Llanocetus

Llanocetus
Temporal range: Priabonian
↓
Skull of Llanocetus denticrenatus at the Smithsonian Museum of Natural History
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Mammalia
Order:Artiodactyla
Infraorder:Cetacea
Parvorder:Mysticeti
Family:†Llanocetidae
Genus:†Llanocetus
Mitchell, 1989
Species: †L. denticrenatus
Binomial name
Llanocetus denticrenatus

Llanocetus (“Llano's whale”) is a genus of extinct toothed baleen whales from the Priabonian (Late Eocene) of Antarctica. Its fossilized remains were discovered on Seymour Island in the Antarctic Peninsula, within the La Meseta Formation.[1]

Description and classification

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;[1] 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.[1] The sediments within which the fossil was found seem to indicate a lagoonar environment.[1]

Mitchell created for the specimen the new monotypic family Llanocetidae, as well as the new monotypic genus Llanocetus and the species L. denticrenatus, in honor of the American biologist George A. Llano.[1]

A 2018 cladistic analysis recovers Mystacodon and an unnamed Oligocene specimen from New Zealand as sister to Llanocetus, and more derived than another primitive toothed mysticete, Coronodon.[2]

Biology

In 2018, a nearly complete Llanocetus skull was discovered. Based on this, it is thought the whale measured 8 metres (26 ft), unusually large for an early whale, and was highly predatory or used suction-feeding like contemporary baleen whales.[2]

References

  1. 1 2 3 4 5 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.
  2. 1 2 Fordyce, R. E.; Marx, F. G. (2018). "Gigantism precedes filter feeding in baleen whale evolution". Current Biology. 28 (10): 1670–1676. doi:10.1016/j.cub.2018.04.027.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.