Piece of what I believe is reptile rib bone from Big Brook, NJ. Bone fibers are very dense - any chance it could be dinosaur?

[TRexEliot]

Found about a week ago at Big Brook.

 

[TRexEliot]

@Carl @frankh8147 @Fossildude19

 

Sorry to bother you guys again! Any thoughts?

[Fossildude19]

 

Bones are really not my thing. Sorry.

[shark57]

I'm not sure that is a rib bone. Could be a partial limb bone.

[TRexEliot]

@shark57 That was my first thought as well. A paleontologist that I emailed suggested rib, but the contour lines felt a bit more limb-like to me initially.

[pachy-pleuro-whatnot-odon]

In the context in which it was found, and the specimen being so osteosclerotic, I'd rather guess marine reptile, in which case rib would indeed be the most logical candidate - though limb bone remains a possibility as well. I'd write this of as chunk-a-saurus.

[TRexEliot]

@pachy-pleuro-whatnot-odon Sorry, I'm not sure I followed your comment completely. Isn't hardness/density of the bone usually a sign of terrestrial rather than marine material? I've always been told that the spongier material is more indicative of marine reptile, while dense, tightly-packed bone fiber is an indication that a piece may be terrestrial

[shark57]

4 hours ago, TRexEliot said:

@shark57 That was my first thought as well. A paleontologist that I emailed suggested rib, but the contour lines felt a bit more limb-like to me initially.

 

[pachy-pleuro-whatnot-odon]

7 hours ago, TRexEliot said:

@pachy-pleuro-whatnot-odon Sorry, I'm not sure I followed your comment completely. Isn't hardness/density of the bone usually a sign of terrestrial rather than marine material? I've always been told that the spongier material is more indicative of marine reptile, while dense, tightly-packed bone fiber is an indication that a piece may be terrestrial

 

One of the problems faced by aquatic animals is to achieve neutral buoyancy, so that they neither sink to the sea floor, nor float to the top of the ocean. To do this they increase the weight of their bones. For this, there are two strategies, either increasing the thickness of the bone cortex in a process called pachyostosis, or increasing the density of bone fibre in a process known as osteosclerosis. If both conditions occur simultaneously, this is known as pachyosteosclerosis, which is what's seen in most secondarily aquatic creatures.

 

The bone being spongier would allow for it to be lighter, as there's more room for air, therefore making it less likely to belong to a secondarily aquatic creature and more likely to be a larger terrestrial animal, who often incorporates air pockets in their bones to lighten them. This is taken to the extreme in animals like pterosaur - which bones are thin-walled and almost completely hollow - and sauropods - which have a lot of air sacks in their bones. The latter is where Camerasaurus gets its name...

[Carl]

I wouldn't go past IDing this is merely a bone fragment, likely reptile.