Unlike Arctodus simus

a semi-aquatic predator of exceptional size that inhabited the river systems of North Africa

Ichthyostega poseía una combinación única de características anatómicas que lo distinguían tanto de los peces acuáticos como de los tetrápodos terrestres posteriores

Las aletas delanteras eran largas y anchas

en el rango de tiempo conocido como el Maastrichtiano

Thylacinus cynocephalus Variant:Hand-painted Unlike Arctodus simusThylacinus cynocephalus, known as the thylacine or "Tasmanian wolf," was a recently extinct carnivorous marsupial whose general morphology remarkably converged with that of placental canids. Its cranial anatomy constitutes one of the species' most characteristic and functionally relevant aspects. The skull of Thylacinus cynocephalus was elongated, narrow, and relatively low, with an almost straight dorsal profile. It could reach approximately 2124 cm