Alethinophidia

The Alethinophidia are an infraorder of snakes that includes all snakes other than blind snakes and thread snakes. Snakes have long been grouped into families within Alethinophidia based on their morphology, especially that of their teeth. More modern phylogenetic hypotheses using genetic data support the recognition of 19 extant families (see below), although the taxonomy of alethinophidian snakes has long been debated, and ultimately the decision whether to assign a particular clade to a particular Linnaean rank (such as a superfamily, family, or subfamily) is arbitrary. The infraorder name Alethinophidia derives from the two Ancient Greek words ἀληθινός (alēthinós), meaning 'truthful, genuine', and ὄφις (óphis), meaning 'snake'.