December 4, 2009
In contrast to the exhaustive research into venom produced by snakes and spiders, venomous fish have been neglected and remain something of a mystery. Now, a study of 158 catfish species, published in the open access journal BMC Evolutionary Biology, has catalogued the presence of venom glands and investigated their biological effects.
Jeremy Wright, from the University of Michigan, USA, carried out the investigation. He said, "I used histological and toxicological techniques to elucidate the diversity and distribution of venomous catfish. I found that at least 1250, and possibly over 1600 species of catfish may be venomous, a number far greater than any previous estimate of venomous catfish diversity"
Wright's analyses indicate that there are at least two independent evolutionary origins of catfish venom glands. In addition, the toxic peptides show strong similarities with, and might be derived from, previously characterized toxins found in catfish epidermal secretions. "Further examination of the chemical composition of the venoms will provide valuable insight into the mechanisms and potential selective factors driving venom evolution in fishes", comments Wright.
Diversity, phylogenetic distribution, and origins of venomous catfishes. Jeremy J Wright. BMC Evolutionary Biology (in press)
Image Courtesy J Wright, BMC Evolutionary Biology
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