Named By: R. Kellogg - 1968.
Classification: Chordata, Mammalia, Cetacea, Mysticeti.
Species: D. hiatus (type). D. chichibuensis, D. shobarensis.
Diet: Filter feeder.
Size: Total length about 6 meters long.
Known locations: Japan - Korematsu Formation and Nagura Formation. USA, Mayland - Calvert Formation, Calvert Beach Member, and Virginia - Calvert Formation, Plum Point Member.
Time period: Burdigalian through to the Serravalian of the Miocene.
Fossil representation: Several individuals represented by skulls and partial post cranial remains.
was first named from fossils recovered from the United States by R.
Kellog in 1968, establishing the type species Diorocetus
Then in 2003 and 2008 respectively two new species,
Diorocetus chichibuensis and Diorocetus
shobarensis were named from
fossils discovered in Japan. Out of these D. shobarensis
be the earliest with fossils roughly dated to the Burdigalian of the
Miocene, while at the time of writing fossils for D.
hiatus and D.
chichibuensis are Langhian to Serravalian in age. Noted
quite a slender skull for a mysticetid whale,
considered in a 2009 study by Beatty & Dooley to
be a bottom feeder as opposed to feeding in open water like the baleen
whales that we know today.
Diorocetus might have been preyed upon by large ‘megatoothed sharks’ such as C. chubutensis and of course the famous C. megalodon.
|More information on these whales can
be found on their respective pages; 1 - Pakicetus,
2 - Ambulocetus, 3 - Rodhocetus, 4 - Dorudon, 5, Brygmophyseter, 6 - Diorocetus.
- A hitherto unrecognized Calvert Cetothere. Bulletin of the United States National Museum 247(6):133-161 - R. Kellogg - 1968.
- New cetothere (Cetacea: Mysticeti) from the Miocene Chichibumachi Group, Japan. - Bulletin of the Saitama Museum of Natural History 20-21:1-10. Bulletin 247:133-161. - K. Yoshida, T. Kimura & Y. Hasegawa - 2003.
- Cladistic analysis and a revised classification of fossil and recent mysticetes. - Zoological Journal of the Linnean Society 150:875-894. - M. E. Steeman - 2007.
- Cetotheres from the early Middle Miocene Bihoku Group in Shobara District, Hiroshima Prefecture, West Japan. Miscellaneous Reports of the Hiwa Museum for Natural History 49 (2) :1-66. - H. Otsuka & Y. Ota - 2008.
- Injuries in a Mysticete Skeleton from the Miocene of Virginia, With a Discussion of Buoyancy and the Primitive Feeding Mode in the Chaeomysticeti. - Jeffersoniana, Virginia Museum of natural History, 20. Brian Lee Beatty & Alton C. Dooley Jr - 2009.