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From: Dan_Chure@nps.gov [mailto:Dan_Chure@nps.gov]
Sent: Tuesday, February 26, 2002 7:40 AM
To: Tracy L. Ford
Subject: RE: Terror of the terrible Theropods! :)
I got this response from Dan Chure about a recent post that I thought was a
bit inappropriate in the way it was written and his response.
This brings up things that is important to all of us and we all need to keep
in mind thesis are basically a work in progress and should only be mentioned
and not reported on as fact until the author has published on it themselves,
which may take years (unfortunately). I have no problem in putting the
thesis work in personal work that others will not see. But if that material
is mentioned without the author's permission isn't a good thing, this also
includes taking photos of talks or posters and publishing them without the
author's permission. I think the best way to do this is just put the
specimen number, material etc as a new genus to be described and leave it at
The dissertation is publicly available and can be cited, so I see no harm
in discussing its contents. Saying it is known as "Alshansaurus" is, of
course, incorrect, as a dissertation does not meet the standards for the
ICZN code. I would have preferred to have it simply referred to as a new
genus rather than mention the name itself, but maybe this guy doesn't know
Daniel J. Chure, Ph.D.
Dinosaur National Monument
Jensen UT 84035 USA
Is this kosher to put this on the list before you've published it formally?
> Could anyone help me with some info or pictures of the following genera?
> - Chilantaisaurus (both C. maortuensis and C. t.)
C. maortuensis is now known as "Alashansaurus" maortuensis. It is known
from a maxilla, quadrates, posterior section of skull, axis and six caudal
vertebae. Both Rauhut (2000) and Chure (2001) classify it as a
Characters include- fused/absent interdental plates; no promaxillary
fenestra; unfused frontals; transversely straight nasofrontal suture;
sagittal crest on frontals and parietals; no quadrate-quadratojugal
foramen; single quadrate head; no helical groove on quadrate; highly
pneumatized braincase; parasphenoid not inflated; ventrally projecting
processes; occipital condyle with constricted neck. Where exactly it goes
is not known, but perhaps my analysis will shed some light.
C. tashuikouensis is the holotype and is known from a humerus, first manual
ungual, fragmentary ilium, femora, fibula and metatarsus. It has been
allied with basal tetanuraens, allosaurids segnosaurs and tyrannosaurids.
It was placed in the Spinosauroidea as the sister group of spinosaurids by
Rauhut (2000) based on- humerus straight in lateral view; bluntly rounded
vertical ridge on the antero-medial side of the distal end of the tibia.
Sereno et al. (1994) classifies Chilantaisaurus as a torvosauroid
(Afrovenator, Eustreptospondylus, Torvosaurus, spinosaurids) and renamed
the clade Spinosauroidea for their 1996 and 2000 papers. Of the
synapomorphies listed by Sereno et al. (1994, 1996), none can be determined
in C. tashuikouensis as they are all cranial. The torvosaurid +
spinosaurid subgroup is diagnosed by "manual ungual I elongate (three times
proximal articular end)", which is present in C. tashuikouensis. Also, in
2000, Sereno added deltopectoral crest more than 45% of humeral length,
which is almost true of C. tashuikouensis. Although these two characters
are present in Chilantaisaurus, it is debatable if they imply a relationship
to torvosauroid/spinosauroid taxa. If Sereno's manual ungual length is
along the curve (as it must be for Baryonyx to exhibit the trait, so I
assume it's implied), Chilantaisaurus has a ratio of 3.17, while Baryonyx
has a ratio of 3.2 and Torvosaurus has a ratio of 3.4. Neither
Herrerasaurus, coelophysoids, Dilophosaurus, Afrovenator or Allosaurus show
these proportions. However, several basal coelurosaurs have the derived
condition (Nqwebasaurus, Dryptosaurus, Sinosauropteryx, most
although others don't (Compsognathus, Scipionyx, tyrannosaurids). This
shows the character distribution to be more complex than previouly thought.
Chilantaisaurus's deltopectoral crest extends 44% of humeral length. This
compares to 37 in Allosaurus, 40 in Liliensternus and Dilophosaurus, 41 in
Ceratosaurus, 42 in Segisaurus and Elaphrosaurus "philtippettorum", 43 in
Eustreptospondylus and Baryonyx, 46 in Torvosaurus and 51 in Carnotaurus.
Thus, if the synapomorphic percentage is moved from over 45 to over 42, the
character still holds (allowing convergence with abelisaurs), but I don't
think a one percent difference from other theropods means much. Because of
this extremely minor difference in length between torvosauroids and other
theropods, I wouldn't trust this character. Still, it seems to be best
placed as a spinosauroid for now.
Tracy L. Ford
P. O. Box 1171
Poway Ca 92074