New Ruben et al. dinosaur physiology reference

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

Greetings,

I don't recall seeing this before, but here is a new paper out by Ruben et
al. The abstract is included.  It is primarily a review and summary of their
previous work: nice to have it all in one place.

The URL for the issue is:
http://www.journals.uchicago.edu/PBZ/journal/contents/v76n2.html

Physiological and Biochemical Zoology 76(2):141-164. 2003.
INVITED PERSPECTIVES IN PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY

Respiratory and Reproductive Paleophysiology of Dinosaurs and Early
Birds

John A. Ruben, Terry D. Jones, Nicholas R. Geist,


ABSTRACT

In terms of their diversity and longevity, dinosaurs and birds were/are
surely among the most successful of terrestrial vertebrates.  Unfortunately,
interpreting many aspects of the biology of dinosaurs and the earliest of
the birds presents formidable challenges because they are known only from
fossils. Nevertheless, a variety of attributes of these taxa can be inferred
by identification of shared anatomical structures whose presence is causally
linked to specialized functions in living reptiles, birds, and mammals.
Studies such as these demonstrate that although dinosaurs and early birds
were likely to have been homeothermic, the absence of nasal respiratory
turbinates in these animals indicates that they were likely to have
maintained reptile-like (ectothermic) metabolic rates during periods of rest
or routine activity. Nevertheless, given the metabolic capacities of some
extant reptiles during periods of elevated activity, early birds were
probably capable of powered flight. Similarly, had, for example, theropod
dinosaurs possessed aerobic metabolic capacities and habits equivalent to
those of some large, modern tropical latitude lizards (e.g., Varanus), they
may well have maintained significant home ranges and actively pursued and
killed large prey. Additionally, this scenario of active, although
ectothermic, theropod dinosaurs seems reinforced by the likely utilization
of crocodilian-like, diaphragm breathing in this group. Finally, persistent
in vivo burial of their nests and apparent lack of egg turning suggests that
clutch incubation by dinosaurs was more reptile- than birdlike. Contrary to
previous suggestions, there is little if any reliable evidence that some
dinosaur young may have been helpless and nestbound (altricial) at hatching.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796