Selachinematidae Cobb, 1915

Leduc, Daniel, 2013, Two new genera and five new species of Selachinematidae (Nematoda, Chromadorida) from the continental slope of New Zealand, European Journal of Taxonomy 63, pp. 1-32 : 3

Family Selachinematidae Cobb, 1915

Diagnosis

(Modified from Decraemer & Smol 2006.) Body usually stout. Cuticle punctated with or without lateral differentiation. Head sensillae may be jointed. Amphideal fovea usually multispiral, rarely loopshaped. Buccal cavity spacious, divided into two compartments, either reinforced by cuticularised rhabdions in both portions ( Choniolaiminae ), or with posterior rhabdions modified into protrusible mandibles ( Selachinematinae ). Pharynx with or without posterior bulb, anterior bulb sometimes present ( Cheironchus and Pseudocheironchus gen. nov.). Males usually with two outstretched testes, either on same or different sides of the intestine; pre-cloacal supplements usually present, usually cup-shaped, sometimes setose, papilliform, rarely tubular. Female didelphic-amphidelphic with reflexed ovaries.

Remarks

The holophyly of the family Selachinematidae is based on the holapomorphy of a spacious buccal cavity without teeth or, if teeth are present, they are not homologous with teeth found in other Chromadorida ( Lorenzen 1981) .The family placement of Richtersia Steiner, 1916 and Desmotersia Neira & Decraemer, 2009 remains uncertain and these genera are considered by some as intermediate between the Selachinematidae and Desmodoroidea (e.g., Pastor de Ward & Lo Russo 2007; Neira & Decraemer 2009). The genus Dignathonema Filipjev, 1918 was synonymised with Cheironchus Cobb, 1917 by Filipjev (1926). Trogolaimus Cobb, 1920 was classified in the subfamily Selachinematinae by Gerlach (1964), but, as Tchesunov & Okhlopkov (2006) noted, this genus should be assigned to the Choniolaiminae based on the structure of the buccal cavity. The latter authors considered Trogolaimus to be a synonym of Gammanema Cobb, 1920 . Nunema Cobb, 1933 and Pteronium Cobb, 1933 were considered doubtful by Hope & Murphy (1972).