Holden Beach Large Bone ID?

[Spr]

Found almost fully submerged in the wet sand beneath the waves of Holden Beach. It was found within newly replenished sand from dredging that’s occurring currently a couple miles off the coast. Very heavy and dense(1.257kg), porous of course and it’s not perfectly symmetrical at any angle I view it from. I’d guess some whale bone but I know very little about fossils. There’s also tens of thousands of Hardouinia Mortonis (PeeDee Cretaceous) coming up through the dredge pipes if that helps in any way. 
Longest length ≈ 15cm

Longest width ≈ 10cm

Longest depth/height ≈ 8cm

Narrowest depth/height ≈ 3cm

Any help is appreciated, thanks. Also vinegar to try and clean the barnacles and such off?

[SawTooth]

Probably a fragment of whale joint bone.

[FranzBernhard]

Lovely recent epibionts, especially the coral !
Franz Bernhard

[Plax]

If the modern epis were Cretaceous that would have helped with this nondescript bone. I wouldn't clean it because to me it is far more interesting with the epifauna. To each his own though of course. The third shot looks concave like the end of a vert  but some limbs can look like that as well.

[pachy-pleuro-whatnot-odon]

From this post it seems that much of the dredged material is Cretaceous in age. And, in fact, the bone does looks quite heavily mineralised and has a dense bone structure, so definitely a marine species. If indeed Cretaceous, I suspect mosasaur may be a candidate, although that would be a huge specimen. Arguing in favour of this interpretation, however, is that whale vertebrae, as I understand, are amphiplatian - i.e., having two flat ends (see diagram below; source) - whereas mosasaur vertebrae are procoelous, having one concave and one convex end. Same goes for crocodiles, by the way.

 

 

And as @Plax rightly pointed out, the surface in the third photograph does look like the concave end of a vertebra. Not only that, the second photograph suggests there's a convex end on the left-hand side. Compare to the below specimen, which has been variously identified as either mosasaur but more likely crocodilian.

 

 

I therefore suspect this is a reptile vertebra. But whether it's a mosasaur or a crocodile - or, in fact, whether reptile at all - I find hard to say with certainty. Still, a very cool find. And, as has been mentioned before, the epifauna make this a really interesting piece - probably more so than a clean bone in and of itself, since it's not likely to be fully identifiable anyway. I too would just leave the epifauna on

[Plax]

There are modern and Pleistocene fossils being pumped on the beach also so it's tough without seeing the bone in person. I agree with your analysis of course Pachy.

[pachy-pleuro-whatnot-odon]

12 minutes ago, Plax said:

There are modern and Pleistocene fossils being pumped on the beach also so it's tough without seeing the bone in person. I agree with your analysis of course Pachy.

 

Wow! This beach is getting more and more confusing by the moment/post!

First @hemipristis explains that the site is mixed Cretaceous/Pliocene depending on what's carried out by the rivers, but that vertebrate finds there are most likely Cretaceous. Then @sixgill pete states that most of the material found is dredged Cretaceous Peedee Formation. And now you're telling me Pleistocene material is also pumped onto the beaches there? If all three statements are correct, this means you've got one huge palimpsest situation, making it very hard to ID certain similar-looking fossils being found there...

[Plax]

Hemipristis is accurately quoting the literature for the region and not specifically the dredge sediment. Sixgill is correct in that most of the material on the beach is from the Peedee. I'm providing my first hand observations of the material on the beach. The region is rife with scour and valley fills of neogene formations filling depressions in the Cretaceous Peedee. What we are seeing on the beach is a sample from a specific stretch of seafloor. The modern shell collectors are going nuts there by the way. 

[JohnJ]

8 hours ago, pachy-pleuro-whatnot-odon said:

I suspect mosasaur may be a candidate, although that would be a huge specimen.

 

8 hours ago, pachy-pleuro-whatnot-odon said:

But whether it's a mosasaur or a crocodile - or, in fact, whether reptile at all - I find hard to say with certainty.

 

If mosasaur, it would be a huge vertebra, indeed.  The erosion makes an identification difficult.  Some characteristics look like reptile bone preservation; others don't.  I expect mosasaur bone to be more consistently solid.

 

Large eroded mosasaur vertebrae I have found typically retain their relative proportions.  So, it would be very unusual (but not impossible) to find a such a difference in diameter between the articulating surfaces.  The proportion of the length to width (diameter) also seems too extreme.  These features and the lack of more solid calcite mineralization point me away from reptile bone.

 

Another possibility could be the dense bone of a mammal acetabulum.  A broken and eroded acetabulum could present in a similar manner.

[fossil_lover_2277]

My first reaction was mosasaur, the shape is right for it, and it certainly has that black color of a lot of the PeeDee material. But the others are right it would be a monster mosasaur. 

Edited April 30, 2022 by fossil_lover_2277

[pachy-pleuro-whatnot-odon]

5 hours ago, fossil_lover_2277 said:

But the others are right it would be a monster mosasaur. 

 

That having been said though, I recently saw a well-preserved post-pygal this size - i.e., with the articular surface the size of an adult male hand - so mosasaurs definitely grew this big...