Semitobrilus

Gagarin, Vladimir G. & Gusakov, Vladimir A., 2013, Neotripyla vulgaris gen. n., sp. n. and Semitobrilus andrassyi sp. n. (Nematoda, Triplonchida) from freshwater bodies of Vietnam, Zootaxa 3716 (4), pp. 565-576 : 575-576

Key to valid species of the genus Semitobrilus

1. 10 supplement; vulva postequatorial (V = 61–64 %)............................................. S. parapellucidus

– 6–8 supplements; vulva praequatorial or equatorial (V = 38–55 %).............................................. 2

2. Crystalloids absent; length of outer labial setae is equal 60 % of labial region width........................ S. pellucidus

– Crystalloids present; length of outer labial setae is equal 23–40 % of labial region width............................. 3

3. Spicules 102–122 µm long....................................................................... S. ebsaryi

– Spicules less 100 µm long............................................................................... 4

4. ♂♂ L = 1.60–1.72 mm; outer labial setae 4.0–6.0 µm long, 23–25 % of labial region width........... S. closlongicaudatus

– ♂♂ L = 1.96 mm or more; outer labial setae more 9 µm long, more 25 % of labial region width....................... 5

5. Spicules 65 µm long, keel-like projection at distal portion absent........................................ S. gagarini

– Spicules 71–80 µm long, keel-like projection at distal portion present.............................. S. andrassyi sp. n.