Pacific Mastodon - Mammut pacificus - Printable Version

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Pacific Mastodon - Mammut pacificus - Taipan - 03-30-2019

Pacific Mastodon - Mammut pacificus

[Image: 5-newspeciesof.jpg]
Left side view of a skull of Mammut pacificus, from Dooley et al. 2019.

Temporal range: Pleistocene

Scientific classification
Kingdom:  Animalia
Phylum:  Chordata
Class:  Mammalia
Order:  Proboscidea
Family:  †Mammutidae
Genus:  †Mammut  Blumenbach, 1799
Species: †Mammut pacificus Dooley et al., 2019

Mastodons (Greek: μαστός "breast" and ὀδούς, "tooth") are any species of extinct proboscideans in the genus Mammut (family Mammutidae), distantly related to elephants, that inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of the Pleistocene 10,000 to 11,000 years ago. Mastodons lived in herds and were predominantly forest-dwelling animals that fed on a mixed diet obtained by browsing and grazing with a seasonal preference for browsing, similar to living elephants.
M. americanum, the American Mastodon, and M. pacificus, the Pacific mastodon, are the youngest and best-known species of the genus. Mastodons disappeared from North America as part of a mass extinction of most of the Pleistocene megafauna, widely believed to have been caused by overexploitation by Clovis hunters.

M. pacificus —based on a 2019 analysis, Pleistocene specimens from California and southern Idaho have been transferred from M. americanum to this new species. It differs from the eastern population in having narrower molars, six as opposed to five sacral vertebrae, a thicker femur, and a consistent absence of mandibular tusks.

New species of mastodon discovered in California

by Bob Yirka, Science X Network,

A team of researchers affiliated with several institutions in the U.S. has discovered a new species of mastodon. In their paper uploaded to the peer-reviewed journal PeerJ, the group describes discovering the new species and why it has only just been found.
Mastodon were large animals that resembled modern elephants. They existed during parts of the Miocene and Pleistocene epochs, and were related to mammoths. They have been extinct for approximately 3000 years. Scientists have known of their existence for approximately 200 years—and they have been studied extensively, which makes the discovery of a new species very much a surprise.
The new discovery did not come about due to a new dig—indeed, the bones that gave evidence of the new species have been held in several museums throughout California for over 20 years. The discovery was accidental—some of the team members were doing a study of mastodon teeth and found differences between the samples in California and those that were from other parts of North America. Those in California had molars that were smaller and less wide compared to those from mastodons in other places. This finding prompted the team to take a closer look, which revealed that the specimens also had more vertebrae, lacked a lower tusk and had femurs that were somewhat different.
The California fossils were found at Diamond Valley Lake in the 1990s, where 100,000 skeletal fossils were unearthed—the area is now covered over by an emergency water reservoir, so it is unlikely that more will be found. The researchers note that in addition to the obvious physical differences, there is evidence that the animals living in California were isolated from other species for thousands of years, and that they lived during the Pleistocene. They suspect there are also genetic differences. The researchers claim that the cumulative evidence strongly points to the discovery of a new species, making it the first new North American mastodon species reported in 50 years. Other researchers will have to review the work and conduct studies of their own before the new find can be officially recognized as a new species: Mammoth pacificus.

[Image: 5c9def56e0509.jpg]
Mammut pacificus sp. nov., WSC 18743, holotype cranium and tusks. Cranium in: (A) dorsal, (B) ventral, © left lateral, (D) right lateral, (E) posterior, (F) distal end of left tusk (I1), lateral, and (G) right tusk (I1), lateral view. Teeth include left and right M2–M3. (A–E) are images of a resin cast of the holotype cranium on exhibit at the Western Science Center. All images are orthographic views of photogrammetric models. Scale = 10 cm. Credit: PeerJ (2019). DOI: 10.7717/peerj.6614

Journal Reference:
Alton C. Dooley et al. Mammut pacificus sp. nov., a newly recognized species of mastodon from the Pleistocene of western North America, PeerJ (2019). DOI: 10.7717/peerj.6614

A new species of mastodon from the Pleistocene of western North America, Mammut pacificus sp. nov. is herein recognized, with specimens identified throughout California and from two localities in southern Idaho. This new taxon differs from the contemporaneous M. americanum in having narrower teeth, most prominently in M3/m3, as well as six sacral vertebrae, femur with a proportionally greater mid-shaft diameter, and no mandibular tusks at any growth stage. All known Pleistocene Mammut remains from California are consistent with our diagnosis of M. pacificus, which indicates that M. americanum was not present in California.