Re: Re: Therizinosaurus

[Thomas_R_HOLTZ@umail.umd.edu (th81)]

>>>Giganotosaurus is, I belive, Cenomanian, so it is indeed a little younger
>than Acrocanthosaurus.
>
>Other giant non-tyrannosaurid theropods include the ?allosaurid
>Chilantaisaurus, the allosaurid Saurophaganax, the megalosauroid Torvosaurus
>(=Edmarka), Carcharadontosaurus, Bahariasaurus, Spinosaurus, and
>Deinocheirus.
> Oops, forgot Therizinosaurus, too.<<
>
>Therizinosaurus?  I recall that there was evidence that _Therizinosaurus_
>isn't a theropod at all.  Some say, and I trust, that Therizinosaurus is
>really an herbivorous segnosaur, a late-surviving relative of the
>sauropodomorpha.

Recent discoveries by Dale Russell and others point (arguably) to a theropod
origin for the Therizinosauroidea (formerly Segnosauria).

> Those claws did not really look like they were suited for
>killing; I don't think the claws were really THAT sharp and efficient.

Being a theropod does not automatically make you a predator.  Several
theropod lines (ornithomimid, troodontid, oviraptorosaur, therizinosaur, and
many, many lines of birds) evolved omnivory, herbivory, molluscivory, and
other diets.

> More
>or less, like the iguanodont spike-thumb, Therizinosaurus's claws, if it was
>indeed a segnosaur, were probably for defense against predators...
 
The claws of Therizinosaurus are the most blade-like of any theropod.  As
well as defense, they may have served in some manner for food procurement.

>Then again, I may be wrong.

No, you just mention one of a couple of possibilities.

Thomas R. Holtz, Jr.
Vertebrate Paleontologist
Dept. of Geology
University of Maryland
College Park, MD  20742
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
Fax: 301-314-9661
Phone:301-405-4084