Plesippus is a genus of extinct horse from the Pleistocene of North America. Although commonly seen as a subgenus of Equus recent cladistic analysis considers it a distinct genus.

Equus simplicidens, also known as the Hagerman horse and American zebra, is an extinct species of equine native to North America during the Pliocene and Early Pleistocene. [1] . It is one of the oldest and most primitive members of the genus Equus.

In this contribution, we assess the validity of the genera Plesippus, Allohippus and Equus by cladistic analysis combined with morphological and morphometrical comparison of cranial anatomy.

A seeker of vertebrate paleontological adventure in California's Coso Range explores badlands topography carved in the appropriately named Pliocene Coso Formation, which here yields several species of mineralized mammalian remains some 4.8 to 3.0 million years old--inluding teeth and post cranial skeletal elements of the Hagerman Horse...

Equus simplicidens is considered one of the earliest known members of the genus Equus, which includes the modern horse and all other equids. Originally described as Plesippus francescana, but is now recognized as Equus simplicidens. Photograph courtesy a public domain document. Click on the image for a larger picture.

Plesippus shoshonensis was named by Gidley (1930) [also, but incorrectly said to be 1921]. Its type specimen is USNM 11986, a partial skeleton, and it is a 3D body fossil. Its type locality is Hagerman (Gidley Horse Quarry), which is in a Blancan terrestrial horizon in the Glenns Ferry Formation of Idaho.

Jul 8, 2018 · † Equus (Plesippus) simplicidens Cope 1892—American Zebra Synonyms. Plesippus simplicidens. Sites. Late Blancan: 111 Ranch (Morgan and White 2005: ?). Late Blancan/Irvingtonian: Anza-Borrego (Murray 2008: cf.). Literature. Morgan …

Plesippus ? sp See more items in Paleogeneral Mammals Terrestrial - Neogene Mammalia Pliocene Blancan Hagerman (Horses) Paleobiology Taxonomy Animalia Chordata Vertebrata Synapsida Mammalia Eutheria Laurasiatheria Perissodactyla Equidae NMNH - Paleobiology Dept. Record ID nmnhpaleobiology_3378767

Plesippus is a genus of extinct horse from the Pleistocene of North America. Although commonly seen as a subgenus of Equusrecent cladistic analysis considers it a distinct genus. Two species are recognized by Barron et al.(2019), P. simplicidens and P. idahoensis.

James W. Gidley, the Smithsonian paleontologist, who led the initial excavations at Hagerman in 1929, felt that the horse being uncovered was different enough in its skeleton that it represented a new species distinct from any other known fossil horse. …