Taphonomy of a Multiple Poebrotherium kill site
- an Archaeotherium meat cache

Dr. Kent A. Sundell
Tate Museum at Casper College, Casper, Wyoming

A multiple Poebrotherium specimen measuring 115cm x 110cm x 20cm and containing 594 exposed bones (estimate 700 total) was collected from lower Orellan beds within the White River Formation near Douglas Wyoming. One fully articulated skeleton, six partially articulated skeletons and various disarticulated bones contain numerous tooth impressions and bite marks on the skulls, necks and thoracic/lumbar vertebrae. Diameter of the punctures, depth of the punctures, spacing between the punctures and width spacing between the rows of punctures best fit premolars of a medium size (60 cm skull length) Archeotherium. The rib cages with fully articulated front legs and feet were preferentially not consumed (6 specimens). Pelvic regions with rear legs and feet were preferentially consumed (1 and remain). The dense stacking of skeletons (4 deep) and the articulation of scapulas and distal phalanges suggest rapid burial of a single event. Bite marks on this unique specimen, combined with commonly observed similar bite marks on the skulls of other Archaeotherium indicates that Archaeotherium was an attack predator. It would run alongside the prey species (Poebrotherium) and bite with a quick snap at the posterior skull and upper cervical elements. When prey was plentiful it severed the deceased prey's vertebrae near the thoracic/lumbar transition and preferentially ate meaty, easier to swallow, articulated rear halves of prey and stockpiled articulated thoracic leftovers in meat caches.

 

Evidence of Predation by Archaeotherium

  1. Bite marks in head and neck regions (Why bite head if scavenging?)
  2. Distance between punctures - same jaw (40-45 mm)
  3. Distance between punctures - jaw to jaw (70-80 mm)
  4. Articulated distal phalanges and front legs attached to rib cage (no scavenging)
  5. Pelvis' and rear legs preferentially gone (1.5 pelvis' vs. 7 rib cages)
  6. Archaeotherium throat size (150+mm diameter) vs. camel pelvis (60x80x150mm)
  7. Similar style of bite marks on other Archaeotherium skulls (fighting style)
  8. Lack of other possible large suspects (bite marks do not match Hyaenodon, saber tooth cats, or other carnivores)


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