Brygmophyseter shigensis

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 2006. A month later since the naming of Brygmophyseter, another study classified this species 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 16–15 million years old (middle Miocene). The Brygmophyseter holotype is thought to have been 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 (often shortened to "raptorial") 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.

==History of discovery== The holotype specimen, SFM-0001, was excavated from the Bessho Formation in the Nagano Prefecture in Japan in 1988 by the residents of Shiga-mura with assistance from the staff of the Shiga Fossil Museum. The specimen is nearly complete, and consists of a partial skull, the jawbone, the lingual bone in the neck, vertebrae, ribs, the breastbone, and humeri and radii in the limbs. It was dated to the Langhian stage of the Miocene 14–15 million years ago (mya), and the specimen is currently on display at the Gunma Museum of Natural History in Japan.