Molecular systematics of pitvipers: paraphyly of the Bothrops complex

Phylogenetic relationships among pitvipers are inferred from a parsimony analysis using cytochrome b DNA sequences: 396 bp in the 5'end of the gene were sequenced in eight species of pitvipers (Agkistrodon blomhoffi, Agkistrodon contortrix, Bodiriechis schlegelii, Bothriopsis bilineata, Bothrops atrox, Crotalus atrox, Lachesis muta and Trimeresurus stejnegeri) and in four taxa used as outgroups (Atractaspis micropholis, Boa constrictor, Cerastes cerastes and Elapsoidea semiannulata). The monophyly of pitvipers and that of the group formed by the genera Atractaspis and Elapsoidea are confirmed. Among pitvipers, the genus Agkistrodon is paraphyletic. The Bothrops complex is polyphyletic, since the Central American genus Bothriechis is the sister group of the genus Crotalus and not clustered with the South American genera Bothriopsis and Bothrops.