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Re: Dinosaurs burrowed to keep warm



Dann Pigdon wrote:

I haven't read the paper itself, but apparently the robust forelimbs and structure of the jaw may be adaptations for some sort of digging activity.

There's adaptations in the pelvic region too. As digging adaptations in _Oryctodromeus_, the authors mention a wide, fused premaxillae (to loosen or move dirt); robust scapula with a prominent acromion process and scapular spine (for muscle attachments); and a strengthened 'fulcrum' in the pelvic region (including seven sacrals, and expanded proximal caudals).


Several of these features are also seen in _Zephyrosaurus_ and _Orodromeus_, and (not surprisingly) the phylogenetic analysis recovers these two and _Oryctodromeus_ as a clade. This clade might have been specialized for digging, say the authors. The clade comes out near the base of the Euornithopoda, above an _Agilisaurus_-_Yandusaurus_-Othnielia_ clade, and below other "hypsilophodont-grade" ornithopods.

There's no mention of _Drinker_. I had a vague recollection that Bakker had mentioned that _Drinker_ had been found in burrows, but I don't know if this was actually published (at least scientifically).

I wonder whether the tails of these species were less stiffened than the 'average' hypsilophodontid?

No mention of that. In fact, the base of the tail is reinforced.

Cheers

Tim

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