ABSTRACT
The advanced snakes (Caenophidia) constitute the most diverse group of living snakes. They include the medically important venomous snakes and have therefore received considerable research attention. A large body of recent phylogenetic work has resulted in a consensus that caenophidians as a group are more phylogenetically complex than portrayed by previous family-level classications. The traditional family Colubridae is nonmonophyletic and composed of multiple deep clades that deserve taxonomic recognition at the family level. Moreover, all Caenophidia (and probably all snakes and many lizards) are descended from a single venomous ancestor, making the venom apparatus a homologous feature of all snakes. Molecular markers and further exploration in several continents are revealing considerable hitherto unsuspected diversity of venomous snakes, including the discovery of new species and the reassessment of existing species, which often turn out to be more heterogeneous than previously suspected. Here we review the most recent taxonomic changes and the new discoveries involving venomous snakes worldwide.
