Dinopic of the day 9: OUCH!

Ouch! This hurts!

The neural arches and the base of the tail of another Brachylophosaurus canadensis from the Judith River Dinosaur Institute. This is JRDI 0002, and although preservation is again excellent, as in the case of JRDI 200 of Dinopic 8 and JRDI 116H of Dinopic 4, this find is much less complete. Erosion has taken the entire body but for part of the hips away, along with skull, neck, and the limbs except for a femur head. All that remains is a beautifully preserved tail and hips, with a big old bite mark on it. One that had started to heal quite a bit, too. Check out the huge callusses on the neural arches. One neural arch has been bitten off – yes, I am sure there is not simply a piece missing. The callus has not broken off, but runs “smoothly” (as far as a callus surface can do that) around the entire tip of the neural arch stub. Maybe the missing piece was not ripped out of the body, and was later lost during burial, fossilization or excavation, but this neural arch was certainly in two separate pieces after the bite.

The ossified tendons got shredded quite a bit, too. You can’t see it in this pic, but on all the rest of the tail they are in prefect order and shape. Only where the callus formation indicates injury are they mangled and torn to bits and pieces.

Interestingly, this attack happened in the one place I would choose as ideal. If you’re a predator that can bite into a hadrosaur from the top, the base of the tail is the place where the least damage has the greatest effect, unless you manage to grab hold of the neck. If you sever the epaxial muscles and tendons at the tail base, the hadro can’t run anymore. They are needed to keep the tail from flexing down when the caudofemoralis muscle contracts to pull the hindlimb back. If the tail flexed down, running is massively inhibited and you’re sure of your prey.

About Heinrich Mallison

I'm a dinosaur biomech guy
This entry was posted in Dinopics, Dinosauria, Hadrosauridae, JRDI, Ornithischa. Bookmark the permalink.

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