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RE: # of bones in Amargasaurus
skull- 2 each of- premaxilla, maxilla, nasal, lacrimal, jugal, quadratojugal,
prefrontal, frontal, parietal, postorbital, squamosal, exoccipital-opisthotic,
prootic, laterosphenoid, orbitosphenoid, stapes, quadrate, pterygoid,
ectopterygoid, palatine, vomer
1 of- supraoccipital, basisoccipital, parabasisphenoid
lower jaw- 2 each of- dentary, splenial, surangular, angular, prearticular,
articular
2 hyoids, ~20 sclerotic plates
neck- 2 proatlases, 13 cervical vertebrae, 24 cervical ribs (the first vertebra
doesn't have any)
back- 9 dorsal vertebrae, 18 dorsal ribs
1 fused sacrum
tail- ~77 caudal vertebrae, ~47 chevrons
pectoral girdle- 2 each of- scapula, coracoid, interclavicle, sternal plate
1 of- interclavicle
~10 sternal ribs, ~4 gastralia
forelimb- 2 each of- humerus, radius, ulna, carpal, manual ungual
10 metacarpals, 10 manual phalanges
pelvis- 2 each of- ilium, pubis, ischium
hindlimb- 2 each of- femur, tibia, fibula, astragalus, calcaneum
10 metatarsals, 18 pedal phalanges, 6 pedal unguals
So a final total of ~373 bones, ignoring teeth. The number's not exact because
we have only one incomplete skeleton of Amargasaurus, so e.g. the tail count is
based on Janensch's (1936) reconstruction of the related Dicraeosaurus, the
skull, hands and feet on other diplodocoids, and the pectoral area on the very
new Tschopp and Mateus (2013) study available online-
https://urldefense.proofpoint.com/v2/url?u=http-3A__onlinelibrary.wiley.com_doi_10.1111_joa.12012_pdf&d=CwIFAw&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=x82f3Wlkwtmbr1z8IAt9jA&m=op2vES4uQfRBnkzA8oh58RZIeAWRDSksRD90fMHLsus&s=q_7CFH_uyFlhCYNiphQ_YRUCkD4ASRSgQ1twqp70T7Y&e=
. Also, as dinosaurs grow they fuse more bones together, so in sauropods
like Amargasaurus, the cervical ribs will fuse to the vertebrae, the scapula to
the coracoid, the braincase will fuse together, etc.. Technically, in a young
Amargasaurus, each vertebra is made of two bones- the upper and lower part, and
that sacrum is five vertebrae
and ten ribs. It all makes the idea of an exact bone count impossible, but I
think I gave pretty standard fusion assumptions for a young adult sauropod.
Mickey Mortimer
The Theropod Database-
https://urldefense.proofpoint.com/v2/url?u=http-3A__theropoddatabase.com_&d=CwIFAw&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=x82f3Wlkwtmbr1z8IAt9jA&m=op2vES4uQfRBnkzA8oh58RZIeAWRDSksRD90fMHLsus&s=yWdk1Nc9vcNV-bvpDCz2922fPcICXFub-RGrtHkqMxM&e=
----------------------------------------
> Date: Sat, 20 Feb 2016 09:22:25 -0800
> From: darwinsbulldog@gmail.com
> To: dinosaur@usc.edu
> Subject: # of bones in Amargasaurus
>
> Hello - My 4th grade son is doing a short write up about Amargasaurus
> for school. He would like to know how many bones there are in the
> skeleton of Amargasaurus.
>
> Thanks for the help!
>
> <,,><
>
> Michael D. Barton
> Portland, OR
> darwinsbulldog@gmail.com
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