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Or just among maniraptorans in general. Not many avians are
Yes, true. But archaeopterygids may have been, so I thought I'd limit my
generalization to non-avian maniraptorans.
Given their size, I find it hard to not imagine lots of insects in their
However, there's *Shenzhouraptor* with the gingko fruits in its stomach, and
then there's *Omnivoropteryx*. I suppose those are why Lindsay Zanno simply
declared the birds ancestrally omnivorous in her talk without further
comment. As far as I remember, she used up her whole 15 minutes, which means
there was no time for questions.
I avoided citing "noncarnivory" as a maniraptoriform trend because some
phylogenetic analyses recover predatory theropods such as _Ornitholestes_,
compsognathids, and even tyrannosaurids inside Maniraptoriformes (i.e.,
closer to birds than ornithomimosaurs are).
Her own analysis seems not to.
There's _Boluochia_ of Early Cretaceous (Barremian) age, which had a
hooked beak and so might have been predatory.
And then there are all those avisaurids with big claws in general and a very
big claw on the 1st toe in particular. Strongly curved claws, too. No skulls
Darn, wish I'd seen Lindsay's talk. (Sadly, I wasn't at SVP either, but
Bristol is looking promising.)
Here's the abstract:
The phylogeny of Therizinosauria (Theropoda: Maniraptora): Implications for
the evolution of coelurosaurs
The past decade has witnessed a surge in our knowledge of therizinosaurs.
From their once poor fossil representation, these bizarre raptor dinosaurs
[!] are rapidly becoming one of the most diverse theropod clades, with at
least 14 species arrayed across Asia and North America. Within the past
eight years alone, more new therizinosaurs have been described than were
known during the preceding half century of paleontological research. Once a
topic of controversy, the broad phylogenetic relationships of therizinosaurs
have recently been substantiated by the discovery of "transitional" Early
Cretaceous forms (e.g. *Beipiaosaurus*, *Falcarius*) whose anatomy indicates
a clear ancestry among maniraptoran dinosaurs. However, in-group
relationships among therizinosaurs are poorly constrained and the purported
monophyletic relationship between Therizinosauria [sic] and
Oviraptorosauria, although a widespread hypothesis, has received little
testing in a comprehensive phylogenetic framework. The recent discovery of
the most primitive and most complete therizinosaur known -- *Falcarius
utahensis*, from the Barremian of Utah -- offered the opportunity to
reevaluate our current understanding of this intriguing group of theropods
in light of novel anatomical information. A comprehensive phylogenetic
analysis of 14 therizinosaurs, 62 outgroup taxa, and 345 characters was
conducted to test previously proposed hypotheses on the evolution of
therizinosaurs. Results of this analysis support Therizinosauria as sister
taxon to all other maniraptoran lineages, and do not indicate a monophyletic
grouping with oviraptorosaurs. The unusually high degree of convergence
between these groups underscores the critical role of primitive taxa in
phylogenetic studies of coelurosaurian theropods. Several evolutionary
trends evident in basal therizinosaurs and oviraptorosaurs (e.g. marked
heterodonty characterized by elongate, incisiform rostral teeth) are
indicative of a dietary shift from macrofaunal predation. These features
coupled with the alternative dentition of basal ornithomimosaurs and
alvarezsaurs suggest that dietary experimentation may have been a primary
driver in the rapid diversification of Coelurosauria.
Anyway, in the case of troodontids, if these were non-hypercarnivorous,
this was probably secondary given that _Sinovenator_ (the most basal known
troodontid) was most like dromaeosaurids in its ecomorphology.
What about *Jinfengopteryx*? And who except Scott knows where this one
http://dml.cmnh.org/2005Oct/msg00461.html belongs and what teeth it has...