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big crocs



>     The really big crocodillian is a large argument in it's favor, because
>it had survived into the Pleiocene, and it had a large body mass, and
>crocodillians have pineal glands!!!!!  Quite probably the largest individuals
>did not survive, but the large species did actually make it through the
>calamity.

The giant Pliocene alligator is not a descendant of the two giant
Maastrichtian crocodiles.  It was an independant evolution of gigantism
within the Crocodylia.  As far as is known, Deinosuchus and the giant
species of Crocodylus did not survive the K-T boundary.

>     Troodon did not survive(as far as I know, however the finds  after the
>K-T barrier discussed that dinosaurs were found, but I don't know for sure
>what types or species did).
>   I will do more research into pineal gland function before I write more on
>this subject.   I still want to know why Troodon and Velociraptor didin't
>make it and the crocodillian did.

Since crocs have a considerably different life style than coelurosaurs,
there is probably a lot more than differences in pineal glands responsible
for differential survival.  Check into the paper listed below for some
evolutionary implications of pineal glands:

Roth, J.J., Roth, E.C., and Hotton, N. III.  1986.  The parietal foramen
and eye: their function and fate in therapsids.  In Hotton, N. III,
MacLean, P.D., Roth, J.J., and Roth, E.C. (editors), The Ecology and
Biology of Mammal-like Reptiles.  Smithsonian Institution Press, pp.
173-184.

                                     

                                
Thomas R. Holtz, Jr.
Vertebrate Paleontologist in Exile
U.S. Geological Survey
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA  22092

email:  tholtz@geochange.er.usgs.gov 
Phone:  703-648-5280
FAX:            703-648-5420