Mesonychids: Andrewsarchus

Purchase includes free access to book updates online and a free trial membership in the publisher's book club where you can select from more than a million books without charge. Excerpt: Andrewsarchus mongoliensis (pronounced ANN-drew-SARK-us), (Andrews ] Greek, "ruler"), was a mammal that lived during the Eocene epoch, roughly between 45 and 36 million years ago. It had a long snout with large, sharp teeth and flat cheek teeth that may have been used to crush bones. Because Andrewsarchus is only known from a single skull, whether it was an active predator or merely a large scavenger is open to debate, as is its exact time range. Andrewsarchus is named for the famous explorer and fossil hunter Roy Chapman Andrews. It was discovered in June 1923 by Kan Chuen Pao, a member of Andrews' expedition, on a site in the Gobi Desert in Mongolia known as Irdin Mahna on the third Asiatic expedition that was led by Andrews and sponsored by the American Museum of Natural History. The American Museum of Natural History is where the skull section of the fossil is now on display: the lower jaw was not found. It was classified in the clade Mesonychia due to the similarity in structure between its teeth and skull with those of other mesonychid species known from complete skeleton, however, much of this was based only on Osborn's original publication, and more recent studies have found it to have no special mesonychid affinities, instead grouping with various artiodactyl clades. Size comparison of Andrewsarchus against other carnivores. Shown in orange. Reconstruction of A. mongoliensisAndrewsarchus is known only from an enormous skull (32.8 in/83 cm long and 22/56 cm wide) and pieces of bone. If Andrewsarchus was proportioned in the same manner as Mesonyx obtusidens, it had a length from the snout to the back of the pelvis of about 11 feet (3.4 m) and a height from the ground to the shoulder or middle of the back of about 6 feet (1.8 m). Thus... More: http: //booksllc.net/?id=1039393