Tyrannotitan chubutensis

[gigadino96]

Tyrannotitan chubutensis (Novas et. Al 2005)


Mounted skeleton of T. chubutensis

Tyrannotitan chubutensis is a genus of Theropod dinosaur that lived in Argentina, South America, about 112-121 milion years ago, in the early Cretaceous (Aptian stage). This dinosaur is possibly part of the sub family Giganotosaurinae (Coria & Currie, 2006), and one the oldest giant Carcharodontosaurid know. This Theropod was described by Fernando E. Novas, Tom Rich, Pat Vickers-Rich and Silvina de Valais in 2005. The fossils of this dinosaurs were discovered in Cerro Barcino Formation, in the Chubut Province, Argentina. The holotype of this dinosaur (MPEF-PV 1156) is estimated to reach ~ 11.4 meters, and the paratype (MPEF-PV 1157) is likely about 7 % larger, and this would represent a animal comparable in size with Giganotosaurus holotype. We don't know much about this Theropod, as his description is brief. However, his skeleton has a acromion curves about 90 degrees from the shaft axis, make it tyrannosaurid-like. His arms were small, despite the fact that the scapulocoracoid is much better developed than that of Giganotosaurus. A proximal caudal has a neural spine about twice the height of its centrum. 


Know remains of T. chubutensis skeleton


Two Tyrannotitan chubuitensis. Image made by Sergey Krasovskji.

Know materials:

MPEF-PV 1156 (Holotype) - partial dentaries, teeth, third to eighth dorsal vertebrae, eleventh to fourteenth dorsal vertebrae, ribs, proximal caudal vertebra, chevrons, proximal scapula, coracoid, distal humerus, ulna, ilial fragments, incomplete pubes, ischia, femur, fibula, metatarsal II
MPEF-PV 1157 (Paratype) - jugals, dentary (680 mm), teeth, atlas, ninth cervical vertebra, seventh dorsal vertebra, tenth dorsal vertebra, thirteenth dorsal vertebra, ribs, five sacral centra, distal caudal vertebrae, femur (1.40 m), incomplete metatarsal II, phalanx II-1, phalanx II-2, pedal ungual II, phalanx III-3
 
References:

1- Novas, F. E.; S. de Valais, P. Vickers-Rich, and T. Rich (2005). "A large Cretaceous theropod from Patagonia, Argentina, and the evolution of carcharodontosaurids". Naturwissenschaften 92 (5): 226–230. doi:10.1007/s00114-005-0623-3
2-http://archosaur.us/theropoddatabase/Carnosauria.htm#Tyrannotitanchubutensis

[theropod]

Skull size scaled after Acrocanthosaurus atokensis:


Based on Fossils from Novas et al., 2005. Skull restoration from Eddy & Clarke, 2011 (CC-By)

[creature386]

The theropod clade Carcharodontosauridae is a broadly distributed group of large allosauroid theropods. The carcharodontosaurids recorded in the Albian–Cenomanian of Gondwana are the youngest and most derived members of this clade. Tyrannotitan chubutensis, from the Cerro Castaño Member of Cerro Barcino Formation (Albian; Chubut Group), Central Patagonia, Argentina, is of prime interest among Gondwanan carcharodontosaurids as it represents the oldest record of the group. Here we offer a detailed osteological comparative description of the holotype and paratype of Tyrannotitan chubutensis together with a new diagnosis of the species. The new information results in a better understanding of this taxon and Carcharodontosauridae. Furthermore, a comparative study of the anatomy of the pectoral girdle of Giganotosaurus is reinterpreted as very similar to that of Tyrannotitan and Mapusaurus. We also present a phylogenetic analysis of Carcharodontosauridae that recovers Tyrannotitan as a derived carcharodontosaurid, being the sister group of the clade formed by Giganotosaurus and Mapusaurus, all nested in the clade Giganotosaurini.

www.tandfonline.com/doi/full/10.1080/08912963.2013.861830#.Us7aUyhfKEJ

[Cross]

Just something based on independent observations by me and Andrea Cau theropoda.blogspot.com/2014/01/tyrannotitan-reloaded.html
MPEF PV 1157 has colossal dorsals and femora, especially for carcharodontosaurid standards. Novas et al (2005) stated that MPEF PV 1157 is approximately 7% larger than the holotype specimen of T. chubutensis (MPEF PV 1156), the holotype estimated at ~11.5 meters, going by the percentage provided by Novas et al, that indicates that the paratype is about the size of Giganotosaurus or slightly longer by a few dozen centimeters. So that's within the range of 12.4 - 13 meters as estimated by Thomas Holtz and Greg Paul.
Image :
Notice how the the centra are nearly 30cm wide, and the dorsal neural spine is also quite prominent. This animal had an enormously wide ribcage, possibly comparable to the robusticity of the largest Tyrannosaurs.
Going by this data, Tyrannotitan chubutensis may possibly be the most massive theropod dinosaur as far as discovery goes. More massive than both Spinosaurus and Giganotosaurus, and dwarfing most T. rex specimens in terms of bulk (E.G BHI 3033, MOR 55S). This is of course, ignoring ridiculous overestimations in excess of 10-15 tons for other theropods like those in Therrien and Henderson (2007), Dal Sasso et al. (2005), and Hutchinson et al. (2011).

[Grey]

Very interesting Cross

Is Cau in agreement about this observation ?

[blaze]

The diapophyses are in the transverse process and are not completely preserved in those vertebrae, I frankly don't see how they would even approach those of Sue.

That size comparison was made by me btw

[Cross]

May 28, 2015 3:07:06 GMT 5 blaze said:

The diapophyses are in the transverse process and are not completely preserved in those vertebrae, I frankly don't see how they would even approach those of Sue.

That size comparison was made by me btw

In that case, I should probably perform a reverse image search next time...

See the link to Cau's post if you need more data (assuming you haven't already seen it, which you probably have...)
I apologize for misidentifying the transverse processes and diapophyses, it appears I was looking at the vertebrae of Sue in the image and mistook them for those of T. chubutensis (wonder why I didn't catch that detail the description too..smh). I should probably edit that to "centra and femora" and omit "transverse processes and diapophyses.
To quote Andrea Cau

"Although it is little mentioned, the second copy of Tyrannotitan is, along with the famous Tyrannosaurus "Sue", the largest specimen of theropode that is based on the remains sufficiently complete to be able to estimate the total size accurately. In fact, the femur, the long 141 cm wide and with a shaft almost 30 cm across, it is the largest known throughout Theropoda femur, and this supports the hypothesis that the specimen in life was of comparable size to the largest tyrannosauridi. In addition, the posterior dorsal centers are comparable in volume to those larger than Tyrannosaurus, and are therefore more than double in volume compared to the center rear dorsal largest holotype of Spinosaurus. These bones, both directly related to the support function of the body weight, are among the best indicators of the mass of an animal as a biped theropode. Even without speculating on the absolute value of this mass, the gigantic size of Tyrannotitan are confirmed also by the relative comparison with the bones of the other homologous carcharodontosauridi, which are relatively less massive. For example, the holotype of Carcharodontosaurus saharicus has a femur shorter than twenty centimeters and significantly more frail than Tyrannotitan to the shaft, while the backbones of Acrocanthosaurus suggest theropode with a mass less, comparable to that of Spinosaurus."


translate.google.com/translate?u=http%3A//theropoda.blogspot.com/2014/01/tyrannotitan-reloaded.html&hl=en&langpair=it|en&tbb=1&ie=UTF-8 

[blaze]

Don't worry

Based on the dimensions alone I don't agree that there's sufficient evidence to suggest Tyrannotitan was as massive as the largest Tyrannosaurus, the femur is 141cm yes and the longest known of any theropod* but with a circumference of 541mm it falls behind a couple of specimens of Tyrannosaurus and the largest Deinocheirus, moreover the vertebral centra are not as massive as in Sue from my size comparison above I estimate a volume of 4275cm^3 for the 6th dorsal centrum of MPEF-PV 1157 and 5857cm^3 for that of Sue, a 37% difference.

*Assuming that of the type of Giganotosaurus is not 143cm as originally reported

Femur circumference also appears to get larger in older animals, comparing Tyrannosaurus rex CM 9380 with Stan, they have similarly long femora and are not much different in body size but the former has a femur almost 6% greater in circumference, I'm of the idea that this is similar comparison to MPEF-PV 1157 and the holotype of Giganotosaurus, after all, there the difference is less than 4%. If only someone had published a proper monograph of Giganotosaurus so we oould compare its vertebrae to Tyrannotitan.

[dinosauria101]

Here's a neat skeletal I found (by franoys)