segnosaurs & sloths

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

>From: egood@ALPHA2.CURTIN.EDU.AU
> >
> >     I find it hard to imagine dinosaurs as large as the segnosaurs
> > existing on insects. ...
> > Most insectivrous creatures today are small, with the exceptions of the
> > aardvark, and the giant anteater.
>
>It is interesting to note that these, the largest modern insectivores,
>are slow-moving, and specialize in insect that can be found in large
>concentrations (eusocial ones, that is).
>
>Of course the suggestion that the segnosaurs may have been insectivores
>comes from the general similarity of the Therizinosaurus claws to those
>of anteaters - which it uses to open termite mounds and ant hills.
>
>Still, an anteater the size of Therizinosaurus rather boggles the mind.
>Those ants must sure have been large :-)

Not to say that I support the idea of an arboreal ancestor of the
therizinosauroids (aka segnosaurians), but it IS interesting that, of all
mammals, ground sloths seem to be the best analogue for these strange
dinosaurs.  And ground sloths, after all, were simply the giant,
herbivorous, secondarily-terrestrial descendants of small,
once-insectivorous, then-herbivorous, arboreal forms...

(The two "D. Russells", Don E. and Dale A., consider therizinosaurs to be
chalicothere analogues.)

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