Guyanema longispiculum sp. n. (Nematoda:Dracunculoidea) from Loricariichthys brunneus (Pisces) in Venezuela.

A new nematode species, Guyanema longispiculum sp. n. is described from the abdominal cavity of the freshwater armoured catfish, Loricariichthys brunneus (Hancock), from two localities in western Venezuela. It differs from all hitherto known members of the genus in having unusually long spicules (0.480-0.609 mm) and from individual species also by other morphological and biometrical features. It is characterized by the presence of eight cephalic papillae arranged in two circlets, localization of deirids anterior to the nerve ring, a conical, undivided tip of the tail in both sexes, four pairs of preanal and six pairs of postanal papillae in the male, and a markedly elevated vulva in the female. A key to species of Guyanema is presented.