Redescription of the nematode parasites of lizards: Strongyluris oscari Travassos, 1923 (Heterakidae) from Brazil and Pharyngodon mamillatus (Linstow, 1897) (Pharyngodonidae) from Egypt.

Abstract

Strongyluris oscari Travassos, 1923, parasite of Topidurus torquatus (Wied-Neuwied, 1820) (Tropiduridae) from Brazil and Pharyngodon mamillatus (Linstow, 1897) of Chalcides ocellatus (Forskal, 1775) (Scincidae) from Egypt, were redescribed based on light and scanning electron microscopy, and re-evaluation of specimens from parasitological collections. The following features were accurately observed in S. oscari for the first time: structure of lips and pharyngeal valve, presence and distribution of somatic papillae, number and arrangement of caudal papillae, presence of inner sclerotised structures supporting the ventral sucker and the ventral region in tail of males, and structure of the posterior anal lip in females. The unpaired papilla on the inferior edge of the ventral sucker in males of S. oscari is a cuticular groove instead of a true papilla. Regarding the morphology of P. mamillatus the following features were given in details for the first time: structure of the cephalic end in both male and female, location of amphids, position of phasmids in females and the accurate morphology of caudal bursa in males, including the distribution of caudal papillae and the genital cone morphology. Strongyluris oscari and P. mamillatus have no intraspecific morphological variations, but wide range on biometric features. These variations may be accounted by host/environment attributes, since they exhibit wide host and geographical spectra. The present results increased the morphological knowledge of P. mamillatus and S. oscari, strengthening their taxonomic validity.