Gavialoid

Classification

Gavialoidea is cladistically defined as Gavialis gangeticus (the gharial) and all crocodylians closer to it than to Alligator mississippiensis (the American alligator) or Crocodylus niloticus (the Nile crocodile). This is a stem-based definition for gavialoids, and is more inclusive than the crown groupGavialidae. As a crown group, Gavialidae only includes the last common ancestor of all extant (living) gavialids and their descendants (living or extinct), whereas Gavialoidea, as a total group, also includes more basal extinct gavialid ancestors that are more closely related to living gavialids than to crocodiles or alligators. When considering only living taxa (neontology), this makes Gavialoidea and Gavialidae synonymous, and only Gavialidae is used. Thus, Gavialoidea is only used in the context of paleontology.