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RE: Info on some less well known taxa



Tim Williams (twilliams_alpha@hotmail.com) wrote:

<I haven't yet seen or read these papers; but AFAIK most abelisaurs have 
rather small teeth (_Carnotaurus_ is an exception).>

  I just got the issue today in the mail. Rauhut argues that the
premaxilla is as equally long as high below the external nares, and that
the aspect of the crowns (length to FABL) is higher than abelisaurids,
arguing that *Carnotaurus* has short teeth. Indeed, arguing that there are
virtually no abelisaurid features shared exclusively with them, Rauhut
finds a few features in common with *Ceratosaurus,* including extreme
mediolateral compression of the crowns, and their length. The same
features are notable and thus Rauhut suggests that *Genyodectes* is a
ceratosaurid. It should also be of note that the same features are found
in the tooth Das-Gupta described as *Orthogoniosaurus matleyi*, and
implies the presence of Gondwanan ceratosaurids. Rauhut notes that similar
mediolateral compression of teeth in theropods only really occur in
charcharodontosaurs [I would add "velociraptorines" and likely
*Sinornithosaurus* to this, as well], and that the jaws otherwise show
fused interdental plates, but their share features with ceratosaurids
precludes *Genyodectes* being an allosauroid. Rauhut offers a potential
synapomorphy of *Genyodectes* and *Ceratosaurus*: longest maxillary tooth
exceeds in length the minimal height of the dentary.

---

  Otherwise noteworthy is the presence of a Mali titanosaur (O'Leary,
Roberts, Head, Sissoko, and Bouare, 2004: 923-930) which appears to be too
fragmentary to name [CNRST-SUNY-1, osteoderm; CNRST-SUNY-194, possible
fibula; CNRST-SUNY-195, distal caudal; CNRST-SUNY-196, mid-caudal;
CNRST-SUNY-197 anterior caudal], but features of its anatomy suggest it is
a "higher" titanosaur as it lies in a polytomy with opisthocoelicaudines,
saltasaurines, nemegtosaurs, etc., but more advanced than *Euhelopus,* in
adding it to Curry-Rogers & Forster's *Rapetosaurus* analysis and Wilson's
2002 analysis, based on the presence of distal caudals with distinct
procoely.

  Smith, Sanders and Stadtman (2004: 850-856) discuss new material of
*Mesodactylus ornithosphyos,* including vertebrae, a complete femur,
nearly complete humerus, a partial braincase, ribs, and long bones of the
distal wing. The dicussion is relatively brief, and notes primarily that
there isa  mix of advanced and primitive features, at first suggestive of
a "transitional" form: no pneumatic foramen of the humerus, no distal
humeral expansion, no pneumatic foramina on the occiput, the parietal is
excluded from the occiput, the femoral caput inclines 45 degrees from the
proximal shaft (strongly bowed shaft cranially is almost 1/4 wider than
deep, and there is no extensor groove in the distal femoral condylar
region); supposedly "advanced" features include the expansion of the
supraoccipital to form most of the occiput, and short cervical centra. A
cervical was CT-scanned and found to be, as in advanced sauropods, highly
camerate, or filled with large camarae throughout all regions of the bone
(the authors use the word "camella," but given Wedel's use of terminology,
with large chambers and corresponding thin bony walls separating them, the
term camara is more correct).

  As Tim noted, *Rebbachisaurus tessonei* has been officially named
*Limaysaurus tessonei,* ending the history of "Limaysaurus" as a nomen
nudum and internet name. It is referred to the Rebbachisauridae along with
*Nigersaurus* and *Rebbachisaurus garasbae,* as well as *Rayososaurus
agrioensis.* Material is also described for *Limaysaurus* sp., including a
variety of vertebrae, femora, tibiae, a fibula, pelvic elements, a
coracoid, and haemal arches, as well as a single tooth (claimed "unworn"
but bearing wear facets, so they may be referring to a different form of
wear).

  The late Betsy Nicholls and Manabe Makoto (2004: 838-849) describe their
giant ichthyosaur from British Columbia, Canada, as *Shonisaurus
sikanniensis,* which includes most of the pre-pelvic skeleton, a portion
of the pelvis, and a series of caudal vertebrae. The skull is massive, and
photos of this skull have been seem by many and all, and I recall Betsy
herself describing the size of this animal primarily by reference to its
huge eyes, well over a meter across, and likely about 4 feet across,
though the skull has been crushed.

  Stucchi and Urbina (2004: 974-978) describe a new sulid, *Rhamphastosula
ramirezi,* from the early Pliocene of Peru, a sulid with a deep,
crescentid beak reminiscent of toucans (hence the name).

  Perhaps most wonderful, Caldwell and dal Sasso (2004: 980-985) describe
a fossil of *Pontosaurus* (noted as cf. *Pontosaurus* sp.) from the Valley
of Al Gabour in Lebanon which includes impressions of scalation around the
head, legs and tail, showing that a lagerstätten will show scales in a
scaled animal, and not really just random collagen fibers scattered about
or arrayed in angle. *Pontosaurus,* a dolichosaur mosasauroid, shows the
transition from lizards to snakes retained a micro-scaled facial region
with a highly modified, large hexagonal tail scalation pattern, as in
snakes. Keeled scutes along the tail also recall snakes, so the
soft-tissue, as noted by the authors, will likely be of important
phylogenetic understanding of the origin of snakes.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
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