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RE: Wrong Reconstructions
It's pretty tricky labeling scansoriopterygids as similar to much of
anything, given how divergent their anatomy is and how little we know about
simple things like skull anatomy. *Epidexipteryx* differs quite a bit from
*Epidendrosaurus*/*Scansoriopteryx*, impairing the use of the skull as an
extrapolation, and that's most of what fills in the details of skeletal anatomy
that is lacking in the latter specimens. In those specimens/taxa, all that we
have of the skull are partial braincases, posterior mandibles, and a
bowed-U-shaped mandibular symphysis without any clear indication of teeth,
while *Epidexipteryx* has fantastic detail and huge teeth.
The real issue is that aside from the "ebff"s, "feathers" in all fossils are
non-plumulaceous, lacking apparent barbs, and nothing similar to "feathers" in
the conventional (modern) sense.
Varricchio's theories on male multi-clutch brooding and unlikelihood of
pair-bond feeding "chicks" in "Troodon" nests found in Two Medicine may be
accurate, but there are a few caveats:
The nests Varricchio is referring to are similar to those of *Citipati
osmolskae* in forming concentric rows of stacked eggs set in pairs around a
common center; this laying pattern is consistent with a single female laying,
rotating, laying, rotating, etc. and not consistent with multiple females
laying in a common clutch. At least some older papers referred nests now
considered to belong to *Orodromeus makelai* to "troodontids," showing a less
organized, erratic clutch pattern similar to that advocated by Varricchio of
"Troodon" in the Two Medicine.
So on this point at least, Varricchio would be correct but about the wrong
taxon. Implications of *Citipati osmolskae* and "Troodon" nests indicate rather
that there were female brooders, while juvenile fossils found in oviraptorid
nests imply prey may have been gathered at the nest, possibly to feed
hatchlings. If so, the last two images would be correct on the brooding/feeding
You'll have to forgive the next bit.
Owl auditory bullae are large, very large, and extend largely to the external
margins of the skull, such that the ear is essentially flush with the skull of
the head. In a facial disk, this permits the sound to transfer directly into
the funnel without being redirected at an angle before entering the auditory
canal. Troodontids (or at least the Dinosaur Park skulls) lack the auditory
bullae seen in owls, and the otic region is confined to within the braincase
and between the quadrates, rather than extended poteriorly and lateral to them.
This makes the case of a troodontid facial disk highly unlikely. I must say,
however, that the restoration is fantastic and you should go ahead with it
Jaime A. Headden
The Bite Stuff (site v2)
"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)
"Ever since man first left his cave and met a stranger with a
different language and a new way of looking at things, the human race
has had a dream: to kill him, so we don't have to learn his language or
his new way of looking at things." --- Zapp Brannigan (Beast With a Billion
> Date: Tue, 25 Jan 2011 12:17:19 -0500
> From: email@example.com
> To: firstname.lastname@example.org
> Subject: Wrong Reconstructions
> I have posted three incorrect reconstructions of maniraptorans on my website.
> I drew them between 2003 and 2008. I am looking forward to hearing the
> thoughts of dml'ers on the subject of reconstruction errors.
> Jason Brougham
> Senior Principal Preparator
> American Museum of Natural History
> (212) 496 3544