File:Teleoceras major (fossil barrel-bodied rhino) skull (Ash Hollow Formation, Miocene, 11.83 Ma; Ashfall Fossil Beds, Nebraska, USA) 1.jpg

English: Teleoceras major Hatcher, 1894 - fossil barrel-bodied rhinoceros skull from a Miocene ash fall deposit in Nebraska, USA.

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From on-site info.:

Skull of young female rhino

This skull was removed during construction of the Rhino Barn. It shows clear evidende of the excess bone growth caused by suffocation over a period of weeks (hypertrophic pulmonary osteodystrophy). The small incisor tusk shows that the animal was female and the presence of one heavily-worn milk tooth in the upper and lower jaws indicates she was not fully mature.

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The most abundant large animal discovered in the volcanic ash bed is an extinct rhinoceros with a body shape similar to today's hippopotamus. Like hippos, barrel-bodied rhinos may have wallowed in the waterholes that dotted the ancient savannas of the Great Plains. Unlike modern-day rhinos, which are primarily solitary creatures, the Nebraska rhino probably was a social species that formed herds. By studying the age and sex of more than 100 skeletons from Ashfall, paleontologists concluded that Teleoceras males (with large tusks) may have defended "harems" of females (with small tusks) and their calves. Young adult male skeletons are remarkably rare in the ash bed, suggesting that "bachelor males" may have been excluded from the breeding herds and forced to live elsewhere.

Adult males were only about 3.5 feet tall at the shoulder but were over 10 feet long and 10 feet in circumference around the belly. Females measured 20% smaller.

[Teleoceras - ] the name means "perfect horn" and refers to the fact that both mle and female skulls have rough bumps near the end of their nasal bones, proving that they had a true horn in life.

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All mammal skeletons from the volcanic ash bed in Ashfall Park show a condition called "Marie's Disease", or Hypertrophic Pulmonary Osteodystrophy (HPOD). In modern animals, this abnormal bone growth is associated with lung failure (prolonged suffocation). The volcanic ash that covered the area nearly 12 million years ago was so fine-grained that it apparently caused HPOD in all mammals that could not retreat into burrows.

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Classification: Animalia, Chordata, Vertebrata, Mammalia, Perissodactyla, Rhinocerotidae

Stratigraphy: Cap Rock Member, Ash Hollow Formation, Ogallala Group, Miocene, 11.83 Ma

Locality: Hubbard Rhino Barn, Ashfall Fossil Beds State Historical Park, northeastern Nebraska, USA

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Info. at: en.wikipedia.org/wiki/Teleoceras and

en.wikipedia.org/wiki/Ashfall_Fossil_Beds