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Tooth Decay Found On 100 mya Ichthyosaur Tooth

Came across this by chance...hand't really considered tooth decay on these
critters before.


Thursday, 6 February, 2003, 15:04 GMT

As the young sea creature swam through the prehistoric sea, it probably
felt a slight pain in its mouth - a toothache.

Things went from bad to worse when the juvenile ichthyosaur became sick or
was attacked, and was left for dead on the seabed.

Nearly 110 million years later its fossilised skeleton has been found in
Queensland, Australia, and that tiny tooth has become a vital clue for

Palaeontologist Ben Kear says the tooth decay is providing information
about the creature's eating habits. 
"The discovery of dental caries (cavities) in ichthyosaurs is not simply a
novel find.

"It provides us with invaluable clues for reconstructing aspects of
behaviour and biology in an animal that has been extinct for over 90
million years and has no living descendants or even relatives."

The U-shaped cavity Mr Kear discovered is just 1.83mm high and 3.97mm

After studying it with an electron microscope, he has made deductions
about how ichthyosaurs may have attacked their prey.

"Perhaps they were more vicious when feeding than has been previously
suspected, actively tearing the prey apart by shake feeding like a shark.

"Such active food processing would have facilitated the entrapment of food
particles between the teeth and allowed dental caries to develop."

Mr Kear, based at the South Australian Museum, said the discovery of tooth
decay in any fossilised reptile, such as dinosaurs or ichthyosaurs, was
"almost unheard of".