Acrophyseter
Encyclopedia
Acrophyseter is a genus
of stem-sperm whales that lived around 6 million years ago.
, and penguins like Spheniscus urbinai that lived in the area at that time.
Various skull characteristics such as the size of the teeth and presence of tooth enamel
which living sperm whales don't have indicate that Acrophyseter is probably a sister group to the Brygmophyseter
and Zygophyseter
group and to the group comprising Aulophyseter
and living physeteroids, the kogiids and physeterids.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of stem-sperm whales that lived around 6 million years ago.
Description
Acrophyseter is derived from the Greek akros, meaning acute, which describes the short, pointed upturned snout, and Physeter, the scientific name for sperm whales. But unlike today's sperm whales, A. deinodon was relatively short at around 4 meters and had teeth on both the upper and lower jaws; 12 on each side of the upper jaw and 13 on each side of the lower. These teeth were large, sharp, and set firmly in deep sockets; the species epithet deinodon is from the Greek deinos, meaning terrible, and odon, tooth. The lower back teeth were close together suggesting they were used for shearing, unlike the suction feeding used by today's sperm whales, which don't even have teeth on their upper jaws. These differences imply that Acrophyseter fed on comparatively large prey, such as the smaller whales like Piscolithax, pinnipeds like AcrophocaAcrophoca
Acrophoca longirostris is an extinct species of pinniped whose fossils have been discovered in Peru and Chile. It is thought to have been the ancestor of the modern leopard seal....
, and penguins like Spheniscus urbinai that lived in the area at that time.
Various skull characteristics such as the size of the teeth and presence of tooth enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...
which living sperm whales don't have indicate that Acrophyseter is probably a sister group to the Brygmophyseter
Brygmophyseter
Brygmophyseter is an extinct genus of toothed whale in the sperm whale family with one species Brygmophyseter shigensis. When first described, this species was placed in an extinct form genus Scaldicetus of toothed whale, as Scaldicetus shigensis)...
and Zygophyseter
Zygophyseter
Zygophyseter varolai is an extinct cetacean, similar to the sperm whale. The common name of "killer sperm whale" refers both to its relation to modern day sperm whales, and to its similarity in size to and its "probable similar feeding adaptation to the extant delphinid killer whale ".The...
group and to the group comprising Aulophyseter
Aulophyseter
Aulophyseter is an extinct genus of sperm whale from the Miocene formations of the West and East coasts of North America as well as the Patagonian region of South America...
and living physeteroids, the kogiids and physeterids.