Planocraniidae

Planocraniidae is an extinct family of eusuchian crocodyliforms known from the Paleogene of Asia, Europe and North America. The family was coined by Li in 1976, and contains three genera, Boverisuchus, Duerosuchus and Planocrania. Planocraniids were highly specialized crocodyliforms that were adapted to living on land. They had extensive body armor, long legs, and blunt claws resembling hooves, and are sometimes informally called "hoofed crocodiles". Prior to 2013, the term Pristichampsidae/Pristichampsinae was used for this group. However, the type specimen of Pristichampsus was found to be undiagnostic, and considered to be a nomen dubium. As such, Brochu (2013) transferred the other species placed in Pristichampsus to Boverisuchus, and resurrected Planocraniidae to replace Pristichampsidae/Pristichampsinae as the name for the clade. Brochu cladistically defined Planocraniidae as Planocrania hengdongensis and crocodyliforms more closely related to it than to Alligator mississippiensis (American alligator), Crocodylus niloticus (Nile crocodile), Gavialis gangeticus (gharial), Thoracosaurus macrorhynchus, Allodaposuchus precedens, or Hylaeochampsa vectiana. Phylogenetic analyses based purely on morphological data have generally placed planocraniids in a basal position within the crocodilian crown group. Some of these analyses have found that planocraniids lie just outside Brevirostres, a group that includes alligators, caimans, and crocodiles but not gharials. However, molecular studies using DNA sequencing have found the group Brevirostres to be invalid upon finding that crocodiles and gavialids are more closely related than alligators. A 2018 tip dating study by Lee & Yates using both molecular, morphological and stratigraphic data instead recovered the planocraniids outside crown group Crocodylia. Below is a cladogram from that study: In 2021, Rio & Mannion conducted a new phylogenetic study using a heavily modified morphological data set, and also noted the lack of consensus and difficulty in placing Planocraniidae.