[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: _Nanotyrannus_



>Message Originally Posted 25 March 1995:
>
>        The _Orlando Sentinel_ (Saturday, 25 March 1995, page A-3)
>featured an AP photo of a technician at Merida South Pointe Hospital in
>Warrensville Heights, Ohio, preparing to CAT-scan the skull of
>_Nanotyrannus_ (misspelled "Nanotyrannosaurus" in the caption).  According
>to the caption, "The tests . . . may help determine if the giant reptile
>was warm- or cold-blooded when it prowled the Earth"  (_sic_!). Any
>background on who's doing the research?
>                                                -= Tuck =-

[That's right - THIS is the question I responded too when the net crashed...]

They are probably refering to the work of John Ruben and his colleagues, on
the turbinal structure in various amiote groups.  Turbinals are the very
thin, very convoluted laticework of bone in the nasal cavities of many
animals.  They are associated with the sense of smell (attachment of
receptors) and respiration (e.g., trapping moisture being exhaled).

At SVP 1994, Ruben presented a very nice talk about the proposed physical
evidence for dinosaurian endothermy.  With each example, he showed how one
or more modern ectotherm demonstrates the same feature today.  So, about 13
minutes through the (15 minute) talk, he had pretty well established that
there is no feature yet found that can unequivocally be considered evidence
for endothermy.

Then, the last couple of minutes, he said that complex respiratory
turbinals (which are not yet known for dinosaurs) are unequivocal evidence
of endothermy.  He may be correct, but the first 13 minutes of his talk
suggest to me that more work needs to be done.

                                
Thomas R. Holtz, Jr.                                   
tholtz@geochange.er.usgs.gov
Vertebrate Paleontologist in Exile                  Phone:      703-648-5280
U.S. Geological Survey                                FAX:      703-648-5420
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA  22092
U.S.A.