Notocolossus is a beast
January 20, 2016
(a) Type locality of Notocolossus (indicated by star) in southern-most Mendoza Province, Argentina. (b) Reconstructed skeleton and body silhouette in right lateral view, with preserved elements of the holotype (UNCUYO-LD 301) in light green and those of the referred specimen (UNCUYO-LD 302) in orange. Scale bar, 1 m. (González Riga et al. 2016: figure 1)
This will be all too short, but I can’t let the publication of a new giant sauropod pass unremarked. Yesterday Bernardo González Riga and colleagues published a nice, detailed paper describing Notocolossus gonzalezparejasi, “Dr. Jorge González Parejas’s southern giant”, a new titanosaur from the Late Cretaceous of Mendoza Province, Argentina (González Riga et al. 2016). The paper is open access and freely available to the world.
As you can see from the skeletal recon, there’s not a ton of material known from Notocolossus, but among giant sauropods it’s actually not bad, being better represented than Argentinosaurus, Puertasaurus, Argyrosaurus, and Paralititan. In particular, one hindfoot is complete and articulated, and a good chunk of the paper and supplementary info are devoted to describing how weird it is.
But let’s not kid ourselves – you’re not here for feet, unless it’s to ask how many feet long this monster was. So how big was Notocolossus, really?
Well, it wasn’t the world’s largest sauropod. And to their credit, no-one on the team that described it has made any such superlative claims for the animal. Instead they describe it as, “one of the largest terrestrial vertebrates ever discovered”, and that’s perfectly accurate.
(a) Right humerus of the holotype (UNCUYO-LD 301) in anterior view. Proximal end of the left pubis of the holotype (UNCUYO-LD 301) in lateral (b) and proximal (c) views. Right tarsus and pes of the referred specimen (UNCUYO-LD 302) in (d) proximal (articulated, metatarsus only, dorsal [=anterior] to top), (e) dorsomedial (articulated), and (f) dorsal (disarticulated) views. Abbreviations: I–V, metatarsal/digit number; 1–2, phalanx number; ast, astragalus; cbf, coracobrachialis fossa; dpc, deltopectoral crest; hh, humeral head; ilped, iliac peduncle; of, obturator foramen; plp, proximolateral process; pmp, proximomedial process; rac, radial condyle; ulc, ulnar condyle. Scale bars, 20 cm (a–c), 10 cm (d–f). (Gonzalez Riga et al 2016: figure 4)
Top row: my attempt at a symmetrical Notocolossus dorsal, made by mirroring the left half of the fossil from the next row down. Second row: photos of the Notocolossus dorsal with missing bits outlined, from Gonzalez Riga et al (2016: fig. 2). Scale bar is 20 cm (in original). Third row: the only known dorsal vertebra of Puertasaurus, scaled to about the same size as the Notocolossus vertebra, from Novas et al. (2005: fig. 2).
The anterior dorsal tells a similar story, and this is where I have to give González Riga et al. some props for publishing such detailed sets of measurements in the their supplementary information. They Measured Their Damned Dinosaur. The dorsal has a preserved height of 75 cm – it’s missing the tip of the neural spine and would have been a few cm taller in life – and by measuring the one complete transverse process and doubling it, the authors estimate that when complete it would have been 150 cm wide. That is 59 inches, almost 5 feet. The only wider vertebra I know of is the anterior dorsal of Puertasaurus, at a staggering 168 cm wide (Novas et al. 2005). The Puertasaurus dorsal is also quite a bit taller dorsoventrally, at 106 cm, and it has a considerably larger centrum: 43 x 60 cm, compared to 34 x 43.5 cm for Notocolossus (anterior centrum diameters, height x width).
Centrum size is an interesting parameter. Because centra are so rarely circular, arguably the best way to compare across taxa would be to measure the max area (or, since centrum ends are also rarely flat, the max cross-sectional area). It’s late and this post is already too long, so I’m not going to do that now. But I have been keeping an informal list of the largest centrum diameters among sauropods – and, therefore, among all Terran life – and here they are (please let me know if I missed anyone):
- 60 cm – Argentinosaurus dorsal, MCF-PVPH-1, Bonaparte and Coria (1993)
- 60 cm – Puertasaurus dorsal, MPM 10002, Novas et al. (2005)
- 51 cm – Ruyangosaurus cervical and dorsal, 41HIII-0002, Lu et al. (2009)
- 50 cm – Alamosaurus cervical, SMP VP−1850, Fowler and Sullivan (2011)
- 49 cm – Apatosaurus ?caudal, OMNH 1331 (pers. obs.)
- 49 cm – Supersaurus dorsal, BYU uncatalogued (pers. obs.)
- 46 cm – Dreadnoughtus dorsal, MPM-PV 1156, Lacovara et al. (2014: Supplmentary Table 1) – thanks to Shahen for catching this one in the comments!
- 45.6 cm – Giraffatitan presacral, Fund no 8, Janensch (1950: p. 39)
- 45 cm – Futalognkosaurus sacral, MUCPv-323, Calvo et al. (2007)
- 43.5 cm – Notocolossus dorsal, UNCUYO-LD 301, González Riga et al. (2016)
(Fine print: I’m only logging each taxon once, by its largest vertebra, and I’m not counting the dorsoventrally squashed Giraffatitan cervicals which get up to 47 cm wide, and the “uncatalogued” Supersaurus dorsal is one I saw back in 2005 – it almost certainly has been catalogued in the interim.) Two things impress me about this list: first, it’s not all ‘exotic’ weirdos – look at the giant Oklahoma Apatosaurus hanging out halfway down the list. Second, Argentinosaurus and Puertasaurus pretty much destroy everyone else by a wide margin. Notocolossus doesn’t seem so impressive in this list, but it’s worth remembering that the “max” centrum diameter here is from one vertebra, which was likely not the largest in the series – then again, the same is true for Puertasaurus, Alamosaurus, and many others.
(a) Time-calibrated hypothesis of phylogenetic relationships of Notocolossus with relevant clades labelled. Depicted topology is that of the single most parsimonious tree of 720 steps in length (Consistency Index = 0.52; Retention Index = 0.65). Stratigraphic ranges (indicated by coloured bars) for most taxa follow Lacovara et al.4: fig. 3 and references therein. Additional age sources are as follows: Apatosaurus[55], Cedarosaurus[58], Diamantinasaurus[59], Diplodocus[35], Europasaurus[35], Ligabuesaurus[35], Neuquensaurus[60], Omeisaurus[55], Saltasaurus[60], Shunosaurus[55], Trigonosaurus[35], Venenosaurus[58], Wintonotitan[59]. Stratigraphic ranges are colour-coded to also indicate geographic provenance of each taxon: Africa (excluding Madagascar), light blue; Asia (excluding India), red; Australia, purple; Europe, light green; India, dark green; Madagascar, dark blue; North America, yellow; South America, orange. (b–h) Drawings of articulated or closely associated sauropod right pedes in dorsal (=anterior) view, with respective pedal phalangeal formulae and total number of phalanges per pes provided (the latter in parentheses). (b) Shunosaurus (ZDM T5402, reversed and redrawn from Zhang[45]); (c) Apatosaurus (CM 89); (d) Camarasaurus (USNM 13786); (e) Cedarosaurus (FMNH PR 977, reversed from D’Emic[32]); (f) Epachthosaurus (UNPSJB-PV 920, redrawn and modified from Martínez et al.[22]); (g) Notocolossus; (h) Opisthocoelicaudia (ZPAL MgD-I-48). Note near-progressive decrease in total number of pedal phalanges and trend toward phalangeal reduction on pedal digits II–V throughout sauropod evolutionary history (culminating in phalangeal formula of 2-2-2-1-0 [seven total phalanges per pes] in the latest Cretaceous derived titanosaur Opisthocoelicaudia). Abbreviation: Mya, million years ago. Institutional abbreviations see Supplementary Information. (González Riga et al. 2016: figure 5)
The [humeral] diaphysis is elliptical in cross-section, with its long axis oriented mediolaterally, and measures 770 mm in minimum circumference. Based on that figure, the consistent relationship between humeral and femoral shaft circumference in associated titanosaurian skeletons that preserve both of these dimensions permits an estimate of the circumference of the missing femur of UNCUYO-LD 301 at 936 mm (see Supplementary Information). (Note, however, that the dataset that is the source of this estimate does not include many gigantic titanosaurs, such as Argentinosaurus[5], Paralititan[16], and Puertasaurus[11], since no specimens that preserve an associated humerus and femur are known for these taxa.) In turn, using a scaling equation proposed by Campione and Evans[20], the combined circumferences of the Notocolossus stylopodial elements generate a mean estimated body mass of ~60.4 metric tons, which exceeds the ~59.3 and ~38.1 metric ton masses estimated for the giant titanosaurs Dreadnoughtus and Futalognkosaurus, respectively, using the same equation (see Supplementary Information). It is important to note, however, that subtracting the mean percent prediction error of this equation (25.6% of calculated mass[20]) yields a substantially lower estimate of ~44.9 metric tons for UNCUYO-LD 301. Furthermore, Bates et al.[21] recently used a volumetric method to propose a revised maximum mass of ~38.2 metric tons for Dreadnoughtus, which suggests that the Campione and Evans[20] equation may substantially overestimate the masses of large sauropods, particularly giant titanosaurs. Unfortunately, however, the incompleteness of the Notocolossus specimens prohibits the construction of a well-supported volumetric model of this taxon, and therefore precludes the application of the Bates et al.[21] method. The discrepancies in mass estimation produced by the Campione and Evans[20] and Bates et al.[21] methods indicate a need to compare the predictions of these methods across a broad range of terrestrial tetrapod taxa[21]. Nevertheless, even if the body mass of the Notocolossus holotype was closer to 40 than 60 metric tons, this, coupled with the linear dimensions of its skeletal elements, would still suggest that it represents one of the largest land animals yet discovered.
So, nice work all around. As always, I hope we get more of this critter someday, but until then, González Riga et al. (2016) have done a bang-up job describing the specimens they have. Both the paper and the supplementary information will reward a thorough read-through, and they’re free, so go have fun.
References
- Bonaparte, J. F., and Coria, R. A. (1993). Un nuevo y gigantesco saurópodo titanosaurio de la Formación Río Limay (Albiano-Cenomaniano) de la Provincia del Neuquén, Argentina. Ameghiniana, 30(3): 271-282.
- Calvo, J. O., Porfiri, J. D., González Riga, B. J., and Kellner, A. W. A. 2007. Anatomy of Futalognkosaurus dukei Calvo, Porfiri, González Riga & Kellner, 2007 (Dinosauria, Titanosauridae) from the Neuquén Group (Late Cretaceous), Patagonia, Argentina. Arquivos do Museu Nacional, Rio de Janeiro, 65(4): 511-526.
- Fowler, D. W. and Sullivan, R. M. 2011. The first giant titanosaurian sauropod from the Upper Cretaceous of North America. Acta Palaeontologica Polonica 56 (4): 685–690.
- González Riga, B. J., Lamanna, M. C., Ortiz David, L. D., Calvo, J. O., and Coria, J. P. 2016. A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot. Scientific Reports 6, Article number: 19165. doi: 10.1038/srep19165
- Janensch, W. 1950. Die Wirbelsaule von Brachiosaurus brancai. Palaeontographica (Suppl. 7) 3:27-93.
- Lacovara, Kenneth J.; Ibiricu, L.M.; Lamanna, M.C.; Poole, J.C.; Schroeter, E.R.; Ullmann, P.V.; Voegele, K.K.; Boles, Z.M.; Egerton, V.M.; Harris, J.D.; Martínez, R.D.; Novas, F.E. (September 4, 2014). A Gigantic, Exceptionally Complete Titanosaurian Sauropod Dinosaur from Southern Patagonia, Argentina. Scientific Reports. doi:10.1038/srep06196.
- Lü J, Xu L, Jia S, Zhang X, Zhang J, Yang L, You H, Ji Q. 2009. A new gigantic sauropod dinosaur from the Cretaceous of Ruyang, Henan, China. Geological Bulletin of China 28(1): 1-10.
- Novas, F., Salgado, L., Calvo, J., and Agnolin, F. (2005). Giant titanosaur (Dinosauria, Sauropoda) from the Late Cretaceous of Patagonia. Revista del Museo Argentino de Ciencias Naturales Nueva Serie, 7(1): 31-36.
Sauropod Vertebra Picture of the Week 
January 20, 2016 at 9:54 am
So this is a different new giant Argentinian titanosaur from the one that David Attenborough as talking about?
Man, we sure live in a golden age of new giant Argentinian titanosaurs.
January 20, 2016 at 10:53 am
Fascinating! Though I can’t help but think “Definitelyacolossus” would be a better name…
January 20, 2016 at 12:24 pm
Actually, I rather like the Noto– prefix (meaning Southern) as in Notoceratops and indeed Giganotosaurus. It also crops up, in a different form, in the plant genus Nothofagus, the so-called “southern beeches”.
January 20, 2016 at 1:04 pm
Notocolossus is definitely a much more evocative name for one of the largest things ever to walk the earth than is Argentinosaurus.
January 20, 2016 at 1:15 pm
Great post, Matt — and thanks for your kind words on the paper!
January 20, 2016 at 1:28 pm
ps… lucky me, I got a sweet default avatar pic. What is that, a TV with lobster claws?! :-)
January 20, 2016 at 2:06 pm
Some kinda eumalacostracan.
January 20, 2016 at 2:36 pm
Marvelous ! I knew the aeolosaurus. Now, it has a brother ! Many thanks !
January 20, 2016 at 9:21 pm
Very smart web site!;
thanks for the post
January 21, 2016 at 1:14 am
As the author said, there were other sauropods from Argentina and elsewhere there that were bigger. So Notocolossus was not a colossus – I’m sorry, I just HAD to say that.
January 21, 2016 at 5:05 am
Am I the only one wondering why the skeletal has 13 cervicals?
None of its sister taxa, or other relatives have 13 cervicals. The only titanosaur that has a completely preserved cervical column is Futalognkosaurus and it has only 10-11 cervicals. Dreadnoughtus doesn’t have a compete enough cervical column to bracket from. Its other closest relative Tapuiasaurus doesn’t have enough cervicals to support the idea of Lithostrotians having ~13 cervicals.
Not that I’m calling Gonzales et al. liars, nor am I criticizing their expertise. I’m just wondering where they got that number from.
January 21, 2016 at 5:23 am
Luigi, good question. The skeletal reconstruction has 14 cervical vertebrae, although at first glance it looks like 13 since the atlas (cervical 1) is small. We based this number off of Futalognkosaurus, which as you note has a complete neck. However, the neck of Futa has 14 cervicals, not 10-11. See papers by Calvo et al. (2007a, 2007b). Here are links to freely download these papers:
Click to access 3205_Calvo_altri_2007b.pdf
http://www.scielo.br/scielo.php?pid=S0001-37652007000300013&script=sci_arttext
January 21, 2016 at 10:40 am
About centra (anserw about Ruyangosaurus dorsals from China – 2013-12-27
Dear Krzysztof Stuchlik,
Thank you for your enquiry.
We are displaying the reconstruction of Daxiatitan binglingi, but not Huanghetitan ruyangensis. The total body lengths of Daxiatitan and Huanghetitan are estimated to be 30 and 18 metres respectively.
About 270 pieces of fossils, including sacral vertebrae, dorsal vertebrae, ribs, femur and tibia of Ruyangosaurus giganteus were unearthed since 2006. One of the vertebrae is huge and measures up to 68 centimetres in diameter. This is the thickest vertebral ever discovered in the world so far. We are displaying this vertebra and another 13 real fossils of vertebrae and a replica of femur of Ruyangosaurus.
I wish you have a nice trip in China. For details of our special exhibition, please visit: http://hk.science.museum/ms/lgd/eindex.html
Regards,
SO Chu Wing
Assistant Curator
January 21, 2016 at 6:22 pm
Thanks, everyone, for the comments. Matt and Bernardo, I’m glad you liked the post. I liked your paper – congratulations!
Shahen, thanks for the information. Do you know if any measurements or scaled photos of the 68-cm vertebra have been published? I haven’t seen any, and I’m a bit skeptical about that measurement for the following reasons:
(1) A centrum 68 cm in diameter would be more than 10% larger than the centra of Puertasaurus and Argentinosaurus. But the other elements of Ruyangosaurus measured by Lu et al. (2009) suggest an animal somewhat smaller than either. For example, Lu et al. estimated that the complete femur was 200 cm, compared to 250 cm for Argentinosaurus.
(2) That measurement is not mentioned by Lu et al. (2009), which is odd, since – as SO Chu Wing notes – it would be the largest vertebra by diameter of any animal, ever. Unless this is from another find, or from material prepared after the publication of Lu et al. (2009)?
(3) The wording is strange – “up to” 68 cm in diameter – which makes me think that possibly the measurement was not taken across either of the articular surfaces, or that it is an estimate from incomplete material, or that it was taken from a distorted vertebra whose dimensions were exaggerated by crushing. This does happen – Curtice et al. (1996) reported that the anterior centrum height for BYU 9044, a dorsal of Supersaurus, is 50 cm as preserved, but the vertebra is clearly distorted and they estimated that the actual diameter in life was more like 36 cm.
On the other hand, presumably SO Chu Wing is reporting accurately, It’s just hard to square the reported dimension with everything else we know about Ruyangosaurus. I’d like to get in touch with Wing and see if we can get more information and possible a photo. If you have an email address you’d be willing to share, please drop me a note at mathew.wedel@gmail.com.
January 21, 2016 at 6:44 pm
A little more info, after reading around a bit.
From what I can gather from the website, the Hong Kong Science Museum seems to be a purely educational institution, without collections or a collections-oriented curatorial staff. The current staff chart (here) does not list a SO Chu Wing, so I’m guessing that person either is no longer employed at the museum, or is actually a curator at another museum commenting on the traveling exhibition. I intend no disrespect to SO Chu Wing, it just seems like their connection to the actual fossils might be a bit tenuous (and as always, please do set me straight if I’m mistaken).
The more I think about it, the more I suspect that the “up to 68 cm” refers to the possible dimensions of an incomplete vertebra – like the big cervical illustrated by Lu et al. (2009), the cotyle of which is only about half complete. That would essentially explain everything. FWIW, Lu et al. (2009) give a centrum width of 51 cm for that vertebra, and although they do not provide measurements for the complete dorsal vertebra, from the scaled photo it also seems to have a max diameter of 51 cm.
In any case, given that the only report of the 68-cm diameter vertebra comes from an email from a curator linked to a traveling educational exhibit, and given the odd wording, I am inclined to discount it. It’s almost impossible to rule out a typo, misunderstanding, or exaggeration (possibly well upstream of SO Chu Wing) as the source of the reported dimension. And so far, there is no other evidence to support it, and in fact what other evidence is available is inconsistent (as explained in my last comment).
I’d love to be wrong about this, so if anyone has any more information, please let me know!
January 21, 2016 at 7:40 pm
Matt, maybe Junchang Lu (lead author of the Ruyangosaurus paper) would be able to confirm or deny this report? If you need an email address for him drop me a line and I’ll pass it on.
January 21, 2016 at 7:42 pm
Yep, good suggestion. I’ll email you shortly.
January 21, 2016 at 10:36 pm
Second message was
Dear Krzysztof Stuchlik,
Thanks for your enquiry again.
The vertebrae being displayed is the dorsal vertebrae of Ruyangosaurus giganteus. Here are some figures for your reference:
Total length of 14 sections of dorsal vertebrae is about 4 metres.
The total width of each vertebra ranges from about 0.8 metre to 1 metre.
The total height of each vertebra ranges from about 0.8 metre to 1.1 metre.
The centrum width of the largest vertebra (near posterior part of body) is about 68 cm.
Hopefully they are useful for you.
Regards,
SO Chu Wing
HK Science Museum
I don’t have more information when I was asking- no anserw…\
The femur was 230 cm (not 200 cm like first in paper)
But about dorsals- 14 when any titanosaur not have more than 12? (I’m not shure) and second on the foto last vertebra is sacral no drosal maybe this vertebra have 68 cm centrum diameter.
January 21, 2016 at 11:01 pm
This vertebras
And also if we speak about dorsals, Dreadnoughtus anterior dorsal have 46 cm width diameter
January 22, 2016 at 12:36 am
First, good catch on Dreadnoughtus – I had missed that completely. According to Lacovara et al. (2014) Supplementary Table 1, ?D4 has a cotyle 44cm tall and 46cm wide, ?D5 has a condyle 47cm tall, ?D7 has a cotyle 43cm wide, and ?D8 has a cotyle 47cm wide. Some of those might be exaggerated a bit by distortion – the ?D8 cotyle is only 24cm tall – but the ?D4 cotyle is approximately circular so can’t be explained by squishing. I’ll update the post shortly.
As for Ruyangosaurus, the claim of 14 dorsal vertebrae is an immediate red flag. That would be unprecedented for any neosauropod. And from the photo, it looks like there’s some “plastersaurus” going on in the middle of the series, like one fragmentary vertebra was built out into at least one and possibly two additional ones. That could be how they got 14 exhibited dorsals out of a probable 12.
Anyway, the claimed count of 14 does not inspire my confidence that the person has much familiarity with sauropod anatomy – and so my confidence in the 68cm vertebra diameter is correspondingly decreased.
The femur was 230 cm (not 200 cm like first in paper)
Is that based on a new, complete femur, or a reconstruction, or an estimate?
January 22, 2016 at 1:34 am
From what I know about the one David Attenborough was talking about (= the one just mounted at the AMNH), Notocolossus is different. Firstly, Notocolossus was found in Mendoza province and not Chubut where the ‘AMNH’ one was discovered. Secondly, the ‘AMNH’ titanosaur is known from much more material. We don’t have the femur of Notocolossus, but we do have the femur of the ‘AMNH’ titanosaur. From what I’ve heard, a description is in the works. They seem to be taking their time, which is good.
January 22, 2016 at 6:17 am
Thanks for the correction, Matt! When I mentioned the numbers 10-11, I was mistakenly remembering the number DORSALS for Futalognkosaurus instead of the cervicals. The paper reported it having 10-11 dorsals, and 14 cervicals. My mistake.
January 22, 2016 at 7:01 am
About femur
Is probably reconstruction because
is 230 cm long
January 22, 2016 at 5:39 pm
What is the the height to the tallest point of the back for largest titanosaurs like this one, Argentinosaurus, Puertasaurus, etc?
Regards,
January 22, 2016 at 8:17 pm
We should really ping Scott Hartman for his thoughts on that – and I’ll do that shortly – but from looking at mounts and skeletal recons of big (and tall) critters like Giraffatitan and Argentinosaurus, my guess is 6-7 meters. Anyone have anything more precise? And if so, how, given the uncertainties with reconstructing the incomplete big ones?
January 22, 2016 at 9:33 pm
[…] At SVPOW, Matt Wedel covers the new giant titanosaur Notocolossus. He covers some pretty interesting stuff about the morphology of the giant’s bones, including the fact that the known vertebrae of Notocolossus are remarkably similar to those known of Puertasaurus. You can find this post here. […]
January 22, 2016 at 11:18 pm
Hi Liviu (and thanks for the ping, Matt). I just measured and I’m getting 7.15 meters right over the shoulders, which are usually the highest point on my reconstructions. Of course exactly how tall the back would have been depends on a series of interpretations about limb posture and pectoral girdle placement, but >7m seems like a good bet.
January 22, 2016 at 11:25 pm
I should have said “I just measured my reconstruction of a couple giant titanosaurs…”
January 23, 2016 at 9:36 am
Here’s a thing. An average giraffe is about 5 m tall, and the tallest ever measured was about 6 m tall. That means that these titanosaur individuals — and remember there is no reason to think they are especially big representatives — are significantly taller at the shoulder than the top of the head of the word-record giraffe.
January 25, 2016 at 5:23 am
While we’re on the subject of how titanosaurs are better than giraffes, even the record largest giraffe individuals are still less than 1/50 the mass of your average lithostrotian.
Heck, Basu, Falkingham, and Hutchinson (2016) volumetrically estimated Sivatherium giganteum ,both the largest ruminant and the largest giraffe in history, at just 800kg-1,200 kg.
Diplodocus alone is around 10 times more massive than that, and Diplodocus is considered slender and fairly average-sized for a neosauropod.
January 25, 2016 at 9:30 am
Speaking of intraspecific variability… how accurate a metric for ‘size comparisons’ do you think the centra (or, indeed, most bone) sizes really are? André the Giant and Peter Dinklage were / are both adult humans, but certainly have vastly different frames. I know it’s probably the best that we may be able to get, but I think it’s important to keep in mind.
Is this ever discussed in papers attempting to measure sauropods? Left the world of dead things for the world of live things, so have been out of the ‘literature loop.’
January 25, 2016 at 12:23 pm
Thank you very much for that info
January 25, 2016 at 1:16 pm
[…] https://svpow.com/2016/01/20/notocolossus-is-a-beast/ […]
January 25, 2016 at 4:13 pm
Tor asked,
Speaking of intraspecific variability… how accurate a metric for ‘size comparisons’ do you think the centra (or, indeed, most bone) sizes really are?
Short answer: probably horrible. I collect them mainly for trivia, and because I’m interested in superlatives.
Long answer: centrum diameter is probably worse than most other single-bone measures, because of the complicating effect of pneumaticity. Let’s say a big, four-square quadruped of mass Y and athleticism Z needs a mid-dorsal centrum cross-sectional area of X. If that quadruped is Jobaria, which has apneumatic dorsal centra past about D3 or D4, the centrum may actually have a cross-sectional area of X. But if the dorsal centra are pneumatized, the same cross-sectional area of bone can be distributed more widely for a negligible increase in mass. If the air space proportion (ASP) is 0.5, meaning the vertebra is 50% air (e.g., Camarasaurus, X bone can be spread over an area of 2X. If the ASP is 75% (Giraffatitan), 4X, and if 87.5% (Sauroposeidon, “Angloposeidon”), 8X. That’s simplistically assuming that the cross-sectional area of bone tissue has to remain the same – it is more likely that the more pneumatic taxa could get away with less bone by deploying it more advantageously. Still, it illustrates the problem of comparing centra across taxa of varying ASPs – which is pretty much all of them, among sauropods.
It would be VERY interesting to make a big table of humerus and femur cross-sectional areas, mid-dorsal cross-sectional area “as-is”, and mid-dorsal cross-sectional area “corrected” for ASP, and see if there are any correlations. I’m the obvious person to do that, but I’m already snowed under with other things I’m even more interested in doing, so I’m releasing that idea into the wild. Anyone who is interested should feel free to run with it.
January 25, 2016 at 7:23 pm
We should maintain a page of projects that we’ve though of but don’t have time to do, inviting people to take one and run with it. We could track what’s happening with them all.
August 9, 2017 at 12:34 pm
[…] Maximum dorsal centrum diameter in Argentinosaurus is 60cm (specimen MCF-PVPH-1, Bonaparte and Coria 1993). In Puertasaurus it is also 60cm (MPM 10002, Novas et al. 2005). In Patagotitan it is 59cm (MPEF-PV 3400/5, Carballido et al. 2017). (For more big centra, see this post.) […]
August 19, 2017 at 7:10 pm
Gunnar to the rescue! According to Lu, et. al. 2014, the centrum width of the dorsosacral of Ruyangosaurus is 68cm. This is by far the widest centrum I’ve come across for any dinosaur. As for the dorsals, Lu, et. al. found 13 at the site (excluding the two holotypic dorsals), but most of these appear to actually overlap rather than belonging to a single complete sequence of vertebrae.
The holotype femur as preserved is 120cm long, & was originally restored as 235cm. A second smaller, complete femur (167cm) was recovered from the site, but this femur looks far more euhelopodid than any sort of lognkosaur or other basal titanosaur femur, & it certainly doesn’t match the holotype femur very well (interestingly enough though, that of Patagotitan does, as do the posterior dorsals).
References
José L. Carballido; Diego Pol; Alejandro Otero; Ignacio A. Cerda; Leonardo Salgado ; Alberto C. Garrido ; Jahandar Ramezani ; Néstor R. Cúneo ; Javier M. Krause (2017). “A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs”. Proceedings of the Royal Society B: Biological Sciences. 284 (1860): 20171219. doi:10.1098/rspb.2017.1219.
Lü, J.; Pu, H.; Xu, L.; Jia, S.; Zhang, J.; Shen, C. (2014). “Osteology of the giant sauropod dinosaur Ruyangosaurus giganteus Lü et al., 2009.” Geological Publishing House Beijing, 211 pp.
Sassani N.; Bivens G. T. (2017). “The Chinese colossus: an evaluation of the phylogeny of Ruyangosaurus giganteus and its implications for titanosaur evolution.” PeerJ Preprints5:e2988v1 https://doi.org/10.7287/peerj.preprints.2988v1
November 16, 2019 at 8:10 pm
[…] probably the second-largest-diameter vertebra of anything from all of North America (see the list here). It was also Alton’s idea to fill in the missing bits using one of Marsh’s plates of […]
June 19, 2020 at 4:13 pm
Well, surprisingly, it looks to me like Gonzalez-Riga et al. 2016 wasn’t actually all that far off with 45-76 metric tons for Notocolossus! Greg Paul recently estimates it at 50-55 tonnes, with the possibility that it may have been larger at 65-75 tonnes:
Click to access Titanomass.pdf
The only other titanosaur I can think of that’s been given a reasonable mass via limb bone allometry is Futalognkosaurus (38.1 tonnes). So this certainly is something.