ANATOMY AND PHYLOGENETIC ANALYSIS OF THE NEOTROPICAL CALLICHTHYID CATFISHES (OSTARIOPHYSI, SILURIFORMES)

Based mainly on morphological characters, the phylogenetic relationshi ps among genera and some species groups of the neotropical family Call ichthyidae were examined. A study of the osteology of a generalized ca llichthyid, Callichthys callichthys (Linnaeus), with detailed comparis ons among representatives of the remaining genera in the family, is pr esented and used as a basis for the phylogenetic analysis. A single mo st parsimonious tree supported the monophyly of the family Callichthyi dae based on 28 derived features and the division of the family in the subfamilies Corydoradinae and Callichthyinae. In the subfamily Corydo radinae, the genus Aspidoras is the sister-group of the clade formed b y Corydorac plus Brochis. Five derived features support the monophyly of this clade and four support the monophyly of Brochis. No characters , however, were found to support the genus Corydoras. In the subfamily Callichthyinae, Dianema and Haplosternum are sister-taxa. Megalechis represents the sister-group of Dianema plus Hoplosternum and Lepthoplo sternum represents the sister-group to Megalechis plus Dianema plus Ho plosternum. Finally, Callichthys is considered the least derived membe r of the subfamily, and is hypothesized as the sister-group of the rem aining species. A key to all callichthyid genera is provided. (C) 1998 The Linnean Society of London.