Neoalloionema tricaudatum gen. n., sp. n. (Nematoda: Alloionematidae) associated with a cyclophorid snail in Cuc Phuong Natural Park, Vietnam

Abstract

A new nematode genus and species associated with terrestrial gastropods from Vietnam is described and illustrated. Partial SSU and ITS rDNA sequences were obtained and subjected to phylogenetic analysis. Both morphologically and molecularly, Neoalloionema tricaudatum gen. n., sp. n. is closest to Alloionema appendiculatum, another gastropod associate. It is differentiated from A. appendiculatum by the presence of an outstretched vs reflexed testis and the absence of denticles in the stoma, by the parasitic juveniles inhabiting the pallial cavity vs the foot of the host and having six vs two lips and large sucker-like phasmids vs pore-like. The most peculiar feature of N. tricaudatum gen. n., sp. n. is the presence of paired, solid appendages located at the mid-tail region of juveniles from the pallial cavity of the host. The nature of the association between N. tricaudatum gen. n., sp. n. and its gastropod host is discussed.