title: A new species of Hysterothylacium (Nematoda: Anisakidae) parasite of Ariopsis guatemalensis (Osteichthyes: Ariidae) from Tres Palos lagoon, Mexico.
abstract: Hysterothylacium perezi n. sp. is described from the intestine of the "cuatete" Ariopsis guatemalensis Günther, 1864 (Osteichthyes: Ariidae), in Tres Palos, a coastal lagoon located in the Mexican Pacific basin. The new species differs from all other species of Hysterothylacium Ward and Magath, 1917, in possessing a spinous postcloacal pad. In addition, H. perezi is readily distinguished from the 21 species described in fishes from America and Hawaii by having the greatest number of caudal papillae (47 to 51 pairs + 1 single, precloacal papillae). This species is the third described from hosts inhabiting estuarine environments in America and the fourth reported in Mexico.
authors.affiliation: Laboratorio de Helmintología, Instituto de Biología, Universidad Nacional Autónoma de México, A.P. 70-153, C.P 04510, México DF.
authors.forename: Luis
authors.initials: L
authors.lastname: Gopar-Merino
authors.forename: David
authors.initials: D
authors.lastname: Osorio-Sarabia
authors.forename: Luis
authors.initials: L
authors.lastname: García-Prieto
mesh_terms: D000818:Animals; D017191:Ascaridida Infections / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D001199:Ascaridoidea / Q000033:anatomy & histology / Q000145:classification* / Q000302:isolation & purification / Q000648:ultrastructure; D002397:Catfishes / Q000469:parasitology*; D005260:Female; D005393:Fish Diseases / Q000453:epidemiology / Q000469:parasitology*; D008297:Male; D008800:Mexico / Q000453:epidemiology; D015995:Prevalence; D012623:Seawater