Unknown Chesapeake Bay fossil

[SallyB]

Hi all! I could use some help IDing this fossil (thanks in advance for any insights!). Found on a beach in Maryland (nearish Calvert Cliffs). Could be a tooth (?), ~1in long, has a 'midline' on one side and 4 knob-like 'roots' on the bottom. Not conical but tapers to a point. Pics are front, back, and side.

 

 

[caldigger]

It's a fish hyperostotic bone aka: Tilly bone.

[Rockwood]

22 minutes ago, caldigger said:

hydrostatic bone

?

 

[daves64]

I think @caldigger meant Hyperostotic bone (or something similar). 

[caldigger]

Ya sorry my phone auto-corrects when I hit send.  Usually with something completely different from what I meant. 

[Rockwood]

Ah! The auto error feature. Isn't technology great ?  

[daves64]

Auto correct's real name is actually "Auto Not Really Correct, But It's A Feature On Your New Phone, So Deal With It". But for some reason, they didn't think that would sell very well, so they shortened it.. Something about being too wordy I guess.  

[b. bartron]

Often refered to as a tilly bone. Which i believe is a misused term for a lot of fish bones. I could be wrong but i thought tilly bones are actually the deformed parts of bones (mostly associated with verts) that doesnt deteriorate like the rest of the bone and often found as small pieces. Anyone have thoughts about this. What to correct my train of thought?

[SallyB]

Thanks everyone for the helpful insight! I had never heard of "tilly" bones (I study extant mammals and know little about fish or fossils). After talking to my ichthyologist friend, it sounds like hyperostotic bones in fish are caused by abnormal and often excessive bone growth but are not necessarily linked to a specific bone. They are relatively common in fossil and extant fishes and are most commonly linked to verts, ribs, and cranial bones (so yep, @b. bartron you're pretty much spot on). 

[caldigger]

13 hours ago, daves64 said:

they didn't think that would sell very well, so they shortened it.

You mean they "corrected" the nomenclature?!