus.The swollen females comparatively larger,vulval lips enlarged,protruding and bulges out from the body contour,and with shorter tail.The male devoid of stylet,spicules 17.5(17.0-18.0)μm long.Phylogeny analysis based on rDNA sequences showed that Paratylenchus sinensis located at different clades with other species with stylet more than 40 μm,which can be easily differentiated based on morphology,and supporting its status as a new species.2.Description of Paratylenchus n.sp.from Zhengzhou,Henan,China.A pin nematode population in the rhizosphere of Aesculus chinensis from Zhengzhou,Henan,China,was described as a new species in Paratylenchus.The new species characterized by having both swollen and slender females,lateral field with four incisures,submedian lobes absent.Cephalic region narrow,rounded,not offset from body.Cephalic sclerotization weak.Stylet short with pyriform basal bulb,excretory pore position slightly anterior to or at midway of basal pharyngeal bulb,advulval flap present,post uterine sac absent,anus indistinct,tail slender,relatively curved,gradually tapers to form a finely rounded to subacute terminus.Phylogeny analysis based on different rDNA sequences revealed that Paratylenchus n.sp.from Zhengzhou,grouped with species of Group 3 possessing advulval flap,4 lateral lines and stylet shorter than 40 μm.3.Updated description of Paratylenchus lepidus and a new record species,P.minor,from China.Two pin nematode populations were found in rhizosphere of Elaeocarpus sylvestris and Pinus tabuliformis in Taizhou and Hangzhou,Zhejiang,China,were identified as Paratylenchus lepidus and P.minor based on morphological and rDNA characters,respectively,in which P.minor was a now record species in China.The present studies provided the main morphological features under SEM and rDNA information of the two species.It was found that advulval flap of P.minor is not distinct under light microscope,but tiny advulval flap can be observed under SEM.The description about advulval flap of P.minor was corrected,and the species was moved to Group 3 from Group 4.Phylogeny analysis based on rDNA revealed that P.lepidus and P.minor are in two well-separated clades and grouped with those species having shorter stylets and advuval flap.