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>>In the seas there were plesiosaurs (long necked sea beasts),
>>ichthyosaurs (the reptilian equivalent of dolphins),

>But _were_ they reptiles?  I suspect not, that body plan is built for
>a powerful swimmer.  If they weren't out-and-out warm-blooded, I suspect
>they were at least as much so as modern tuna.

>Larry Smith
>larrys@alpha.zk3.dec.com

All phylogenetic evidence for these groups show that they were
lepidosauromorphs (diapsids closer to lizards than to dinosaurs and other
archosaurs), and thus "reptillian".

However, too many people follow Bakker in conflating the taxonomic
statement "reptilian" with the physiological concept "warm-blooded" (in any
incarnation).  

As to their biology, ichthyosaurs were certainly very sophisticated, and
perhaps tuna-level heterotherms.

(Incidentally, I'm back, but at a new e-mail address)

                                     

                                
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