Llanocetus

Llanocetus Temporal range: Priabonian PreЄ Є O S D C P T J K Pg N ↓
Skull of Llanocetus denticrenatus at the Smithsonian Museum of Natural History
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Class:	Mammalia
Order:	Artiodactyla
Infraorder:	Cetacea
Parvorder:	Mysticeti
Family:	†Llanocetidae Mitchell 1989
Genus:	†Llanocetus Mitchell 1989
Species[1]
L. denticrenatus Mitchell 1989

Llanocetus (“Llano's whale”) is a genus of extinct baleen whales from the Priabonian (Late Eocene) of Antarctica. Its fossilized remains were discovered on Seymour Island in the Antarctic Peninsula, within La Meseta Formation.^[2]

The remains — a partial skull — were described in 1989 by Edward D. Mitchell, who argued they belonged to a medium-sized whale which shared traits of both archaeocetes and mysticetes:^[2] it carried a wide, flat, and dorsoventrally flat rostrum, its jaw had heterodont teeth separated by wide diastemata, and the cheek teeth were two-rooted and palmated with accessory denticles. Additionally, fine grooves around the alveoli indicate the palate had a rich blood supply.
Mitchell interpreted Llanocetus as a basal mysticete with filter feeding behaviour, probably feeding on euphausiids or similar small animals.^[3] The sediments within which the fossil was found seems to indicate a lagoonar environment.^[4]

Mitchell created for the specimen the new monotypic family Llanocetidae, as well as the new monotypic genus Llanocetus and the species L. denticrenatus. The three new taxa were dedicated to the American biologist George A. Llano.^[1]

References

1. Mitchell, op. cit., p. 2220
2. Mitchell, op. cit., p. 2219
3. Mitchell, op. cit., p. 2227
4. Mitchell, op. cit., p. 2223

Bibliography

Mitchell, E. D. (1989). "A new cetacean from the Late Eocene La Meseta Formation, Seymour Island, Antarctic Peninsula". Canadian Journal of Fisheries and Aquatic Sciences. 46: 2219–2235. doi:10.1139/f89-273.

External links

Llanocetus page on Fossilworks.org