RE: Paralititan Theory

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

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Steven Coombs
>
> Charcharodontosaurus was an African dinosaur and when it lived 98
> to 93 MYA
> (Albian to early Cenomanian) it lived in the Northern part of
> Africa. An we
> all know that Charcharodontosaurus is related to Giganotosaurus,
> it evolved
> by crossing a landbridge to South America to where we get Giganotosaurus.
>
> I seen that Paralititan lived in the same region as
> Charcarodontosaurus, and
> Paralititan is a Titanosaurid and is related to Argentinosaurus.
> So could it
> be the same for Paralititan as Chararodontosaurus by crossing the
> landbridge
> to South America.
>
> Would this be a good theory?
>

There are many faunal similarities (including fish, amphibians,
non-dinosaurian reptiles, and of course carcharodontosaurs, spinosaurs, and
titanosaurs) between Aptian-Cenomanian northern Africa and Aptian-Cenomanian
South America (Argentina and Brazil).

However, one doesn't need to invoke a land bridge to explain these
similarities.  South America and Africa were connected to each other well
into the Early Cretaceous.  There is some debate as to when the final
rifting between these two continents occurred, but some estimates place this
within 10 million years or so of the deposition of the Rio Limay and
Baharija Formations (for example).  So it is possible that the similarities
of the fauna may be survival of a shared common assemblage rather than
evidence of a land bridge per se.

If you want to see some paleogeographic maps of the mid-Cretaceous here
(http://www.scotese.com/cretaceo.htm) and here
(http://vishnu.glg.nau.edu/rcb/100_1st.jpg).

Incidentally, these come from two of the most useful sites on the web for
Earth History:
Dr. Christopher Scotese' Earth History site:
http://www.scotese.com/earth.htm

and Dr. Ron Blakey's paleogeography pages:
http://vishnu.glg.nau.edu/rcb/globaltext.html

                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