Any idea what this could be? Interesting shaped piece of what appears to be reptile bone from Big Brook, NJ. About half an inch long.

[TRexEliot]

Found this morning at Big Brook. I believe it's reptile bone, as I can see cancellous bone on the inside where it's broken. Any ideas what it might be?

 

 

 

 

Edited yesterday at 04:41 AM by TRexEliot

[Anomotodon]

Very cool find!! I actually think this is from a shark - specifically, a rostral node, basically the snout of the shark. I believe rostral nodes are typically diagnostic, but I’m not very familiar with them, since they rarely fossilize.

 

Here is an example -

 

[Fossildude19]

@frankh8147  @Carl

 

It does look more like fossil cartilage than bone. 

[TRexEliot]

@Fossildude19 I don't think it's cartilage, but I could be wrong. The broken end shows what looks like spongy cancellous bone, which I don't think would be present on cartilage?

 

@Anomotodon I definitely see the resemblance, but I'm having trouble finding more pictures to get a better sense of the range of shapes they can come in. The "underside" (for lack of a better word, since I don't know the orientation) of this one has two pronounced ridges that form a saddle between them, while the same area on the one you showed doesn't seem to have any structure.

[Anomotodon]

5 hours ago, TRexEliot said:

@Fossildude19 I don't think it's cartilage, but I could be wrong. The broken end shows what looks like spongy cancellous bone, which I don't think would be present on cartilage?

 

@Anomotodon I definitely see the resemblance, but I'm having trouble finding more pictures to get a better sense of the range of shapes they can come in. The "underside" (for lack of a better word, since I don't know the orientation) of this one has two pronounced ridges that form a saddle between them, while the same area on the one you showed doesn't seem to have any structure.

Typical shark cartilage consists of prismatic structures, but sharks also have some skeletal elements that can be ossified and resemble bone. For example, vertebrae and some skull parts.

 

Those ridges on the edges of the supposed dorsal side also seemed weird to me. Most descriptions of fossil rostra I found are from Cenozoic large lamnids, which definitely wouldn’t fit your specimen. Considering the size I assume it could be from a small odontaspidid or perhaps orectolobiform, squatiniform or some other benthic species. Maybe @Al Dente could weigh in?

[Carl]

9 hours ago, Fossildude19 said:

@frankh8147  @Carl

 

It does look more like fossil cartilage than bone. 

I'm seeing bone there rather than cartilage, especially if this is a chondirchthyan.

 

I'm also not seeing a shark snout. But I have no good ideas here. Intriguing specimen!

Edited 9 hours ago by Carl

[Ivaldir]

Just to open it up: if the age fits, consider part of a skull base or dorsal part of a vertebra (where the arcusses meet and start to form the proc. spinosus). 

[Al Dente]

4 hours ago, Anomotodon said:

Typical shark cartilage consists of prismatic structures, but sharks also have some skeletal elements that can be ossified and resemble bone. For example, vertebrae and some skull parts.

 

Those ridges on the edges of the supposed dorsal side also seemed weird to me. Most descriptions of fossil rostra I found are from Cenozoic large lamnids, which definitely wouldn’t fit your specimen. Considering the size I assume it could be from a small odontaspidid or perhaps orectolobiform, squatiniform or some other benthic species. Maybe @Al Dente could weigh in?

 

I think the texture is wrong for this being a shark rostral node. Here are a couple close up photos of one of my Yorktown Formation rostral nodes.

 

 

[Rockwood]

Any chance it could be a tumbled plate from a turtle shell?

[TRexEliot]

@Al Dente Yeah, I definitely agree after seeing that close-up. The texture looks like reptile bone to me in hand. It's hard to photograph the vesicles, but there is spongiform bone exposed on the broken end as well as on the corners where it's a bit worn.

Edited 1 hour ago by TRexEliot

[TRexEliot]

@Rockwood I don't think turtle shell. I could definitely imagine some sort of turtle bone, but it's mostly intact except for the one broken bit were it's very narrow and round. No idea what part of a turtle shell would look like this. Some kind of skull/vertebral element seems possible...

Edited 5 hours ago by TRexEliot