Josephoartigasia monesi – a giant rodent that lived in what is now Uruguay from the Pliocene to early Pleistocene, 4 to 2 million years ago – may have used its incisors just like an elephant uses its tusks, according to a group of paleontologists headed by Dr Philip Cox from the University of York, UK.
Josephoartigasia monesi. Image credit: James Gurney.
Discovered in 2008, Josephoartigasia monesi is the largest fossil rodent ever found.
This species was about 3 meters in length and had an estimated body mass of approximately 1,000 kg.
In a new study, Dr Cox and his colleagues used computer modeling to estimate how powerful the bite of the species could be.
The study involved CT scanning the Josephoartigasia monesi specimen and making a virtual reconstruction of its skull.
This was then subjected to finite element analysis, an engineering technique that predicts stress and strain in a complex geometric object.
The scientists found that, although the Josephoartigasia monesi’s bite forces were very large – around 1400 N, similar to that of a tiger, its incisors would have been able to withstand almost three times that force.
“We concluded that the rodent must have used its incisors for activities other than biting, such as digging in the ground for food, or defending itself from predators,” said Dr Cox, the first author of a paper published in the Journal of Anatomy.
“This is very similar to how a modern day elephant uses its tusks.”
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Philip G. Cox et al. Predicting bite force and cranial biomechanics in the largest fossil rodent using finite element analysis. Journal of Anatomy, published online February 04, 2015; doi: 10.1111/joa.12282
