We examined the phylogenetic relationships among the major lineages of otophysan fishes (Cypriniformes, Characiformes, Siluroidei, and Gymnotoidei) using a combined analysis of molecular and morphological characters. The molecular characters comprised 160 phylogenetically informative sites from nuclear-encoded ribosomal RNA and 208 phylogenetically informative sites from the mitochondrial genes...

Spermatic characteristics were studied in 10 species representing several distinct groups within the catfish family Doradidae. Interestingly, different types of spermatogenesis, spermiogenesis and spermatozoa are correlated with intrafamilial groups previously proposed for Doradidae. Semi-cystic spermatogenesis, modified Type III spermiogenesis, and biflagellate sperm appear to be unique within...

Vari, Richard P., and Hernan Ortega. The Catfishes of the Neotropical Family Helogenidae (Ostariophysi: Siluroidei). Smithsonian Contributions to Zoology, number 442, 20 pages, 9 figures, 3 tables, 1986.—The Neotropical catfish family Helogenidae is revised. Contrary to recent practice, a single genus Helogenes Giinther is recognized, with Leyvaichthys Dahl treated as a synonym. Four species ar...