Redescription of Cruzia americana Maplestone, 1930 (Nematoda: Kathlaniidae) a parasite of Didelphis virginiana (Kerr) (Mammalia: Didelphidae) in the USA.

Cruzia americana Maplestone, 1930 is a common nematode parasite of opossums in North America. However, our present knowledge on the morphology of this species is still limited and its validity is uncertain. In the present study, specimens of C. americana collected from the type-host Didelphis virginiana (Kerr) (Mammalia: Didelphidae) in the USA were studied using light microscopy and, for the first time, scanning electron microscopy (SEM). The SEM observations revealed the internal structures of the pharynx of C. americana and the presence of pharyngeal lamellae rather than pharyngeal teeth/tooth-like structures. In addition, the detailed morphology of the lips, vulva, eggs and phasmids in females and the caudal papillae in males are also reported for the first time.