Genus Tylocephalus

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Family: Plectidae

Genus: Tylocephalus

Genus Tylocephalus Crossman, 1933

Diagnosis: “Anterior end with bilateral and dorsoventral symmetry.  Subventral and subdorsal pairs of lips fused, forming mid-dorsal and mid-ventral median ridges, respectively.  Cervical expansions bulbiform, annulated under light microscope and SEM, each extends orally into one median ridge.  Ourter labial sensilla (subdorsal and subventral pairs) are located at inner end of the median ridge.  Four setiform or flat cornua.  Mid-lateral projections short oval.  Lateral rims not fimbriate.  Female reproductive system didelphic, amphidelphic, ovarian branches reflexed antidromously, usually located on alternate sides of intestine with anterior branch on right side.  Vagina short and straight, without epiptygmata.  Rectum short.  Spicules arcuate, manubrium usually with large lateral fenestra.  Gubernaculum absent.   Tail conoid, ventrally arcuate.  Caudal glands present.  Spinneret functional.  The most recent identification key is given in Holovachov et al. 2004.” Holovachov and DeLey, 2006.


Holovachov, O and P. DeLey.  2006.  Order Plectida.  In: Eyualem Abebe, Traunspurger W., and Andrassy I. (eds) Freshwater Nematodes: Ecology and Taxonomy. CABI Publishing, Cambridge, MA, pp. 611-647