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Alamosaurus sizes by palaeozoologist Alamosaurus sizes by palaeozoologist
This is a diagram I came up with showing the various sizes of purported individuals of the saltasaurid titanosaur Alamosaurus.

The largest individual (at just under 27 meters and about 74 tonnes) is based solely on an incomplete tibia that would have been about 170 cm long, discribed by Rivera-Sylva et al. in 2006. The smallest individual (at under 8 meters and less than 2 tonnes) is based on a partially complete specimen described by Lehman and Coulson in 2002.

The second largest specimen to second smallest specimen pictured are based off of, in order, incomplete individuals described by Fowler and Sullivan (2011), undescribed specimen housed at the Perot Museum of Nature & Science, a partial sacrum mentioned by Mateer (1976) and the specimen described by Charles Gilmore (1946). All sizes are approximate due to the fragmentary nature of the specimens, and are subject to revision upon discovery of more complete specimens.

References:

Gilmore, C.W. 1946. Reptilian fauna of the North Horn Formation of central Utah. U.S. Geological Survey Professional Paper 210−C: 29–51.

RIVERA-SYLVA, GUZMAN-GUTIÉRREZ, & PALOMINO-SÁNCHEZ. Preliminary Report on a vertebrate fossil assemblage from the Late Cretaceous of Chihuahua, Mexico. HANTKENIANA 5 (2006)

Fowler, D. W., and R. M. Sullivan. 2011. The first giant titanosaurian sauropod from the Upper Cretaceous of North America. Acta Palaeontologica Polonica 56 (4).

Lehman, T.M. and Coulson, A.B. 2002. A juvenile specimen of the sauropod dinosaur Alamosaurus sanjuanensis from the Upper Cretaceous of Big Bend National Park, Texas. Journal of Paleontology 76: 156–172.

Mateer, N. 1976. New topotypes of Alamosaurus sanjuanensis Gilmore (Reptilia: Sauropoda). Bulletin of the Geological Institutions of the University of Uppsala, New Series 6:93–95.
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:iconwolfysnackrib:
WolfySnackrib Featured By Owner Jan 16, 2016
Need sir human fella guy dude for comparisonsorz!
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:iconpalaeozoologist:
palaeozoologist Featured By Owner Jan 21, 2016  Hobbyist General Artist
Thanks for the input, I will do so in the future.
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:iconwolfysnackrib:
WolfySnackrib Featured By Owner Jan 22, 2016
Yay!
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:icongozer-the-destroyor:
Gozer-The-Destroyor Featured By Owner Apr 18, 2013
I didn't realize they got that big! The size chart I used had the specimen at least as big as a t. rex, but not much larger.
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:iconpalaeozoologist:
palaeozoologist Featured By Owner May 3, 2013  Hobbyist General Artist
Yes, they are big. In fact, probably one of the larger sauropods all things considered.

Note that most of the larger specimens are very incomplete, known from only a few bones or in some cases only one bone.
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:icongozer-the-destroyor:
Gozer-The-Destroyor Featured By Owner May 5, 2013
Excellent. I'm working on a concept where the KT extinction is instead caused by an outbreak of the undead, and a huge, titanosaur-sized zombie was something on my list of "wants" as I was looking up late cretaceous fauna, which is why I was disappointed with finding a size chart that showed Alamosaurus only getting as big as a Tyrannosaur.

Because fighting off waves of zombie dinosaurs is bad enough, but huge, sauropod zombies? Talkin' bout sweet, beautiful overkill.

Thanks again for your help. :3
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:iconpalaeozoologist:
palaeozoologist Featured By Owner May 5, 2013  Hobbyist General Artist
You're welcome! :D
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:iconeofauna:
EoFauna Featured By Owner Dec 31, 2012  Professional General Artist
Hello,

Great work!. We have check the Rivera-Sylva et al. in 2006 paper, and there is no mention to the gigantic tibia. Could you give us the correct reference please?

Many thanks!
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:iconeofauna:
EoFauna Featured By Owner Dec 31, 2012  Professional General Artist
Sorry, we checked the incorrect one. Now we've downloaded the correct one. Thanks!
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:iconpalaeozoologist:
palaeozoologist Featured By Owner Jan 2, 2013  Hobbyist General Artist
Glad you found it! Sorry I took so long to reply, but I have not had access to the internet for a few days.
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:iconeofauna:
EoFauna Featured By Owner Jan 3, 2013  Professional General Artist
Don't worry! it is Ok, Many thanks!
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:iconfragillimus335:
Fragillimus335 Featured By Owner Dec 24, 2012  Hobbyist General Artist
So the Fowler and Sullivan Alamo turned out to be only 22.6 meters long??? It had one honkin' big cervical!
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:iconpalaeozoologist:
palaeozoologist Featured By Owner Dec 24, 2012  Hobbyist General Artist
Well, I assumed it was the posterior-most cervical which may or may not be a valid assumption. If it was more anteriorly placed then it could definitely be larger :)

The width of the posterior end of the centrum decreases substantially as you go anteriorly in the cervical series of Malawisaurus for instance. There the posterior end of the centrum is about 16.5 cm in the 13th cervical and 12.5 cm in the 11th cervical.

Unfortunately, I do not have posterior view photos of all the Perot cervicals, so I can't tell whether this substantial decrease holds true for Alamosaurus or not. As reconstructed in my skeletal, the posterior most cervical is about 37.7 cm wide, so interpolating from Malawisaurus the 11th cervical might be roughly 28.6 cm wide. If the Fowler and Sullivan cervical turned out to be the 11th instead of the 13th one, than maybe that individual would have been just under 30 meters long and roughly 100 tonnes. This is why I said at the end of my description above that "All sizes are approximate due to the fragmentary nature of the specimens, and are subject to revision upon discovery of more complete specimens." ;)
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:iconfragillimus335:
Fragillimus335 Featured By Owner Dec 24, 2012  Hobbyist General Artist
Cool! Thanks for the explanation!
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:icontyrannosaurusprime:
TyrannosaurusPrime Featured By Owner Dec 23, 2012
Strange, for some reason I thought that the largest specimen would exceed 30 meters long. Oh well.:P Great job anyway. ;)
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:iconpalaeozoologist:
palaeozoologist Featured By Owner Dec 23, 2012  Hobbyist General Artist
Thanks! So did I, but when I went to scale it, it came out to just under 27 meters. Alamosaurus appears to have had an average length neck and shorter tail proportionally compared to some other titanosaurs, which is probably why it is not as long as expected.
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