Ceratoasterformes
Ceratoasterformes are an order of Lagnodactyls defined by their keratinous "teeth" and strong bilateral symmetry. Some species in this order have an endoskeleton of various extent and complexity. Like all Lagnodactyls, they have a radially symmetric life stage and they "hold hands" with their anal arms in order to mate.
Many 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.
Subgroups
Family Ceratoasteridae
Jawless Ceratoasterformes, which have circular inverting mouths similar to those ancestral to Lagnodactyls but featuring keratinous "teeth". These have pelvic rings inside their bodies which serve as muscle attachment, and paired jaw-like teeth.
Superfamily Phyllomylosoidea
Benthic, typically tripodal Ceratoasterformes with keratinous spines in their mouths for grinding plant matter and a ring of eyes around their faces
Family Phyllomylosidae
Primitive Phyllomylosoids which retain the ancestral radially symmetric appearance.
Family Ericiasteridae
Phyllomylosoids with defensive spikes covering their bodies.
Family Asterostridae
Phyllomylosoids which have jaws used to consume crystal flora and similar hard foods.
Family Asterchelonidae
Pelagic, superficially turtle-like Phyllomylosoids