| Pseudorca yokoyamai Temporal range: Pleistocene | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Artiodactyla |
| Infraorder: | Cetacea |
| Family: | Delphinidae |
| Genus: | Pseudorca |
| Species: | †P. yokoyamai |
| Binomial name | |
| †Pseudorca yokoyamai Matsumoto, 1926 | |
Pseudorca yokoyamai is an extinct species of oceanic dolphin from the Calabrian stage of the Pleistocene of Japan, an extinct relative of the modern day false killer whale (P. crassidens).
Pseudorca yokoyamai was described in 1926 by Matsumoto Hikoshichiro of the Tohoku Imperial University. The holotype specimen is represented by two teeth–probably the very last two in the back of the mouth–and a paratype specimen consists of the right ramus of the mandible with seven teeth, though four teeth are incomplete. The holotype was found in Hommoku, Yokohama–the species name honoring the place of its discovery–and the paratype in the Kazusa Province on the opposite side of Tokyo Bay. It may represent an intermediary phase between the modern false killer whale and pilot whales (Globicephala spp.). [1] [2]
The teeth of P. yokoyamai are largely conical, though bend backward, with a smooth enamel coating. On the holotype, the second-to-last and last teeth measured respectively 47 and 50 mm (1.9 and 2.0 in) in height. P. yokowamai had smaller, though a greater number of, teeth than the modern false killer whale. [1]
The paratype represents the last seven teeth in the jaw, and there were perhaps three or four more teeth in front of it. The diameter of the tooth crown at the gumline is 14–15 mm (0.55–0.59 in), and the series of seven teeth is 177 mm (7.0 in) long. [1]
A wholphin is an extremely rare cetacean hybrid born from a mating of a female common bottlenose dolphin with a male false killer whale. The name implies a hybrid of whale and dolphin, although taxonomically, both are within the oceanic dolphin family, which is within the toothed whale parvorder. Wholphins have been born in captivity and have also been reported in the wild.
The false killer whale is a species of oceanic dolphin that is the only extant representative of the genus Pseudorca. It is found in oceans worldwide but mainly in tropical regions. It was first described in 1846 as a species of porpoise based on a skull, which was revised when the first carcasses were observed in 1861. The name "false killer whale" comes from having a skull similar to the orca, or killer whale.
Pseudorca is a genus of cetaceans with three members which include Pseudorca yokoyamai, Pseudorca yuanliensis and Pseudorca crassidens, of which P. crassidens is the only extant member.
Brygmophyseter, known as the biting sperm whale, is an extinct genus of toothed whale in the sperm whale family with one species, B. shigensis. When it was first described in 1994, the species was placed in the genus Scaldicetus based on tooth morphology, but this was later revised in 1995. In 2006, it was classified into the genus Naganocetus, which is considered to be a junior synonym. The only known specimen, a nearly complete skeleton, was dated to be around 15–14 million years old. Brygmophyseter is thought to have been 6.5–7 meters (21–23 ft) long, and it probably had 11 or 12 teeth in the upper and lower jaws. Brygmophyseter is part of a group of macroraptorial sperm whales which tended to be apex predators using their large teeth to catch struggling prey such as whales. It had a spermaceti organ which was probably used for biosonar like in the modern sperm whale. The whale has made an appearance on The History Channel's TV series Jurassic Fight Club.
P. crassidens may refer to:
Livyatan is an extinct genus of macroraptorial sperm whale containing one known species: L. melvillei. The genus name was inspired by the biblical sea monster Leviathan, and the species name by Herman Melville, the author of the famous novel Moby-Dick about a white bull sperm whale. It is mainly known from the Pisco Formation of Peru during the Tortonian stage of the Miocene epoch, about 9.9–8.9 million years ago (mya); however, finds of isolated teeth from other locations such as Chile, Argentina, California, South Africa, and Australia imply that either it or a close relative survived into the Pliocene, around 5 mya, and may have had a global presence. It was a member of a group of macroraptorial sperm whales and was probably an apex predator, preying on whales, seals, and so forth. Characteristically of raptorial sperm whales, Livyatan had functional, enamel-coated teeth on the upper and lower jaws, as well as several features suitable for hunting large prey.
Orcinus citoniensis is an extinct species of killer whale identified in the Late Pliocene of Italy and the Early Pleistocene of England. It was smaller than the modern killer whale, 4 m (13 ft) versus 7 to 10 m, and had around 8 more teeth in its jaw. It may have resembled the modern killer whale in appearance, and could represent a transitional species between the modern killer whale and other dolphins. O. citoniensis could have hunted fish and squid in pods, and coexisted with other large predators of the time such as the orcinine Hemisyntrachelus and the extinct shark Otodus megalodon.
Acer stewarti is an extinct maple species in the family Sapindaceae described from a series of fossil leaves and samaras. The species is solely known from the Early Eocene sediments exposed in south central British Columbia, Canada adjacent to northeast Washington state, United States. It is one of only two species belonging to the extinct section Stewarta.
Orcinus paleorca is a fossil species of Orcinus, the genus of killer whales (orca), dated to the Middle Pleistocene. The only known specimen is a tooth fragment discovered in Honshu, Japan.