%0 Journal Article
%T Diversity, phylogenetic distribution, and origins of venomous catfishes
%A Jeremy J Wright
%J BMC Evolutionary Biology
%D 2009
%I BioMed Central
%R 10.1186/1471-2148-9-282
%X Histological examinations of 158 catfish species indicate that approximately 1250-1625+ catfish species should be presumed to be venomous, when viewed in conjunction with several hypotheses of siluriform phylogeny. Maximum parsimony character optimization analyses indicate two to three independent derivations of venom glands within the Siluriformes. A number of putative toxic peptides were identified in the venoms of catfish species from many of the families determined to contain venomous representatives. These peptides elicit a wide array of physiological effects in other fishes, though any one species examined produced no more than three distinct putative toxins in its venom. The molecular weights and effects produced by these putative toxic peptides show strong similarities to previously characterized toxins found in catfish epidermal secretions.Venom glands have evolved multiple times in catfishes (Order Siluriformes), and venomous catfishes may outnumber the combined diversity of all other venomous vertebrates. The toxic peptides found in catfish venoms may be derived from epidermal secretions that have been demonstrated to accelerate the healing of wounds, rather than defensive crinotoxins.The venoms produced by cnidarians, mollusks, snakes, arachnids, insects, and some mammals have been the subject of multiple studies of chemical structure [1-3], pharmacology [2-5], and toxicology [5-7], in addition to several evolutionary studies [8-12], but information regarding these aspects of fish venoms is relatively sparse [13-18]. Until recently, even reliable estimates of the number of venomous fish species have been unavailable. Morphological examinations, combined with phylogenetic analyses have suggested that 585-650 species of spiny-rayed fishes are venomous, a number which rivals the known diversity of venomous snakes and is significantly higher than previous estimates of about 200 venomous spiny-rayed fish species [18]. We still lack estimates, however, for cat
%U http://www.biomedcentral.com/1471-2148/9/282