What is "xenophidia"

Xenophidia (Caenophidia) is a superfamily of the suborder Serpentes ( snakes) that contains the majority of snake species, with the main exceptions being the boidae and pythonidae. Almost all venomous snakes belong to this superfamily. Additionally, the broad belly scales and rows of dorsal scales correspond to the vertebrae in Caenophidians, while they do not in Henophidians or Scolecophidians.

Caenophidia contains most of the diversity of extant snakes, with over 3,000 species. They are believed to be a recent (Greek prefix caeno- = recent) evolutionary radiation, having evolved in the mid-Cenozoic.