Theristus Bastian, 1865

Revkova, Tatiana N., 2020, Two species of the genus Theristus Bastian, 1865 (Nematoda: Xyalidae) from the hypersaline water bodies of the Crimea (Azov-Black Sea basin), Zootaxa 4881 (2), pp. 372-382 : 373

Genus Theristus Bastian, 1865

Type species: Theristus acer Bastian, 1865

Diagnosis ( Fonseca & Bezerra 2014): Xyalidae . Cuticle striated. Somatic setae usually present. Anterior sensilla in two crowns; inner labial papilliform or setiform and outer labial and cephalic setae setiform. Additional subcephalic setae might be present in the lateral fields together with the outerlabial setae. Ocelli occasionally present. Buccal cavity conical. One or two testes. Spicules usually curved, sometimes very long but primarily as long as the anal body diameter. Gubernaculum slipper-shaped, with or without dorsal apophysis. Tail conical, ventrally curved and without terminal setae.

Number of species: 96 ( Bezerra et al. 2020).