Are These Denticles?

[tommcclees]

I have been taking these fossils home for years. It seems like i find one every time i go out. I have asked a few friends, one of whom suggested they might be denticles. They all have similar structures, but they may be slightly different. The lined pattern on the outside always goes the same way. They also have a unique pattern on the inside when you break them open. I have included a picture of the pattern as well in figure D . The two photographs in the middle are of the same fossils, just flipped over on their other side. Can anyone help me identify these pieces? I have been wondering for years!

A)

C)

D)

[Auspex]

Dunno...otoliths?

[cowsharks]

Very interesting that you would continue to find these "things" on your GMR trips. Wonder if other folks have them as well. Anyhow, I was a bit stumped as well until I noticed a little something in your picture C). It looks like a small portion of the denticle "tip" are of a stingray denticle. I outlined it in your pic. Denticles are joined or grouped together it it makes sense that they would have similar shapes so they can "interlock" or be held tightly together. Just an observation.

Daryl.

[Indy]

Locality and geology information please.

[sixgill pete]

tommcclees, iI have found these same things in GMR on numerous occasions and have always tossed them back(maybe you have all of mine ... haha) believing they are just very worn oyster shells. But I guess they could be denticles, never really considered that.

[Auspex]

Locality and geology information please.

Green's Mill Run, Greenville, NC; Cretaceous on up.

[Al Dente]

These are hyperostotic bones (tilley bones) from a bony fish. I'm not sure the type but do know they are attached to either side of the vertebrae. I have found a couple of examples with part of the vertebra still attached. These are found in the upper Yorktown Formation and are common in Green's Mill Run and other localities where the upper part of the Yorktown outcrops.

[tommcclees]

Ok thanks for the help. In researching hyperostotic bones, i came across some other fossils in my collection that resembled them as well.

1a 1b

2a 2b

Are these pieces tilley bones of boney fish as well? All these fossils are from Green Mill Run.(Cretaceous, Miocene, Pliocene)

One important observation that I had made was the markings and coloration inside the broken pieces have the same sort of pattern even though they are shaped differently.

3 4

Edited August 15, 2011 by tommcclees

[Al Dente]

I don't know what photo #1 is but the objects in #2 are tilley bones and #3 and 4 look like tilley bones with broken surfaces. If you take a whole one from your original photos and break it open you will see growth rings and if you use some magnification you will see some vascular canals running through the bone. An interesting bit of trivia (interesting to me anyway) is that most teleost fish bone is non-cellular but if it becomes hyperostosed, the hyperostosed part will have cellular structure. Many modern species of jacks will develop tilley bones.

[Indy]

Hyperostotic bones (Tilly bones) are known in many different shapes and sizes.

I've been told that Tilly bones are so common in certain areas of Florida

that many collectors no longer even pick them up.

Several years ago I went on a quest to find information about 1 specific shaped

hyperostotic bone (Tilly bone). The project died on the vine, however, the web page

is still on-line. Maybe someday I will resume the quest.

Anyway, I believe all will agree the featured specimen (views 1-8)

showcases a "Gem Quality" specimen.

Link: Click Here

Barry

[Indy]

tommcclees... I know what you may be asking yourself

at this point.

OK, these fossils (you have been collecting for years) are

hyperostotic bones (Tilly bones) from a bony fish. However,

there are so many that look like kissing cousins…they must

have come from a fairly common species. You may be wondering

if any have been found in association with complete or even

partial skeletons? If so, then it may be possible to associate

the Tilly bones you have found with at least a few fish existing

in the fossil record during the same time period of the site you

have been collecting all these years.

Good Luck!

[tommcclees]

it may be possible to associate

the Tilly bones you have found with at least a few fish existing

in the fossil record during the same time period of the site

Indy,

I'm definitely going to look into that. I probably have a half-dozen different types of Tilly bones in my collection, it would be very interesting to see what kind of fish they originated from. Thanks for your input.

Tom

[mako-mama]

Hyperostotic bones (Tilly bones) are known in many different shapes and sizes.

I've been told that Tilly bones are so common in certain areas of Florida

that many collectors no longer even pick them up.

Several years ago I went on a quest to find information about 1 specific shaped

hyperostotic bone (Tilly bone). The project died on the vine, however, the web page

is still on-line. Maybe someday I will resume the quest.

Anyway, I believe all will agree the featured specimen (views 1-8)

showcases a "Gem Quality" specimen.

Link: Click Here

Barry

Barry,

The fine fossil featured on your webpage is the hyperostosed neurocranium of some fish. It is nearly impossible to identify these further, unless some surface detail is diagnostic of a particular species-such as sea robin. It's not really known what causes bones to hyperostose but it's quite common- even in humans. I've caught fish off the coast of NC that had this condition and amazingly, it wasn't apparent until the meat was removed from the head. In fish, the condition has been seen in every bone, including ribs and vertebrae.

[mako-mama]

Two examples of modern pinfish (Lagodon rhomboides). One has hyperostosed "crest" and the other doesnt.

[Indy]

Barry,

The fine fossil featured on your webpage is the hyperostosed neurocranium of some fish. It is nearly impossible to identify these further, unless some surface detail is diagnostic of a particular species-such as sea robin. It's not really known what causes bones to hyperostose but it's quite common- even in humans. I've caught fish off the coast of NC that had this condition and amazingly, it wasn't apparent until the meat was removed from the head. In fish, the condition has been seen in every bone, including ribs and vertebrae.

Thanks for the ID on the specimen on my web page.

Just did a web search "neurocranium and fish" ... Guess what? Found a post

on our forum back in March 2009 "Fish Brains or?" and that post also had

a link to my Problematic fossil page... Click Here

Mystery fossil posts which end up being identified as Tilly bones seems

to pop-up from time to time here on this forum as well as others. Decided

to start an archive on my computer of all similar posts because this subject

will come up again and then can point to previous posts instead of taking

the same ground over and over again.

Thanks again for your ID and information.

Archived for future reference

Barry

[Auspex]

Good on ya'; Tillys are frequent fliers here

[Indy]

Tillys are frequent fliers here

I'm stealing that "one liner" and will quote you when future

Mystery Fossils (Tilly bones) are posted!

Just used OUR "Site Search" and entered "Tilly" to find previous

"Mystery fossil" posts with Tilly being referenced. The search

returned 2 pages (45 threads)

A year ago I contacted a friend in Florida and he sent me a 30 Tilly bones

he collected. All different sizes and shapes but (of course) they all have

1 thing in common...bilateral symmetry