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Well, it seems as if Sereno and his team are
leaving Inner Mongolia. I've assembled a list of dinosaur discoveries they
mention and photograph on the site. There are several very cool looking
specimens. I can't wait to see what will be published in Science next
year.
Theropoda indet.
Late Cretaceous
material- partial skull including jaws and
teeth
description- This is a large form. The
premaxillary teeth are said to be non-incisiform, which indicates it is not a
tyrannosauroid. The lateral teeth also suggest this, as they are narrow
and blade-like, not robust as in tyrannosaurids. Being in the Late
Cretaceous, there are few possibilities for its identity- abelisaurid,
carcharodontosaurid, basal coelurosaur, dryptosaurid,
dromaeosaurid.
Coelurosauria? incertae sedis
Late Cretaceous
material- (juvenile?) vertebrae, ribs, caudal
series, radius, ulna, manus, hindlimbs, pedes
description- Not nearly enough was said of this
specimen. Something with an elongate, tridactyl manus.
Coelurosauria? indet.
Cretaceous
material- pedal phalanx
Dryptosauridae? incertae sedis
Early Cretaceous
material- forelimb elements, manual ungual (127
mm)
description- The
manual ungual resembles Dryptosaurus most, differing only in the more extensive
area under the lateral groove proximally and possibly the more anteriorly placed
flexor tubercle (assuming the area isn't broken). Perhaps the two are
related. Segnosauria incertae sedis
Late Cretaceous
material- partial skeleton including
forelimb
Troodontidae? incertae sedis
Late Cretaceous
material- many elements including two cervical
vertebrae and manual ungual
description- Sereno et al. refer to this as a
dromaeosaurid, but based on the photos, I have some doubts.
Differences from Deinonychus- much more elongate
cervicals; ventral margin of centra more concave; much lower neural spines; more
gently curved dorsal margin of prezygopophyses; very low epipophyses; manual
ungual less recurved; flexor tubercle more prominent, placed further
anteriorly. Saurornitholestes is also reported to have short
cervicals, tall neural spines and large epipophyses than project past the
postzygopophyses (Makovicky 1995). Saurornitholestes' manual unguals
(Sues, 1978) differ in the same ways as Deinonychus'. Now perhaps the
neural spines and epipophyses are broken in Sereno's specimen, but it doesn't
look that way. I suppose some taxa close to dromaeosaurids
(Sinornithosaurus, etc.) may have more elongate cervicals with different
morphologies, but this is unknown at present. I would say these vertebrae
and ungual are not dromaeosaurid.
An obvious alternative is the Troodontidae.
Troodontid cervicals are poorly illustrated in the literature, but are described
in detail by Makovicky. They resemble Sereno's specimen more than
dromaeosaurids in having more elongate centra, low neural spines and reduced
epipophyses. In addition, Makovicky describes the ventral edge of the
centrum as having a sigmoid curve, which is present in the new specimens.
The manual claws of troodontids are also more similar to the new form, as they
have less curvature and more distally placed flexor tubercles.
Coelurus is also quite similar to the new specimen,
as it also has elongate centra, low neural spines, reduced epipophyses, a
sigmoid ventral outline, poorly curved unguals and distally placed flexor
tubercles. Differences from Coelurus include more decurved
prezygopophyses, more slender centra, taller postzygopophyses, a more concave
ventral margin and smaller flexor tubercles.
Another taxon with elongate cervicals is the
Ornithomimosauria. These share the characters listed above for Coelurus,
but differ in that their postzygopophyses are more elongate, the sigmoid curve
is interupted by the enlarged parapophyses and the unguals are much
straighter with lower and more distally placed flexor tubercles. It was
clearly not an ornithomimosaur.
Segnosaurs have somewhat elongate cervicals, but
shorter centra, lower neural spines and much deeper manual unguals.
Oviraptorosaur claws vary quite a bit. The
ungual is similar to caenagnathid unguals, assuming the proximodorsal lip is
broken. Only posterior cervicals are known for caenagnathids, but they
have the large parapophyses like ornithomimids, lower neural spines and less
angled central faces. Oviraptorid unguals are quite different and their
cervicals are shorter with lower neural spines than Sereno's
specimen.
Finally, Avimimus cervicals have somewhat elongate
centra and reduced epipophyses, but non-decurved prezygopophyses, longer
postzygopophyses and more prominent rectangular neural spines.
In conclusion, this taxon resembles Coelurus and
troodontids most, the latter identification being more temporally
parsimonious.
Eumaniraptora incertae sedis
Early Cretaceous
material- teeth, limb elements
description- The teeth lack anterior serrations,
which is only known in some troodontids and eumaniraptorans. The former
have very distinctive teeth, and since Sereno calls this a dromaeosaurid tooth,
it's probably from a dromaeosaurid or related deinonychosaur.
Iguanodontia incertae sedis
Early Cretaceous
material- ribs and other elements
Hadrosauridae incertae sedis
Late Cretaceous
material- dorsal vertebrae, scapula, manual
elements
Psittacosaurus sp.
Early Cretaceous
material- partial skull
articulated skeleton with gastroliths
description- Shorter, rounder skull than P.
mongoliensis.
Protoceratops sp.
Late Cretaceous
material- (juvenile) partial mandible
Mickey
Mortimer |