DOS NUEVOS NEMATODOS PARASITOS DE ANUROS DEL SUR DE PUEBLA

Resumen

A new diagnosis is given in this paper of the genera Oxysomatium Railliet & Henry, 1913 and Aplectana Railliet & Henry 1916; and two new species of Nematoda from the large intestinE of Scaphiopus multiplicatus Cone (Amphibia). Are described under the names of Aplectana itzocanensis and A. hoffmanni.
Both species have three lips not easily observad, in the anterior or cephalic extremity, with a small chitinous hook-shaped piece on the inner border of each lip; small pharynx; oesophagus separated from the bulb by a constriction; three chitinous valves inside the bulb; nervous ring in the middle region of the oesophagus: pre-bulbar excretory pore; caudal extremity ending acutely and in somewhat curved towards the ventral side. In the females, the vulva is in the posterior part of the body and in this region several papillae may be seen in the cuticle; the ovopositor is anterior and S shaped; the uterus shows eggs in advanced development. In the males the gubernaculum is rather thick and the spicules have at their tip a hyaline membrana like a hood.

The differences between the two species are the following: oesophagus shorter in Aplectana hoffmanni; diferent number of pre-anal papillae in the males, A. itzocanensis has 5 sub-ventral pairs and from 9 to 12 lateral; the spicules in A. itzocanensis are subequal and equal in A. hoffmanni. In the latter species the sexual dimorphism is more noticeable than in A. itzocanensis.