Archaeotherium
Archaeotherium | |
---|---|
Skeleton in American Museum of Natural History | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Artiodactyla |
Family: | †Entelodontidae |
Genus: | †Archaeotherium Leidy, 1850 |
Type species | |
†Archaeotherium mortoni Leidy, 1850
| |
Synonyms | |
|
Archaeotherium (
Taxonomy
Archaeotherium was named by Joseph Leidy (1850).[1] Its type is Archaeotherium mortoni. It was synonymized subjectively with Entelodon by Leidy (1853) and synonymized subjectively with Elotherium by Leidy (1857). It was assigned to Entelodontidae by Leidy (1850), Peterson (1909), Scott (1940), Galbreath (1953), Russell (1980), Carroll (1988) and Effinger (1998).[4][5]
Archaeotherium, along with all other Entelodontidae, is an
Description
Archaeotherium was about 1.2 m (3 ft 11 in) tall at the shoulder and around 2 m (6 ft 7 in) long. Adults weighed 150–250 kg (330-530 lbs). The largest specimens, though much less common, which had been described under the name Megachoerus had skulls up to 80 cm (31 in) long, stood about 1.5–1.6 m (4 ft 11 in – 5 ft 3 in) tall at the shoulder and weighed up to 500–600 kg (1,100–1,300 lb).
There is no sign of sexual dimorphism in the canine teeth; females and males may have been similar in size. Though Archaeotherium is one of the best preserved of all entelodonts, skulls of entelodonts are far more commonly preserved than full skeletons, and the large size of the head in proportion to the body makes it difficult to accurately estimate the animal's living size and weight.[7]
In life, Archaeotherium probably somewhat resembled a cow-sized
Paleobiology
It lived in forested and riverbank environments before the evolution of grasslands. Like all entelodonts, the genus had typical
Reproduction
Archaeotherium, like all entelodonts, possessed huge jugal projections. These projections are sexually dimorphic, with the males having much larger jugals than the females.
Feeding and diet
The largest (and type) species, A. mortoni, has been analyzed as an omnivore with specializations for biting and chewing resistant objects, such as hard fruits, stems, and bones. Like all entelodonts, the teeth and jaws resemble no living animal, though there are some similarities to peccaries, pigs, bears, predatory carnivores, rhinos, and bone-crushing scavengers. There is a full dentition. The canines, premolars, and molars were all large and heavily enameled, and show heavy wear. The jaws were enormously strong and operated largely by chopping, though they could move laterally enough for the flat molars to grind. There are no blades or notches on any teeth for slicing meat, which are seen in all living and fossil taxa of predators that can chew. Archaeotherium did not have the ability to slice its meat like most modern predators, but they would have used their strong neck musculature, using their entire head and neck to rip off chunks instead.[11] Fossil evidence suggests that in North America they may sometimes have hunted the early camel Poebrotherium,[12] severing the body in half and crushing and swallowing the foot-long rear section [13] Bite marks on the cervical vertebrae of the camels suggests they attacked by running alongside their prey, snapping at their necks. The remains of these camels have been found together, implying Archaeotherium brought its kills to caches for later consumption.[13]
Unlike both grazers and hypercarnivores, Archaeotherium teeth frequently show uneven wear that indicates the animal favored chewing on one side of the jaw, usually the result of tooth damage from hard foods. But the teeth do not show the bone-eating "piecrust fractures" seen in the larger Daeodon (Dinohyus), which may have specialized more at eating large carcasses. Tooth wear patterns suggest the interlocking front teeth of A. mortoni were frequently used to strip leaves from plants, but do not show soil scratches from rooting in the ground.[7] Among living animals, Archeotherium has some resemblance to peccaries, and may have been a similarly aggressive mixed feeder; it was able to take animals considerably smaller than itself, scavenge on carcasses, and exploit plant foods few other animals can process. (The largest living peccary species, Catagonus wagneri, eats mostly cacti.[14])
Adult Archeotherium had huge
References
- ^ PaleoBiology Database: Archaeotherium, basic info
- ^ Foss, Scott E.; Fremd, Theodore (1998). "A survey of the species of entelodonts (Mammalia, Artiodactyla) of the John Day Basin, Oregon" (PDF). Dakoterra. 5: 63–72.
- ^ Wilson, John Andrew (1971). "Early Tertiary vertebrate faunas, Vieja Group, Trans-Pecos Texas: Entelodontidae". Pearce-Sellards Series, Texas Memorial Museum. 17: 1–17.
- ^ O. A. Peterson. 1909. Memoirs of the Carnegie Museum
- ^ W. B. Scott. 1940. The mammalian fauna of the White River Oligocene; Part 4, Artiodactyla; Part 5, Perissodactyla. Transactions of the American Philosophical Society 28(4):363
- ^ Geisler, Jonathan H., and Mark D. Uhen. "Morphological Support for a Close Relationship between Hippos and Whales" Journal of Vertebrate Paleontology 23, no. 4 (2003): 991-96. JSTOR
- ^ a b c Joeckel, R. M. "A Functional Interpretation of the Masticatory System and Paleoecology of Entelodonts" Paleobiology 16, no. 4 (1990): 459-82.
- ^ CLIFFORD, ANDREW B. "THE EVOLUTION OF THE UNGULIGRADE MANUS IN ARTIODACTYLS" Journal of Vertebrate Paleontology, vol. 30, no. 6, 2010, pp. 1827–1839. JSTOR, .
- ISBN 1-84028-152-9.
- ISBN 978-0-253-01608-9.
- ^ a b Foss, S. E., 2001, Systematics and paleobiology of the Entelodontidae (Mammalia, Artiodactyla) [Ph.D. dissertation]: Dekalb, Northern Illinois University, 222 p.
- ^ "Camels". The Fossils of the White River Badlands. Retrieved 2019-05-18.
- ^ JSTOR 4524027.
- ^ Raffo, Erica. "Catagonus wagneri (Chacoan peccary)". Animal Diversity Web. Retrieved 2019-05-18.