Prosynthetoceras is an 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 early Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

 epoch (Hemingfordian to Barstovian

Barstovian

The Barstovian 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 16,300,000 to 13,600,000 years BP, a period of . It is usually considered to overlap the Langhian and Serravallian...

 stages) 20.6—13.6 Ma, existing for approximately .

Taxonomy

Prosynthetoceras was named by Patton (1967) [named as subgenus of Synthetoceras by Frick 1937; raised to genus level (?)]. It is not extant. It was assigned 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 Patton (1967) and Carroll (1988); and to Synthetoceratini

Synthetoceratini

Synthetoceratini is an extinct tribe of the subfamily Synthetoceratinae within the family Protoceratidae belonging to the order Artiodactyla endemic to North America during the Miocene, living epoch 20.6—4.9 Ma, existing for approximately .-Taxonomy:...

 by Webb (1981), Prothero (1998), Webb et al. (2003) and Prothero and Ludtke (2007).

Morphology

In appearance, Prosynthetoceras looked much like Syndyoceras

Syndyoceras

Syndyoceras is a small extinct genus of Artiodactyla, of the family Protoceratidae, endemic to central North America from the Eocene epoch 24.8—20.6 Ma, existing for approximately .-Taxonomy:...

, Kyptoceras

Kyptoceras

Kyptoceras is a small extinct genus of Artiodactyla, of the family Protoceratidae, endemic to southeastern North America from the Miocene to Early Pliocene epoch 23.03—3.6 Ma, existing for approximately .-Taxonomy:...

, and Synthetoceras

Synthetoceras

Synthetoceras is a large extinct genus of Artiodactyla, of the family Protoceratidae, endemic to North America from the Miocene epoch, 13.6—5.33 Ma, existing for approximately .-Taxonomy:...

 with rostral or snout horns and cranial horns above the orbital socket

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...

s.

Body mass

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

• Specimen 1: 95.5 kg (210.5 lb)
• Specimen 2: 88.2 kg (194.4 lb)
• Specimen 3: 108.2 kg (238.5 lb)
• Specimen 4: 78.9 kg (173.9 lb)