English: Procamelus grandis Gregory, 1939 - fossil ancestral camel skull from the Miocene of Nebraska, USA.

This fossil skull is from an ancestral camel, the bones of which show symptoms of a lung disease caused by inhalation of volcanic ash. The specimen comes from Nebraska's Ashfall Fossil Beds, where wind-blown volcanic ash buried a vertebrate-rich biota at what was originally a Miocene waterhole. The source volcano was in the Bruneau-Jarbidge Volcanic Field in southwestern Idaho's Snake River Plain.

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From on-site info.:

Patches of light-colored, porous bone are symptoms of lung disease.

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Except for horses, camels were the most abundant medium-sized animals found in the Ashfall Fossil Beds. Remains of several dozen individual camels - from young calves to adults of both sexes - have been found in the volcanic ash bed. Apparently an entire herd of medium-sized camels died in the waterhole, mostly belonging to the species Procamelus grandis. Detailed studies of the skeleton and skull of this species support the idea that it is the ancestor of the one-humped and two-humped camels that live in Asia and Africa today.

Adult males were about 5 feet tall at the shoulders. Females were slightly smaller.

Procamelus means "before" or "ancestral to" the camel.

Remains of this animal have been found: X - in the "RECOVERY" layer (sandstone above the ash) X - in the "DISASTER" layer (volcanic ash bed) X - in the "WATERHOLE" layer (sandstone below the ash)

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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, Artiodactyla, Camelidae

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

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

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

en.wikipedia.org/wiki/Ashfall_Fossil_Beds