November 24th, 2012 by James Ayre
A 9.2 million years old fossilized rhino skull has been discovered buried in volcanic ash. Fossils preserved in volcanic rock are very rare, and account for less than two percent of the world’s known specimens.
The specimen was discovered in Turkey, by Pierre-Olivier Antoine and his fellow researchers from the University of Montpellier, France.
The fossil is of a large two-horned rhino species that was common in the area around the Eastern Mediterranean during that time period. “According to the researchers, unusual features of the preserved skull suggest that the animal was ‘cooked to death’ at temperatures that may have approached 500° C, in a volcanic flow similar to that of the eruption of Mt. Vesuvius in Italy in 79 A.D.”
The death would have been nearly-instantaneous, and followed immediately by extreme dehydration of the body. The researchers describe it thusly, “the body was baked under a temperature approximating 400°C, then dismembered within the pyroclastic flow, and the skull separated from body.” The skull was then carried over 30 km north of the eruption site by the volcanic flow.
Fossils of soft-bodied organisms have been found preserved in volcanic ash before, but it is very rare. The extreme temperatures of a volcanic eruption typically completely destroy organic matter, leaving no trace.
The finding was just described in a paper published November 21st in the open access journal PLOS ONE.
Some background on rhinos:
“Rhinoceros, often abbreviated as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia.”
“Members of the rhinoceros family are characterized by their large size (they are some of the largest remaining megafauna, with all of the species able to reach one tonne or more in weight); as well as by a herbivorous diet; a thick protective skin, 1.5–5 cm thick, formed from layers of collagen positioned in a lattice structure; relatively small brains for mammals this size (400–600 g); and a large horn. They generally eat leafy material, although their ability to ferment food in their hindgut allows them to subsist on more fibrous plant matter, if necessary. Unlike other perissodactyls, the two African species of rhinoceros lack teeth at the front of their mouths, relying instead on their powerful premolar and molar teeth to grind up plant food.”
Modern rhinos have had their numbers severely reduced over the past century as a result of poaching, and many species run a real risk of going extinct in the coming decades. Three of the five currently extant species are listed as critically endangered by the IUCN.
“Rhinoceros are killed by humans for their horns, which are bought and sold on the black market, and which are used by some cultures for ornamental or (pseudo-scientific) medicinal purposes. The horns are made of keratin, the same type of protein that makes up hair and fingernails. During 2011, 448 rhino were killed for their horn in South Africa alone.”
There are estimated to be less than 275 sumatran rhinos, less than 5,000 black rhinos, and less than 50 javan rhinos remaining in the wild. And many other subspecies have already been declared extinct.
Image Credits: Reconstruction by Maëva J. Orliac; Antoine et al.. (2012) A Rhinocerotid Skull Cooked-to-Death in a 9.2 Ma-Old Ignimbrite Flow of Turkey. PLoS ONE doi:10.1371/journal.pone.0049997; Rhinos via Wikimedia Commons
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