Joined: Fri Feb 24, 2006 1:20 am Posts: 2649 Location: Southern California, U.S.A.
It would be interesting to know if this observation might help the separation of the bones of land-living dinosaurs from the like bones of those which were water-living, on the basis of relative bone porosity in specimens of approximately the same mass
It may be splitting hairs but experts say there were no aquatic dinosaurs because all sauropods were terrestrial. Wiki says:
"Many prehistoric animals are popularly conceived of as dinosaurs, such as ichthyosaurs, mosasaurs, plesiosaurs, pterosaurs, and Dimetrodon, but are not classified scientifically as dinosaurs. Marine reptiles like ichthyosaurs, mosasaurs, and plesiosaurs were neither terrestrial nor archosaurs; pterosaurs were archosaurs but not terrestrial; and Dimetrodon was a Permian animal more closely related to mammals. Dinosaurs were the dominant terrestrial vertebrates of the Mesozoic, especially the Jurassic and Cretaceous."
But that begs the question of whether there's a bone density difference between sauropods and prehistoric aquatic reptiles. I haven't been able to find any information on that.
I think a question of equal importance is how did bone density figure into supporting such massive animals on land? The paper above questions the traditional belief that many of the huge creatures solved the mass/gravity problem by spending most of their time in water.
Joined: Fri Oct 30, 2009 9:19 pm Posts: 591 Location: Las Vegas, NV
Well, I call the individual sections of color 'cells' and will continue to call them 'cells'. You can call them whatever you deem biologically appropriate.
Perhaps we need a resident Paleontologist to give us the answers we are looking for in determining whether the animal was aquatic or land living. I know of some dino bone that has been identified right down to the specific species of former animal. I'm fairly confident that in this day someone could examine the 'cell' structure of a certain dino bone and narrow it down pretty close to what it was 150 million years ago. One might help narrow down a possible species suspect list down by noting that most, if not all available "gem" material is found in the Utah/ Colorado area made of a sedimentary formation from the late Jurassic. If the area was never under water, such as was my area of Southern Nevada, it's likely that none of the gem bone you see is from an aquatic creature. I've done quite a bit of research online about gem bone, but haven't seemed to find much detailed information. There are a few books written on the subject, perhaps I need to find them.
..... how did bone density figure into supporting such massive animals on land? The paper above questions the traditional belief that many of the huge creatures solved the mass/gravity problem by spending most of their time in water.
Not sure - and there may be different perspectives on this. Until recently the largest *saur was Diplodocus I think and that, I was taught in school, was semi-aquatic (say like a hippo?). However, the Tyrannosaurus would surely have wasted its time in the water. Sadly, my education never ran to the finer points of differentiation of one *saur from another. But we return, don't we?, to the central point that the size and spacing of the voids may tell us something about the environment in which a creature evolved to spend most of its time in. Also, if the shape of the voids is in any way indicative of species and/or bone function.
Last edited by Kerensky on Thu Oct 06, 2011 8:14 pm, edited 1 time in total.
Interesting - more for what it does not say than what it does. 'Song birds' spend relatively little time on the wing and most of it hopping about on the ground, pulling worms, grubs and insects out of holes. Now, compare that existence with that of an albatross - which may remain airborne for days/weeks on end, planing for most of that and not even landing to feed.. Albatross is a big bid and getting airborne is a strain and requires favourable conditions, not normally found mid-ocean. I can see that a small land-based bird might need bones similarly strong to those of a rodent of of the same sort of size. Bone *shape* though is another matter
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