Ceratoasterformes

Ceratoasterformes are an order of Lagnodactyls defined by their ancestral "jaw spikes" or "lateral mandibles", keratinous "teeth", and strong bilateral symmetry. All species in this order have an endoskeleton of various extent and complexity, which includes a "pelvic ring" which is used for muscle attachment in their arms and sometimes mouthparts, and 4 gills derived from their ancestral chemoreceptive patches. Like all Lagnodactyls, they have a radially symmetric life stage and they "hold hands" with their anal arms in order to mate.

All extant Ceratoasterformes have fins derived from their anal fingers. To avoid complications when mating, the membrane stretching between the fingers in many species can be pulled back to free the fingers for hand-holding.

Family Ceratoasteridae
Jawless Ceratoasterformes, which have circular inverting mouths similar to those ancestral to Lagnodactyls but featuring keratinous "teeth".

Superfamily Astergnathoidea
Jawed Ceratoasterformes, which are distinguished by the presence of a proper circulatory system and vertebrae-like bones in their arms and fingers.

Family Astergnathidae
Aquatic, fish-like Astergnathoids.

Family Amphibiasteridae
Amphibious Astergnathoids which retain gills in adulthood.

Family Ranasteridae
Amphibious, two-eared Astergnathoids which have all of their organs in front of their limb girdle.

Family Cerritulabiidae
Terrestrial, four-eared Astergnathoids with long necks, flexible lips, and an arthropod-like abdomen behind their limb girdle.