Oxyaenodonta

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Oxyaenodonta
Patriofelis, drawing by Charles R. Knight.

Patriofelis , drawing by Charles R. Knight .

Temporal occurrence
Middle Paleocene (Tiffanium) to Upper Eocene
60.2 to 33.9 million years
Locations
Systematics
Synapsids (Synapsida)
Mammals (mammalia)
Higher mammals (Eutheria)
Laurasiatheria
Ferae
Oxyaenodonta
Scientific name
Oxyaenodonta
Van Valen , 1971

The Oxyaenodonta (partly also Oxyaenida) are an extinct group of carnivorous mammals that were found in North America , Europe and Asia . They appeared with the North American, cat-sized Tytthaena as early as the middle Paleocene and died out in North America in the middle, in Europe and Asia at the end of the Eocene .

features

Oxyaenodonta had an external resemblance to today's cats , crawling cats and martens , with which they are not closely related. Her body was elongated, legs and tail were short. They were sole walkers and not adapted to running fast. The mobility of their feet made it possible for them to climb trees.

Skull of Sarkastodon

Their jaws housed a scissor bite that was not as developed in the smaller forms from the Paleocene as in later genera. In the Oxyaenodonta, the crushing scissors were formed from the entire row of molars, with an emphasis on the first molar in the upper jaw and the second molar in the lower jaw. In the possibly related Hyaenodontidae, the second molar in the upper jaw and the third in the lower jaw were of greater importance, in the more recent predators the fourth premolar in the upper jaw and the first molar in the lower jaw.

Skull fragment from Palaeonictis occidentalis in the Museum für Naturkunde Berlin

It is likely that the Oxyaenodonta were opportunistic carnivores that ate smaller mammals, birds, insects, and eggs, much like the crawling cats do today. Dipsalodon from the late Paleocene and Palaeonictis from the same period and early Eocene had stronger jaws and sturdy teeth adapted to breaking bones. They could have been scavengers. While early Oxyaenodonta were rather small and weighed between 3 and 8 kg, Oxyaena was about the size of a wolf and the Palaeonictis peloria , known only from an incomplete, approximately 20 cm long jaw, was the largest carnivore in its habitat.

External system

The Oxyaenodonta were originally placed together with the dog or hyena-like Hyaenodonta in the order of the Creodonta , also called original predators in German. There and under Oxyaenidae on family level. The Oxyaenodonta appeared in fossil records as early as the middle Paleocene and died out earlier than the Hyaenodonta. In contrast to the more widespread Hyaenodonta, the Oxyaenodonta are limited to the North American continent with a few Eurasian exceptions. Both groups hardly share synapomorphies , so that the validity of the Creodonta taxon is questioned. Along with the recent predators (Carnivora) and the shed animals (Manidae) form the Oxyaenodonta and Hyaenodonta the taxon ferae . The name Oxyaenodonta was proposed in 1971 by Leigh Van Valen , who found the Creodonta to be non- monophyletic in his phylogenetic studies .

Internal system

Skeleton of Oxyaena
Skull of Machaeroides

The order of the Oxyaenodonta is structured as follows:

  • Order Oxyaenodonta Van Valen , 1971
  • Family Oxyaenidae Cope , 1877
  • Subfamily Tytthaeninae Gunnell & Gingerich , 1991

The Ambloctoninae may also be listed in the subfamily of the Palaeonictinae, which was introduced in 1938. Within the subfamily, Dormaalodon is partially synonymous with Palaeonictis . The affiliation of the Machaeroidinae to the Oxyaenodonta is uncertain, since the group is sometimes seen in a closer relationship to the Limnocyoninae, which in turn form part of the Hyaenodonta. However, an analysis of an almost complete skeleton from Utah , which was published in 2018, suggests closer ties between the Machaeroidinae and the Oxyaenodonta.

literature

  • Thomas S. Kemp: The Origin & Evolution of Mammals. Oxford University Press, Oxford 2005. ISBN 0198507615 .
  • Gregg F. Gunnell and Philip D. Gingerich: Systematics and evolution of late Paleocene and early Eocene Oxyaenidae (Mammalia, Creodonta) in the Clarks Fork Basin, Wyoming. Contributions from the Museum of Paleontology 28 (7), 1991, pp. 141-180 ( [2] )

Individual evidence

  1. ↑ Michael Morlo, Gregg Gunnell, and P. David Polly: What, if not nothing, is a creodont? Phylogeny and classification of Hyaenodontida and other former creodonts. Journal of Vertebrate Paleontology 29 (3 suppl), 2009, p. 152A
  2. ↑ Floréal Solé: New proviverrine genus from the Early Eocene of Europe and the first phylogeny of Late Paleocene-Middle Eocene hyaenodontidans (Mammalia). Journal of Systematic Paleontology 11, 2013, pp. 375-398
  3. ^ Leigh Van Valen: Adaptive Zones and the Orders of Mammals. Evolution 25 (2), 1971, pp. 420-428
  4. ^ Gregg F. Gunnell and Philip D. Gingerich: Systematics and evolution of late Paleocene and early Eocene Oxyaenidae (Mammalia, Creodonta) in the Clarks Fork Basin, Wyoming. Contributions from the Museum of Paleontology 28 (7), 1991, pp. 141-180
  5. ^ Richard K. Stucky and Tom G. Hardy: A New Large, Hypercarnivorous Oxyaenid (Mammalia, Creodonta) from the Middle Eocene of the Wind River Formation, Natrona County, Wyoming. Bulletin of Carnegie Museum of Natural History 39, 2007, pp. 57-65
  6. ↑ Stephen GB Chester, Jonathan I. Bloch, Ross Secord and Doug M. Boyer: A New Small-Bodied Species of Palaeonictis (Creodonta, Oxyaenidae) from the Paleocene-Eocene Thermal Maximum. Journal of Mammalian Evolution 17 (4), 2010, pp. 227-243
  7. ↑ a b Floréal Solé, Emmanuel Gheerbrant and Marc Godinot: New data on the Oxyaenidae from the Early Eocene of Europe; biostratigraphic, paleobiogeographic and paleoecologic implications. Palaeontologia Electronica 14 (2), p. 13A ( [1] )
  8. ^ Shawn P. Zack, A skeleton of a Uintan machaeroidine 'creodont' and the phylogeny of carnivorous eutherian mammals. Journal of Systematic Palaeontology, 2018 doi: 10.1080 / 14772019.2018.1466374

Web links

Commons : Oxyaenidae  - Collection of images, videos and audio files