Strange Concretions And A Shark Tooth

[Shellseeker]

I was at a different location than normal. Usually I stick to the Peace River. I was digging in 75% fossil seashells and 20% gravel. I picked up an odd concretion... and then a 2nd, 3rd, 4th, 5th, etc of similar size. What is this?

I was finding a lot of turtle fossils a few armadillo osteoderms, and small shark teeth (Mako, Hemi, Bull, Dusky and Lemon) and then this tooth. In the Peace, I sometimes find a tooth that looks like this and think it is not a Meg -- I will be pleased if this one is not a Meg. I realize that an ID would be easier if the tooth had a full root.

Thanks for all comments. SS

[calhounensis]

The tooth looks like a great white to me, the 'concretions' are bizarre.

Edited May 22, 2014 by calhounensis

[cowsharks]

The shark tooth in question is definitely an upper Great White (C. carcharias).

Daryl.

[Shellseeker]

The tooth looks like a great white to me, the 'concretions' are bizarre.

The shark tooth in question is definitely an upper Great White (C. carcharias).

Daryl.

YES! YES! YES!!!! This is only the 2nd GW I have found in 5 years of hunting SW Florida. Usually I mis-identify Megs with tiny bourlettes as possible GWs. Thanks for the ID.

[claire01]

I sometimes find things similar to (the appropriately positioned) picture #2 that end up being evidence of fecal material of some sort.

[fossilized6s]

I agree with GW.

And I've found bits of barnacles in the Peace, but these don't look like barnacles to me. IDK?

[Sélacien34]

1/3 Looks to sponges or calcisponges

http://annali.unife.it/museologia/article/viewFile/355/308

4/5 Clearly a GW tooth

Edited May 22, 2014 by Sélacien34

[digit]

As I read down the list of replies after your initial post I can see that I can't answer your question on the tooth but only throw my support behind the GW tooth. I've only one in my collection and it was found on my birthday on a shore dive off Venice. Won't find one this year on my birthday as I'll be up searching for Mazon Creek fossil nodules instead (a good alternative).

Calcisponges are an interesting option to the mystery concretions which I hadn't considered (mainly because I didn't know that these formed such nice specimens in the fossil record as Sélacien34 has shown above). To me the mystery items look more like trace fossils (burrows). They seem to be smoother on the inside than the outside and if they appear to be composed of sand grains and rubble that would lend some weight to this guess. There are a number of segmented words, crustaceans, and other animals that will form mucus lined burrows which will occasionally cement together with calcium carbonate precipitating out of the water to form more lasting structures that can and do "fossilize". Take a look at the inside and outside surfaces with a magnifying glass (or photographers loupe) and see if you can see any regular pore-like patterning which would indicate sponge. Sponges are in the phylum profifera = hole bearing. If the surface Is more irregular than I'd lean more to them being burrows (though calcisponge fossils would be infinitely cooler). My $0.02.

You're up 2 GW to my 1 so I need to get busy now.....

Cheers.

-Ken

[Shellseeker]

Thanks to all the input. I have little/no expertise in these environments that are primarily marine fossil based. Here are a few more up-close photos. A photo of the holes from 2 different examples. The holes are far smoother than the exterior. Also on the 2nd hole I see concentric circles around the top edge especially on the rim of the 2nd hole.

Then a photo of the exterior (clicking on the photo zooms in). While I would love this to be sponge, the exteriors seems like bits of mud, and imbedded materials, more like a burrow than a sponge. That implies a relatively large occupant with a girth like a walnut..

Ken, it seems a little selfish of me when I find so many Megs and Hemis to be so ecstatic on finding a slightly beat-up Great White, but local rarity is the driving force.

[Sélacien34]

Good pictures, that's right, most likely a burrow.

[Jace]

Hey, Nice shark tooth, The other object looks like a Mud-Wasp pot, possibly a very old one?

[digit]

Ken, it seems a little selfish of me when I find so many Megs and Hemis to be so ecstatic on finding a slightly beat-up Great White, but local rarity is the driving force.

I totally agree--I'd have traded my whole bag of fraglodons from my last phosphate quarry dig for even another partial GW. The general rule of thumb seems to be that you find about 20 meg frags for every nice complete meg tooth and I think maybe 1 GW for every 20 complete megs. Another GW is high on my Peace River bucket list. I'm going to try to get out one last time on the Peace this Monday and you know it would make my season to score another GW to keep my first one company.

Cheers.

-Ken

[Miatria]

Congrats on GW!

[JohnnyMorales]

Sélacien34 is right. That's a sponge fossil.

Burrows are cast trace fossils, but you seem to be mixing up the fact that there are animals that create tube shaped shells (like tube dwelling snails and tube worms) with a cast trace fossil, which definitely is not.

Also you're going to be hard pressed to find many examples of burrow fossils hollowed out so nicely with a definite bottom and completely free standing.

Mud resting against mud would find it extremely difficult to create all those patterns on your fossil sponge.

And there are sponge patterns galore.

The various seemingly random spaced circular shapes are the pores you are looking for. You don't need any magnification to see them. I'd guess they're the size of a pea.

The furrows on the second photo on the right side were the underside of the some of tubes that criss crossed the sponge tissue when it was alive.

There is also a surprising amount of symmetry in the thing, but the fossilization left it less than perfect. If you use some imagination, you can see how the rim of the opening looks like a bunch of little tubes, a few with openings of their own laid side by side and rolled into one big tube.

Because most sponges look like mishappen rocks, and do NOT resemble the pretty, easy to recognize stuff most get completely overlooked as people focus in on the pretty and easy to ID fossils.

Here is a great German site that with really good examples of quality sponge fossils that look like your basic, boring totally not a fossil rock

http://www.kreidefossilien.de/bildergalerien/spongien

You don't have to know German to figure it out, because all you have to do is look at the pictures of the rocks er I mean sponges to see my point. LOL

[Shellseeker]

Sélacien34 is right. That's a sponge fossil.................................

Thanks Johnny (and belatedly to Sélacien34.

I find TFF really fantastic. Here I post an unknown find in May and 6 months later get an insightful and thought provoking identification. Your knowledge and expertise is clear -- I usually leverage a find to increase my knowledge and now I am really curious about these Calcisponges: like what is the fossilization process (like a dugong rib or not), how many thousands or myas were they living, what scientific papers have been written about Florida fossil sponges, and what is the exact type of my sponges..

I have a lot of work to do --- Thanks