Re: Theropod Diet and Niches

["David Marjanovic" <david.marjanovic@gmx.at>]

> <What is the current consensus on the diet of the following
> theropods?

Consensus... hmmm... there isn't much consensus AFAIK...

>  Ornithomimosauria

I'd say anything that was small enough. Isotopic investigations of bones
from 2 individuals seem to indicate that one was a carnivore and the other
one an omnivore.

>  _Caudipteryx_

Possibly insects (may explain its gastroliths: it pierced the insects with
its remaining needle-like teeth, and the gastroliths squeezed out the
contents) or maybe snails (see below).

>  _Nomingia_
>  Caenagnathidae
>  Oviraptoridae

Hm. They were apparently crushing something. The oldest suggestion is eggs;
consensus is that their beaks were overdesigned for that. Another suggestion
is clams; here some people say that their beaks were not strong enough for
that. I suggest the water snails that were abundant in LK Mongolia.
        HP Paul has suggested plants. This is believed by few and rarely
discussed, so I don't know many arguments for and against this. However, the
archives could be full of such discussions...

>  _Avimimus_

[whistling innocently]
Nobody seems to have thought about that one. However, this may change in
some months when the more complete specimens recently found are described in
JVP.

>  Confuciusornithidae

Leaves because their beaks were good for cutting. Maybe.

>  Enantiornithes>

This is a large and diverse group. Beakless forms like *Sinornis* were
probably insectivores, *Boluochia* with its hooked beak is agreed to have
been a bird of prey (never seen an illustration...)... no idea about
*Enantiornis*, *Gobipteryx* and the like.

> <Also, a question regarding HP Holtz's division of theropodan
> hypercarnivores into three categories based on hunting style
> (grapple-and-slash, grapple-and-bite, pursuit-and-bite). Into
> which of these three categories (if any) do the following
> theropods fit?
>  Compsognathidae
>  _Coelurus_
>  Troodontidae
>  _Archaeopteryx_
>  _Rahonavis_
>  _Microraptor_>

I don't know these categories. Anyway, the listed groups seem to have fed on
prey much smaller than themselves, so probably they don't fall into these
categories.