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RE: Archaeopteryx bone physiology



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Tom Holtz wrote:
=20
> But no non-avian dinosaur grows at the phenomenal rates like modern
> altricial birds=2C nor even as fast as precocial birds.
=20
But didn't large sauropods take only 15 years to reach full size? And hadro=
saurs only four=2C or something similar? But I guess that's still not as fa=
st as modern precocial birds.
=20
> Note what they state: "Growth analysis for Archaeopteryx suggests that th=
ese
> animals showed exponential growth rates like non-avialan dinosaurs=2C thr=
ee
> times slower than living precocial birds=2C but still within the lowermos=
t
> range for all endothermic vertebrates."

Well=2C there you go. I KNEW I missed something!

----------------------------------------
> From: tholtz@umd.edu
> To: tehdinomahn@live.com=3B dinosaur@usc.edu
> Subject: RE: Archaeopteryx bone physiology
> Date: Fri=2C 9 Oct 2009 14:39:05 -0400
>
>> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
>> On Behalf Of Michael Erickson
>>
>> This makes no sense. The authors claim that the slow growth
>> nature of *Archaeopteryx* bone is consistent with non-avian
>> dinosaur bone? Dinosaurs were VERY fast growers=2C according to
>> all studies I am aware of.
>
> But no non-avian dinosaur grows at the phenomenal rates like modern
> altricial birds=2C nor even as fast as precocial birds. Look at the right=
 hand
> plot of Fig. 9: the uppermost dashed line is altricial bird growth rates=
=2C
> and the next highest dashed line (for most of the figure: crosses under
> placental mammals above the 10 ton range) is precocial birds. Note that t=
he
> figure for Archie (the open diamond) is well below both lines
>
>> And how could Archaeopteryx (and
>> non-avian dinosaurs for that matter) possibly be ectothermic?
>
> Note what they state: "Growth analysis for Archaeopteryx suggests that th=
ese
> animals showed exponential growth rates like non-avialan dinosaurs=2C thr=
ee
> times slower than living precocial birds=2C but still within the lowermos=
t
> range for all endothermic vertebrates."
>
> Thomas R. Holtz=2C Jr.
> Email: tholtz@umd.edu Phone: 301-405-4084
> Office: Centreville 1216
> Senior Lecturer=2C Vertebrate Paleontology
> Dept. of Geology=2C University of Maryland
> http://www.geol.umd.edu/~tholtz/
> Fax: 301-314-9661
>
> Faculty Director=2C Earth=2C Life & Time Program=2C College Park Scholars
> http://www.geol.umd.edu/~jmerck/eltsite/
> Faculty Director=2C Science & Global Change Program=2C College Park Schol=
ars
> http://www.geol.umd.edu/sgc
> Fax: 301-314-9843
>
> Mailing Address: Thomas R. Holtz=2C Jr.
> Department of Geology
> Building 237=2C Room 1117
> University of Maryland
> College Park=2C MD 20742 USA
>                                         =0A=
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