Trischistoma Cobb, 1913

Zhao, Zeng Qi, 2011, A review of the genus Trischistoma Cobb, 1913 (Nematoda: Enoplida), with descriptions of four new species from New Zealand, Zootaxa 3045, pp. 1-25 : 3-4

Genus Trischistoma Cobb, 1913

Description (after Andrássy 2007)

Body length 0.6–2.2 mm. Very slender, often dorsally bent in posterior part. Cuticle smooth, thin, and not annulated. Six longer outer labial setae and four shorter, thinner cephalic setae well separated in two circles. Oesophagus cylindrical, strongly mucular. Stoma denticles minute. Female prodelphic, ovary reflexed, with or without post-vulval uterine sac; vulva posterior (73–83%). Tail bent dorsally, 3–7 times as long as anal body diameter, mostly more or less S-shaped. Spermatozoa fusiform, unusually large, 2.5–5.5 times as long as corresponding body diameter. Supplements none or few (1–3), restricted to pre-cloacal region.

Type species

Trischistoma pellucidum Cobb, 1913

Diagnosis and Relationships

This genus is characterized by having widely separated circles of outer labial and cephalic setae, a prodelphic female genital tract, vulva located far posterior, very large spermatozoa, spicules not completely surrounded by muscle layer, and with few or no supplements ( Andrássy 2006).

Etymology

Trischistoma is composed of the Greek words treis (τρεϊς) = three, kiste (κίστη) = a box or compartment, and stoma (σόμα) = the mouth.