Morphological and molecular characterisation of new and known species of Tripyla Bastian, 1865 (Triplonchida: Tripylidae) from northern Iran, with phylogenetic relationships, compendium and identification key.

During a nematological survey of the family Tripylidae, two new and two known species of the genus Tripyla, namely T. paraffinis sp. n., T. parafilicaudata sp. n., T. glomerans and T. setifera, were identified and described from soil samples collected from the rhizosphere of forest trees in northern Iran. Three populations of T. paraffinis sp. n., found in different locations, are described and morphometric data of the type and other populations provided. Tripyla paraffinis sp. n. is characterised by its body length of 1.21-1.89 mm, dorsal tooth wedge-shaped and triangular, short outer labial and cephalic sensilla, tail bent ventrad and gradually tapering to the end, horn-shaped spicules bearing a distinct constriction in the middle, and presence of 16-20 ventromedian supplementary papillae. Tripyla parafilicaudata sp. n. is described and illustrated from four different locations. It is characterised by females with a body length of 1.48-1.95 mm, dorsal tooth hook-shaped, vaginal wall with a downward pointing tooth-like projection in the middle, long outer labial and setiform cephalic sensilla, long tail, sausage-shaped spermatozoa, males with horn-shaped spicules and 11-17 ventromedian supplementary papillae. Tripyla glomerans and T. setifera are new records for the Iranian nematofauna. The results of phylogenetic analyses based on sequences of the partial 18S and D2-D3 expansion segments of 28S rRNA from T. paraffinis sp. n. and T. parafilicaudata sp. n. and other species in the genus clearly support the proposal of T. paraffinis sp. n. and T. parafilicaudata sp. n. as new species, as well as indicating that Tripyla shares a more recent common ancestor with Tobrilus, Tripylella, Prismatolaimus, Diphtherophora and two trichodorids, Trichodorus and Paratrichodorus. The Tripylidae is placed in a main clade within the Triplonchida. [ABSTRACT FROM AUTHOR]