New and known species of Tylencholaimus De Man, 1876 (Dorylaimida, Nematoda) from Italian beech forest with a key to the species

Abstract

A survey of nematodes of Italian beech forests provided six species of Tylencholaimus, two of which, T. minutus sp. n. and T. constrictus sp. n., are new and are described and illustrated. T. minutus is characterized by its small size, prominent lips with inner disc-like cap, gonad prodelphic, absence of postvulval sac, conoid, bluntly pointed tail. T. constrictus is characterized by its large size, gonad prodelphic with short postvulval sac, lips with a disc-like inner portion markedly set off by a deep constriction, elongate hemispheroid tail. Males of the species were not found. Of the other four species (T. mirabilis, T. proximus, T. stecki and T. teres) some morphological and ecological characteristics are given. The species T. alpinus Vinciguerra, 1982 is considered to be a synonym of T. stecki Steiner, 1914. A key to the species of Tylencholaimus is provided.