Redescription of Syphacia mesocriceti (Nematoda: Oxyuroidea) Parasite of the Golden Hamster

Abstract

The oxyuroid Syphacia mesocriceti Quentin, 1971, from the golden hamster, Mesocricetus auratus (Waterhouse, 1839), is described with the aid of light and scanning electron microscopy. Cephalic extremities of males and females differ from those of all other species of the genus Syphacia. Males and females have reduced lips and a triangular stoma but differ from species of the subgenus Syphatineria with similar features by having a flanged esophageal cuticle with serrated edges. The operculate eggs are large. Three mamelons on the previously undescribed males put this species in the subgenus Syphacia. Syphacia mesocriceti Quentin, 1971, originally was described from females collected in Alaska from laboratory-reared golden hamsters, Mesocricetus auratus (Waterhouse, 1839). Discovery of additional specimens including males in the same host made possible a complete description of this species. Additional information obtained with scanning electron microscopy (SEM) on cephalic structures and cuticles of both males and females permits comparison of this species with others in the genus reviewed by Ogden (1971). MATERIALS AND METHODS Nematodes, recovered from the cecum of hamsters reared in a commercial animal breeding establishment at Ontario, Canada, were fixed in hot 70% alcohol with 5% glycerin. Whole mounts were made by clearing and mounting in glycerin and sealing the cover slip with Glyceel (ESBE Laboratory Supplies, 3431 Bathurst St., Toronto 19, Ontario). The anterior end was removed and mounted en face in glycerin jelly. Nematodes were prepared for SEM by freeze-drying according to the method of Dick and Wright (1973) and viewed with a Cambridge Stereoscan electron microscope. The following description is based on 6 female and 3 male metatypes. Drawings were made with the aid of a camera lucida. All measurements are in microns unless otherwise stated. Syphacia mesocriceti Quentin, 1971