Menoceras
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 . Description. 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. Either gender of "Menoceros" grew to a length of 5 feet (1.5 meters) long. Paleobiology. "Menoceras" roamed across a tropical, savanna-like grassland and  plains environment that covered much of North America. Because of the massive accumulations of fossil bones of this animal, particularly at Agate Springs Nebraska, "Menoceras" may have lived in large herds. Other sites include Martin-Anthony site Martin County, Florida, and Cady Mountains Horse Quarry, San Bernardino County, California. Taxonomy. "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. Tanner (1969), Wilson and Schiebout (1981), Prothero and Manning (1987), Carroll (1988) and  Prothero et al. (1989); and to Menoceratinae by Prothero (1998). Fossil distribution. 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)" It was reposited in the Smithsonian Institution, Washington, D.C. Other sites: