Menoceras Temporal range: early Miocene[1] |
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Mounted skeleton | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Perissodactyla |
Family: | Rhinocerotidae |
Genus: | †Menoceras (Troxell, 1921) |
Type species | |
†Diceratherium arikarense |
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Species[2] | |
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Synonyms | |
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Menoceras ("Crescent Horns") is a genus of extinct, small rhinoceros endemic to most of southern North America and ranged as far south as Panama during the early Miocene epoch. It lived from around 30.7—19.7 Ma, existing for approximately 11 million years.
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Menoceras roamed a grassland and plains environment of the North America (Prothero, 2005). Because of the massive accumulations of fossil bones of this animal, particularly at Agate Springs Nebraska, Menoceras may have lived in large herds. However, other sites i.e. Martin-Anthony site Martin County, Florida, and Cady Mountains Horse Quarry, San Bernardino County, California.[4]
Male Menoceras sported two horns side by side at the tip of the nose, whereas the females were hornless. All other rhino genera, save the related genus Diceratherium, have their horns arranged one behind the other. Menoceros grew to a length of 5 feet (1.5 meters) long, around the size of a large pig.
Menoceras was named by Troxell and assigned to Rhinocerotidae by Troxell in 1921. It was synonymized subjectively with Diceratherium by Matthew in 1931 and Wood in 1964. Again assigned to Rhinocerotidae by Prothero, Guerrin, Manning in 1989.[5] Tanner (1969), Wilson and Schiebout (1981), Prothero and Manning (1987), Carroll (1988) and Prothero et al. (1989); and to Menoceratinae by Prothero (1998).[6]
Fossil distribution is as far north as New Jersey, south to Florida (3 collections) and Texas (6 collections), as far west as Nebraska (7 collections) and California (2 collections).
The Panamanian find was determined to be 19.7 Ma (AEO). It was found in the Gaillard Cut in Panama in "a 45 m thick section (narrow stratigraphic interval)"[7] It was reposited in the Smithsonian Institute, Washington, D.C. Other sites:
Three specimens were examined for estimated body mass by M. Mendoza, C. M. Janis, and P. Palmqvist. [8] These specimens were estimated to weigh:
One specimen was examined by Mikael Fortelius, University of Helsinki and J. Kappelman[9] and estimated a body mass of: