Acrophoca was around 1.5 metres (5 ft) long, and was not as well-adapted to swimming as its descendants, possessing less developed flippers and a less streamlined neck. This may indicate that it spent a lot of time near the coast. Its teeth were built for piercing, implying a diet consisted primarily of fish. However, it also had interdigitated tooth cusps causing the teeth on the upper jaw to fit with the teeth of the lower jaw, which is consistent with filter feeders. Unlike other earless seals, Acrophoca had a long and flexible neck, with an elongated body. The orientation of the pelvis, which in comparison to modern earless seals is everted, as well as adaptations to the hind limbs suggest that swimming was mainly powered by the back flippers. It was less adapted for the sea than the lobodontine seals, suggesting it inhabited nearshore waters.[3][4]
^Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 226. ISBN1-84028-152-9.
Further reading
World Encyclopedia of Dinosaurs & Prehistoric Creatures: The Ultimate Visual Reference To 1000 Dinosaurs And Prehistoric Creatures Of Land, Air And Sea ... And Cretaceous Eras (World Encyclopedia) by Dougal Dixon