Using the sample, it is evident that the mental plate ( a dermal bone that forms the upper part of the jaw ) of antiarchs is homologous with the suborbital plate found in other placoderms.
22.
Despite being amphibians, they seem to be well developed for life on land, with well-developed limbs, solid vertebrae, and a row of armour plates of dermal bone, which both protected the animal and further strengthened the backbone.
23.
These features include delicate dermal bones with ornament consisting of continuous anastomosing ridges rather than tubercles, a dorsal trunk shield narrower than long and with a continuous and pronounced dorsal median ridge, and a pre-median plate that is wider than it is long .
24.
Jawless fish and sharks only possess a cartilaginous endocranium, with the upper and lower jaws of cartilaginous fish being separate elements not attached to the skull . Bony fishes have additional dermal bone, forming a more or less coherent skull roof in lungfish and holost fish.
