| [Thread Prev] | [Thread Next] | [Thread Index] | [Date Prev] | [Date Next] | [Date Index] |
This week's issue of Nature carried the description of a new dinosaur, as
cited in this meaty email (slightly edited) from Tom Holtz:
Subj: Introducing: Sinovenator changii
Date: 2/13/02 5:12:43 PM EST
From: tholtz@geol.umd.edu (Thomas R. Holtz, Jr.)
Xu, X., M.A. Norell, X.-L. Wang, P.J. Makovicky & X.-C Wu. 2002. A basal
troodontid from the Early Cretaceous of China. Nature 415: 780-784.
Troodontids have "traditionally" (since 1969) been considered the sister
taxon to dromaeosaurids, in a clade Colbert & Russell called
Deinonychosauria. This position has been found by most, but not all, authors.
Okay, back in 1994 I published a paper which placed troodontids as the sister
taxon to ornithomimosaurs, in the new clade Bullatosauria. This study
suggested that some features (previously observed by others, such as Currie)
shared by ornithomimosaurs and troodontids (bulbous parasphenoid,
arctometatarsalian pes, and more) were signs of the common ancestry of these
two, while the similarities between troodontids and dromaeosaurids were
convergences and/or basal features "overprinted" by the derived
ornithomimosaurs. A similar conclusion was reached by Perez-Moreno et al. at
just about the same time.
In 2000 (analysis done in early 1999) my study found troodontids to be
equally parsimoniously explained as bullatosaurs or as the sister taxon to
dromaeosaurids plus birds. Analyses by Norell et al. (finally published in
2001) and some of the Chinese teams found troodontids to be the sister to
"enigmosaurs."
As I discussed in the Ostrom Symposium, part of this problem stems from the
lack of basal members of the Troodontidae, to resolve which features are
ancestral in that lineage, and which derived. That lack has ended.
Enter Sinovenator changii, (Meeman Chang's China hunter) based on a partial
skull and skeleton and a referred skeleton from the lowest part of the Yixian
Formation. Associated fauna are Psittacosaurus, Jeholosaurus, and the mammal
Repenomamus. Sadly, the horizon it is from does not preserve the integument
of the critter, one way or the other.
The anatomy, briefly:
The promaxillary fenestra is present and in the basal position.
The parasphenoid capsule is NOT inflated.
The basipterygoid processes do not appear to be hollow.
Denticles are absent on anterior teeth and small on maxillary teeth.
Dorsals have fan-shaped neural spines (shades of Sinosauropteryx!)
Glenoid fossa on scap-coracoid faces laterally.
Pelvis is *OPISTHOPUBIC* (not vertically oriented, but well past 90 degrees)
Metatarsal III is somewhat constricted, but non-arctometatarsalian.
The analysis includes species-level OTUs, which I won't reproduce entirely
here. Although they do not include all the higher level names I will use,
here is their tree:
Avetheropoda
Allosaurus
Coelurosauria
Tyrannosauridae
Maniraptoriformes
Ornithomimosauria
Maniraptora
Ornitholestes
Metornithes
Alvarezsauridae
ye olde classic maniraptorans
"enigmosaurs"
Therizinosauroidea
Oviraptorosauria (incl. Avimimus)
Paraves
Avialae
Deinonychosauria
Troodontidae
Sinovenator
all later troodontids
Dromaeosauridae
Sinornithosaurus
all later dromaeosaurids
You know, I am quite pleased with these results, and think we (theropod
systemicists) are reaching a consensus for this part of the tree.
So, to sum up:
Troodontids are almost certainly deinonychosaurs. I was wrong about
troodontids in 1994, but don't care. The Yixian is the place to find cool
specimens And even more are on their way... :-)
-----------------------------------------------------------------
Later there were these emails concerning Sinovenator to the dinosaur list
from David Marjanovic (which, incidentally, never arrived here), Nick
Pharris, and Ben Creisler:
Subj: Sinovenator: Emendation needed!
Date: 2/15/02 3:07:16 AM EST
From: NJPharris@aol.com
David Marjanovic sent this earlier, but no one seems to have taken notice.
In a message dated 2/14/02 3:50:28 AM Eastern Standard Time,
david.marjanovic@gmx.at writes:
> Just had a look at
> http://www.fieldmuseum.org/museum_info/press/press_sinovenator.htm... says
> Zhang Miman is a woman. Thus the name *Sinovenator chang_ii_* must already
> be emended, no?
Dang, beat me to it! However, you are correct. From the article:
"Etymology...The specific name honours Meeman Chang of the IVPP for *her*
significant role in the study of the Jehol fauna" (emphasis added).
The name will need to be emended to S. changiae. The -i- Latinizes Chang's
name, but it does not make her male!
Subj: Sinovenator changiae (NOT changii)
Date: 2/15/02 3:13:15 AM EST
From: bh480@scn.org
From: Ben Creisler bh480@scn.org
Sinovenator changiae (NOT changii)
I haven't seen the Nature paper yet but the press release at (all one line):
http://www.fieldmuseum.org/museum_info/press/press_sinovenator.htm
states that the species name honors a woman. Therefore the species name needs
to be emended to changiae (feminine gender).
Sinovenator changii is named after Dr. Meeman Chang, a leading Chinese
paleontologist who spent more than a year time studying fossil fishes at The
Field Museum on different occasions, most recently in 1998.
"As head of the Beijing's Institute of Vertebrate Paleontology and
Paleoanthropology for many years, Dr. Chang has helped raise the standards
for paleontological inquiry in China," says Lance Grande, PhD, curator of
fossil fishes at The Field Museum. "She is dedicated to improving the quality
and productivity of Beijing's natural science institutions through training
students, publishing, and improving collection and research facilities in
China. She has also played an important role in making it easier for foreign
paleontologists to work in China, thereby broadening the scope and importance
of paleontological sciences there."
-----------------------------------------------------------------
Accordingly, I add as genus #937
Sinovenator Xu, Norell, Wang, Makovicky & Wu, 2002
and the species entry in the forthcoming Mesozoic Meanderings #3 second
edition will read something like this:
Sinovenator Xu, Norell, Wang, Makovicky & Wu, 2002
S. changiae Xu, Norell, Wang, Makovicky & Wu, 2002 emend.†
= Sinovenator changii Xu, Norell, Wang, Makovicky & Wu,
2002†§
with the emendation credited to whoever gets it into print first (ideally,
one or more of the original authors). In case the special characters fail to
transmit, there's a dagger following the first species name to indicate that
it is the type species, and a dagger and section sign following the second
species name to indicate that this was originally the type species but was
emended to the immediately preceding name.
-----------------------------------------------------------------
Then I received this interesting email:
Subj: NEW SAUROPOD: FERGANASAURUS VERZILINI
Date: 2/16/02 1:24:46 PM EST
From: mrossi83@hotmail.com (mark reds)
I tried to send this message to the DML, but for some reason it doesn't
appear on the archives.So,I decided to send it to someone on the list to
spread the news. I hope it will be a new update to your Dinosaur Genera
List...:)
Here's the link:
http://www.magtech.ab.ca/jurassic/averianov.htm
Don't forget to look at the other projects:
http://www.magtech.ab.ca/jurassic/prevgrnt.htm
Sorry if you know about it yet.
-----------------------------------------------------------------
I am passing the message along as requested. I visited the URLs and
discovered that the "sauropod from Fergan," which I have been carrying in my
dinosaur lists as a dinosaur "to be described" since the 1970s(!), will at
last receive its name and description in an article by Alifanov and Averianov
in a forthcoming issue of JVP. When that happens, I'll cheerfully add
Ferganasaurus to the Dinosaur Genera List; but I can't add it just yet
because as far as I know it exists only as an Internet name.
Partial index: