Scientists from Brazil have completed a new molecular study of callichthyid catfishes in an effort to unravel the relationships and evolution of the family.
Roberto Reis of the Universidade Estadual Paulista, and Cristiane Kioko Shimabukuro, Fausto Foresti and Claudio Oliveira of the Pontificia Catolica do Rio Grande do Sul, examined molecular material from the mitochondrial genes of 28 different members of the family Callichthyidae.
The material examined included 12 different Corydoras, plus smaller numbers of Aspidoras, Brochis, Hoplosternum, Callichthys, Dianema, Megalechis and Lepthoplosternum, as well as various other nematogenyid, astroblepid, trichomycterid and loricariid catfishes as outgroup taxa.
Perhaps unsurprisingly in some people's eyes, the study found that the family is monophyletic and that it is made up of two distinct groups - the Corydoradinae subfamily and the Callichthyinae subfamily. This backs up previous morphological studies on the family and shows us that previous attempts at phylogenetic reconstruction have been pretty good.
However, the authors state that intrafamilial relationships in the callichthyidae subfamilies do differ from those that have been previously published through studies looking purely at morphological characters.
For more details see: Kioko Shimabukuro, C; Foresti, F; Oliviera, C and Reis, R. (2004) - Molecular phylogeny of the armored catfish family Callichthyidae (Ostariophysi, Siluriformes). Molecular Phylogenetics and Evolution, Volume 32, Issue 1 , July 2004, Pages 152-163.