[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
RE: Archaeopteryx bone physiology
> 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, according to
> all studies I am aware of.
But no non-avian dinosaur grows at the phenomenal rates like modern
altricial birds, 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,
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 the
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 these
animals showed exponential growth rates like non-avialan dinosaurs, three
times slower than living precocial birds, but still within the lowermost
range for all endothermic vertebrates."
Thomas R. Holtz, Jr.
Email: email@example.com Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Faculty Director, Earth, Life & Time Program, College Park Scholars
Faculty Director, Science & Global Change Program, College Park Scholars
Mailing Address: Thomas R. Holtz, Jr.
Department of Geology
Building 237, Room 1117
University of Maryland
College Park, MD 20742 USA