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Andesaurus delgadoi

By Paleo-King
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FORGOTTEN GIANTS: species #3 - Andesaurus delgadoi

Location: El Chocón, Argentina (Río Limay Formation)
Time: Albian-Cenomanian epochs (transition from Early to Late Cretaceous)
Length: 100ft. (30m)
Probable mass: 65-70 tons

WARNING: This image is OUTDATED! Andesaurus was not 100 ft. long, it was more like 66 ft. long. The vertebrae are far smaller than those of Argentinosaurus. I produced this image due to lack of reliable information at the time (and the flat-out wrong numbers in Dougal Dixon's books...). However I am not taking it down, because I want people to know how often "accepted facts" about dinosaurs are often not based on the actual data. To see the corrected version, click here: [link]

The large basal titanosaur Andesaurus delgadoi, fully restored in hi-fi profile and frontal views for the FIRST TIME ever. The skeletal art is also the first ever done for this species.

Andesaurus was described in 1991, but since then very little research has been done on it. It's the founding member of the family Andesauridae, one of the most primitive families of titanosaurs - yet despite being the namesake of the group that includes the famed Argentinosaurus, it's very obscure and still not well-understood. It was long, with tall neural spines on its back (which was probably close to horizontal) and very robust hips. It's not a very extreme design for a titanosaur - its elegance lies in its subtlety. This animal was the template - the forerunner of all subsequent titanosaur body designs.

Missing bones whose shapes can be reasonably well-approximated are shaded, I did not figure speculative neck bones since we literally have no clue what they would have looked like. Skeletal and accompanying diagrams of specific vertebrae are based on photographs of the fossils and on scale diagrams in Salgado et. al. 1997.
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© 2010 - 2021 Paleo-King
Comments76
anonymous's avatar
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dinosaurusbrazil's avatar
Can I use it as reference for a drawing for a series that I am working?
Paleo-King's avatar
Yes, as long as you give me credit for it.

But please use the updated version: [link] because the one you see here above has some major mistakes (including being far too big).
RajaHarimau98's avatar
Glad to know you did this - now I have a reference for my newest drawing! Lovely reconstruction!
Paleo-King's avatar
Careful with that... as I pointed out in the text, this version is outdated. Andesaurus actually looked more like this: [link]
RajaHarimau98's avatar
Ah, good to know, readjusted the Andesaurus in my drawing then. :)
Algoroth's avatar
We got us an Andesaurus. Now we need us a Barneysaurus!
Algoroth's avatar
Just as an afterthought...that side view is an extraordinarily beautiful drawing. Even if I disagree with some elements in your restorations, I find your art inspiring. :clap:
Algoroth's avatar
I was wondering: is delgadoi named for Jose Delgado? (I think it was Jose), the guy who made models for Willis O'Brien to animate? You know, the guy who animated the monsters in King Kong, Mighty Joe Young, etc..
Paleo-King's avatar
I suspect it was a different Delgado. Probably a farmer in Argentina who first spotted the bones, though I can check the paper to see for sure. That's how a lot of Argentinian dinosaurs are found and named. Puertasaurus reuili was named after two farmers who first found the bones on their ranch: Pablo Puerta and Santiago Reuil.
Algoroth's avatar
Congratulations to the farmer, if that was so, but Jose Delgado deserves to be remembered with a scientific name, if anyone does. I wonder if he's been honored that way?
SameerPrehistorica's avatar
Very nice...
Titanosaur family Sauropods are huge monsters :)
Paleo-King's avatar
Thanks! There will be more of them coming soon.
SameerPrehistorica's avatar
Hmm...i see.Can't wait to see them.
BrooksLeibee's avatar
very nice, as always!
are you sure that you aren't Greg?
Paleo-King's avatar
Hehe yeah I'm sure. I'm a lot younger than Greg (and lack his decades of experience lol), I don't look much like him, and I haven't written any books yet (though I aim to change that soon). However we're both from Baltimore originally.

Greg hasn't illustrated Andesaurus yet, and my restoration is the first and so far only accurate one. Though I can see how it's easy to mistake it for Greg's work. He tends to avoid titanosaurs overall... his new book doesn't have a lot of titanosaur skeletals, and the ones it does contain look a bit rushed and reluctant compared to the rest of the book. I also recall reading somewhere that Greg doesn't restore a dinosaur unless over 50% of the skeleton is known, or that he needs the pelvis, among other requirements.

I have a much simpler rule with big sauropods including titanosaurs - if I can get a hold of photos or scale diagrams of the bones, I'm down to restore it. Whether it's one bone or twenty. I'll take the risk. Just from a few bones it's possible to tell the dinosaur's general affinities, even its family. The bigger, the better. That's why I'm doing "Forgotten Giants". To illustrate the biggest, rarest, and oddest representative members of a superfamily that's the most widespread yet least understood group of dinosaurs to this day. Most titanosaurs have NEVER gotten a decent restoration. Some have never been drawn period. There's the challenge - there's literally no artistic precedent to go on. Check out my Puertasaurus for a good example: [link]
BrooksLeibee's avatar
oh wow! I had no idea!
palaeozoologist's avatar
Your Andesaurus size estimate is way too big. The posterior dorsal vertebrae was tiny, only about 24 cm long. That is about half the size of the dorsal vertebrae of Argentinosaurus which average about 47 cm long. Even assuming a liberal length estimate of 37.5 meters (120 ft) for Argentinosaurus would suggest a length of half that, or ~19 meters. Probably massed no more than 10 tonnes at max.

Also, the family Andesauridae is paraphyletic and was abandoned by Wilson and Upchurch in their review of the genus Titanosaurus. And I quote from their (2003) paper, "Andesauridae is based on primitive characters that by definition specify a paraphyletic group. Until taxa are found sharing synapomorphies with Andesaurus, ‘Andesauridae’ will remain an informal name."

If one compares the actual morphology of the dorsal vertebrae of Argentinosaurus to Andesaurus, they are quite different--the hyposphene-hypantrum complex notwithstanding (in fact, the hyposphene-hypantrum complex in Argentinosaurus is actually quite a bit different than that of basal titanosaurs; one unpublished analysis actually places Argentinosaurus as a derived lithostrotian titanosaur related to Rinconsaurus, Aeolosaurus and Ampelosaurus in fact--see Salgado et al (2008)).

Some cervical vertebrae actually have been referred to Andesaurus, sadly they have not been published outside a talk on the material at a conference years ago (this info comes courtesy of Tracy Ford's website Paleofile).

Your restoration is quite good for Andesaurus, Nima. The only thing I would change is the scale bar and your size estimates. Otherwise, good job!

Refs--

Wilson, Jeffrey A., Upchurch, Paul. 2003. A revision of Titanosaurus Lydekker
(Dinosauria – Sauropoda), the first dinosaur genus with a ‘Gondwanan’ distribution. Journal of Systematic Palaentology 1 (3): 125–160.

Salgado, Leonardo, de Souza Carvalho, Ismar . 2008. Uberabatitan ribeiroi, a new titanosaur from the Marilia Formation (Bauru group, Upper Cretaceous), Minas Gerais, Brazil. Palaeontology, Vol. 51, Part 4, 2008, pp. 881–901
Paleo-King's avatar
You got me Zach! Very observant. I knew you'd unmask this beauty sooner or later ;) This was actually my "big version" of Andesaurus that everyone hastily imagines based on all the romantic rumors, I have a smaller version (soon to be added) that's based straight off the scale bars that came in Salgado et. al. 1997. Thanks for that paper BTW. It's sad Andesaurus was so overhyped for size (and not given attention for much else)... I feel odd that I may have contributed to that in some minuscule way, but this estimate of 30m was floating around like smog and styrofoam for years and years earlier. Odd, humored, cracking up in laughs perhaps, but definitely not regretful. As you said, this is a very accurate Andesaurus in every aspect other than scale (thanx BTW 8-)). And soon that will be fixed too. As for Upchurch - I find McIntosh's phylogeny more convincing - and it's not just because I've met him and not Upchurch. Or at least I don't recall meeting Upchurch. SVP was a nonstop hurricane of knowledge and famous cutting-edge people, I'm surprised I was able to keep track of as much stuff as I did.
palaeozoologist's avatar
Haha, just checking ;)

But when was the McIntosh's phylogeny that you refer to published? If it was before Wilson and Upchurch's, then I am skeptical of its accuracy.

Unless McIntosh has identified some actual synapomorphies that Andesaurus shares with other taxa (other than the basal characteristics of the titanosauria), it doesn't matter what McIntosh's phylogeny looks like; 'Andesauridae' would be paraphyletic anyways, which is a no-no. Because of that, 'Andesauridae' would either be monogeneric and paraphyletic (if you include other genera it would be just be polyphyletic, which is a no-no) or it would have include the vast majority of the Somphospondylia in order for it to be monophyletic. So, if we define 'Andesauridae' as monophyletic (as all legit clades are), then not only would 'Andesauridae' include Argentinosaurus, but also Rapetosaurus and other lithostrotians. In essence, the existence of a monophyletic clade termed 'Andesauridae' is strongly in doubt as traditionally defined.

What is the ref for McIntosh's phylogeny, BTW? If you have the paper, I'd be interested in getting a copy (please)...
Paleo-King's avatar
So you're telling me you think Andesaurus belongs with Euhelopus in Somphospondyli and not in Titanosauria proper? That's a pretty bold statement... also considering that most of the skeleton isn't known, it may be different than Upchurch's phylogeny suggests.

I have to hunt up McIntosh's paper... do you have Upchurch's?
palaeozoologist's avatar
Well, since the Titanosauria is *part* of the Somphospondyli, yes. What I said is that
it would include "the vast majority of the Somphospondylia [sic]." So, I wasn't saying that Andesaurus isn't part of the Titanosauria, in fact, the Titanosauria was defined to be the most recent common ancestor of Andesaurus and Saltasaurus and all of its descendants.

What I *was* trying to say, is that 'Andesauridae', if it was to be defined monophyletically (is that even a word? lol) then it would include the "majority" of the Somphospondyli--namely, Titanosauria proper--to the exclusion of Euhelopus and Euhelopus-grade titanosauriforms (although I admittedly didn't specifically say that previously). This is because 'Andesauridae' doesn't have any unique characteristics (synapomorphies) that are shared with other titanosaurian taxa to the exclusion of other titanosaurs. I guess it would have been better to say "it would include the vast majority of the Titanosauria" than to say Somphospondyli (although the vast majority of the titanosauria would probably still be the vast majority of the Somphospondyli going by currently described taxa).

So my statement wasn't that bold, especially since it was said by Wilson and Upchurch 7 years ago (in 2003) and (as far as I know) has not been supplanted by any further recent work.

I do indeed have Wilson and Upchurch's paper. It's available freely online. Just search the citation I gave in my first comment.
Paleo-King's avatar
Ok so basically according to Wilson and Upchurch, Andesaurus does not have any unique features or synamorphies that are shared with some titanosaurs to the exclusion of the rest, so you can't assign it to a family... how about the hypantrum-hyposphene connection? How many other titanosaurs is this present in?

Whatever Andesaurus was, it belongs in some family, so basically the verdict of Wilson and Upchurch is that there isn't enough information or fossil material to erect a clade Andesauridae because Andesaurus lacks enough unique features AND relatives with those features. So is Andesaurus just supposed to be floating around the basal end of Titanosauria? And what does this mean for potentially more basal creatures like Janenschia and Paluxysaurus? Are they more or less basal than Euhelopus? Are they fit to be titanosaurs? And what is your opinion on the position of Huanghetitan and the other Gansu giants?
anonymous's avatar
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