New host and Distribution Records of Cosmocephalus obvelatus (Creplin, 1825)(Nematoda: Acuariidae)with Morphometric Comparisons

Abstract

This is the first record of Cosmocephalus obvelatus (Creplin, 1825) Seurat, 1919 (Nematoda: Acuariidae), from Argentina (Valdés Peninsula, province of Chubut) and from the Magellanic penguin Spheniscus magellanicus (Aves: Spheniscidae). The prevalence of this parasite was 31.3% and the mean intensity was 5.4. Despite the wide geographic distribution and the great variety of hosts parasitized by C. obvelatus (14 families belonging to 8 orders), there were no significant differences in morphological characteristics and measurements from previous records. Both the wide distribution and the morphometrical stability of C. obvelatus may be explained by its ecology and mode of transmission.