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Argyrosaurus superbus by Paleo-King Argyrosaurus superbus by Paleo-King
Forgotten Giants species #4: Argyrosaurus superbus

Location of holotype site: Left bank of the Río Chico, near the Pampa Pelada, to the northeast of Lake Colhué-Huapi, Chubut, Argentina.
Length: ~90+ ft.
Mass: ~50 tons
Time: Late Cretaceous, but beyond that, estimates vary. Its formation, the Bajo Barreal, has been dated using some methods to the Santonian and Campanian epochs, but by others to the earlier Cenomanian. Its contemporaries include dinosaur species which sometimes overlap into the Allen formation and other faunas considered to be Campanian in age, so the former estimate is what I find more likely.

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After a LONG time of studying and cross-scaling, here is the FIRST EVER scientific restoration of the mysterious "silver lizard" of Argentina, Argyrosaurus superbus. Named for its proximity to silver mining towns, this is one of the largest and strangest giant dinosaurs ever found - and ironically it was also one of the first to be named.

The obscure discovery of this massive plant-eater over a century ago was barely reported in the papers, but for a while Argyrosaurus was actually the largest dinosaur known to science. Described a full 10 years before Brachiosaurus, and over three decades before its record was beaten by Antarctosaurus giganteus, this monster is still known from only a handful of remains, yet they indicate a creature unusually massive and large even by the standards of other South American titanosaurs.

Argyrosaurus is characterized by very long, wide humeri proportionally similar to a giant snowboard, and massive femora wider than those of almost any other known sauropod, which rival those of Antarctosaurus giganteus for sheer size. The lower arm is relatively short, the shoulder blade large and deep, and the vertebrae massive and roughly similar in shape to those of Epachthosaurus.

Several likely specimens of Argyrosaurus are known, mostly just isolated limb bones from individuals of spanning a wide range of sizes and ages. The most complete specimen is the referred teenager PVL 4628, which includes both limb elements and vertebrae, and is the only specimen complete enough to give an idea of the overall proportions of Argyrosaurus. Thus it is the critical "keystone" specimen for unlocking the secrets of this mysterious dinosaur and its relatives. The isolated scapula indicates that PVL 4628 was not a mature animal, as its coracoid and scapula were not yet fused. It would have been roughly 65-70 ft. in length at the time of its death, while the largest individuals, known only from colossal limb bones, could have topped 90 ft. And given the extremely robust proportions of this dinosaur, it would have been several times as massive as most dinosaurs of similar length.

Argyrosaurus is the founding member of a family which currently contains only one other genus, the even more incompletely known Paralititan, which was similarly robust and heavy-bodied for its length even by titanosaur standards. Their closest relative outside the family appears to be the far smaller Epachthosaurus, which puts the Argyrosauridae in a relatively derived position - more primitive than Antarctosaurids and Saltasauroids, but more advanced than Lognkosaurians.

This animal is also remarkable in having a highly weird and RECURRING tendency to leave behind its right femur as fossil evidence, and not much else.* :XD:

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References:

Lydekker, R., 1893. "Contributions to the study of the fossil vertebrates of Argentina. I. The dinosaurs of Patagonia", Anales del Museo de la Plata, Seccion de Paleontologia 2: 1-14

Powell, J.E., 2003, "Revision of South American titanosaurid dinosaurs: palaeobiological, palaeobiogeographical and phylogenetic aspects", Records of the Queen Victoria Museum 111: 1-173

von Huene, F., 1929. Los saurisquios y ornitisquios del Cretacéo Argentino. Anales del Museo de La Plata (series 3) 3: 1–196. [In Spanish]

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Some referred remains:

The assigned material comes from 8 localities, some of which do not correspond to the provinces of Chubut and Neuquén. For this reason, they are listed with geographic, stratigraphic, and chronologic provenance. The old geo-terminology "pre-Maastrichtian Senonian" refers to two consecutive Late Cretaceous epochs, the Santonian and Campanian, which were respectively the third-last and second-last epochs of the entire Mesozoic.

1. An anterior caudal vertebra (Huene, 1929:79). West bank of Lake Colhué-Huapi, Chubut Province. Chubut Group, Castillo Formation or Bajo Barreal Formation. Pre- Maastrichtian Senonian.
2. Two caudal vertebrae “…of the region of Neuquén” (Huene op. cit.:7). Geographic and stratigraphic provenance unknown.
3. An incomplete femur (Lydekker, 1893, pl. 5, 2; Huene, 1929:80, pl. 38, 1). To the south of the bend of the Río Sengerr, Chubut Province, probably Bajo Barreal Formation. Pre-Maastrichtian Senonian.
4. An incomplete right femur (Huene, op. cit.:80, pl. 38, 2). Near the railroad bridge over the Río Neuquén, Neuquén Province. Neuquén Group, Río Colorado Formation, perhaps Bajo de la Carpa Member. Pre-Maastrichtian Senonian.
5. A complete right femur (Huene, op. cit.:80-81, pl. 38, 3). Sierra San Bernardino, 45 km west of Colonia Sarmiento, Chubut Province. Chubut Group. Bajo Barreal Formation. Pre-Maastrichtian Senonian.
6. A humerus of a juvenile individual, referred with doubts to Argyrosaurus (Huene, op. cit.:81, pl. 37, 6). Probably from Neuquén. Uncertain geographic and stratigraphic provenance.
7. A left humerus, referred with doubts to Argyrosaurus superbus Huene, op. cit.:81, pl. 37, 4). Left margin of the Río Uruguay, near Colón, Entre Ríos Province. ?Asencio Formation. Upper Cretaceous.
8. Caudal vertebrae (Huene, op. cit.:79). To the east of the Río Leona, between lakes Viedma and Argentino, Santa Cruz Province, Upper Cretaceous (Dibenedetto, pers. comm.).

Source: Dinodata


*NOTE: the unnamed and uncatalogued "Argyrosauridae" femur from Powell (2003) is most likely a lognkosaur judging from its proportions, not an Argyrosaur.
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:iconalgoroth:
Algoroth Featured By Owner Feb 5, 2013  Professional General Artist
Just a small, tiny question. AHEM! Should the limb elements of upright quadrupeds be restored in terms of what we can see of sprawlers, like crocs and lizards, or upright animals, like birds and mammals? Just asking.

Frankly, I think most all of us have them wrong, including me, you, Zack, Jurassic Park, and most of the dino documentaries I have seen. I think many artists have theropod hindlimbs correctly, but few correct (IMO!) front limbs.
Reply
:iconpaleo-king:
Paleo-King Featured By Owner Feb 10, 2013  Professional Traditional Artist
What do you mean? The articulation of sauropod from limbs clearly only makes sense in a vertical upright posture. Not that it had to be PERFECTLY vertical (there was a slight 10-15 degree bowing at the elbow when either arms was in rear stride - this is normal in elephants and such today). But they were definitely not build for sprawling. Also their rib cages are usually so deep that if they had sprawled, they would have needed to find giant ruts to run in, because their bellies would have been well below the ground level of the hands and feet (and all their joints would have to be dislocated).

Plus it's also important to note that sauropods evolved from bipedal (and warm-blooded) ancestors. Crocs and lizards did not. To date there has never been a group of quadrupedal animals whose forelimbs have a completely different posture from their hindlimbs - it's literally impossible to coordinate movements in such an animal especially with spines as rigid as most large dinosaurs. And dinosaur footprints all point to erect forelimbs in quadrupeds.
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:iconalgoroth:
Algoroth Featured By Owner Feb 11, 2013  Professional General Artist
I was talking about lower limb robustness compared to upper limb robustness, not the vertical positioning, about which you are absolutely correct. Most upright quadrupedal animal and bipedal animals (birds and the occasional human ;)) have lower limbs that can be downright thin. But the upper limbs are often so well muscled they can scarcely be seen, as in horses, canines rhinos, etc. Even elephants' legs are well integrated with the upper bodies (skin-wise, yes, but not separate almost all the way to the shoulder), and are not thin.

When we get to sprawlers, we have a different picture. The upper limbs are mostly separate and the lower limbs, especially in the large species....crocs and large varanids...are close to being as thick as the upper limbs.

None of this is proof, of course, but, since dinosaurs and birds are so similar, why do we...me included...so often make the upper and lower limbs so alike in muscularity...whether thick or saran-wrap style?
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:iconbrolyeuphyfusion9500:
Argyrosaurus was never the largest dinosaur known to science...

Amphicoelias fragillimus was discovered in 1878, which was about 15 years before Argyrosaurus was discovered.
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:iconpaleo-king:
Paleo-King Featured By Owner Jun 13, 2012  Professional Traditional Artist
Yeah but A. fragillimus wasn't really "known" at the time aside from a handful of field workers and Cope himself. He published a brief paper on it which included no size estimates, it was soon lost or destroyed, and even at the same time many people considered it a hoax.

Most scientific publications of the 20th century listed Brachiosaurus as the biggest dinosaur (in fact up until the 80s even most paleontologists said so in their books; they forgot about Argyrosaurus and "Antarctosaurus" giganteus even though these were never lost or destroyed.) So while they were saying Brachiosaurus was the biggest, there was something larger (at least in terms of mass) discovered 10 years earlier, with published photos rather than sketches, more than a single bone, assigned an actual museum catalog number, and the material is still in existence.
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:iconteratophoneus:
Teratophoneus Featured By Owner May 11, 2012
Hey Nima, I amplanning to use this as a reference for a scientific reconstructuion of elaltitan-or better Argyrosaurus itself as you said the bone of elaltitan is that of a argyrosaurus. For this I have to know how big the specific specimen (length and height) of the elaltitan/argyrosaurus was. I hope you can help me :)
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:iconpaleo-king:
Paleo-King Featured By Owner May 11, 2012  Professional Traditional Artist
Use the scale bar, it's there for a reason LOL! :D

Both the adult and the teenage Argyrosaurus (aka "Elaltitan") are to scale with the scale bar.

The teenager is roughly 70 ft. long if I remember from last time I re-scaled it. Of course the live animal may have looked nothing like this. This is just my interpretation of how it looked based on the few bones found, and comparing it with other large titanosaurs like Alamosaurus.
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:iconpalaeozoologist:
palaeozoologist Featured By Owner May 7, 2012  Hobbyist General Artist
The dorsal vertebrae, anterior caudal vertebra, scapula and the pelvic and forelimb elements of PVL 4628 have now been referred to a new genus and species, Elaltitan lilloi, so you should probably change the name on your image for the smaller individual.

Ref--

Mannion, P. D.; Otero, A. (2012). "A reappraisal of the Late Cretaceous Argentinean sauropod dinosaur Argyrosaurus superbus, with a description of a new titanosaur genus". Journal of Vertebrate Paleontology 32 (3): 614-638.
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:iconpaleo-king:
Paleo-King Featured By Owner May 11, 2012  Professional Traditional Artist
Thanks Zach. But given what I've seen of this animal, I don't see a basis for the reclassification. Mannion previously also made some statements about titanosaur taxonomy that I consider unwarranted and flat-out wrong (such as claiming Ruyangosaurus wasn't even a titanosaur in his redescription of Andesaurus).

Based on Powell 2003 (the better scans of it anyway) PVL 4628 has basically the same arm morphology as the Argyrosaurus holotype. So much so that there is little point in referring it to "basal titanosauria" while putting PVL 4628 in derived lithostrotia.

The differences that Mannion does cite in the abstract are a bit obscure as he only says: "This specimen
is distinct from *Argyrosaurus* and can also be differentiated from other
sauropods based on an unusual character combination (including plesiomorphic
tarsus), plus one autapomorphy."

VAGUE VAGUE VAGUE. I will not endorse this conclusion until I read the paper (which is locked up behind a paywall... I wonder how much of the paleosphere is actually paying attention to SV-POW and the point they're making). One autapomorphy, plus plesiomorphic tarsus (?) and an unusual character combination.... Well it's too premature to separate it from Argyrosaurus based on ANYTHING other than a comparison of the arms, since that's all the Argyrosaurus holotype is. And the tarsus is not in the arm. A single autapomorphy (which may or may not overlap with the Argyrosaurus holotype skeletally) is pretty weak proof. It would be more parsimonious to classify PVL 4628 as an immature Argyrosaurus sigen overall morphology of the arm, and the matching formation/time horizon.

For my part I suspect any differences in the arms of the two individuals are minor enough that they can be put down to ontogeny (PVL 4628 is clearly immature based on the scapula not being fused to a coracoid), the arm elements of both individuals are very similar in overall shape and proportions. The ulnae are SO similar it's kind of freaky. So YES I am lumping. Go sue me Dr. Mannion LOL 8-)

BTW I'm curious, how did name "Elaltitan" come about? I've heard some weird rumors. Is it really named after an airline?
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:iconpalaeozoologist:
palaeozoologist Featured By Owner May 15, 2012  Hobbyist General Artist
Just because Phil Mannion has made statements in the past that you consider wrong on titanosaur phylogenetics, doesn't mean he is wrong here. I think we can both agree that Ruyangosaurus needs to be redescribed before judgement can be passed on its phylogenetic relationships. I'm aware you think it is a lognkosaur, but until it is properly scored, put in a comprehensive phylogenetic analysis, I think that is a untested hypothesis/assumption (especially since not all lognksaurs have super-wide diapophyses on their dorsal vertebrae, i.e. Mendozasaurus and Drusilasaurus). But I digress.

I'm also having a hard time seeing why you think Mannion is being vague when he says (and I quote), "Argyrosaurus can be diagnosed by five autapomorphies (marked by an asterisk), as well as a unique combination of character states: (1) medial margin of humerus forms a transversely wide ridge that projects prominently anteriorly∗; (2) midshaft of humerus extremely compressed anteroposteriorly (transverse to anteroposterior width ratio = 2.6)∗; (3) transverse width of distal end of radius only slightly greater than midshaft width (ratio = 1.3)∗; (4) radius is subtriangular in distal end view∗; (5) presence of ossified carpals; (6) extreme elongation of metacarpals (longest metacarpal to radius length ratio = 0.6)∗;(7) metacarpals II and III longest elements in metacarpus." (p. 615-616)

On Elaltitan he says, "Elaltitan can be diagnosed by an unique combination of character states, as well as one autapomorphy (marked by an asterisk): (1) spinopostzygapophyseal laminae in middle–posterior dorsal vertebrae bifurcate into medial and lateral branches; (2) dorsoventrally tall neural arch restricted to anterior half of centrum (excluding condylar ball) in anterior-most caudal vertebrae∗; (3) astragalar ascending process does not extend to the posterior margin of the astragalus; (4) presence of a calcaneum." (p. 623)

I'm sorry, but I'm having a hard time seeing how this is "vague".

Also, the arms don't have the same proportions:


Humerus: Elaltitan: 1300 mm, Argyrosaurus: 1370 mm
Radius: Elaltitan: 730 mm, Argyrosaurus: 858 mm
Ulna: (lft)Elaltitan: 827 mm, Argyrosaurus: 965 mm
Ulna: (rght)Elaltitan: 880 mm, Argyrosaurus: not preserved

H-R ratio: Elaltitan: 1.780821918, Argrosaurus: 1.596736597
H-U (both lft) ratio: Elaltitan: 1.571946796, Argrosaurus: 1.419689119
R-U ratio (both lft): Elaltitan: 0.882708585, Argrosaurus: 0.889119171
R-U (left,right)(Elaltitan only): 0.829545
H-U (left,right)(Elaltitan only): 1.477273

Only the Radius-Ulna ratios are similar, but the Humerus-radius and Humerus-ulna ratios are quite a bit different.

I also find it odd that you think the holotype Argyrosaurus specimen and the Elaltitan specimens are of differenet ontogenetic stages. Based on what? The scapula is not preserved with the holotype specimen so you can't compare the ontogeny of the two specimens without a histological analysis (which has not been done AFAIK). Size is very misleading when it comes to ontogeny (as Triceratops specimens show), and smaller specimens of the same species can actually be more mature than larger specimens.

Their arm proportions are actually different (see my comparisons above). Another interesting difference between them, in Elaltitan, "At midshaft,the humerus has a transverse to anteroposterior width ratio of just under 2.0" (p. 629) whereas in Argyrosaurus it is "At midshaft, the humerus is strongly compressed anteroposteriorly, and it has the highest transverse to anteroposterior width ratio of any known sauropod (2.64 [measured on the anteroposteriorly thicker medial side]; see Table 1)[...] we regard the extreme condition in Argyrosaurus as an autapomorphy of the genus."

BTW, the tarsus autapomorphy for Argyrosaurus is not used to distinguish it from Elaltitan, but from other titanosaur sauropods (i.e., it is currently diagnostic when compared to other titanosaurs for which it can be compared).

There are other differences between Elaltitan and Argyrosaurus in the morphology of the radius and ulna such as:

* distal end of radius is mediolaterally expanded in comparison
to the shaft - ratio of 1.7 in Elaltitan compared to 1.3 in Argyrosaurus

*proximal end transverse width to ulna length ratio of 0.45,and differing from the more gracile morphology seen in Argyrosaurus ratio of 0.34

Mannion lists other differences that I will not go into here, but I hardly think they and the ones I have mentioned are "vague".

One point that I might concede is that it is possible for arms to change proportions through ontogeny, this is known to be the case in Alamosaurus for instance, where the humerus gets proportionally longer. However, the other differences in the ratios are not so easily chalked up to ontogeny. In any case, I think the case for taxonomic distinction has been proved beyond a reasonable doubt with the current amount of evidence available.

I also think it is interesting that you think that Elaltitan could morph into Argyrosaurus gaining an autapomorphic medial ridge on the humerus, but you feel that fenestration in Triceratops-Torosaurus is impossible. In other words, Triceratops and Torosaurus share every diagnostic feature except their frills, whereas Elaltitan and Argyrosaurus differ in every diagnostic feature that we can compare them on.

As for the name, the paper says, "EtymologyElal (ee-lal), the creator god of the Tehuelche people of Chubut Province; titan, giant in Greek mythology. Specific name in honor of Miguel Lillo, for his contribution and legacy to natural sciences in Tucuman." So no airline, AFAIK.
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:icontyrannosaurusprime:
TyrannosaurusPrime Featured By Owner Sep 25, 2012
"As for the name, the paper says, "Etymology—Elal (ee-lal), the creator god of the Tehuelche people of Chubut Province; titan, giant in Greek mythology. Specific name in honor of Miguel Lillo, for his contribution and legacy to natural sciences in Tucuman." So no airline, AFAIK."

Not sure about you, but I still find Elaltitan to be a lame name (admittedly mainly it's personal bias, but partly because it sounds like eLOLtitan :XD:). They should have used Argentinotitan as the genus name IMO.;)
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:iconpaleo-king:
Paleo-King Featured By Owner May 16, 2012  Professional Traditional Artist
If someone could prove that the muscle crests on the arms of both animals are radically different, lets say as equidistant phylogenically as the Argyrosaurus holotype is from Epachthosaurus (or for that matter any other titanosaur known from a complete arm), then I'd be ready to buy the argument that PVL 4628 is a different genus. This would be more conclusive than bone length ratios.

However the fact remains that arm proportions can and do change in ontogeny, and titanosaur ontogeny is still poorly understood (as is the anatomy of Argyrosaurus). And there are no axial elements known from the holotype, which makes comparisons tricky.
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:iconpalaeozoologist:
palaeozoologist Featured By Owner May 21, 2012  Hobbyist General Artist
You are completely missing the point. We don't need the muscles crests to be radically different for two reasons. (1)"Radically different" is not a scientific concept. (2) All we need them to be is diagnostic and phylogenetically distinct or informative. The autapomorphies of Argyrosaurus are diagnostic and are phylogenetically informative (at least, at present they are, new discoveries could render them nondiagnostic in the future, but that is neither here nor there).

Argyrosaurus possesses 4 autapomorphies in elements that overlap with Elaltitan which Elaltitan does not possess (and which no other titanosaur possesses, by definition). If there were an analagous concept in science for "radically different" in taxonomic phylogeny, it would mean being phylogenetically diagnostic and distinct (autapomorphic). In that sense then, the autapomorphies of Argyrosaurus are "radically different" from Elaltitan. BTW, an autapomorphy basically means "as equidistant phylogenically as the Argyrosaurus holotype is from Epachthosaurus (or for that matter any other titanosaur known from a complete arm)" as it is from Elaltitan. Wikipedia says, "an autapomorphy is a distinctive anatomical feature, known as a derived trait, that is unique to a given terminal group. That is, it is found only in one member of a clade, but not found in any others or outgroup taxa, not even those most closely related to the group (which may be a species, family or in general any clade)." The 4 autapomorphies that are on comparable elements for Argyrosaurus and Elaltitan are just that: they are not found anywhere else in the Titanosauria--by definition being an autapomorphy. Only if these traits were found to vary ontogenetically and are subsequently found in various other taxa could an argument for synonymy be made. As it stands, the synonymy argument fails all scientific tests.

And as I said in my other comment, arm proportions are observed to change in Alamosaurus...in specimens demonstrably on opposite ends of the ontogenetic spectrum and of radically different sizes! Neither of which are demonstrably true for Elaltitan and Argyrosaurus. So again, your argument for synonymy fails when tested.
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:iconpaleo-king:
Paleo-King Featured By Owner May 16, 2012  Professional Traditional Artist
Telling "Elaltitan" from Argyrosaurus is indeed a lot more vague than you make it out to be. For starters, most of Mannion's autapomorphies cannot even be compared to the Argyrosaurus holotype due to the lack of overlapping material.

On Elaltitan he says, "Elaltitan can be diagnosed by an unique combination of character states, as well as one autapomorphy (marked by an asterisk): (1) spinopostzygapophyseal laminae in middle–posterior dorsal vertebrae bifurcate into medial and lateral branches;
This can not be compared to the Argyrosaurus holotype as none of its vertebrae were found!

(2) dorsoventrally tall neural arch restricted to anterior half of centrum (excluding condylar ball) in anterior-most caudal vertebrae∗;
Same problem as before. No vertebrae in the holotype to compare this to.


(3) astragalar ascending process does not extend to the posterior margin of the astragalus;
There's no astragalus in the holotype to compare it to


(4) presence of a calcaneum." (p. 623)
Once again no overlap with the holotype; BTW the presence of a calcaneum doesn't prove much of anything. Being so small and often only connected to other bones by cartilage, the calcaneum in sauropods tends to get washed away. Most if not all sauropods probably had a calcaneum. Most artists tent to omit the calcaneum from species for which it is known, including Greg Paul.

Now while the rations of the arm bones do differ in PVL 4628 and the holotype, there's no conclusive way to prove that it isn't ontogeny. Like you said, the arms of Alamosaurus do change proportions over time. However you MAY be able to prove they are different species by locating some muscle crest or lamina in the arm bones of one that is not present in the other. For example there are small rugose laminae on the porimal part of the humerus of Brachiosaurus which are not present in Giraffatitan, aside from the shapes of the humeri being different. However you haven't pointed out any significant morphological differences between the arm elements of the Argyrosaurus holotype and PVL 4628. Does Mannion ever actually compare the morphology of the individual arm bones of the two animals aside from that "medial ridge"? Or does he simply settle for length ratios and leave it at that? One single autapomorphy that can actually be compared between both specimens is a pretty weak basis for splitting. By contrast, Triceratops and Torosaurus can be split on the basis of many more observable differences, many of which have nothing to do with their frills (for example beak shape, nostril elongation, beak/snout ratio and radically different patterns of horn ontogeny - plus, Horner & Co. have never entered all known Torosaurus postcrania into a data matrix along with a good sample of Triceratops postcrania from different growth stages - they claim they have data backing their conclusions, well let them actually crunch it and honestly report the result).

In the best scans I can find of Powell (2003) the two specimens have very similar morphology of the arm bones, the humeri for example have the same wide-shafted, flattened "snowboard" shape which is rare in most titanosaurs (for example Alamosaurus, Neuquensaurus, Saltasaurus, Uberabatitan and even apparently some immature Futalognkosaurus, if field photos can be believed, have a twisted curvature to the humerus and very forward-projecting deltopectoral crests). Aside from Argyrosaurus, only Paralititan, Epachthosaurus, and a couple of australian titanosaurs have flattened wide-shafted humeri with little forward projection of the deltopectoral crest - and none of them resemble the holotype Argyrosaurus in overall poportions as much as PVL 4628 does.

Furthermore, the lack of a scapula with the holotype actually does not support your view: simply because there's no scapula to compare with PVL 4628, that does not mean that PVL 4628 is more mature or somehow violates lumper ontogeny the way Torosaurus does. Indeed, there would be only two possible outcomes if the Argyrosaurus holotype were found with a well-preserved scapula: (1) a coracoid is fused to it, which means the holotype is adult or close to adult, which agrees with the ontogeny theory; or (2) a coracoid is absent, which means that both the holotype AND PVL 4638 are immature animals, meaning there is no way to tell which is more mature based on morphology alone, and a histology study may be needed to determine age and relative maturity for both animals. This second possibility also does not conflict in any way with the ontogeny theory - both specimens clearly had some growing left to do.

The only way to DISprove ontogeny between these two Argyrosaurus specimens is to either find radically different posterior dorsal vertebrae, anterior caudals, femur, astragalus, or a pubis for the holotype or a specimen overlapping with it (which doesn't seem likely any time soon) or to do a detailed morphological inspection (like Borsuk-Bialynicka did on Opisthocoelicaudia) the both animals, which yields very different results for muscle attachment configurations.

Now that said, I don't think ontogeny is a certain fact in the case of PVL 4628. It MAY just be another species of Argyrosaurus or another genus in argyrosauridae (in fact I simply call it Argyrosaurus sp. for now). But it's the most complete specimen of any argyrosaur so far known, so it's the best there is for scaling reference for Argyrosaurus superbus, and may be the same animal based on stratigraphy and location.

As I said before, I can't endorse any part of Mannion's theory until I see the paper for myself. And BTW, Mendozasaurus and Drusilasaura DO have very wide dorsal diapophyses. Especially Drusilasaura, its anterior dorsal is basically a scaled-down copy of Puertasaurus proportion-wise, the diapophyses on that thing are huge (and wedge-shaped with deep buttressing laminae beneath, just like in Puertasaurus and by the look of things, Ruyangosaurus).
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:iconpalaeozoologist:
palaeozoologist Featured By Owner May 21, 2012  Hobbyist General Artist
No, it is not "vague". Vague means "not clearly or explicitly stated or expressed." Mannion's hypothesis is clearly and explicitly expressed. You could maybe say that you think his hypothesis is "unsound" or "unfounded" or "weak" (characterizations which I still would disagree with—see below), but it is definitely not vague.

You also appear not to have read what I said, because when I quote Mannion’s autapomorphies I do so in the context of showing that Mannion is not vague at all, but it is very explicit and clear in his hypothesis. You appear to have conflated the different aspects of my argument. So your first four bolded statements are useless in supporting your argument because I already implicitly acknowledged that those autapomorphies do not overlap.

Also, you incorrectly focus on the autopamorphies of Elaltitan instead of Argyrosaurus. Of the 5 autapomorphies listed for Argyrosaurus (marked with an asterisk), 4 can be compared to Elaltitan - and Elaltitan shares none of them!

As for the arm proportions, yes, you are correct in saying there is no way to conclusively prove that the changes are not ontogenetic. However, the reverse is also true (that is, there is no way to conclusively prove that the changes are ontogenetic). This means you are assuming a priori that they are ontogenetic in order to support your hypothesis. You are going about that completely backward. You must show that ontogeny is a factor before synonymizing, not after.

Also, as for arm proportions changing ontogenetically in Alamosaurus: the difference in proportions is seen between an animal with a 605 mm humerus compared to a one with a 1360 mm humerus, meaning there is a factor of 2.24 in size. Yet there is only a size factor of 1.05 between the humeri of Elaltitan and Argyrosaurus (a factor of only 1.17 between the radii, and a factor of only 1.16 between the ulnae). This means you are proposing significant proportional and morphological features occurring in animals that are already nearly the same size humerus-wise. (Huh…this is beginning to sound awfully like Horner and Scanella’s late ontogenetic trajectory hypothesis (LOTH) for Torosaurus v. Triceratops-which you reject-even though Horner and Scanella’s hypothesis is backed up by histology whereas your hypothesis Elaltitan v. Argyrosaurus is not. Therefore, you actually support LOTH if it conveniently supports your favored taxonomic hypothesis, but are against LOTH if it doesn’t support your hypothesis. This sounds an awful lot like the pot calling the kettle black.)

Also, in Triceratops and in Torosaurus the beak shape, nostril elongation and beak/snout ratio are not diagnostic and are individually variable between specimens (whereas the autapomorphies for Argyrosaurus actually are diagnostic and different from Elaltitan). We don’t have young Torosaurus specimens to compare horn morphology for (at least not yet described).

You said: “In the best scans I can find of Powell (2003) the two specimens have very similar morphology of the arm bones.”

This is not the case (as I already have said, they have different proportions and Argyrosaurus has 4 autapopmorhies not seen in Elaltitan for which there are overlapping elements to compare).

You said: “ the lack of a scapula with the holotype actually does not support your view: simply because there's no scapula to compare with PVL 4628, that does not mean that PVL 4628 is more mature or somehow violates lumper ontogeny the way Torosaurus does.”

…and you’ll notice that I never said that PVL4628 is more mature or violates lumper ontogeny, all I said is that there is no way to know, based on the external morphology, what their relative ontogenetic stages are. You put the cart before the horse here: assuming ontogenetic differences when you have yet to prove they are actually ontogenetically different! You assume ontogeny is the factor, based on size differences, which we know are an unreliable indicator and they are actually not that different in size (see humeri ratios above: 1.05 vs. 2.24)! Even if they were of different ontogenetic stages, there still are 4 of 5 autapomorphies listed for Argyrosaurus that Elaltitan does not have(and for which they can be compared). I know of no precedence for this occurring in ontogeny.

You said: “ The only way to DISprove ontogeny between these two Argyrosaurus specimens is to either find radically different posterior dorsal vertebrae, anterior caudals, femur, astragalus, or a pubis for the holotype or a specimen overlapping with it (which doesn't seem likely any time soon) or to do a detailed morphological inspection (like Borsuk-Bialynicka did on Opisthocoelicaudia) the both animals, which yields very different results for muscle attachment configurations.

Wrong. They do not need to be radically different (which is not a scientific concept—I know of no meaningful or useful scientific definition for this). All they need to be is diagnostically different (meaning phylogenetically informative). I’m sorry that a medial ridge is not “radical” enough or sexy enough for you, but it is diagnostic and phylogenetically informative as well as distinct. Being diagnostic and phylogenetically informative is what a scientist should care about, not if it is “radical” enough (which is a subjective and unscientific concept).

Also, Mannion did do a detailed morphological inspection and found that PVL 4628 and the Argyrosaurus holotype share no diagnostic characters.

It is unlikely that Elaltitan is closely related to the holotype specimen of Argyrosaurus since Argyrosaurus predominantly possesses characters that are present in basal (plesiomorphic) titanosaurs (e.g., “possesses carpal bones, which are unknown in all other titanosaurs. Secondly, the longest metacarpals are Mc. II and III, a feature Argyrosaurus shares with the putative basal titanosaur Janenschia") whereas Elaltitan possesses a suite of characters that indicate a derived position within Titanosauria (e.g., “the absence of postzygodiapophyseal laminae in dorsal vertebrae; diapophyses positioned dorsal to the prezygapophyses/ parapophyses in posterior dorsal vertebrae; middle–posterior dorsal neural spines that are sub-triangular in anterior view; strongly procoelous anterior caudal centra; and the presence of a prominent muscle scar on the posterolateral surface of the humeral deltopectoral crest.”) It is true that these basal features and derived features cannot be directly compared between the two taxa, but it is also true there is nothing to indicate that Elaltitan and Argyrosaurus are more closely related to each other than to any other titanosaur taxon. There is no shared feature between Elaltitan and Argyrosaurus that is not also found in other titanosaur taxa, therefore referring to the Elaltitan as an argyrosaur is completely unfounded (and actually, vague—what is an “argyrosaur”? What features diagnose that clade? If you want to include Elaltitan in the argyrosaur clade by definition, then that clade may be very large, including most, if not all of, the Titanosauria).

As for stratigraphy, Mannion also covers this, and surprise, surprise, they are differerent: “Additional support for the generic separation of Argyrosaurus and Elaltitan comes from recent stratigraphic revision of the Bajo Barreal Formation. Elaltitan comes from the lower member of the formation in the area of the Rio Senguerr, which is dated as middle Cenomanian–Turonian (Archangelsky et al., 1994; Bridge et al., 2000; Lamanna et al., 2002), whereas Argyrosaurus is probably from the upper member in the area of the Rio Chico, tentatively dated as Campanian–?Maastrichtian (Casal et al., 2007).”

Therefore, there is no justification for referring Elaltitan to Argyrosaurus. All your arguments for synonymy are wrong, ambiguous or hypothetical. On the other hand, arguments for their separation pass all standard taxonomic tests: they have different autapomorphies on the overlapping material, belong to different stratigraphic groups, and share no diagnostic characters that are not shared by other non-argyrosaur titanosaur taxa. In other words, synonymy of the two would require a considerable amount of new evidence. Thus, their taxonomic distinction appears to be justifiably warranted. Separating them requires special pleading.

BTW, I can send you the paper, or you could ask Phil, as he responded quite quickly when I asked for his papers (within a day). The best way to get a paper if it is not open access is to email the corresponding author (which is neither time consuming or terribly inconvenient). They are usually ecstatic that you would request there paper and I have had authors send me related papers that I didn’t even ask for!

I'll go into the Drusilasaura and Mendozasaurus argument at another time. I think this comment is already sufficiently long.
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:icontyrannosaurusprime:
TyrannosaurusPrime Featured By Owner May 25, 2012
Could you please e-mail me the Elaltitan paper? Thanks.:)
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:iconpalaeozoologist:
palaeozoologist Featured By Owner May 26, 2012  Hobbyist General Artist
Sure thing, send me a note with your email address and I'll send it. :)
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:icontyrannosaurusprime:
TyrannosaurusPrime Featured By Owner May 26, 2012
My e-mail is leoike21@gmail.com. ;)
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(1 Reply)
:iconpaleo-king:
Paleo-King Featured By Owner May 24, 2012  Professional Traditional Artist
Ok please email me the paper I will definitely look at it.

Bajo Barreal's proper age was a pain in the neck to decipher for many years... I saw lots of conflicting estimates.

Argyrosaurs are the clade formed by Argyrosaurus + Paralititan (as per Tom Holtz's definition). Very robust titanosaurs with wide, flat "snowboard" humeri, anteroposteriorly compressed centra in the anterior caudals, and very tall, anteriorly curved neural spines on the posterior sacrals/anterior caudals. This latter feature is found in both Paralititan and PVL 4628. It does not appear in Lognkosauria, Saltasauridae, or any basal titanosaurs.

"Separating them requires special pleading." Wait a minute... weren't you arguing they should be separated?

BTW, I don't know why you say that beak shape and the other unique features of Torosaurus aren't diagnostic. They are found in ALL Torosaurus skulls for which the relevant material exists, but not in Triceratops. Torosaurus had a long low "condor beak", not the shorter and more recurved "eagle beak" of Triceratops. Also Torosaurus had a greater beak/snout length ratio than Triceratops, the nasal horn is located further back. And the horns do not curve forward in one direction in the most mature animals like in Triceratops. The ANSP skull is the most ontogenically immature Torosaurus, and has a much smaller frill than the others. Yet the horns in the older specimens are actually straighter, and none of them curve forward and down like in Horner's oldest Triceratops skulls. If Horner ever bothered to enter beak curves and beak/snout length ratios as well as horn angle and curvature into a data matrix, there would be a LOT more phylogenic distance between Torosaurus and Triceratops than just the frill. That said, one Triceratops does have similar skull proportions to Torosaurus - this is the "T. eurycephalus" skull. It is a very old individual (though not remarkably large) and has almost completely reabsorbed epoccipitals, nevertheless these follow the Triceratops pattern, the frill long and flat but not perforated, yet the brow horns are straight as in mature Torosaurus. If anything this is the most basal Triceratops, the form closest to its ancestral split with Torosaurus.
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:iconpalaeozoologist:
palaeozoologist Featured By Owner May 26, 2012  Hobbyist General Artist
Ok, I'll send the paper soon.

I'm not sold on the differing ages for the different parts of the Bajo Barreal formation, but it seems they are separated enough...

You are correct in saying that Argyrosaurus and Paralititan are consistently found as each other's closest relatives. That said, I'm not sure that clade will include Elaltitan. The shape of the humeri of Argyrosaurus and Paralititan is not shared by Elaltitan. Also, the anteriorly curved and very tall neural spines on the anterior caudals that you cite are also seen in Alamosaurus (which is in the Saltasauridae)--we don't have preserved neural spines for the sacrals in Paralititan, Elaltitan or Argyrosaurus, nor in Alamosaurus so I don't see how they are relevant.

You said: ""Separating them requires special pleading." Wait a minute... weren't you arguing they should be separated?"

<headdesk> Oops, sorry that was typo. I meant to say "Synonymizing them requires special pleading". Man, that's embarrassing--I guess I get that for not proofreading more carefully (!).

I say the beak shape of Torosaurus isn't diagnostic because they differ in the described specimens as does the angle and and curvature of the horns (both orbital and nasal), and because there is much observed variation in Triceratops in beak and horn shape (see the many "species" of Triceratops that were erected on those and similar bases...they just aren't diagnostic, since a range of extremes are present in between the specimens of one species, there is no strict separation of these features and therefore are not diagnostic; I should mention that in T. horridus and T. prorsus, these features can be distinguished, but the Torosaurus specimens fall in the T. horridus range of variation (which are not diagnostic); in fact, who uses those features (even in the pro-separation camp) to reliably distinguish Triceratops from Torosaurus?).

That said, if further specimens of Torosaurus are described and they can reliably be distinguished from T. horridus, then there might be a case for taxonomic distinction. Whether that is a specific only or generic distinction depends on one's "genericometer". That said, Torosaurus and Triceratops are very closely related.
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:iconpaleo-king:
Paleo-King Featured By Owner May 27, 2012  Professional Traditional Artist
There are preserved rear sacral neural spines for Paralititan, and these are very tall. Not quite caudals, but close enough to indicate the caudal spines were tall as well...
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:iconsameerprehistorica:
SameerPrehistorica Featured By Owner Feb 20, 2012  Hobbyist
Another giant...hmm..Very nice
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:iconpaleo-king:
Paleo-King Featured By Owner Feb 20, 2012  Professional Traditional Artist
Thanx! 8-)
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:iconsameerprehistorica:
SameerPrehistorica Featured By Owner Feb 20, 2012  Hobbyist
U r welcome :)
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:iconasier11:
Asier11 Featured By Owner Oct 5, 2011
Ok, Thank you for your explanations, I think that you can be right about FMNH 13019 femur.

Otherwise, about the erosion on FMNH 13018 femur that you point, is somewhat subjective. In the photo doesn´t look like need to add more bone. When a bone fossilized among millions of years, can lost the original bone from the tips but this lost is replaced by other natural elements, so the length use to be very similar to the original one. Probably you can add only few centimeters but not as much as you add in your drawn. Also I check that you pointed that is around 18% larger than B.altithorax´s one, that would be a mega-femur of 240 cm which is not possible for FMNH 13018 femur.
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 5, 2011  Professional Traditional Artist
Actually FMNH 13018 is roughly 2.15m long (215cm) in my reconstruction when you go off the scale bar I included, that's nowhere near 240. I was very careful with the scaling. The femur is not too long. Also in both that photo and Powell (2003) the ends of the bone appear eroded. In any case I added just 5cm to the bone. The original length came out to 210cm based on cross-scaling. Even if you go by Huene's 200cm estimate (which was probably rounded down), that leaves only a maximum difference of 15cm that I added. And 15cm is not big at all, it's smaller than the span of a human hand. And in the photo with Dr. Abbott, you can see how small a human hand looks next to these huge femurs.
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:iconasier11:
Asier11 Featured By Owner Oct 5, 2011
The best way to know the real length of FMNH 13018 would be to ask someone at FMNH to measure it, but I think that most proper should be to rely on Huene measurement of 200 cm because he measured and published it, but ok 15 cm is not too much, although in terms of mass would be a difference of 22%. By the way, you have drawn humerus, ulna radius and metacarpals on the large individual. Are Have ever been found these bones? or is your estimation?

Thank you.
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 5, 2011  Professional Traditional Artist
Huene published HUNDREDS of bones in his 1929 paper, literally the entire collection of the MLP among other bones they dug up and sent to FMNH and elsewhere, many of which were somewhat hastily sketched. And he was one man doing it all by himself, which you never see in big fossil survey papers or collection papers anymore. So it's entirely possible that not all of his measurements are 100% spot-on. I doubt the bone was exactly 200cm long, so I did my own calculation, which came out only slightly larger. It's not the biggest dinosaur anymore by any means, but it IS downright huge and robust. Giraffatitan and Brachiosaurus have femurs of similar length, but much more slender.


The arm bones in the adult reconstruction are scaled up from the holotype which Lydekker described in 1893. The actual holotype arm is a bit smaller (though the same shape) and the animal it belonged to would likely have had a femur less than 200cm long.

It's hard to tell if either the holotype or FMNH 13018 represent adult specimens - without shoulder material for either specimen it's hard to tell. But the PVL 4628 specimen is definitely not an adult since the scapula isn't fused with a coracoid - and judging based on other large titanosaurs, my best guess is that FMNH 13018 is probably an adult given it's a good bit larger than the PVL teenager, although whether it's a large adult and the holotype is a smaller adult, is unknown. The holotype individual was intermediate in size between FMNH 13018 and the PVL teenager.
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:iconasier11:
Asier11 Featured By Owner Oct 6, 2011
Thank you very much for your explanations, I´m with you . You have to know that all my criticism are constructive and I would like to help you with your reconstructions.

According to my information, the PLV 4268 has a humerus/femur ratio of 0.7 (with a conservative restoration of the femur) and in your reconstruction is about 0.9 which make your argyrosaurus too high at the shoulder region.
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 7, 2011  Professional Traditional Artist
I initially though so too, but when I cross-scaled the vertebrae of PVL 4628 with the humerus, and again with the femur, (assuming correct scaling with all the relevant scale bars) they came out different sizes, about 20% difference. So I checked again and found a photo of Jose Bonaparte standing with both the arm and the femur - they were proportionally roughly the same as if you scaled them to the same scale from Powell's diagrams - BUT the latter was considerably closer to the viewer than either Bonaparte or the forearm. In reality the arm should have been about 20-25% bigger relative to the femur than it appears in the photo. Which results in a humerus/femur ratio that's around 0.8-0.9, similar to where I put it (with my measurements it comes out to ~0.88) I doubt it was shorter than this, because then based on the photo the radius and ulna would be ridiculously short for an animal of this size, only about half the length of the tibia! Only Isisaurus has anything like such proportionally short lower arms relative to its size (yet has proportionally higher shoulders than Argyrosaurus due to its even more overextended humeri) but I doubt that Argyrosaurus was built anything like that, judging by the rest of the known remains.
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:iconasier11:
Asier11 Featured By Owner Oct 4, 2011
Thank you for your kind response.

I´m sorry but I have to correct you, the femur on the left is not from is not from Argyrosaurus but from Antarctosaurus wichmannianus, the largest femurs found of this species are from 1770 mm to 1855 mm. The femur on the right side is from Argyrosaurus (FMNH P130018), but the length would be about 1850 mm, much smaller than your reconstruction.

Reference:

Glut encyclopedia (1997): page 170.
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 4, 2011  Professional Traditional Artist
No, sorry, I have checked the exact proportions of both femurs. And I checked the scale of the diagrams from both Powell (2003) and Von Huene (1929). The femur on the left is not an Antarctosaurus femur. There's only one femur known from Antarctosaurus wichmannianus, the type femur, and it's smaller than either of the femurs in the photo (it's also far more angular at its head than the femur on the left). The femur on the left is over 2m long, just like the scale bars in Powell (2003) indicate, the robustness and the shape of the femur head are the same as the photo of FMNH 13018 in Powell (2003).

The femur on the right is actually FMNH 13019. It's smaller and more angular than FMNH 13018, and I drew it smaller in the diagram. If you don't believe me read Powell (2003), he's very specific about lengths and reference numbers. Both femurs in the photo are from Argyrosaurus and FMNH 13018 (on the left) is over 2m long. If you want I can email you the paper, but it's a VERY big file.

I've read both papers in detail and checked the measurements multiple times. That's why this restoration took over a year to produce - getting all the sizes and proportions right. Glut's encyclopedia is simply a compilation of many papers by different authors, it DOES have mistakes as one might expect - it's a secondary source. I don't use Glut or his measurements, I go directly to the original sources (I have the original papers, so I don't need the encyclopedia). Glus hasn't actually gone out and measured the specimens in person, whereas both Von Huene and Powell have. And both Von Huene and Powell identify the femur on the left as Argyrosaurus sp. FMNH 13018, the huge curved femoral head is very distinctive, and much more robust than Antarctosaurus as well as larger, the length is around 2.15m depending on where you measure it. The same femur is identified as FMNH 13018 in BOTH papers, with matching illustrations!
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 4, 2011  Professional Traditional Artist
BTW, you might be curious to know that the photo was taken at the FMNH, and they don't have any Antarctosaurus femora in their collection, and have never had any in the past.... the type femur of Antarctosaurus wichmannianus (which is missing most of the femoral head, unlike these two Argyrosaurus femurs) is in the Museo de La Plata in Argentina, not in the Field Museum. It never left South America! What's more, even the cracks in both femora in the photo match up precisely with the photos of FMNH 13018 and 13019 in Powell (2003). Which matches the ink drawings of both femora in Von Huene (1929) precisely in shape. I didn't make a mistake, the femur on the left IS Argyrosaurus sp., and it's over 2m long, which matches up with my reconstruction :D
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:iconvjushkovia:
Vjushkovia Featured By Owner Jan 6, 2013
The femur FMNH 13019 and the tibia FMNH 13020 were originally assigned to Antarctosaurus wichmannianus? by von Huene (1929, p. 74), but subsequently moved to cf. Argyrosaurus sp. by Powell (2003). Given that Glut's (1997) work precedes Powell's (2003), his figure caption was correct at the time.
However, Glut's other figure (1997, p. 171) for Argyrosaurus is completely wrongly labelled though: the figure caption says that the elements shown are the holotype humerus, carpal and ulna of Argyrosaurus superbus, when what are actually shown are: a humerus assigned to Titanosaurus australis; a caudal vertebral centrum referred to Argyrosaurus superbus; and the humerus of Microcoelus patagonicus. These assignations all follow Lydekker's original (1893) assignations, all of which have now been amended: the larger humerus was removed from Titanosaurus (now Neuquensaurus) australis and assigned to Titanosaurus sp. by Powell (2003); the Microcoelus patagonicus humerus was assigned to Neuquensaurus australis (Otero, 2010); and the caudal vertebra was designated as an indeterminate titanosauriform by Mannion & Otero (2012). All other non-holotype specimens previously assigned to Argyrosaurus (including the FMNH material) were designated indeterminate titanosauriformes as well, with the exception of PVL 4628 which was made the holotype of Elaltitan lilloi by Mannion & Otero (2012). I know some of this has been said above, but this summarises my thoughts.

Glut, D. F. 1997. Dinosaurs: The Encyclopedia. 1076 pp. McFarland & Company, Inc., Jefferson.
Huene, F. v. 1929. Los Saurisquios y Ornitisquios del Cretáceo Argentina. Anales Museo de La Plata 3:1-196.
Lydekker, R. 1893. Contributions to the study of the fossil vertebrates of Argentina. I. The dinosaurs of Patagonia. Anales del Museo de la Plata, Seccion de Paleontologia 2:1-14.
Mannion, P. D., and A. Otero. 2012. A reappraisal of the Late Cretaceous Argentinean sauropod dinosaur Argyrosaurus superbus, with a description of a new titanosaur genus. Journal of Vertebrate Paleontology 32:614-638.
Otero, A. 2010. The appendicular skeleton of Neuquensaurus, a Late Cretaceous saltasaurine sauropod from Patagonia, Argentina. Acta Palaeontologica Polonica 55:399-426.
Powell, J. E. 2003. Revision of South American titanosaurid dinosaurs: palaeobiological, palaeobiogeographical and phylogenetic aspects. Records of the Queen Victoria Museum 111:1-173.
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:iconasier11:
Asier11 Featured By Owner Oct 4, 2011
I have both papers thank you. First of all I recommend you to be very careful with the scale bars, from my experience there are horrible to calculate the bones lengths the margin of error could be over 30%...

I can assure you that there are several femurs of A. wichmannianus and also stored at FMNH. The femur FMNH P13019, same as FMNH 13019, is from Antarctosaurus and its length is 1855 mm according to Mazzeta (2004):

[link]

According to Huene (1929) the femur FMNH P13018 or the femur found in La Sierra de San Bernardo is just 200 cm (check page 81).
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 4, 2011  Professional Traditional Artist
I'm well aware of the problem with calculating scale bars, as you could tell from my entries on Futalognkosaurus. Fortunately I compared the scale bars of 4 different Argyrosaurus specimens in Powell (2003) with photos that include a human for scale. Also I cross-scaled the photos with written measurements in other papers and scale photos of other bones in the same paper to make sure the scale bars were accurate (something whose importance I learned from the whole Futalognkosaurus ordeal), and none of them were off by more than 10%, and I corrected for that. Also I corrected for erosion on both ends of FMNH 13018 which increased the length by a few cm. Yes Huene did list the length of this huge femur at 200cm - that equals 2m! So it's not a wimpy 1700cm Antarctosaurus femur like you were claiming. However the femur exceeds 200cm if you account for erosion at the ends.

Also, don't take this personally but it looks like now you changed your story, claiming that the smaller FMNH femur (FMNH 13019) is actually the one from Antarctosaurus. That femur WAS referred to Antarctosaurus by Huene (and Mazzeta was just going verbatim off of Huene's referral, his paper had nothing to do with taxonomy), but Powell referred it to Argyrosaurus because it proportions are more in line with Argyrosaurus than the Antarctosaurus holotype despite its condyle angularity, and I tend to agree more with Powell's assessment - especially since his paper is far more recent, and is backed up with actual photos, not just line drawings. FMNH 13019 could represent a different species of Argyrosaurus OR a new species of Antarctosaurus - but that doesn't matter because I didn't use FMNH 13019 in my skeletal. I used the larger femur, FMNH 13018.

There are not several Antarctosaurus femurs at FMNH. There are two referred Argyrosaurus femurs, the smaller of which (FMNH 13019) has sometimes been referred to Antarctosaurus without absolute certainty. Antarctosaurus wichmannianus itself is only known with certainty from one femur, which is part of the holotype material in the MLP. There are other things which have been referred to Antarctosaurus, but none of them look like they could belong to A. wichmannianus.
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:iconasier11:
Asier11 Featured By Owner Oct 3, 2011
Hi!

Would you be kind enough to tell me the bibliographic reference of the FMNH 13018 femur, please?

Thank you!
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 3, 2011  Professional Traditional Artist
Sure! 8-)

FMNH 13018 is mentioned and shown in two papers:

Powell, J.E., 2003, "Revision of South American titanosaurid dinosaurs: palaeobiological, palaeobiogeographical and phylogenetic aspects", Records of the Queen Victoria Museum 111: 1-173

von Huene, F., 1929. Los saurisquios y ornitisquios del Cretacéo Argentino. Anales del Museo de La Plata (series 3) 3: 1–196. [In Spanish]

For this reconstruction I went by the photos in Powell (2003) rather than the somewhat sketchy ink diagrams in Von Huene (1929). Also there's a photo floating around the internet of Dr. John B. Abbott preparing both of the FMNH Argyrosaurus femur specimens and the juvenile tibia FMNH P 13020: [link]

FMNH 13018 is the femur on the left. Although it looks only a bit larger than FMNH 13019 on the right, it is in fact even larger than the photo indicates.
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:iconemperordinobot:
EmperorDinobot Featured By Owner Sep 5, 2011
[link]

betchplz.
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:iconvasix:
vasix Featured By Owner Aug 30, 2011  Hobbyist Digital Artist
One can reconstruct Paralititan on the basis of this guy? Superb, I've seen sooo many Paralititans on the net....which all look like, different from each other
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:iconpaleo-king:
Paleo-King Featured By Owner Aug 30, 2011  Professional Traditional Artist
Yes, you could theoretically reconstruct Paralititan based on it (the anterior tail vertebrae and the humeri look almost identical, though much of the rest of the body is unknown and could show some variance). Which is really cool since Paralititan is also in my list. It will be the first accurate Paralititan given the limited remains, most of the versions by other artists don't even get basic sauropod anatomy right, let alone titanosaur or argyrosaur anatomy!
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:iconvasix:
vasix Featured By Owner Aug 30, 2011  Hobbyist Digital Artist
Thanks!! :)
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:iconfranchescco:
Franchescco Featured By Owner Aug 29, 2011
Great how there is an reconstruction for this "Silver lizard." I have a question thought, while I was reading your thumbnail I saw that you said Argyrosaurus belongs with its own family including the primitive Epachthosaurus and was not a Saltasauridae( though the classification of Titanosaurian genera are still very confusing and sort of a genus dump if you ask me). However, although millions of years separated them, Argryosaurus still closely related to the more advanced Saltasaurians such as Saltasaurus and Antarctasaurus and not basal forms like Epachthosaurus. Still like your work, I might use this refrence for future work
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:iconpaleo-king:
Paleo-King Featured By Owner Aug 29, 2011  Professional Traditional Artist
Thanks :D Argyrosaurus is one of the few real giants that didn't get a decent reconstruction for over 100 years, I'd say it was about time!

Hmmm.... your statements about Epachthosaurus are not quite correct. First off I said that Epachthosaurus seems to be the closest relative of the Argyrosaurids OUTSIDE of that family (therefore it's not an argyrosaurid itself) - that's what I actually said. Second, I assumed (probably wrongly) that it's pretty common knowledge that Epachthosaurus was actually fairly advanced. There's really nothing "primitive" about it, other than its hypantrum-hyposphene complex (and even that seems to be a feature that was retained and lost at different times among different families of titanosaurs, so it doesn't prove anything about primitiveness).

In fact if you look at Epachthosaurus closely, everything else about it screams "derived lithostrotian", not "basal andesaurid". The notion that Epachthosaurus was a primitive creature related to Andesaurus is outdated and pretty much rejected by the field these days, it was a hasty assumption dating back to 1993 and has soundly been refuted by several paleontologists in peer-reviewed papers ever since 1997, most notably Wilson and Upchurch. Epachthosaurus is actually very similar to saltasaurs and argyrosaurs, though its closest relatives appear to be the "Trigonosauridae": Trigonosaurus, Barrosasaurus, and Muyelensaurus. Note that these are not argyrosaurs, they are merely Epachthosaurus's closest relatives - closer to its own branch of titanosauria. The argyrosauridae are not E's closest known relatives, but the opposite may be true, since not that many taxa have been found close to the base of argyrosauridae. I know, it's a bit confusing... probably needs a family tree to explain. Long story short, all of these animals are pretty advanced forms, including Epachthosaurus (In fact I noted above that the similarity of argyrosauridae to Epachthosaurus makes them fairly derived...)
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:iconfranchescco:
Franchescco Featured By Owner Aug 30, 2011
Thanks for responding, I see your point after researching Epachthosaurus. However, if you think of it th Titanosauria branch is really a messy subject to study since most of the better fossils finds are from the group the Saltasaurs and not from "earlier" relatives like Argentinosaurus. That's what I ment by primitive, because most of the information I refered to were stated by Phylogeneticist( paleontogists by the way). Still more future work needs to be done, which is why I've been interested in Titanosaurian taxonomy, and hopefully in the next 20+ years they will be understood like another subgroup of herbivorous
dinosaurs the "Igianodontia".
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:iconpaleo-king:
Paleo-King Featured By Owner Aug 30, 2011  Professional Traditional Artist
Good point.... Titanosauria is a very confused taxonomic tangle, but fortunately it's becoming less confused than before. There are really only a few titanosaurs that I don't know where to place, the rest are actually quite easy once you take a close look at their best remains. Epachthosaurus is pretty derived based on the best research of the past decade, in fact some people like Paleozoologist (Zach Armstrong), consider it a saltasaur (I don't, but I agree that it's not a basal form). Argentinosaurus is more basal but it may still be substantially more derived than Andesaurus.

You're right that basal titanosaurs are not well known, in fact the taxonomy of things like Phuwiangosaurus, Sonidosaurus, Baotianmansaurus, Chubutisaurus, Venenosaurus, etc. is VERY murky. But even these sorts of creatures tend to sort out into some distinct groups based on the morphology of certain features of their vertebrae.
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:iconfranchescco:
Franchescco Featured By Owner Aug 31, 2011
Yeah I agree, this is a really interesting subject since it requires more than just one hypothesis and idea. I've also made my own Titanosaurian taxonimic chart, however I have been backed up so it will be awhile before anyone can see it.

Also, if you like at genera's like Argentinosaurus, Paralititan,possibly Bruhathkayosaurus,etc. they have alot in common and are probably not that basal but more unique and derived than Andesaurus and other primitve Titanosauroidea specesis's.

P.S.: This has been bugging me for awhile, Im trying to put the emoticons in different areas in my writing, but i don't know how "can you help me out?"
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:iconpaleo-king:
Paleo-King Featured By Owner Aug 31, 2011  Professional Traditional Artist
Click the emoticons link when you hit reply. There will be a list of emoticons and the symbols that code for them. Just type in those symbols.
For example, 8-) is the number 8 followed by a hyphen (-) and an end parenthesis.

Well in my view Argentinosaurus and Paralititan are not closely related to each other, but yes they both do seem more derived than Andesaurus. Paralititan is also more derived than Argentinosaurus since it's an argyrosaur, and Argyrosaurus itself has more advanced vertebrae and femur than Argentinosaurus. Argentinosaurus so far may be in its own group, it used to be in "andesauridae" but its posterior dorsals don't look much like those of Andesaurus, though its anterior dorsals have a similar neural arch design to the posterior dorsals of Andesaurus (but that doesn't tell us anything since comparing two different body parts from two different animals is a pretty silly way to go about determining family relationships).

Bruhathkayosaurus is probably not real. The whole thing seems like a hoax to me. The discoverers (Yadagiri and Ayyasami) never bothered to take photos of the thing, even though it was discovered in the 70s supposedly - and now they allege the whole thing was washed away in a monsoon (apparently they never dug it out of the ground!). Even Richard Lydekker had a camera way back in 1893 when he published Argyrosaurus, there was a PHOTO of the type specimen forelimb! Yadagiri and Ayyasami only supplied a horrible sketch that looked like the work of a 2-year-old. Not only that, but they have only published one other dinosaur description, which was Dravidosaurus - and it turned out THAT wasn't a dinosaur either! It was a plesiosaur, they misinterpreted the chest bones as stegosaur back plates! These guys are either total hoaxers or they have no clue what they're doing.
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:iconfranchescco:
Franchescco Featured By Owner Sep 1, 2011
Thanks this really helped alot :thanks:

About the relationship with Argentinosaurus and other specesis might take a longer processes. I think the key to all of the confusion and misshalf is "skulls."

Skulls you might ask, well if you think about it the best preserved titanosaurs, infact Dinosaurs in general, had a skull intact. The skull can tell alot about an animals feediing apparatus,lifestyle, and how it relates to other specesis. If we find more skulls for Titanosaurs I guaranty you that it will clarify that taxinomic relationship. :yawnstretch:

So thanks again and continue your work. :work:
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