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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, 
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- 
  .  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- 

> 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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