Franoys

Just as predicted six years ago by Andcrea Cau in his blog, and four years ago by user , "Amphicoelias fragilimus" is now redescribed as a new rebbachisaurid taxon;  Maraapunisaurus fragillimus by no less than the renowned doctor in paleontology Kenneth Carpenter, the same sciencist that catapulted the 60 meters diplodocid version to fame in 2006.

The publication suggests that the morphological characters of AMNH 5777 show shared apomorphies (defining characters) with rebbachisauridae, and that thus should be considered to be part of said group. Going by this, Maraapunisaurus fragillimus would be the largest and oldest member known of this peculiar family; perhaps meaning that the clade could have originated in what today is north america in the upper Jurassic, archieving practically wordlwide distribution by the early cretaceous (exceptuating Asia and Antartica).




To the left (shown above; original drawing by Cope (1878) labeled in Willson et al (2011). To the right, it compared with dorsal vertebrae of other rebbachisaurids (Rebbachisaurus grasbae and Histriasaurus boscarollii).

Maraapunisaurus fragillimus is known from a single partial neural arch of massive dimensions if we go by Cope's measurements (total elevation of neural arch preserved, 1500 mm; elevation of posterior zygapophyses, 585; transverse expanseof posterior zygapophyses, 190; vertical diameter of base of diapophysis, 390) . The older reconstruction by Carpenter of the complete vertebra was 2.7 m tall, and newer one is 2.4 m, just twice the height as the preserved dorsal vertebra of Limaysaurus tessonei (120 cm). This leaves us with an animal 2x the linear dimensions of Limaysaurus tessonei and 8x (2^3) it's mass asuming perfect isometry, although the distance between the neural canal and the postzygapophysis seems larger in proportion in Maraapunisaurus fragillimus than in Limaysaurus, meaning that this discrepancy could have been smaller and not a direct translation on how the vertebral heights correlate.

Asuming perfect isometry in reconstructed vertebral height, the length of Maraapunisaurus fragillimus would be between 28.6 and 30 m (going by the skeletal restorations of Limaysaurus by and Gregory S.Paul) and the mass between 56 and 61.6 metric tonnes ( mass of Limaysaurus is 7 t going by Greg Paul's estimate in the priceton field guide 2016, 7.7 t going by GDI of a slightly edited Limaysaurus restoration using my matlab script (specific gravities applied are 0.7 for the head, 0.6 for the neck, 0.9 for the torso, 1 for the tail and limbs).

Link to Limaysaurus GDI estimate.
i.imgur.com/Gkn1P7o.png

Diagram from Carpenter 2018, showing relative dimensions between the newer and the older version of his reconstruction of AMNH 5777. Old estimate involved a 2.7m high vertebra using a D.carnegii like body plan:



There is a posibility that the neck was slightly more elongated than what isometry predicts, as the neck length in several neosauropods scale with torso dimensions to the power of 1.35 as described by Parish (2006). This augments the posible linear dimensions up to 32 m, with mass increasing only slightly, as sauropod necks are not very massive in proportion and heavily pneumatized.

What happens with Amphicoelias as a whole, and with Amphicoelias altus specifically?

This would make it so M.fragillimus stops being closely related to Amphicoelias altus, and thus Amphicoelias altus survives as their own genus and species. Cope came to this conclussion in 1878 since A.altus was the only diplodocoid he had named, and while they still have the general resemblance expected in two diplodocoid taxa, M.fragillimus shares at least 2 apomorphies with all of rebbachisauridae, and other characters in common with some of them. Amphicoelias altus has been recovered within apatosaurinae according to Tschopp & Mateus 2017 analysis, and it's femoral dimensions (177 cm maximum length as indicated by Osborn & mook 1921) are close to that of B.louisae specimen CM 3018: with femoral length 178.5 cm and an estimated mass 22.4 tonnes by GDI analysis by myself using Scott Hartman's skeletal with a dorsal view by Gregory S.Paul ;Greg Paul's own estimate for this taxon is 18 tonnes) ,so despite the genus surviving, it now doesn't hold any record holder in terms of size.

Is M.fragilimus the largest sauropod dinosaur (and thus, largest terrestrial vertebrate) ever found according to this information?

Mazzeta et al 2004 proposed a mass of 73 t for Argentinosaurus huinculensis based on a referred femoral shaft using regression equations; an estimate close to a GDI done in 's Argentinosaurus reconstruction (in which I collaborated), that yielded between 71.4 and 75.4 metric tonnes depending on varying the ribcage width between plausible values. Patagotitan mayorum as described in Carballido 2017 could be slightly smaller than Maraapunisaurus fragillimus, with a convex hull +21% model of 55 t, though the maximum model (reconstructed with much more soft tissue than that applied to Limaysaurus mass estimates) yielded up to 77 tonnes.

Here is a comparison of M.fragilimus and A.huinculensis: (Argentinosaurus huinculensis by , Maraapunisaurus fragillimus silhouette by using Limaysaurus tessonei skeletal by as a base)


Here is the great SVPOW post on the matter:

svpow.com/2018/10/21/what-if-a…

And the original publication, discussing certain matters much further than I and SVPOW members did.

www.utahgeology.org/publicatio…

Congratulations are in order for fellow deviantartist that has actually been acknowledged in the publication. 

Here is the original post that he made in this very same site:

Was Amphicoelias a rebbachisaur?Update (10/22/18): Dr. Ken Carpenter has recently published a new paper supporting the view below (and cites me favorably), but I would also be remiss to not recongize Dr. Andrea Cau for having thought up this idea 2 years before me. Sadly, he was not cited in Carpenter's paper. He and I both were unaware of Cau's work.
The last time I wrote about the size of Amphicoelias, I still used Diplodocus as a comparison. One of the comments that was made was that my size estimate was likely wrong, as Amphicoelias was probably a basal diplodocoid, not a diplodocid proper. After a little investigation, it turned out that two phylogenetic analyses have been published that included Amphicoelias, and both found Amphicoelias to be a basal diplodocoid. Whitlock (2011) was

References:

• Carpenter, Kenneth. 2006. Biggest of the big: a critical re-evaluation of the mega-sauropod Amphicoelias fragillimus Cope, 1878. pp. 131-137 in J. Foster and S. G. Lucas (eds.), Paleontology and Geology of the Upper Jurassic Morrison Formation. New Mexico Museum of Natural History and Science Bulletin 36.
• Carpenter, Kenneth. 2018. Maraapunisaurus fragillimus, n.g. (formerly Amphicoelias fragillimus), a basal rebbachisaurid from the Morrison Formation (Upper Jurassic) of Colorado. Geology of the Intermountain West 5:227–244.
• Cope, Edward D. 1878. A new species of Amphicoelias. American Naturalist12:563–565.
• Paul, Gregory S. 2016. The Princeton field guide to dinosaurs. Princeton, Princeton University Press. 360 pages.
• Taylor, Michael.p (2018) What if Amphicoelias fragillimus was a rebbachisaurid? Sauropod Vertebra Picture of the Week, 22 october 2018.
• Osborn, H.F; Mook C.G (1921) CAMARASA URUS, AMPHIC(ELIAS, AND OTHER SAUROPODS OF COPE. Memoirs of the American museum of Natural history. New series, volume 3, part lll.

Introduction:

As Chritopher Brochu once noted in his osteological study on Tyrannosaurus: "Nothing evokes prehistory more than Tyrannosaurus rex. Nearly any five-year-old in the industrialized world knows what it is, and to many, Tyrannosaurus is the quintessential predatory dinosaur-as Paul (1988:344) stated, "this is the theropod." It is the only nonavian dinosaur (and one of the few organisms) popularly known by the specific rather than generic name-"T. rex" is as common in the popular media as "Tyrannosaurus."

As well as:

“Tyrannosaurids are no more relevant to phylogenetics or comparative biology than any other group of organisms, but they are extremely popular. When we do science with Tyrannosaurus, we do it with a broader audience than if it were done with almost any other animal.”

Along with the biggest fame, come the greatest hyperboles, and the highest numbers of fanatics, as well as the most intense of them. However so do the most harsh minusvalorations, and the highest ammount of detractors, as well of the most insistent of them.

Despite the subjective appreciations of each individual, Tyrannosaurus is still just an extint animal which can be anylized by scientific methodology just as any other, nothing more, and nothing less. On the basis of theese premises and without further dilation; the results of this mass estimation on FMNH PR 2081 and the multiview restoration used are ofered.

Results:





Restoration analyzed:




Discussion of the methodology:

The totality of the animal has been reconstructed from several views based on it's osteological description (Brochu 2003) and LIDAR scans (Hutchinson 2011), as well as those of other Tyrannosaurid specimens, in order to produce the mass estimation, and each body section has been analyzed and weighted by a high fidelity MATLAB script, made by my partner and me (a big thank you to her for always being my greatest support) .

For those unfamiliarized with the method, the program analyzes two views of the same section of the body, for example the torso seen from top and from the side, and then constructs a three-dimensional model of it based on a lot of eliptical sections put together, with one of the elypsis' axis based on one view, and the other one on the other.

The program makes this Graphical Double Integration method ( svpow.com/2011/01/20/tutorial-… ) as exact as it can be, doing one slice per pixel in order to produce the pixel wide elypsis that will be put together. Being one meter equal to 490 pixels in my restorations, the program produces thousends of eliptical sections in order to weight the animal, much more than the 50-100 ish that can be done with a paper and a pencil or with excel.

In order to produce the torso, all the ribs were attached to the dorsal vertebrae in anterior view, and then projected to the dorsal view and angled from above in order to give the torso of the animal a shape.

Example of the methodology used to reconstruct the trunk sections:



The torso has been produced in a somewhat conservative manner.

Hutchinson (2011) assests "that the torso of the mount is inflated in width due to a dorsal displacement of the transverse processes on the trunk vertebrae, which forced a dorsal displacement of the tubercular articulations and a lateral expansion of the rib cage as a whole."

Therefore the distortion of the transverse processes in the vertebrae was corrected in order to avoid the artificial expansion of some of the ribs. Hutchinson's main concern about their mass estimation is then fixed.

Example of de-crushing applied to all of the vertebrae:


The ribs are more angled from above than those of the mount of FMNH PR 2081 in the Field museum of Chicago, and therefore mounted more similarly to how the BHI articulates the Tyrannosaurus mounts they prepare.
Considering both modifications, it is not surprising that the results of this estimation are moderately lower than those of Hutchinson et al 2011 (8830 kg compared to 9500 for the minimal model).

It is, however slightly larger than the estimation Scott Hartman came up with, and that has adquired a significant amount of fame in the internet due to being compared to that of Giganotosaurus.

Discussion of the result and conclusions:

The estimation of FMNH PR 2081 that I have produced is moderately to substantially higher than the masses that I have calculated using this same methodology for the other largest theropod dinosaur specimens.

The mass of 8830 kg of Tyrannosaurus (FMNH PR 2081) is ofered in contrast to that of 7560 kg of Spinosaurus (MNSM v 4047) , 6840 kg in Giganotosaurus (Mucpv Ch1), 6400 kg in Tyrannotitan (MPEF pv 1157), 6325 kg in Carcharodontosaurus (SGM din 1) and 6110 kg in Acrocanthosaurus (NCSM 14345). Therefore according to theese the largest theropod specimen would belong to Tyrannosaurus rex.

The results compare well with those obtained with other volumetric estimations, falling between the estimations of  (8400 kg static1.squarespace.com/static… ) and Hutchison et al 2011 (9500 kg journals.plos.org/plosone/arti…). Considering that Scott showed concerns regarding the mass probably being on the low end, and Hutchinson showed concerns about their mass estimation potentially being too high, I find the results satisfactory and probable.

Here you can see the mass calculations made on the other animals:
Mathematical analysis on Carcharodontosaurus mass
A mathematical analysis on Tyrannotitan mass.
A mathematical analysis on Giganotosaurus mass.
A mathematical analysis on Spinosaurus mass.
Acrocanthosaurus GDI:
AcroGDIhump

References:

Christopher A. Brochu (2003): Osteology of Tyrannosaurus Rex: Insights from a nearly complete Skeleton and High-Resolution Computed Tomographic Analysis of the Skull, Journal of Vertebrate Paleontology, 22:sup4, 1-138

Hutchinson JR, Bates KT, Molnar J, Allen V, Makovicky PJ (2014) Correction: A Computational Analysis of Limb and Body Dimensions in Tyrannosaurus rex with Implications for Locomotion, Ontogeny, and Growth. PLOS ONE 9(5): e97055.

Bates KT, Manning PL, Hodgetts D, Sellers WI (2009) Estimating Mass Properties of Dinosaurs Using Laser Imaging and 3D Computer Modelling. PLoS ONE 4(2): e4532.

www.skeletaldrawing.com/home/m…

svpow.com/2011/01/20/tutorial-…

As always, the results first:






Here you have the previous calculations made with the method used; graphical double integration, a type of vollumetric estimation:
A mathematical analysis on Tyrannotitan mass.

A mathematical analysis on Giganotosaurus mass.

A mathematical analysis on Spinosaurus mass.

The method consists in constructing a simplified 3D model of the animal mathematically, by building eliptical cross sections and adding them up, given two views of each of it's body sections. The analysis is performed by a matlab mathematical script with pixel accuracy. More information about the method itselft here:

www..com/users/outgoing?https:…

I'll discuss a bit about Carcharodontosaurus here, but briefly since I believe I'll dedicate one more journal, or even more, to it.

The Carcharodontosaurus skeletal is again original research and work. Carcharodontosaurus is a largely incomplete animal, the holotype was only known by a couple of broken nassals, some pieces of a broken maxilla, bones of the occipital region, a braincase, two cervicals, a caudal vertebra and two partial chevrons, partial pubis and ischium, a femur, and a fíbula (Stromer 1931). Furthermore and with like Spinosaurus, Bahariasaurus, and Aegyptosaurus, it's remains were destroyed in the second world war.

The neotype consists of fragments of a skull, that when put togheter, is very big ( Sereno 1996) . When using Tyrannotitan to reconstruct the rear of the skull and Acrocanthosaurus to reconstruct the rest it ends at about 1.53 m long in maximum metric measurements (Currie and Carpenter 2000, Canale 2014) (far from the 1.6+ m that was reported to the press)
The skull is not only not as long as reported; it is also very narrow, and as a result, it's length alone is missleading to judge it's total size, and in fact the head does mass little compared to the more robust heads of other giant predatory dinosaurs. According to my best fit of the skull elements of the holotype and the neotype, the Neotype is an animal that would have a 12.5% bigger skull (roughly). With a skull about 1.35 m in length, the holotype of Carcharodontosaurus was not small headed, and had a similar skull/body ratio than all other Carcharodontosaurines.

The missing elements are based on Tyrannotitan, the animal that is most closely related to Carcharodontosaurus according to the latest phylogenetic analysis (Canale 2014) and also one that shares with it a bunch of very interesting characters that will be discussed in another journal. Carcharodontosaurus is NOT out of the clade that bounds Tyrannotitan, Giganotosaurus , and Mapusaurus togheter, it is in fact strongly bounded to them in Carcharodontosaurinae, a clade of derived, giant Gondwanan Carcharodontosaurids, even if another smaller clade, Giganotosaurini, bound the south american Carcharodontosaurines even more strongly. 

Carcharodontosaurus is barely any bigger than Tyrannotitan in linear dimensions according to how most of the bones compare, the Carcharodontosaurus holotype has a femur smaller than that of the Tyrannotitan holotype, it's extrapolation to SGM din 1 size is barely any bigger than the same element in Tyrannotitan paratype, and the jugal of the Tyrannotitan paratype fits almost perfectly in SGM din 1 skull. Here it is scaled to be a vague (and optimistic) 0.5% bigger in linear dimensions based on marginal differences, and is also given a slightly lengthier tail to fit the only known caudal of the Carcharodontosaurus' holotype better.

However, that couldn't prevent Tyrannotitan being more massive than Carcharodontosaurus, even when Carcharodontosaurus is based mainly on it.  
The difference, although almost negliable, is due to Tyrannotitan having a bigger pubis ( as discussed in the last journal) and a possibly wider skull and neck. The difference in skull width is conservative, because Tyrannotitan could have had a wider head that I gave it credit for; if it's skull was built similarly to Giganotosaurus. For theese journals, I took the middle ground approach for Tyrannotitan skull width. Giving Tyrannotitan a skull similar to the one I used for Giganotosaurus would augment it's mass about 50 kg, augmenting it's mass advantage over Carcharodontosaurus from 75 kg to about 125 kg. 

So, is Carcharodontosaurus the enormous, small headed 8t or 9t+ ultra-giant that some people wanted to see in it's fragmentary ( and not that impressive) remains? It seems like it isn't, but further discussion on that will be for another journal.

Here you have the Carcharodontosaurus restorations:




References:

Stromer 1931 II. Vertebrate remains from the Baharîje Beds (lowermost Cenomanian). 10. A skeletal remain of Carcharodontosaurus nov. gen. 

Paul C. Sereno, Didier B. Dutheil, M. Larochene, Hans C. E. Larsson, Gabrielle H. Lyon, Paul M. Magwene, Christian A. Sidor, David J. Varricchio, Jeffrey A. Wilson (1996): Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation. Science, New Series, Vol. 272, No. 5264 (May 17, 1996), pp. 986-991 

Juan Ignacio Canale, Fernando Emilio Novas & Diego Pol , Historical Biology (2014): Osteology and phylogenetic relationships of Tyrannotitan chubutensis Novas, de Valais, Vickers-Rich and Rich, 2005 (Theropoda: Carcharodontosauridae) from the Lower Cretaceous of Patagonia, Argentina, Historical Biology: An International Journal of Paleobiology.

Fernando E Novas, Silvina de Valais, Pat Vickers-Rich, Tom Rich (2005): A large Cretaceous theropod from Patagonia, Argentina, and the evolution of carcharodontosaurids

Currie P. J. & Carpenter K. 2000. — A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA. Geodiversitas 22 (2) : 207-246.

The results first:




Here you have the previous calculations made with the method used; graphical double integration, a type of vollumetric estimation.

A mathematical analysis on Giganotosaurus mass.First of all, the results:


Conclussions , methodology, and anatomical references: 
For those who don't know which method was used, I recommend reading the previous journal entry, about a mathematical anaylsis on Spinosaurus mass , another legendary carnivorous dinosaur; and this excelent post by SVPOW. https://svpow.com/2011/01/20/tutorial-11-graphic-double-integration-or-weighing-dinosaurs-on-the-cheap/
Overall the method intends to construct a simplified 3D model of the animal by building eliptical cross sections and adding them up, given two views of each of it's body sections. The analysis is performed by a matlab mathematical script with pixel accuracy.
The skeletal used is my own bet on the animal. Sadly, and despite more than 22 years having passed since the animal was first (and very briefly) described, most of it's material is not described in detail, specially the axia

A mathematical analysis on Spinosaurus mass.UPDATE 10/02/2019:
This estimation was in need of an update for a long time. Lots of things have happened since I first produced the first estimate, which was also my first GDI ever. I produced my own lateral view of the skeletal, for an in depth discussion about the taxon and for clearing some doubts about how it was produced, please take a look at it and it's description:

For the first iteration of the model, the lateral view was simply an adaptation of the figure in the Ibrahim et al 2014 supplementary materials scaled to the size of the MSNM v 4047 rostrum, but the fit wasn't as perfect as I would have liked. This new lateral view should be more rigorous.
A second important update has been the production of a dorsal view. First, I used the preserverd fossils of IPHG 1912 to infer the shape of the ribcage and cross sections of it to infer the width, as well as other spinosaurid and megalosaurid specimens to infer the rest of the body, following a similar

The method consists in constructing a simplified 3D model of the animal mathematically, by building eliptical cross sections and adding them up, given two views of each of it's body sections. The analysis is performed by a matlab mathematical script with pixel accuracy. More information about the method itselft here:

svpow.com/2011/01/20/tutorial-…

Some discussing about Tyrannotitan size and overall proportions:

The skeletal used was made by me from scratch, using mainly the information (figures, measurements, and descriptions) in Novas (2005) and Canale , Novas (2014); using Sereno 1996, Coria 1995, and Currie and Carpenter 2000 to fill in the gaps, because Tyrannotitan is not complete, even if it is one of the most complete Carcharodontosaurids that we have by far and long. And it also is one to have a detailed description with a well documented supplementary materials, unlike others like Giganotosaurus which never seems to get a detailed osteological study, even 22 years after the brief and undetailed (and now vastly outdated in every possible sense) description of Mucpv Ch1.

The top view was again modified from Acrocanthosaurus. The width of the skull, and consequently that of the anterior portion of the neck, is intermediate between Carcharodontosaurus and Giganotosaurus, the two most closely related animals to Tyrannotitan, which also preserve a decent portion of their respective skulls. It wouldn't surprise me that the head was wider than what I gave it credit for, since after all, Tyrannotitan is strongly bounded to the tribe Giganotosaurini, even more so than to the subfamily Carcharodontosaurinae, which includes Carcharodontosaurus.

I gave Tyrannotitan an equivalent ribcage width as to Acrocanthosaurus based on comparisons of the vertebrae of the former with that of later. The hips however are wider, following the suggestion of a 40 cm wide hip for Tyrannotitan holotype, as per suggested by Canale 2014. If the paratype was about 7% bigger in average as Novas 2005 suggests, the hip of the paratype would be 42.8 cm wide, which was wider than the Acrocanthosaurus hip scaled to match the length of that of Tyrannotitan.

There are more indications of Tyrannotitan being bulky for it's length compared to other Carcharodontosaurids and Allosauroids, like it's femur circumference; which at 541 mm (Canale 2014 supp materials) would be greater than that of Giganotosaurus holotype ( 520 mm, Campione et al 2014). 

Tyrannotitan of course also has other peculiarities that are woth discussing and that had an impact on it's body mass; for example it's dorsal vertebrae being anteroposteriorly short. None of the vertebrae of the paratype has a centrum over 14 cm long (Canale 2014, supp materials) except one, which barely pushes 15.5 m, furtheremore the 1st and the 14th dorsal are very reduced compared to the other vertebrae wich yields a torso length of about 85% that of Giganotosaurus, which explains the (perhaps) lower than expected body length estimation.

The most cited length of 12.2 m is cited from the theropod database, and the estimation was made way before the detailed osteological study came out, and was probably based on femur scaling using Giganotosaurus as a base. However after the publication of Canale 2014 Tyrannotitan having an equivalent body length to Giganotosaurus doesn't hold up.

Tyrannotitan also shows very tall neural spines, much taller than those of Giganotosaurus. Such feature helps expanding the torso depth and incrementing it's mass, furtheremore the pubis is 11 cm longer than the measurement for Giganotosaurus in the theropod database and 10 cm longer than the extrapolated pubis length of the biggest Carcharodontosaurus specimen (SGM din 1). Even if we were to be skeptical about the extrapolation, Carcharodontosaurus (IPHG 1922) reconstructed pubis was only 1 meter long compared to a 1.26 m long femur, or 79% the length of the femur, while in Tyrannotitan the reconstructed pubis is 86% the femur length, suggesting again that Tyrannotitan had a deep torso, despite it being relatively shorter than in Giganotosaurus.

The skull elements suggest a skull of very large size, specially length; the jugal matches almost exactly in size and shape to the same element in Carcharodontosaurus (SGM din 1) and the dentary of the Tyrannotitan paratype is comparable in size to that of both Giganotosaurus specimens, so Tyrannotitan is certainly a big headed animal, as are all of the members of Carcharodontosaurinae. The preserved quadratojugal in Tyrannotitan and how it articulates and compares in size with the jugal offers valuable information on to how to restore the rear portions of Carcharodontosaurines' skulls.

Link to the Tyrannotitan restorations:



Carcharodontosaurus will be the next, and will come with a couple surprises. Stay tuned!

References:

Juan Ignacio Canale, Fernando Emilio Novas & Diego Pol , Historical Biology (2014): Osteology and phylogenetic relationships of Tyrannotitan chubutensis Novas, de Valais, Vickers-Rich and Rich, 2005 (Theropoda: Carcharodontosauridae) from the Lower Cretaceous of Patagonia, Argentina, Historical Biology: An International Journal of Paleobiology.

Fernando E Novas, Silvina de Valais, Pat Vickers-Rich, Tom Rich (2005): A large Cretaceous theropod from Patagonia, Argentina, and the evolution of carcharodontosaurids

Paul C. Sereno, Didier B. Dutheil, M. Larochene, Hans C. E. Larsson, Gabrielle H. Lyon, Paul M. Magwene, Christian A. Sidor, David J. Varricchio, Jeffrey A. Wilson (1996): Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation. Science, New Series, Vol. 272, No. 5264 (May 17, 1996), pp. 986-991

Rodolfo A.Coria, Leonardo Salgado (1995) A new giant carnivorous dinosaur from the Cretaceous of Patagonia. Nature, Vol 377 (September 21 1995)

Currie P. J. & Carpenter K. 2000. — A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA. Geodiversitas 22 (2) : 207-246.

Stromer 1931 II. Vertebrate remains from the Baharîje Beds (lowermost Cenomanian). 10. A skeletal remain of Carcharodontosaurus nov. gen. 

First of all, the results:






Conclussions , methodology, and anatomical references: 

For those who don't know which method was used, I recommend reading the previous journal entry, about a mathematical anaylsis on Spinosaurus mass A mathematical analysis on Spinosaurus mass.UPDATE 10/02/2019:
This estimation was in need of an update for a long time. Lots of things have happened since I first produced the first estimate, which was also my first GDI ever. I produced my own lateral view of the skeletal, for an in depth discussion about the taxon and for clearing some doubts about how it was produced, please take a look at it and it's description:

For the first iteration of the model, the lateral view was simply an adaptation of the figure in the Ibrahim et al 2014 supplementary materials scaled to the size of the MSNM v 4047 rostrum, but the fit wasn't as perfect as I would have liked. This new lateral view should be more rigorous.
A second important update has been the production of a dorsal view. First, I used the preserverd fossils of IPHG 1912 to infer the shape of the ribcage and cross sections of it to infer the width, as well as other spinosaurid and megalosaurid specimens to infer the rest of the body, following a similar, another legendary carnivorous dinosaur; and this excelent post by SVPOW. svpow.com/2011/01/20/tutorial-…

Overall the method intends to construct a simplified 3D model of the animal by building eliptical cross sections and adding them up, given two views of each of it's body sections. The analysis is performed by a matlab mathematical script with pixel accuracy.

The skeletal used is my own bet on the animal. Sadly, and despite more than 22 years having passed since the animal was first (and very briefly) described, most of it's material is not described in detail, specially the axial skeleton. No photographs, ilustrations, measurement tables, nothing. So even if I used my skeletal for the GDI, the axial skeleton ( the vertebral column) had to be scaled after work. I didn't have much of a choice in that regard.

Most of the skull and the apendicular material has however been mentioned, briefly described, and has several measurements published in the literature (Coria 2003, Coria and Currie 2006, Carrano 2012, Canale 2014, Canale& Carbajal 2015, and other studies, a good deal of them are compiled in the theropod database) I tried for the skeletal to be as up to date and to match as many of the measurements and the descriptions in Coria and Currie 2006 and the other studies as much as possible. The missing elements of the skeleton, like the forelimbs or the feet, were restored after my Tyrannotitan skeletal.

The top view is scaled and drawn after Acrocanthosaurus (Bates 2008) , a similarly sized Carcharodontosaurid, edited to have similar proportions to those of Giganotosaurus. By superimposing Hartman's Giganotosaurus top view with the dorsal view of Bates et al Acrocanthosaurus, it seems to be what he did, or at the very least the results are pretty much identical. I used Hartman's dorsal view to have an idea of how much soft tissue should I add for it to be a fair comparison with other theropod GDIs.

The results pretty much replicate his estimation (6800 kgs), despite several bones differing a substantial deal from his version. They are also coherent with other mass estimations published for Mucpv Ch1 (Mazzeta et al 2004; 6510 kg , Campione et al. 2014;  6349 kg,   Seebacher 2001 ; 6,594.8 kg)

Link to Giganotosaurus restoration: