Sometimes you work on a fossil and just think "oooh, that had to hurt". This tail from a pretty large
Clidastes from the upper Niobrara chalk is fairly boring when viewed from afar. Up close though something just doesn't look right.
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Yep, pretty boring |
Of the 45 bones, 23 are pathological, with 17 of them fused at the centrum in 5 separate masses. All of these bones lack transverse processes, so they come from the lower lobe of
Clidastes' bifurcated tail fin: a bit of dangling flesh that might make for a tasty morsel for a predator.
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I think this mass used to be 8 separate vertebrae, based on the number of chevrons |
The bones, though mostly healed, show bone growth consistent with a long infection. As the tail was the primary means of locomotion/propulsion for mosasaurs, this injury must have been very painful for a very long time for this mosasaur.
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3 verts become one |
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Fused verts, and centra with vertical scars |