Found this little thing a few years ago in a stream where Eocene Manasquan Formation is exposed (although I can't entirely rule out Kirkwood Fm). The four possibilities that I see are 1) ray tail spine barb, 2) fish fin spine, 3) crab claw pincer, or 4) jaw. This doesn't look like any of the ray barbs or crustacean pincers that I have collected so I am leaning towards 2 or 4. While the color/texture looks similar to the Eocene material from this site, it could be modern. What do y'all think?