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RE: Spinosaurus redescribed as giant semiaquatic theropod

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of Tim 
> Williams
> The authors interpret _Spinosaurus_ as a semiaquatic predator that targeted 
> aquatic prey: sharks, sawfish, coelacanths, lungfish, ray-
> finned fishes.  (BTW, there were some whopping big lungfish around at the 
> time.)  The concept of _Spinosaurus_ as an ambush
> predator awaiting the approach of thirsty terrestrial prey is difficult to 
> accord with its overall size (specifically height).  It would be
> difficult for an adult _Spinosaurus_ to 'lurk' in shallow water.
> The piscivorous , semiaquatic lifestyle inferred for _Spinosaurus_ has been 
> compared to early cetaceans ("archaeocetes").  One major
> difference is that early cetaceans evolved from terrestrial quadrupeds, 
> whereas theropods were bipeds (and still are).  The
> semiaquatic _Spinosaurus_ has been regarded as a quadruped when on land, due 
> to its highly reduced pelvis and hindlimb.  We'll
> have to see how this mooted terrestrial quadrupedality stacks up with future 
> discoveries regarding the pectoral/forelimb/manus
> morphology of _Spinosaurus_.  It is even possible that _Spinosaurus_ rarely 
> ventured onto terra firma, except to lay eggs (like
> hesperornithids).
> As a sidebar, the humerus referred to _Spinosaurus_ is especially 
> contentious...
> https://twitter.com/JohnRHutchinson/status/510961698782457856

Rather than go through Hutchinson's link to the blog, here is a direct link to 
the relevant blog post: 

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA