Ascarophis mexicana n. sp. (Nematoda: Cystidicolidae) from two species of Epinephelus (Pisces) from the Gulf of Mexico in southeastern Mexico.

A new cystidicolid nematode, Ascarophis mexicana n. sp., is described from the stomach of 2 species of the genus Epinephelus, E. morio and E. adscensionis (Pisces: Serranidae), from the Gulf of Mexico, southeastern Mexico (states of Yucatan and Veracruz). It is distinguished mainly by small body measurements (body length of male and female 3.39-4.18 mm and 5.94-6.23 mm, respectively), a conspicuously long left spicule (1.58-2.05 mm), length ratio of spicules (1:10-12), and by eggs provided with 2 filaments on 1 pole. Ascarophis mexicana is the second Ascarophis species known to parasitize fishes of the genus Epinephelus (groupers).