Unusual Bone Fragment - Brook Bay, Isle of Wight

[GeschWhat]

Hi All,

I picked this up online because it looked unusual. After looking at it under the microscope, I'm thinking part of a fish skull or jaw. Any thoughts?

Edited August 10, 2016 by GeschWhat

[GeschWhat]

Here are some microscopic views.

[Fossildude19]

Any idea where it is from?

[JohnBrewer]

I've found fish bits from Yaverland. Any idea which pat of the IoW it came from?

[GeschWhat]

All I know is Brook Bay, Wessex Fm.

Edit: The seller thought it was gastropod eggs on a dinosaur bone...but I figured that was unlikely. It just peaked my interest and I wanted to see it under the microscope.

Edited August 9, 2016 by GeschWhat

[The Jersey Devil]

I don't have an exact ID for it, but it kind of looks like shark cartilage.

[GeschWhat]

I don't have an exact ID for it, but it kind of looks like shark cartilage.

I did look at some cartilage online, but looked quite a bit different. Can shark cartilage stick straight up? I'm so far out of my element here. The lighter brown that you see is matrix. I cleaned some of it off along the edge and it exposed a series of little cylindrical protrusions with rounded tops. the do not touch one another. Most that were not protected by matrix are broken off.

[PFOOLEY]

I have seen Cretaceous turtle shell that had similar cylindrical protrusions...figure 9 in this paper is not the best reference, but the closest representation of the bits I have seen.

[GeschWhat]

I have seen Cretaceous turtle shell that had similar cylindrical protrusions...figure 9 in this paper is not the best reference, but the closest representation of the bits I have seen.

Thanks, PFOOLEY! That is an interesting possibility. I have come across specimens similar to those in figure 9. While I don't think this completely matches, this could be a different species of turtle. It is something worth looking into. Thank you so much for the paper!

[fossisle]

Looks to me like the grinding surface on a Ratfish jaw

[GeschWhat]

Looks to me like the grinding surface on a Ratfish jaw

Do you happen to have a close-up photo of the grinding surface of a Ratfish jaw? I couldn't find anything decent online for comparison. I cleaned off the matrix around a couple more of the protrusions, but hesitate to do more because they fracture so easily (I lost two in the process).

[jacob]

Looks like a partial Chimera Dental plate?

[GeschWhat]

Looks like a partial Chimera Dental plate?

Is that the same as a rat fish?

[Auspex]

I also think ratfish/chimera.

[GeschWhat]

Thanks, guys!

[Carl]

Have you looked at Naomichelys?

[GeschWhat]

Have you looked at Naomichelys?

I just looked up Naomichelys. The photos in Figure 7 of this paper look very much like what I have. I had also looked back at some of the old posts on the subject of chimaeras trying to find a photo that matched what I have. In one post I saw that someone had suggested David Ward as an expert on the subject. Small world, I just happened to have met him this last year (as he is also a fan of coprolites). So I shot him an email. He does think it looks like a fragment of a chimaeroid tooth plate. He thinks the "matrix" I cleaned off is actually dentine...oops . He also felt the provenance was off because the Wealdon is freshwater. It is his belief that it actually originated "from the Aptian around Compton Bay a mile or so to the NW."

All that said, even though it looks more like Naomichelys, I think I will go with chimaera ID. Thanks everyone for all of your input. I really had no idea where to begin looking. I had never heard of any of names you all suggested. It is hard make headway googling "fishy looking bone with cylindrical protrusions." Thanks to all of you I learned a lot!

Auspex, any chance you could change/add tags as appropriate?