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Andesaurus new version

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This is a revised version of my Andesaurus skeletal. This is a more rigorous version, with both pairs of limbs shown, an elevated neck, as well as some changes to the (unknown) sternal plates and ribs.

Also, here's the spiel I said about this animal last time:

Andesaurus delgadoi is a poorly known titanosaur sauropod from the Mid-Cretaceous (Albian-Cenomanian) of the Rio Limay Formation in Neuquen Province, Argentina.

Often considered one of the largest dinosaurs in the 60+ tonne range and around 25-30 meters long, a re-description of the specimen by Mannion and Calvo (2011) shows that it was quite a bit smaller than often thought. As restored here, it is about 16 (~52 ft) meters long from the tip of the skull to the end of the tail and probably would have massed about 8-19 tonnes. The mass estimate is much more approximate than for, say, Malawisaurus due to the fragmentary nature of its remains.

The preserved remains include 25 partial to complete caudal (tail) vertebrae, 2 sacral vertebrae, 4 posterior dorsal vertebrae (only 3 of which are complete enough to illustrate), a partial femur and a partial humerus, as well as a pubis and ischium, and some metacarpals.

The rest of the skeletal reconstruction is based primarily on Huabeisaurus due to the extreme similarity of the overlapping remains between it and Andesaurus. Parts of Huabeisaurus that were used for comparison were the nature of dorsal and caudal vertebrae, as well as the pelvic elements. The restored ilium (hip bone), scapula, cervical vertebrae and anterior caudal neural spines were all drawn directly from the description of Huabeisaurus. In the case of the anterior caudal neural spines (which are missing from the first seven caudal vertebrae in Andesaurus) the neural spines were slightly modified from the condition seen in Huabeisaurus.

Some interesting things to note about that anatomy of Andesaurus is that it appears to have a very long, but shallow, torso, a proportionally short tail and a relatively high humerus to femur ratio compared to other titanosaurs. Also interesting is the extremely high neural spines of the dorsal vertebrae.

Oh, and as usual, preserved material that was illustrated in the description is white, while everything else is left in gray (meaning unknown, or in some cases, non-photographed material) .

Refs--

MANNION, P. D. and CALVO, J. O. , Anatomy of the basal titanosaur (Dinosauria, Sauropoda) Andesaurus delgadoi from the mid-Cretaceous (Albian–early Cenomanian) Río Limay Formation, Neuquén Province, Argentina: implications for titanosaur systematics. Zoological Journal of the Linnean Society, no. doi: 10.1111/j.1096-3642.2011.00699.x

Calvo, J.O. & Bonaparte, J.F. 1991. [Andesaurus delgadoi n. g. n. sp. (Saurischia, Sauropoda) a titanosaurid dinosaur from the Río Limay Formation (Albian-Cenomanian), Neuquén, Argentina.] Ameghiniana. 28: 303-310. [In Spanish]

Qiqing, P. and Zhengwu, C. (2000), A New Family of Sauropod Dinosaur from the Upper Cretaceous of Tianzhen, Shanxi Province, China. Acta Geologica Sinica - English Edition, 74: 117–125. doi: 10.1111/j.1755-6724.2000.tb00438.x
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anonymous's avatar
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PigsFly1010's avatar

The posture is not to great. My Andesaurus (based on Greg S Paul's model), is much, much, more elevated, with a roughly 39 degree angle. This seems to me more like early representations of sauropods in the 19th century.

palaeozoologist's avatar

The neck is completely hypothetical - based on Phuwiangosaurus and Huabeisaurus since at the time I did the skeletal they were thought to be basal titanosaurs - and the posture is just a generic semi-alert posture. After all, even giraffes don't always eat with their necks vertical:

Giraffe Horizontal Neck
PigsFly1010's avatar

LOL :) Yes, I see now.

Algoroth's avatar
Here. Legs on sauropod restorations that I consider way too thick. [link]

Not impossible, but what erect limbed tetrapod has leg conformations similar to these? Crocodiles and varanids come to mind in basic sprawling limbed animals.
palaeozoologist's avatar
I think there are more major problems with the anatomy besides the legs in that reconstruction. The legs aren't horrible, but I don't know what species it is either.
Algoroth's avatar
What species? BALLOONOSAURUS! Or BALONEYSAURUS! Why do them so cartoonish then claim scientific accuracy? I love good dino cartoons and have made an effort myself... [link] ...but I make no claims of accuracy. On Tyler, anyway. :chew:
palaeozoologist's avatar
I do love good dinosaur cartoons, actually, but cartooning is not my style of art of choice. I do like to look at it, but I'm afraid I'm too technical too be much of a cartoonist.
Algoroth's avatar
I understand. I like drama, humor, and spirituality too much to thrive on just the technical issues, although they are very important to me as well.

Speaking for myself only, I've never been able to make a pic of an animal, human, or fictional character work good just by doing it technically correct. It comes out accurate, but it lacks soul. You, on the other hand, make most of your restorations seem like live animals. I don't know how you do it, being so technical and all, but I enjoy them just the same.
Algoroth's avatar
I am wondering about something. I often read about how poorly the skeletons are reconstructed and I basically believe the reports. It kind of gives a hard time to those who try to be one hundred percent accurate.

I saw an article on the claim that the coloration and patterns of one kind of dinosaur is now known. Cool, if true, but seeing how variable the coloration of even a single living species can be, can it reasonably be expected that this can be nailed down? It seems to be known for this one specimen. I believe most specimens of the living creature would be similar enough for this to be a guide. What do you think?
palaeozoologist's avatar
You're right. It is near impossible to be 100 percent accurate in any reconstruction of an extinct animal. Few species are known from complete skeletons, and the few that are known fairly completely are rarely described well, especially in the late part of the 20th century until present, few good monograph-type descriptions appear which makes nailing down the proportions very difficult to--to say the least. This problem is compounded if you are not attached to a university and have trouble getting access to the necessary papers.

As for dinosaur colors, only a few have been found, like Anchiornis and Sinosauropteryx. They do tell us the general colors, but do not give us a precise detail of the color patterns and do not tell us (as far as I know) the precise hue, so generally they say reddish or brown in coloration with grey, black and white. Oddly, this combo of colors seems to be relatively common, as this appears to be the color palette for Confuciusornis, too. So, even though we know the general color palette, it still is far from given us a field-guide like look at their living color hues and patterns.
Algoroth's avatar
If you haven't seen this yet, it might interest you.
[link]
palaeozoologist's avatar
Indeed, it is interesting, but not too surprising. Many carnivorous animals will indulge in cannibalism from time to time, although few make a habit of it.
Algoroth's avatar
Oops! Sorry! I should have told you to scroll down to the cartilage article! Try it out!
palaeozoologist's avatar
Ah, haha, ok. I agree that dinosaurs had relatively thick cartilage. I however do not illustrate that in my skeletals. Why? In most cases, studies of the articular cartilage for specific species have not been done. Also, the rest of the cartilaginous part of the skeleton is unknown, so I tend to leave the cartilage out. But it would make my dinosaurs a bit taller.
Algoroth's avatar
Nice looking skeletal! But (and this is a pet peeve of mine), why are the front legs so parsimoniously fleshed out? Was this poor dinosaur fresh from a concentration camp? Does the drawing, which is beautifully done artistically, represent a mummy?

I'm not trying to be mean. You are more knowledgeable than I am about the various skeletal elements of dinosaurs I didn't even know existed before I saw your work and Nima's work, but still...you've scarcely left room for skin, judging by the black outline, never mind muscle and fat tissue and whatever else they had under their skin. The hind leg situation is a lot better, but muscles bulge when they're flexed, even if only slightly. Look at elephants when they walk.

But don't get too close! :sprint:
palaeozoologist's avatar
Hehe, I'll try not get too close to the elephants ;)

You're probably right, I do need to put more flesh on the bones. I can't promise to correct this soon, as I have not had much time for art lately, but eventually I'll take your suggestions and implement them to the best of my ability.
EmperorDinobot's avatar
I'm too lazy to read any of that. But um...Wait for an Andesaurus following general titanosaur proportions soon.
palaeozoologist's avatar
Read what? My conversation with Nima (Paleo-King)?

I don't think there really is a standard for "general titanosaur proportions"...they all tend to be quite unique, but I look forward to your Andesaurus.
Paleo-King's avatar
They do look unique.... all TWO of them lol.... so far we're the only people who have done Andesaurus skeletals. I guess my Andesaurus would fall more into "general titanosaur proportions" that EmperorDinobot is talking about, but in reality there is no such thing. Titanosaurs are such a diverse and often weird group that there is no "typical titanosaur" in the sense of body shape or proportions. Especially when we don't know the full body shape for most of them. And everybody has different ways of looking at it. For someone like Ken Carpenter, the "typical titanosaur" is Saltasaurus - but in reality VERY few titanosaurs have the unique proportions of Saltasaurus. For others it's more like Argentinosaurus, which was the blueprint for a good bit of Greg Pauls titanosaur skeletals. Still, few titanosaurs resemble Argentinosaurus in anything that can be compared. And even within families there are radical differences. For example, Trigonosaurus and Barrosasaurus are obviously related, but their vertebrae are specialized in totally different directions and their body shapes would have been radically different. Same can be said for Phuwiangosaurus and Baotianmansaurus.
palaeozoologist's avatar
Actually, Tracy Ford did a skeletal of Andesaurus too, it can be found on his Paleofile site (to which I no longer subscribe, sadly).

As for "typical titanosaur body shape" I agree that there really is no such thing as "typical" for their overall body shape. The other thing is that titanosaurs are a phylogenetic mess, and I suspect the clade might be polyphyletic to some degree (or, at least some of what we call titanosaurs are not actually titanosaurs--this might be the case for things like Phuwiangosaurus and Huabeisaurus). I think it would be hard to make Argentinosaurus the "typical" titanosaur since it is known from very sparse material.

I unfortunately do not have the descriptive papers for Barrosasaurus or Baotianmansaurus (or all those other sauropods described in Acta Geologica Sinica or Vertebrata PalAsiatica), so I cannot comment on their affinities.
Paleo-King's avatar
Barrosasaurus has the same distinct dorsal vertebral structure as Trigonosaurus - "sharp-cut" prezygapophyses tapered upward with an extremely straight edge, and parapophyses also very angular and high up relative to the centrum. Diapophyses very long but also shallow, with rounded ends (more flipper-like than wing-like as in lognkosaurs). Neural spine swept back, moderately wide at the base laminae, but tapering to a very thin upper portion (not trapezoidal as in derived lognkosaurs). The fossae are also in a similar arrangement to Trigonosaurus. I've looked at Barrosasaurus long and hard, mainly just because it's so weird - and out of my big cache of titanosaur papers the only ones that really share a good number of derived features with it are Trigonosaurus and maybe Muyelensaurus.

As for Baotianmansaurus, it (along with Sonidosaurus) may form a clade with Phuwiangosaurus. All three have some pretty consistent features. Their dorsal vertebrae all have freakishly tall neural arches, but very little neural spine. All have relatively short centra relative to the height of the neural arches, and the centra are not very deep - they are about twice as long as they are wide or deep. The proportions of the different elements of the vertebrae are nearly identical - naural arch, centrum, neural spine, diapophyses. all have hypantrum-hyposphene connections, and more importantly these connections are the same shape in all three genera. Cotyles are generally close to circular. Laminae patterns are similar on the arches. Sonidosaurus also shows some similarities to Tastavinsaurus in the neural canal structure.

All the same the material for any of these other than Phuwiangosaurus is far too incomplete to do an accurate skeletal (though it IS very well-preserved and easily diagnostic enough to plug into a cladistic analysis). I have the papers if you want them, but these are the kind of genera where you have to first restore two or three relatives (not always very close or complete ones either) to even get an idea of how they might have looked. Barrosasaurus is only 3 dorsal vertebrae, that's it! They can tell us a lot and are beautifully preserved, but don't offer any clues as to the animal's shape, and even closely related titanosaurs have turned out looking radically different before. BTW it's Brazilian, not Chinese ;) The paper is an Elsevier publication if I'm not mistaken.
palaeozoologist's avatar
If you could send me the papers, it would be much appreciated :)

(BTW, I realize that Barrosasaurus is not Chinese, I was referring to Baotianmansaurus)
Paleo-King's avatar
Gotcha.

I'll send you the papers soon. Do you have any of Janensch's papers on Giraffatitan or any papers at all on Janenschia?
palaeozoologist's avatar
I have to of Janensch's papers on Giraffatitan, but none for Janenschia. I'll try to send them tomorrow. Remember that the latter was originally Gigantosaurus robustus and then referred to the new genus later. I haven't had any luck on getting papers on Janenschia, unfortunately.
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anonymous's avatar
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