A review of the genus Aponema Jensen, 1978 (Nematoda: Microlaimidae) with description of three new species Author Kovalyev, Shota V. Author Miljutina, Maria A. text Zootaxa 2009 2077 56 68 journal article 10.5281/zenodo.187255 2ef5a369-3da8-4342-8d3d-b57d32249c1b 1175-5326 187255 Aponema Jensen 1978 Emended diagnosis. Microlaimidae . Males monorchic with single outstretched anterior testis. Females didelphic-amphidelphic with outstretched ovaries. Amphidial fovea monospiral, outline rounded. Somatic setae inserted directly on body cuticle, never on a process. Cuticle with transverse striae or optically smooth, without thorns. Pharyngeal bulb varying in shape: from spherical to pyriform. Gubernaculum with or without apophyses. Tail conical or elongated. Type species. A. torosum ( Lorenzen, 1973 ) Jensen, 1978 Remarks. The tendency to reduction of the posterior testis occurs among three other Microlaimidae genera. Among Microlaimus species the posterior testis in M. globiceps De Man , 1880 (see Turpeenniemi, 1997 ) and M. copulatus Jensen, 1988 is only half the size of the anterior testis. In the only species of genus Acanthomicrolaimus Stewart & Nicholas, 1987 —A. jenseni Stewart & Nicholas, 1987 —the posterior testis is also much shorter than the anterior one, and gubernacular apophyses are present as in several Aponema species ( Stewart & Nicholas, 1987 ). This genus differs from Aponema not only by the presence of a short posterior testis but also in the structure of the cuticle, which bears numerous thorns. Bathynox Bussau & Vopel, 1999 , like Aponema possesses only one anterior testis, but its amphids are located very far from the anterior tip of head and somatic setae are situated on short processes, unlike Aponema . In Microlaimus nanus Blome, 1982 , the posterior testis is absent, and this allows us to relate this species to Aponema Jensen, 1978 and to regard it as Aponema nanum ( Blome, 1982 ) comb.n. Nevertheless, Muthumbi & Vincx (1999) described two Aponema having well-developed anterior and posterior testes— A. decramerae Muthumbi & Vincx 1999 and A. mnazi Muthumbi & Vincx 1999 —without emending the diagnosis of the genus Aponema . We suppose that the main difference of Aponema from other Microlaimids is the lack of a posterior testis so it seems doubtful that A. decraemerae and A. mnazi should be considered as belonging to the genus Aponema and we propose to transfer these species to Microlaimus .