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re:babies and ecology (Bakker)



It occured to me that an inordinate amount of my posts (historically) have been to clear up Bob's opinion on something. I've had the privaledge of working with many other talented researchers, and yet somehow...anyway, you can draw your own conclusions there.

As for his baby ecology stuff. He is attempting to erect a new genus of allosaur, which he dubs "Wyomingraptor." He has been using this name for some time, but recently has found a specimen he thinks is different enough from the type(s) to warrant generic distinction. If this order of events seems anachronistic to you...anyway, the biggest problem here is that the name as-of-yet has no published validity, but his common use of a name with the suffix -raptor in it often confuses people into thinking he is referring to a dromaeosaur.
The "stegosaur attack" allosaur pubic boot that was found at Nail quarry is almost certainly the result of a blood born pathology, not an impact fracture. The pathology that fused two caudal dorsals together may be related (Rothchild didn't think so), and it was certainly caused by a blood born pathology. It preserves the gross shape of soft tissue below it, and looks very similar to the pathology Chris Brochu has reported on two of Sue's caudal vertebrae. However, whereas the Sue pathology is almost certainly an imprint of the underlying musculature, I would suggest that it's equally plausible that the Nail specimen may reflect the shape of the kidneys rather than trunk musculature.
As for the evidence for baby feeding itself? Equivicable. The parallel grooves on "prey" material does suggest wear-by-teeth rather than depositional abrasion. On the other hand, the "baby" bite marks are distinguised by the proximity of the grooves only...which could also be due to an adult allosaur raking it's teeth across a bone at an oblique angle.
There are only allosaur teeth found at the site. The large number of chewed bones and very heterogenic taxanomic makeup of the "chewies" does suggest that predators were responsible for concentrating the bones in the quarry. The fact that only allosaur teeth are found, and that there are teeth from very imature allosaur specimens does suggest that allosaurs were excluding other predators from the food concentration, possibly to the benefit of their young. Finally, allosaur forelimb functional anatomy is consistent with modification to reduce stress during mechanical laoding for extended periods, i.e. they could have been improving their ability to carry food to their young, although there may be other more important reasons for these features.


A WARNING TO JURASSIC TEETH PEOPLE

I have run into a number of people who are researching possible maniraptoran teeth from the morrison. Good. But the denticles of alosaur teeth scale allometrically, resulting in an uncanny resembalance of juvenile teeth to the those of troodonts. At the Wyoming Dinosaur Center in Thermopolis, for exapmle, they had identified many juvy allo teeth as possible troodonts. Beware!

Finally

Bob Bakker is no longer associated with the Tate Museum. The collections from Como Bluff are now housed at Glen Rock, Wyoming, which is approx. 25 miles east of Casper. But the Tate still has some interesting stuff...more on that in mid-October.

Sorry about the long email...

Scott
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