Aclistomycter

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Aclistomycter
Temporal range: 35–5 Ma
Late Eocene
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Suborder: Tylopoda
Family: Merycoidodontidae
Subfamily: Aclistomycterinae Lander 1998
Genus: Aclistomycter Wilson 1970
Species
  • A. middletoni Wilson 1970

Aclistomycter is an extinct genus of oreodont during the early Chadronian subepoch (42—39.9 mya, Late Eocene) existing for approximately 2.1 million years [1] from the Chambers Tuff Formation near Adobe Springs in Presidio County, Texas.

Aclistomycter was a very small herbivorous artiodactyl with a short face, small, but tusk-like canine teeth. The type specimen (TMM 41213-1) consists of a skull and jaws and two other specimens are referred to it: TMM 41216-11, skull with C-M^3; TMM 41211-9, skull fragment with M^1-M^3.

Diagnosis[edit]

Generic characters assigned by Wilson (1970):

  • Medium small merycoidodontid with very large and deep, probably perforated, antorbital fossae.
  • Brachycephalic.
  • Posterior part of skull extended.
  • Molar teeth with thick enamel and deep fossettes.
  • Posterior base of zygomatic processes wide, making the skull broad posteriorly.
  • Bullae thought to be inflated (though the bullae are not exposed in the figures of the type specimen illustrated by Wilson).

Taxonomy[edit]

Aclistomycter was named and assigned to Merycoidodontidae and the Merycoidodontinae by Wilson (1971). But Lander (1998) erected a new subfamily for it, the Aclistomycterinae. [2][3] Wilson recognized it was more primitive than Leptauchenia and Lander placed it as more derived than the bathygenines but basal to leptaucheniines and other more derived merycoidodontids.

Morphology[edit]

A single specimen was examined by M. Mendoza for body mass and estimated to have a weight of 87.9 kg (193.7 lbs). [4]

Resources[edit]

  1. ^ PaleoBiology Database: Aclistomycter, basic info
  2. ^ J. A. Wilson. 1971. Early Tertiary vertebrate faunas, Vieja Group. Trans-Pecos Texas: Agriochoeridae and Merycoidodontidae. Texas Memorial Museum Bulletin
  3. ^ B. Lander. 1998. Oreodontoidea. In C. M. Janis, K. M. Scott, and L. L. Jacobs (eds.), Evolution of Tertiary mammals of North America 402-425
  4. ^ M. Mendoza, C. M. Janis, and P. Palmqvist. 2006. Estimating the body mass of extinct ungulates: a study on the use of multiple regression. Journal of Zoology