Skorpiovenator, a new fossil marvel

[Sebastian Apesteguia <sebapesteguia@yahoo.com.ar>]

hi people,
well, I've read the Skorpiovenator paper.
What an specimen! I've seen the original skeleton at El Chocón during a couple 
of years and I was really waiting to see the arising of this paper by Juan 
Canale and others.
A noticeable aspect is the naming of the clade Brachyrostra, an interesting 
name that will be profusely discused in the following days.
A good point in the paper is the confirmation that the wrinkled teeth from the 
Uppermost Cretaceous strata from South America didn't belong to 
carcharodontosaurids (as I said in an abstract some years ago) but to 
abelisaurids. Touchée.
 
However, the paper ends saying that "Given the possibility that these teeth 
actually represent abelisaurids, they cannot be used to contradict an early 
Late Cretaceous (Cenomanian) extinction of carcharodontosaurids in South 
America, as hypothesized by Novas et al. (2005)."
 
The extinction of carchs in SA is far from being a Novas idea. 
Actually, the idea was proposed in a paper co-authored by Novas: 
Leanza, H. A.; Apesteguía, S.; Novas, F.E.; De la Fuente, M. S. 2004. 
Cretaceous terrestrial beds from the Neuquén basin (Argentina) and their 
tetrapod assemblages. Cretaceous Research Volume 25, Issue 1, Pages 1-96., 
discussing the South American stage, where it says: "At this level, the record 
shows the loss of dominance of basal titanosaurs, diplodocoid sauropods and 
carcharodontosaurid theropods, together with the diversification of 
titanosaurids and large endemic coelurosaurs."
 
Furthermore, the original proposal is from Apesteguía, S. 2002. Successional 
structure in continental tetrapod faunas from Argentina along the Cretaceous. 
Boletim do 6º Simpósio sobre o Cretáceo do Brasil / 2º Simposio sobre el 
Cretácico de América del Sur. Sao Pedro, Brasil: 135-141, a paper that most of 
the authors of this paper have.
 
In such paper it is clearly said that:
 
"...At Late Cenomanian times, carcharodontosaurids were still large (Coria & 
Currie, 1997) but they would became extinct no later than Coniacian (except in 
APB, Mata Ama
ayed mid-sized (around 5m long) until Santonian to Early Campanian, when they 
would diversify profusely acquiring bizarre forms or large size along the 
Abelisauroid Greatergondwanan Endemic Domain. Short headed carnotaurines (Coria 
& Chiappe, 2000), long-headed abelisaurines (Bonaparte, 1985) and small and 
bizarre noasaurids (Agnolin et al., in prep.) inhabited NPB. Chicken-sized 
coelurosaurs stayed present (Bonaparte, 1991). Carcharodontosaurids disappeared 
or became rare."
 
and 
 
"...After Cenomanian, large ornithopods seemed to dissapear, together with 
rebbachisaurs and carcharodontosaurids, whereas abelisaurs diversified and 
titanosaurid sauropods diversified occuping new mid-size adptative zones. This 
events seems to be linked somehow."
 
Furthermore, both Leanza et al (2004) and Apesteguia (2002) provide 
illustrations clearly showing the extinction of carcharodontosaurids. Probably 
part of the fault comes from the reviewers, but also from the authors. 
 
In other aspects, the paper is to enjoy a beautiful specimen and its good 
interpretative panorama.
Best
 Sebastian 
  
  
Dr. Sebastián Apesteguía (PhD.)


Área de Paleontología. Fundación de Historia Natural 'Félix de Azara',
Dto. de Ciencias Naturales y Antropología, CEBBAD, Univ.Maimónides, 
V. Virasoro 732 (1405), Buenos Aires, ARGENTINA
Tel-fax: 5411-49051100 i. 1228, sebapesteguia@gmail.com, 
www.fundacionazara.org.ar 



----- Mensaje original ----
De: Dawid Mazurek <dawidmazurek@wp.pl>
Para: DML <dinosaur@usc.edu>
Enviado: lunes 8 de diciembre de 2008, 20:09:42
Asunto: Skorpiovenator, what a name

Canale, J. I., Scanferla, C. A., Agnolin, F., Novas, F. E. 2008. New 
carnivorous dinosaur from the Late Cretaceous of NW Patagonia and the evolution 
of abelisaurid theropods. Naturwissenschaften. doi 10.1007/s00114-008-0487-4.

A nearly complete skeleton of the new abelisaurid Skorpiovenator bustingorryi 
is reported here. The holotype was found in Late Cenomanian-Early Turonian 
outcrops of NW Patagonia, Argentina. This new taxon is deeply nested within a 
erican abelisaurids, named Brachyrostra. Within brachyrostrans, the skull 
shortening and hyperossification of the skull roof appear to be correlated with 
a progressive enclosure of the orbit, a set of features possibly related to 
shock-absorbing capabilities. Moreover, the development of horn-like structures 
and differential cranial thickening appear to be convergently acquired within 
Abelisauridae. Based on the similarities between Skorpiovenator and 
carcharodontosaurid tooth morphology, we suggest that isolated teeth originally 
referred as post-Cenomanian Carcharodontosauridae most probably belong to 
abelisaurids. 



      
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