[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Do we have dromaeosaurid evolution backward?

Not to contradict you here ;) , but Zanno and Makovicky actually left 
Ornitholestes unassigned, as they said its diet was inconclusive.  The only 
"herbivorous" characters it is coded as having are-
1. Decurved dentary.  Not obviously true in the left mandible, this is also 
found in Masiakasaurus, Coelurus and many (probably insectiviorous or 
piscivorous) Mesozoic birds.
2. Ischium longer than 66% pubic length.  This is the basic arrangement for 
theropods... er... archosaurs... er amniotes.  So this is present in 
carnosaurs, tyrannosauroids, megalosauroids, ceratosaurs, etc.. Not a 
herbivory-related character at all.
Given the fairly large, recurved teeth and generally 
carnosaurian-tyrannosauroid nature of the taxon, I would doubt if Ornitholestes 
had more plants in its diet than modern coyotes and such.
The "rather weak cursorial abilities" are based on a tibia which seemingly 
doesn't exist.  I'd like to know what happened to whatever bone Osborn 
identified as a tibia.

Mickey Mortimer

> Date: Fri, 19 Aug 2011 16:04:28 +1000
> From: tijawi@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: Do we have dromaeosaurid evolution backward?
> On Thu, Aug 18, 2011 at 7:53 PM, Renato Santos <dracontes@gmail.com> wrote:
> > Not that I haven't entertained the notion of Ornitholestes as a basal
> > dromaeosaur(id) ever since I noticed it had the incipient sickle claw.
> Not to contradict you here, but although _Ornitholestes_ has
> traditionally been regarded as a predator (including the day it was
> named), Zanno & Makovicky (2010) found that _Ornitholestes_'s
> characters did not correlate with a hypercarnivorous diet. Instead,
> _Ornitholestes_ was interpreted by this study as a possible herbivore
> or omnivore. Add to that the rather weak cursorial abilities of
> _Ornitholestes_ (especially compared to similar-sized coelurosaurs
> like _Coelurus_), and you have a "traditional form" that was arguably
> more similar to _Falcarius_ in its habits than to dromaeosaurids.
> Cheers
> Tim