How big was ‘Huanghetitan’ ruyangensis? I mean, really?
March 3, 2015
I’ve been taking a long-overdue look at some of the recently-described giant sauropods from China, trying to sort out just how big they were. Not a new pursuit for me, just one I hadn’t been back to in a while. Also, I’m not trying to debunk anything about this animal – as far as I know, there was no bunk to begin with – I’m just trying to get a handle on how big it might have been, for my own obscure purposes.
‘Huanghetitan’ ruyangensis was named by Lu et al. (2007) on the basis of a sacrum, the first 10 caudal vertebrae, some dorsal ribs and haemal arches, and a partial ischium. The holotype is 41HIII-0001 in the Henan Geological Museum. Lu et al. (2007) referred the new animal to the genus Huanghetitan, which was already known from the type species H. liujiaxiaensis (You et al., 2006). However, Mannion et al. (2013) found that the two species are not sister taxa and therefore ‘H.’ ruyangensis probably belongs to another genus, which has yet to be erected. Hence my use of scare quotes around the genus name.
Here’s the sacrum of ‘H.’ ruyangensis from Lu et al. (2007: fig. 2). The original small scale bar is supposed to be 10cm. You know how I feel about scale bars (or maybe you don’t, in which case read this and this), but in this case the scale seems pretty legit based on limited measurements that are also given in the paper. I comped in the sacrum of Brachiosaurus altithorax FMNH P25107 from this post (many thanks to Phil Mannion for the photos!), and scaled it according to the max width across the second pair of sacral ribs, which Riggs (1904: p. 236) gives as 105 cm. The sacrum of ‘H.’ ruyangensis is a little bigger, but not vastly bigger. ‘H.’ ruyangensis had six sacrals to Brachiosaurus‘s five, so extra length is mostly illusory, whereas the extra width is mostly legit.
According to Lu et al. (2007), the anterior face of the first caudal vertebra in ‘H.’ ruyangensis measures 26.9 cm tall by 32 cm wide, and the centrum is 18.2 cm long. The same measurements in Brachiosaurus are 28 x 33 cm for the anterior face and 16 cm for the centrum length. It’s basically a tie.
What about the big rib? Lu et al. (2007) show a complete dorsal rib of ‘H.’ ruyangensis that is 293 cm long. That’s nothing to sniff at – the longest rib of Brachiosaurus, and the cause for the specific name altithorax (‘tall-bodied’), measures 274.5 cm, so the ‘H.’ ruyangensis rib is about 7% longer. But it’s not the longest rib known for any sauropod. As far as I know, that honor goes to a Supersaurus dorsal rib measuring 305 cm (Lovelace et al., 2008). The biggest Supersaurus caudal also blows away the caudals of both ‘H.’ ruyangensis and Brachiosaurus, with a anterior face 39 cm tall by 46 cm wide. But then diplodocids were all about that bass, so there’s not much point in comparing tail size with a titanosauriform if you’re trying to get a handle on overall body size. Still, the 35-40 ton Supersaurus shows that you can have 3-meter ribs without being anywhere near Argentinosaurus territory, mass-wise.
So what’s the verdict? ‘H.’ ruyangensis was a little bigger than the holotype of Brachiosaurus altithorax, but only by a few percent. It might have been about the same size as the XV2 specimen of Giraffatitan brancai. Or, who knows, it could have had completely different proportions and massed considerably more (or less). But on the current evidence, it doesn’t seem to have been one of the biggest sauropods of all time. I hope we get some more of it one of these days.
References
- Lovelace, David M., Scott A. Hartman and William R. Wahl. 2008. Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny. Arquivos do Museu Nacional, Rio de Janeiro, 65 (4): 527-544.
- Lu J., Xu, L., Zhang, X., Hu, W., Wu, Y., Jia, S., and Ji, Q. 2007. A new gigantic sauropod dinosaur with the deepest known body cavity from the Cretaceous of Asia. Acta Geologica Sinica, 81: 167-176.
- Mannion, P.D., Upchurch, P., Barnes, R.N., and Mateus, O. 2013. Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms. Zoological Journal of the Linnean Society, 168(1): 98-206.
- Riggs, E.S. 1904. Structure and relationships of opisthocoelian dinosaurs. Part II, the Brachiosauridae. Field Columbian Museum, Geological Series 2, 6, 229-247.
- You, H., Li, D., Zhou, L., and Ji, Q. 2006. Huanghetitan liujiaxiaensis. a new sauropod dinosaur from the Lower Cretaceous Hekou Group of Lanzhou Basin, Gansu Province, China. Geological Review, 52 (5): 668-674.
Sauropod Vertebra Picture of the Week 
March 3, 2015 at 3:20 pm
How. I was reading some tet zoo v. 2 earlier today and came across one of those “identify the taxon in this image” type posts. The answer was Huanghetitan. Upon seeing that there was a new SVPOW post (I check for updates on various blogs using LITTOC) I said to myself “watch this post be about Huanghetitan. And it actually was!
March 21, 2015 at 2:16 am
[…] at Carnegie Quarry. You can find that here. SV-POW! estimates the size of Huanghetitan ruyangensis here. Theropod Thursday returns at dinosaurpalaeo! The awesome Heinrich Mallison wrote up the […]
June 20, 2020 at 10:37 pm
From what I can see, this does seem to be a pretty good sized sauropod even if it’s not the biggest.
Following a sacrum of the same size as Brachiosaurus but a 7% deeper torso due to the longer rib, it ends up at ~45.61 tonnes using this Brachiosaurus GDI (https://i.imgur.com/fXtJHJs.png), and based on the measurements of Camarasaurus’ ribs and sacrum in Osborn & Mook (1921) that I could gauge (95 vs 123 cm sacrum and 207 vs 293 cm rib), using Greg Paul’s 23 tonne C. supremus as a base, it ends up at ~52.36-65.2 tonnes.
July 22, 2020 at 4:37 pm
Bump.
The conversation in the comments of the post of Brachiosaurus size reminded me of this post.
As it turns out, there’s a MUCH larger specimen than the holotype mentioned in Sassani and Bivens 2017 on Page 29 (https://peerj.com/preprints/2988v1.pdf), and if I’m reading the paper correctly it appears to be a very large dorsal. It’s said to be 27.5% larger than the Brachiosaurus holotype, so assuming relative geometric similarity this animal ends up at 94.1 tonnes (45.4×1.275^3)!
So it looks like this animal may indeed be one of the biggest sauropods of all time.
October 19, 2022 at 8:00 pm
time to mention the existence of a massive dorsal and a femur suggesting really large sizes
October 19, 2022 at 8:18 pm
The femur is massive, being comparable to that of Patagotitan mayorum in fact
October 19, 2022 at 11:51 pm
I’m extremely unconvinced by that femur reconstruction. If you look at any other titanosaur femora, you can see that the reconstructed portion is probably too long by half. Was it a big animal? Sure. But there’s no very convincing evidence that it was any bigger than Notocolossus, let alone as big as (or bigger than) Puertasaurus, Patagotitan, or Argentinosaurus. As always, any critter wanting to be in the discussion has to actually show up with measurements, not just a fanciful reconstruction of what was likely only a 2-meter femur.
October 22, 2022 at 9:41 am
Not talking about Ruyangosaurus femur, i’m talking about a complete femur from Ruyang formation
Longest femora:
1. Argentinosaurus huinculensis: ~270? cm
2. Unnamed Plottier Sauropod: ~260? cm
3. Bruhathkayosaurus matleyi?: ~260? cm
4. French unnamed Sauropod: ~250? cm
5. GSP MLP Sauropod: ~240? cm
6, 7. Patagotitan mayorum: 236 and 238 cm
8. Unnamed Moroccan Sauropod: 236 cm
i will finish that list later
October 22, 2022 at 10:03 am
1. Argentinosaurus huinculensis: ~270? cm
2. Unnamed Plottier Sauropod: ~260? cm
3. Bruhathkayosaurus matleyi?: ~260? cm
4. French unnamed Sauropod: ~250? cm
5. GSP MLP Sauropod: ~240? cm
6, 7. Patagotitan mayorum: 236 and 238 cm
8. Unnamed Moroccan Sauropod: 236 cm
i will finish that list later
9. Patagotitan mayorum: 235 cm
9. “Huanghetitan” ruyangensis: 235 cm
11. “Antarctosaurus” giganteus: 231 cm
12. Patagotitan mayorum: 227 cm
13. cf. Puertasaurus reuili: 222 cm
14. Unnamed French Sauropod: 220 cm
15. Giraffatitan brancai: 214 cm
15. Australotitan cooperensis: 214 cm
17. cf. Argyrosaurus superbus: 211 cm
18. Fusuisaurus zhaoi: 210 cm
October 22, 2022 at 10:03 am
19. Ruyangosaurus giganteus: 207 (or 235?) Cm
October 23, 2022 at 9:56 am
Not talking about Ruyangosaurus femur, i’m talking about a complete femur from Ruyang formation
Source?
October 23, 2022 at 10:24 am
Undescribed, but mentioned in a 2009 report.
October 23, 2022 at 7:00 pm
Okay, then the 2009 report is the source. Do you have a reference? This is exactly my point: where are these new data coming from? Is the ~270cm Argentinosaurus femur a new element, or someone’s reinterpretation of the partial femur that previously estimated at ~250cm? If you don’t have sources that can be checked for these numbers, they don’t mean anything.
October 24, 2022 at 4:39 pm
270 cm Argentinosaurus femur is an estimate from Asier Larramendi, and Gunnar Bivens got a similar estimate (267 cm).
235 cm ruyangensis femur is from The Chinese colossus: an evaluation of the phylogeny of Ruyangosaurus
giganteus and its implications for titanosaur evolution.
There are actually two Chinese 235 cm femora there, one is belonging to “H.” ruyangensis and it is actually 5 cm wider than also 235 cm long but 60 cm wide R. giganteus femur.
October 24, 2022 at 4:41 pm
270 cm estimate also agrees with both Argentinosaurus type estimated size and with proportions of Patagotitan femur