JACKSON, K; Harvard University: Evolution of the venom-conducting fang in snakes

Three lineages of colubroid snakes, the elapids, the viperids, and the atractaspidids, possess tubular fangs as part of a system that injects venom into a prey item. All recent phylogenies indicate that these three lineages represent three independent derivations of the tubular fang. Nonetheless, the tubular fangs of these three lineages of snakes show remarkable similarity in their morphology and in their development. This similarity led early authors to the belief that tubular fangs had evolved only once and that all venomous snakes therefore formed a clade. How can the morphological similarity of the tubular fangs of these three lineages of venomous snakes be reconciled with recent evidence of independent origins of elapids, viperids, and atractaspidids?