| Acrophoca | |
|---|---|
 | |
| Display at theSmithsonian National Museum of Natural History | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Clade: | Pinnipedia |
| Family: | Phocidae |
| Subfamily: | Monachinae |
| Tribe: | Lobodontini |
| Genus: | †Acrophoca Muizon, 1981 |
| Species: | †A. longirostris |
| Binomial name | |
| †Acrophoca longirostris Muizon, 1981 | |
Acrophoca longirostris, also known as theswan-necked seal, is anextinctgenus ofLate Miocenepinniped. It was thought to have been the ancestor of the modernleopard seal; however, it is now thought to be aspecies ofmonk seal.
The fossils ofA. longirostris have been discovered in thePisco Formation ofPeru and theBahía Inglesa Formation ofChile.[1] When it was first described in 1981, it was thought to have been closely related to thelobodontine seals which includes the modern-dayleopard seal (Hydrurga leptonyx), thecrabeater seal (Lobodon carcinophaga), theWeddell seal (Leptonychotes weddelli) and theRoss seal (Ommatophoca rossii). However, it is now thought to be abasal species ofmonk seal of the subfamilyMonachinae, closely related to the extinct sealPiscophoca.[2][3]
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 withfilter feeders. Unlike otherearless 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 inhabitednearshore waters.[3][4]
Its fossils have been found alongside those of the marine slothThalassocnus and tusked cetaceanOdobenocetops, as well as modern animals such asbottlenose dolphins,gannets andcormorants.
