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Baurusuchus? albertoi by bLAZZE92 Baurusuchus? albertoi :iconblazze92:bLAZZE92 70 17 Giant ape by bLAZZE92 Giant ape :iconblazze92:bLAZZE92 33 28 The size of Ursus ''maritimus tyrannus'' by bLAZZE92 The size of Ursus ''maritimus tyrannus'' :iconblazze92:bLAZZE92 23 25 Body size in Indarctos spp. by bLAZZE92 Body size in Indarctos spp. :iconblazze92:bLAZZE92 34 12 Arctotherium angustidens by bLAZZE92 Arctotherium angustidens :iconblazze92:bLAZZE92 52 13 Explosion-born reptile (Ekrixinatosaurus novasi) by bLAZZE92 Explosion-born reptile (Ekrixinatosaurus novasi) :iconblazze92:bLAZZE92 38 22 Some big creodonts. by bLAZZE92 Some big creodonts. :iconblazze92:bLAZZE92 82 36 Giant beasts duo by bLAZZE92 Giant beasts duo :iconblazze92:bLAZZE92 34 8 Daeodon shoshonensis by bLAZZE92 Daeodon shoshonensis :iconblazze92:bLAZZE92 145 35 Barinasuchus arveloi by bLAZZE92 Barinasuchus arveloi :iconblazze92:bLAZZE92 39 25 Fasolasuchus tenax skull by bLAZZE92 Fasolasuchus tenax skull :iconblazze92:bLAZZE92 55 65 Arctodus simus: The short-faced bear. by bLAZZE92 Arctodus simus: The short-faced bear. :iconblazze92:bLAZZE92 82 48

Activity


Baurusuchus? albertoi
Many years later and after starting from scratch several times I have finally finished this skeletal. Missing elements after Baurusuchus salgadoensis, Aplestosuchus sordidus and Stratiotosuchus maxhechti. Good thing is that after overcoming the hurdles I had with this one, there are no more excuses to quickly finish the other croc I was working on.






References:

Carvalho et al. (2005) Baurusuchus salgadoensis, a New Crocodylomorpha from the Bauru Basin (Cretaceous), Brazil. Gondwana Research. Volume 8, No. 1, pp. 11-30.

Nascimento (2008) Descrição morfológica e posicionamento filogenético de um Baurusuchidae (Crocodyliformes, Mesoeucrocodylia) do Cretáceo Superior da Bacia Bauru, região de General Salgado. (Dissertação de Mestrado). Universidade de São Paulo, Brasil, 274.

Vasconcellos et al. (2007) The locomotion pattern of Baurusuchus salgadoensis Carvalho, Nobre & Campos, 2005 and the distribution of Baurusuchidae in Gondwanaland. Nature Precedings : doi:10.1038/npre.2007.808.1

Nascimento & Zaher (2010) A new species of Baurusuchus (crocodyliformes, mesoeucrocodyliA) from the upper cretaceous of Brazil, with the first complete postcranial skeleton described for the family Baurusuchidae. Papéis Avulsos de Zoología. Volume 50(21):323‑361.

Riff & Kellner (2011) Baurusuchid crocodyliforms as theropod mimics: clues from the skull and appendicular morphology of Stratiotosuchus maxhechti (Upper Cretaceous of Brazil). Zoological Journal of the Linnean Society 163: S37–S56.

Nascimento & Zaher (2011) The skull of the Upper Cretaceous baurusuchid crocodile Baurusuchus albertoi Nascimento & Zaher 2010, and its phylogenetic affinities. Zoological Journal of the Linnean Society 163: S116–S131. 

Godoy et al. (2014) An Additional Baurusuchid from the Cretaceous of Brazil with Evidence of Interspecific Predation among Crocodyliformes. PLoS ONE 9(5): e97138. doi:10.1371/journal.pone.0097138
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Ursus “maritimus tyrannus”

Described and named in Kurten (1964), it consist of a lone ulna found near Kew Bridge, London, catalogued as BM 24361. The ulna is missing the distal epiphysis which Kurten (1964) interpreted as a sign of the specimen being sub-adult, even with said piece missing the ulna is about 440mm long and it was estimated that it would have been 485mm long when complete.  On plate 2 of his paper, Kurten compared BM 24361 with a large sub-adult polar bear (UZI 3) and here I do the same.

Bones by bLAZZE92


On the face of it BM 24361 is a giant, 13.3% longer than UZI 3 and the maximum proximal diameter corroborates that measurement but looking at the rest of the measurements something does not add up, the notch that articulates with the humerus is only 8% greater while the minimum diameter of the shaft is only 3% greater, in fact, in table 3 of Kurten (1954) we find a recent polar bear that has a thicker ulnar shaft than that of BM 24361 and this ulna was even shorter in length than that of UZI 3 (410mm) there is also an ulna of a cave bear, 383mm long, that not only has diameter of its semicircular notch 14% greater than that of BM 24361, its ulnar shaft is 14% thicker too. We can also compare this ulna with those from Indarctos spp., the ulna of the I. atticus from Pikermi has a shaft 5% thicker and while it doesn’t beat it in maximum proximal diameter, I. oregonensis does and by 5% too.

Comparing the measurements between UZI 3 and BM 24361 we find that that of the later appears to have a shaft that is from 2% to 7% longer proportionally speaking depending if we are comparing their total or their functional lengths, why the difference? because UZI 3 has a considerably more developed olecranon process that is greater even in absolute terms (~55mm vs ~65mm, measured from Kurten 1964 figures following Sorkin 2006),  the olecranon process of BM 24361 is also less developed both in relative and absolute terms than that of FMNH 63802 (Sorkin, 2006) the big brown bear I mentioned in the first part, the implications of this is something I will not touch in here.

I don't know if you noticed that I wrote maritimus tyrannus with quotation marks, this is because while not necessary intended as a taxonomic revision, Ingolfsson & Wigg (2008) mention that scientists at London’s Natural History Museum have restudied the fossil of U. m. tyrannus and are confident that it is not a polar bear but a brown bear, citing a personal communication with Andy Currant in 2008.  To estimate the body dimensions of of U. m. tyrannus and don’t let the length of the ulna alone produce an overestimation I’ll use the geometric mean of all the measurements between it and UZI 3 which I chose because of the measurements and figures of it in Kurten (1964), unknown measurements will be scaled from UAM 16545 (Matheus, 2003), at last I'll tweak the resulting limb lengths to the proportions of brown bears. Why such a convoluted procedure? because I couldn't find any paper that has photos and more than two measurements of an ulna of a brown bear along with measurements of the rest of its bones, still, I’ll too only scale up using just the functional length of the ulna compared to a big brown bear.

The geometric mean of how much larger is BM 24361 than UZI 3 is 5.1%, in the end the functional lengths of the scapula, humerus and radius I estimated are 340mm, 430mm and 389mm respectively, this amounts to 115.9cm which means in a shoulder height of 122cm for the bones in articulation plus flesh and skin based on the ratios of this measurement in my Arctodus skeletal. The upper estimate is just an isometric scaling of how much longer is the functional length of BM 24361 than the ulna of FMNH 63802, estimated functional lengths for the scapula, humerus and radius of this version are 392mm, 495mm and 389mm, respectively, this amounts to 127.6cm and to a shoulder height of 134cm estimated in the same way as before. 

The shoulder height range I estimated (122-134cm) represent a massive animal but they are a far cry from those 180cm+ shoulder heights floating in the internet, of course there’s also the question The size of Ursus ''maritimus tyrannus'' by bLAZZE92

of what are the implications of a sub-adult being this big, could this bone still indicate the existence of giant population of Pleistocene brown bears?  I'm inclined to say no, I'm not aware of any other true giant Pleistocene brown bear fossils.

Notes:

I didn't take almost 3 weeks to do this, I just didn't had time.

References

Ingólfsson, Ó. and Wiig, Ø. (2008). Late Pleistocene fossil find in Svalbard: the oldest remains of a polar bear (Ursus maritimus Phipps, 1744) ever discovered. Polar Research 28 (3): 455-466

Kurtén, B. (1964). The evolution of the polar bear, Ursus maritimus (Phipps). Acta Zoologica Fennica 108: 1–26.

Matheus, P. E. 2003. Locomotor adaptations and ecomorphology of short-faced bears (Arctodus simus) in eastern Beringia. Occasional Papers in Earth Sciences No. 7.

Merriam, J. C., Stock, C. and Moody, C. L. (1916). An American Pliocene bear. University of California Publications Bulletin of the Department of Geology, 10 (7): 87-109.

Roussiakis, S. J. (2001). Postcranial remains of lndarctos atticus (Ursidae, Mammalia) from the classical locality of Pikermi (Attica, Greece), with a description of the front limb. Senckenbergiana lethaea 81(2), 347-358.

Sorkin, B. 2006. Ecomorphology of the giant short-faced bears Agriotherium and Arctodus. Historical Biology 18:1–20.


Comments


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:iconanonymousllama428:
AnonymousLlama428 Featured By Owner Oct 10, 2018  Hobbyist General Artist
You see anything wrong with this? comments.deviantart.com/1/7631…

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:icondinopithecus:
Dinopithecus Featured By Owner Sep 6, 2018
Do you happen to know the average size of known P. onca augusta specimens from North America?
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:iconalmostthere99:
Almostthere99 Featured By Owner Jul 26, 2018
profile pretty good but I see to many mexico-related things here.

6/10
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:iconanonymousllama428:
AnonymousLlama428 Featured By Owner Jul 16, 2018  Hobbyist General Artist
Hello,

Looking at your work, you seem to be familiar with the brown bears of Pleistocene Europe.
I have a little (or big) query, if you don't mind answering.
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:icon105697:
105697 Featured By Owner Jul 16, 2018
Hello there.

I was wondering if you know the regression equation to find carnivoran mammal masses based off limb bones (humerus, femur, etc), and if you do know the equation, what would all the variables of the equation mean?
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:iconblazze92:
bLAZZE92 Featured By Owner Jul 22, 2018
There are many regression equations published, they vary based on the sample, the best would those using data from animals that we have both, their weight and life and skeleton measurements. Is there any particular carnivoran group you are interested in? that way I can share equations based on just that group, that'll be better than a generalized equation based on all sorts of carnivorans. 
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:icon105697:
105697 Featured By Owner Jul 23, 2018
Okay.

The particular carnivoran group in question that I am interested in are felids.
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:iconblazze92:
bLAZZE92 Featured By Owner Jul 25, 2018
Here's a link to Christiansen and Harris (2005), which I think has the best equations so far, given how they are based on animals that were weighted at dead and then had their bone measurements taken. 

The equations are in table 2 for the forelimb and table 3 for the hindlimb, there are lots of them based on several measurements, those with the lowest %SEE and %PE values are the best.
Reply
:icondinopithecus:
Dinopithecus Featured By Owner Jul 10, 2018
Hmm, while I'm waiting for the size comp. there was another thing I was wondering (since you also seem to be knowledgable on this).

Just how healthy are the Inuit? I understand that they may not be the epitome of human health, but are they really unhealthy as a result of their largely carnivorous diet? Come to think of it, how much healthier is a vegan/vegetarian diet compared to a meat eating one?
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:iconblazze92:
bLAZZE92 Featured By Owner Jul 18, 2018
Here's size comparison. 

My nutrition library is rather small but I do remember reading that the Inuit traditionally were very healthy, here's an article from 2004 on the topic. As for the better diet, seems like the answer is "depends", at least going by this meta-review, it's more important that the diet excludes processed foods rather than exclude any food group in particular.
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