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Details on SVP 2002 Part 2
Here's part 2- even more talks.
Carrano et al. have been doing a great job examining every ceratosaur in
existance and making a character matrix of ~350 characters. I'm impressed.
They think Ceratosaurus magnicornis and C. dentisulcatus are probably
synonymous with C. nasicornis. They also listed Indosuchus and Indosaurus
as probable junior synonyms of Lametasaurus. I'll be interested to hear how
the cranial differences in the Indo- forms are dealt with. Noasauridae
contains Noasaurus, Laevisuchus, Masiakasaurus, Velocisaurus and perhaps
Ligabueino. The latter is juvenile though, and apparently difficult to
place. Quilmesaurus is listed as a ceratosaur, but the French "abelisaurid"
maxilla is said to possibly be carcharodontosaurid. The abelisaur jaw
fragments Russell (1996) described from Morocco are reinterpreted as
carcharodontosaurid. Rauhut is apparently working on Genyodectes.
Carr and Williamson gave a great talk on tyrannosauroid phylogeny, including
their two new basal forms. Tyrannosauridae is now defined as the
Albertosaurus + Tyrannosaurus node. I'm not sure how Gorgosaurus libratus
its into the definition, as they consider it and Albertosaurus sarcophagus
sister groups. Tyrannosaurinae is Daspletosaurus + Tyrannosaurus.
The Alabama taxon is from the Late Campanian Demopolis Formation. It's RMM
6670- the anterior skull, two caudal vertebrae, ischium, femur, tibia and
metatarsal(s?). It's apparently primitive due to the shallow alveolar area
of the maxilla and dorsally placed maxillary fenestra, among other
The other new basal taxon is from the Hunter Wash Member of the Kirtland
Shale in New Mexico. It's known from a 1 meter long skull, and unpreparared
postcrania. Primitive characters include the narrow snout. The
"Aublysodon" specimen from New Mexico previously referred to Daspletosaurus
actually belongs to this taxon.
Yet another new taxon was shown, from the Kaiparowitz Formation of Utah. It
includes the maxilla and lacrimal.
Dryptosaurus was discussed in some detail. Tyrannosauroid characters
include the large surangular foramen and Mackelian groove placed at
midheight (also seen in Richardoestesia). It's primitive in having large
forelimbs, no lateral process on the cnemial crest and other characters.
Alectrosaurus was shown to have several apomorphies, including a spike-like
process projecting proximally off a distal femoral condyle, and expanded
distal articular surfaces of the metatarsals.
A phylogenetic analysis of 149 characters was performed, producing the
`--+--New Mexico taxon
| `--MOR 590
I'm not sure if they used Tyrannosaurus bataar or Tarbosaurus bataar.
Clark et al. presented new taxa from China.
The Wucaiwan Formation is thought to be Middle Jurassic, perhaps correlated
with the Xiashaximiao Formation. Previously known taxa are Monolophosaurus,
Klamelisaurus, Bellusaurus and small ornithopods.
I think the following taxon was from this level, but am not sure.
A theropod was shown, known from a partial skull (premaxilla, maxilla,
lacrimal, postorbital, squamosal, frontal, parietal, quadrate,
ectopterygoid, pterygoid) and much of the postcrania. Open neurocentral
sutures show it is not adult. There is probably no prefrontal, a low
sagittal crest is present on the parietals, the endocranial cavity is
enlarged, there is a transverse nasal suture and a deep pocket in the
ectopterygoid. Opisthocoelous cervicals have small pleurocoels. Five
vertebrae make up the sacrum. The forelimbs are less than half the length
of the hindlimbs. Manual unguals have large flexor tubercles. The
postacetabular process is curved ventrally and the pubic foot is reduced.
The femur shows a deep fovea capitalis, fourth trochanter and large anterior
trochanter. The metatarsus is fused, non-arctometatarsalian and shows an
expanded distal mtIII. This was described in the abstract as having a
postorbital similar to troodontids.
The Shishugou Formation has previously given us Sinraptor and Mamenchisaurus
sinocanadorum. It is Late Jurassic, possibly correlated to the
A new Sinraptor specimen, consisting of a skull and cervicals, is known.
The coelurosaur described as potentially ornithomimosaurian is represented
by four partial skeletons. One consists of dorsal and caudal material, with
a pelvis. Another is a tail. The third is a tail and some hindlimbs, and
the fourth has forelimb and cranial material. The tail has the transition
point between the sixteenth and seventeenth caudals, long prezygopophyses
and dorsoventrally long proximal chevrons. There is a slender
Non-theropod material includes a nearly complete small ornithopod, a small
ornithopod skull, and the posterior skeleton of another. These have some
relation to Gongbusaurus? wucaiwanensis. A stegosaur pelvis and ankylosaur
maxilla were also shown.
Clarke et al. gave a talk on Yixianornis. Lots of new morphological
information was revealed with preparation of the specimen. The premaxilla
is anteriorly toothless, but contains four teeth posteriorly. The maxilla
is also toothed and strongly forked posteriorly. The quadrate heads are not
widely separated. Twelve amphicoelous cervicals are present, as are ten
dorsals with lateral fossae. There are nine sacrals and at least four free
caudals. The pygostyle is short, laterally compressed and with a possible
upwards inclination. It is formed of four vertebrae. The sternal keel is
deep. Gastralia and ossified uncinate processes are preserved. The
coracoid has a procoracoid process, lateral process and concave cotyla for
the scapula. There is a small extensor process on metacarpal I and a
pisiform process. The metacarpus is fused proximally and distally. The
pelvic elements are proximally fused. The pubis has a symphysis but no
boot. A trochanteric crest is present on the femur. Proximal tarsals are
fused to each other and the tibia. Metatarsals are fused distally, have a
distal vascular foramen, a posteriorly displaced third metatarsal, no
intercotylar eminence and no hypotarsal grooves.
A phylogenetic analysis was performed-
Note I got the same result for Yixianornis and Yanornis back in December (
http://www.cmnh.org/dinoarch/2001Dec/msg00421.html ) by adding them to
Clarke et al.'s 2001 matrix. The clade of Yixianornis, Yanornis and
Songlingornis might be termed Yanornithidae or Yanornithiformes, both from
Zhou and Zhang 2001. They are united by posterior sternal fenestrae.
Yixianornis and Songlingornis are further united by a flat base to the
furcula. Yixianornis differs from Songlingornis in the furcular diameter
and sternal fenestra size. Also, the first metacarpal is not fused to the
Clarke et al. use Gauthier and de Quieroz's 2001 definition of Ornithurae
(apomorphy-based, for taxa with short upturned pygostyles), explaining why
they called Yixianornis an ornithurine. It's a non-ornithurine
ornithuromorph, using the more widely accepted terminology.
Rauhut's talk was almost a continuation of last year's. Two formations are
now recognized from what used to be the Canadon Asfalto.
The "new" Canadon Asfalto is Oxfordian-Callovian. Previously known taxa
include Piatnitzkysaurus, Volkheimeria and Patagosaurus.
There is a new theropod, known from two cervicals, seven dorsals, two dorsal
ribs, a caudal, a partial ilium, pubis, ischium, femur, tibia and
metatarsus. Characters include deep lateral sacral fossae, a small rounded
cnemial crest, large hypapophyses, cervical pleurocoels posteroventral to
the parapophyses, no incisura tibialis, and a step proximal to the distal
articular surface of metatarsal IV. The lack of an incisura tibialis is
interesting, as I've only noted this in two non-coelurosaur tetanurines
before- "Allosaurus" tendagurensis and an unnamed form from North Africa
(see http://www.cmnh.org/dinoarch/2002Aug/msg00488.html ). Perhaps they are
all related. Rauhut presented a phylogeny-
As Piatnitzkysaurus is a spinosauroid according to both Holtz (pers. comm.)
and Allain (2002), the new taxon might belong in that clade as well.
Patagosaurus, as explained last year, is a chimaera of two forms. The
cranial elements actually belong to the unnamed taxon (MACN CH 934).
The other formation is called the Canadon Clacareo Formation, and is
Kimmeridgian-Tithonian. Tehuelchesaurus was previously described from
Two mid-caudal vertebrae and a chevron are referred to the Coelurosauria
based on the anteroposteriorly elongate chevron morphology and elongate
prezygopophyses. It's possible, but the distalmost chevrons of Allosaurus
are very similar.
A new dicreaosaurid is known from cervical and dorsal material at least. It
has high neural arches, fan-shaped dorsal neural spines and bifurcated
cervical neura spines typical of the family. Unique is the upside down
L-shape to the cervical neural spines, with the point facing forward.
There is also a new brachiosaurid, represented by four vertebrae, a chevron
and a humerus.
A sauropod phylogeny was presented-
`--+--MACN CH 934
Sereno et al. spoke about new African ceratosaurs.
One is from the Neocomian Tiouraren Formation of Niger. It consists of a
complete presacral series and a sacrum. The cervicals have large
epipophyses, elongate centra, an interzygopophyseal lamina and double
pleurocoels. The dorsals are not pneumatic and have elongate cylindrical
parapophyses. The sacrum shows ossified tendons on the neural spines. It
was concluded this form was most similar to Ceratosaurus, and especially
Elaphrosaurus. Sereno alluded to previous Early Cretaceous African
"Elaphrosaurus" remains relating to this taxon.
Another taxon was from the Cenomanian Echkar Formation of Niger. It
consists of most of the skull, including the premaxilla, maxilla, nasal and
braincase. Looks very much like Indosuchus (which Carrano et al. are
calling Lametasaurus). Features include a sagittal crest on the parietals,
textured cranial elements, and a large anteroposterior row of foramina on
the dorsal surface of each nasal. The postorbital and lacrimal contact
lateral to the frontal, but there is a foramen present between the three
bones. It's apparently just basal to abelisaurids.
A third taxon was not described, but was said to be small and known from
axial and limb elements. It's from the Elrhaz Formation of Niger (I think).
Sereno mentioned Deltadromeus and Bagaraatan as possible ceratosaurs (though
he used "ceratosauroid" for the clade). The topology presented was-
Note he now has a trichotomy of coelophysoids, tetanurines and ceratosaurs.
This is it until I get my film developed. Then be prepared for details on
the posters shown.