Further description of Cruzia tentaculata (Rudolphi, 1819) Travassos, 1917 (Nematoda: Cruzidae) by light and scanning electron microscopy.

Species of Cruzia are parasites of the large intestine of marsupials, reptiles, amphibians, and mammalians. Cruzia tentaculata specimens were collected from the large intestine of Didelphis marsupialis (Mammalia: Didelphidae) from Colombia (new geographical record) and from Brazil and analyzed by light and scanning electron microscopy. The morphology of males and females by light microscopy corroborated most of the previous description and the ultrastructure by scanning electron microscopy evidence: the topography of the cuticle, deirids, amphids, phasmids in both sexes, a pair of papillae near the vulva opening, and the number and location of male caudal papillae, adding new features for species identification only observed by this technique.

Structure of the community of the Strongylidae nematodes in the dorsal colon of Equus caballus from Rio de Janeiro state--Brazil.

The structure of the community of Strongylidae nematodes in the dorsal colon of naturally infected horses from the metropolitan region of Rio de Janeiro State was evaluated in 33 samples. Twenty-three species were found: Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicocyclus nassatus and Cyathostomum tetracanthum were the central ones; Cylicostephanus minutus, Cylicostephanus calicatus, Cylicocyclus leptostomus, Cylicodontophorus bicoronatus and Parapoteriostomum euproctus were secondary, and there were 14 satellite species. The community was considered stable, with positive associations and correlations, no significant negative associations and correlations, suggesting little competition among species.