Leptotragulus is a small extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of Artiodactyla, of the family Protoceratidae

Protoceratidae

Protoceratidae is an extinct family of herbivorous North American artiodactyls that lived during the Eocene through Pliocene at around 46.2—4.9 Ma., existing for approximately .-Taxonomy:...

, endemic to North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 from the Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 epoch (Uintan

Uintan

The Uintan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 46,200,000 to 42,000,000 years BP lasting . It is usually considered to fall within the Eocene epoch...

 to Chadronian

Chadronian

The Chadronian age within the North American Land Mammal Ages chronology is the North American faunal stage typically set from 38,000,000 to 33,900,000 years BP, a period of . It is usually considered to fall within the Eocene epoch...

 stage) 40.2—33.9 Ma, existing for approximately .

Taxonomy

Leptotragulus was named by Scott and Osborn (1887). It was assigned to Leptotragulinae by Matthew (1908); to Hypertragulidae

Hypertragulidae

Hypertragulidae is an extinct family of even-toed ungulates , endemic to North America, Europe, and Asia during the Eocene through Miocene, living 46.2—13.6 Ma, existing for approximately ....

 by Peterson (1919); and to Protoceratidae

Protoceratidae

Protoceratidae is an extinct family of herbivorous North American artiodactyls that lived during the Eocene through Pliocene at around 46.2—4.9 Ma., existing for approximately .-Taxonomy:...

 by Scott and Osborn (1887), Carroll (1988), Prothero (1998) and Prothero and Ludtke (2007).

Morphology

Leptotragulus resembled deer

Deer

Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

. However they were more closely related to camelids

Camel

A camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the bactrian has two humps. Dromedaries are native to the dry desert areas of West Asia,...

. In addition to having horns in the more usual place, protoceratids had additional, rostral horns above the orbital cavity

Orbit (anatomy)

In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...

.

Body mass

Four fossil specimens of Prosynthetoceras were measured by M. Mendoza, C. M. Janis, and P. Palmqvist for body mass.

• Specimen 1: 8.79 kg (19.4 lb)
• Specimen 2: 11.1 kg (24.5 lb)
• Specimen 3: 8.85 kg (19.5 lb)
• Specimen 3: 9.91 kg (21.8 lb)

Fossil distribution

Fossils have been recovered from:

• Goshen Hole Formation, Goshen County, Wyoming
• Wiggins Formation, Fremont County, Wyoming