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Something Uncommon


isurus90064

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While it isn't as impressive looking as a 2" serrated giant thresher :wub: , this is the only one of these teeth I've seen in this condition. It's a Hybodont shark -Lissodus selachos from the Cretaceous of Montana. The rare thing about it is that the root is basically complete. Even Elasmo.com doesn't have a picture of one with a full root. This is about average size for the species

Outstanding Lissodus!! ;)

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Marcel

By chance, do you know of any fossil shark workers who have any work in study attempting to add clarity the "murky at best" confusion re the large threshers? I always thought assignment of these teeth with such varying morphologies to Trigonotodus somewhat of a "stretch". Just my 2 cents. ^_^

Hey FS,

I think David Ward may be writing something regarding large threshers. I can check with him and see what he has to say. David Ward also reported the non-serrated/non-cusped version from Malta and Gozo. I have that paper here somewhere and I will look and see what he is calling it. btw I totally agree with you on Trigonotodus being a stretch, not that there is anything wrong with it, we simply don't have a name that accurately reflects this beasts' lineage yet.

That is a very intriguing tooth!!! The morphology is slightly off from the Somniosis teeth I have seen. That doesn't mean it is not Somiosis of course, just very intriguing, thanks.

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well here are my uncommon finds, 2 Alopias Grandis the larger has serrations on the back of the tooth but cant get a picture of it, a smaller Alopias Grandis and a huge lower desori, they dont get much bigger than this!!!!

bmore .... beautiful teeth!

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Eddie: the Pamunkey tooth is roughly contemporary to the other large serrated tooth and appears to be more of an anterior version. You'd have to take that with a grain of salt until somebody finds an associated thresher like that and if that's me I'll mail it to you asap :-).

That makes sense, for what it's worth I think you're probably correct, anterior tooth. I'm hoping to get some more

of these guys (well, the unserrated ones anyway, money is tight these days :) ), and I'll post them if and when I do. :)

These are not as uncommon as some of the other teeth in this thread, but here are some cow shark teeth:

1) Hexanchus griseus/gigas from Lee Creek (along with Notorynchus for comparison above the hex teeth).

2) Hexanchus gigas from Chile. This one is neat, it has 14 "cones"!

3) Notidanodon loozi from Morocco. Got this one for $50 off of EBay!

Great thread here, I've learned of some species that I didn't even know existed.

Thanks,

Eddie

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Hexanchus griseus/gigas is rare from lee creek, am i right?

Yes, they are much more uncommon than the Notorynchus.

Great giant threshers you found, btw! :o

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Hey FS,

I think David Ward may be writing something regarding large threshers. I can check with him and see what he has to say. David Ward also reported the non-serrated/non-cusped version from Malta and Gozo. I have that paper here somewhere and I will look and see what he is calling it. btw I totally agree with you on Trigonotodus being a stretch, not that there is anything wrong with it, we simply don't have a name that accurately reflects this beasts' lineage yet.

Marcel:

I've got that paper also but don't recall Ward's mention of the threshers from Malta/Gozo. I'll look up the paper. Thanks for the reminder :D

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Guest bmorefossil
Yes, they are much more uncommon than the Notorynchus.

Great giant threshers you found, btw! :o

thanks, i thought so my friend only has one from the mine

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Hey FS, I haven't read the paper I metioned in awhile so I could be wrong. I emailed David Ward and explained that we were wondering about the state of the unio with regards to large threshers, so hopefully we will hear soon.

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Seeing the post of the Somniosus microcephalus posted by Synechodus reminded me that I had such a tooth received some years ago in trade with a collector from the Netherlands. I have posted both lingual and labial views of this tooth.

In truth, I know essentially nothing about this species of shark tooth. I do know the species exhibits dignathic heterodonty and hopefully this explains the difference between this tooth and the one belonging to Synechodus. Since my knowledge of this species is so limited, I will apologize in advance if the identification is incorrect. If so, I will be pleased to correct the identification based on other's knowledge.

Thanks for looking.

FS

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Hi FS,

Sorry for the late reply, I was out hunting for echs myself, today.

Was quite successful once again, but that is something for later.

Rest assured, your ID is OK. The depicted tooth is indeed an upper Somniosus microcephalus. I still hope to find one among my micro material from Antwerp some day. The tooth I depicted is a lower jaw tooth.

So just like you said, this species exhibits dignathic heterodonty, which accounts for the fact that the teeth in both our pictures look so different.

See also attached picture of the dentition of an extant Somniosus microcephalus. which I took from the net.

post-456-1215204925_thumb.jpg

Hope this answers your question.

Cheers,

Paul

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"And the men who hold high places, Must be the ones to start

To mould a new reality, Closer to the Heart"

(Rush, "Closer to the Heart" from the album "A Farewell to Kings")

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here the tooth from Pignan area , France

Isitius triangulus ( Cookiecutter )

is very difficult to find and very fragilehttp://www.servimg.com/image_preview.php?i=2&u=12649368

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..... Synechodus: NICE tooth! I've always know these are rare (from anywhere), how rare are these teeth (and I realize that that a somewhaat subjective question)? How many have you seen and what formation/layer do these come from?......

Found this tooth December 2005 and sofar I have only seen two "in the live" but there are more out there, also from Langenboom/Mill.

Actually, the other one I have seen myself was found on exactly the same day by someone else, before I found mine.

Since I had never seen/found one myself I asked him to show me.

About half on hour later I picked this one from my screen @ first thinking it was a cusp of a Cow. But then it dawned on me and asked the other guy "Is this also one?" There were more people out there that day, most of them coming there for years, never finding one.... go figure.

So I guess being rare is always relative.

As to the formation: it was collected in "ex situ" material sucked from the bottom of one of the docks in the Antwerp harbour so there is no way of telling the exact formation or age. Nonetheless it is most likely of Miocene origin.

Cheers,

Paul

  • I found this Informative 1

"And the men who hold high places, Must be the ones to start

To mould a new reality, Closer to the Heart"

(Rush, "Closer to the Heart" from the album "A Farewell to Kings")

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Found this tooth December 2005 and sofar I have only seen two "in the live" but there are more out there, also from Langenboom/Mill.

Actually, the other one I have seen myself was found on exactly the same day by someone else, before I found mine.

Since I had never seen/found one myself I asked him to show me.

About half on hour later I picked this one from my screen @ first thinking it was a cusp of a Cow. But then it dawned on me and asked the other guy "Is this also one?" There were more people out there that day, most of them coming there for years, never finding one.... go figure.

So I guess being rare is always relative.

As to the formation: it was collected in "ex situ" material sucked from the bottom of one of the docks in the Antwerp harbour so there is no way of telling the exact formation or age. Nonetheless it is most likely of Miocene origin.

Cheers,

Paul

Thanks Synechodus.

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Northern, nice Lissodus, how the heck did you get that picture to turn out like that, with a tooth around 3mm in size ... nice!

No tricks involved. I just set my camera zoom as much as it would go and from there, it was just taking picture after picture until I got one in focus. I wouldn't want to try too much smaller, but here are a couple of similar sized pieces, both relatively uncommon as well.

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There's no limit to what you can accomplish when you're supposed to be doing something else

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Hi all,

Before I got a microscope, I took loads of closeup pictures by securing an 8x magnification eyepiece, from an old pair of binoculars, to my camera, with elastic bands. This allowed me to get within about 2cm of the object. The same can be done using a jewellers loupe. As long as the lenses are clean some great photo's can be achieved this way. If you use a mini tripod, you can set up the picture then, using the self timer to eliminate shake, you can get excellent pic's.

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KOF, Bill.

Welcome to the forum, all new members

www.ukfossils check it out.

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Hi FS,

Sorry for the late reply, I was out hunting for echs myself, today.

Was quite successful once again, but that is something for later.

Rest assured, your ID is OK. The depicted tooth is indeed an upper Somniosus microcephalus. I still hope to find one among my micro material from Antwerp some day. The tooth I depicted is a lower jaw tooth.

So just like you said, this species exhibits dignathic heterodonty, which accounts for the fact that the teeth in both our pictures look so different.

See also attached picture of the dentition of an extant Somniosus microcephalus. which I took from the net.

post-456-1215204925_thumb.jpg

Hope this answers your question.

Cheers,

Paul

Hi Paul:

Many thanks for taking the time to provide the response. The example of Somniosus I posted is the only example I have so there were no other teeth for comparison purposes. I also referenced the same source as did you (as you posted) for my ID verification.

This is what makes the Forum so great. Someone/somewhere is always available to provide information when someone is looking for help/verification with the ID of a fossil specimen.

Thanks again :rolleyes::rolleyes:

FS

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Hey FS, I haven't read the paper I metioned in awhile so I could be wrong. I emailed David Ward and explained that we were wondering about the state of the unio with regards to large threshers, so hopefully we will hear soon.

Hi Marcel:

I did dig out the Malta paper - nothing specific to giant threshers.

I appreciate your effort to contact Ward re this subject. The giant threshers certainly exhibit a varied morphology - large w/serrated crowns, large w/non-serrated crowns, large w/cusps and no serrations,and maybe some other combo that I can't think of at the moment.

The subject is most interesting and hopefully Ward or some other fossil shark workers can make some sense of these teeth and where (stratigraphically) they come from. I think it was you that previous posted that there seems to be no straight forward evolution of the varied thresher morphologies.

I hope David does provide some insight into the subject.

thanks again,

FS

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Hey FS, thanks for checking ... and yes the evolution of large threshers is not at all understood today (or at least not by myself :-)). I'm sure that is partly due to the fact that these teeth are rare and that stratigraphic info on these teeth isn't always accurate since many of them come from South Carolina Rivers.

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Hey FS, thanks for checking ... and yes the evolution of large threshers is not at all understood today (or at least not by myself :-)). I'm sure that is partly due to the fact that these teeth are rare and that stratigraphic info on these teeth isn't always accurate since many of them come from South Carolina Rivers.

Excellent point re the fact that many of the teeth come from SC river locations. Such teeth are immediately problematic with regard to definitive stratigraphy. I have two serrated threshers from SC which I'll soon post. Although relatively large and robust, they are quite worn and in no condition comparable to the ones you and others have posted - just some more "river teeth". However, no matter what they may be, such teeth present a most interesting puzzle. If every fossil shark tooth was immediately identifiable and this identity was confirmed by all, the subject of fossil shark teeth would be so much less interesting. I sometimes wonder if Hemipristis serra is the only fossil shark tooth with universal (??) agreement as to identity?

FS

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Excellent point re the fact that many of the teeth come from SC river locations. Such teeth are immediately problematic with regard to definitive stratigraphy. I have two serrated threshers from SC which I'll soon post. Although relatively large and robust, they are quite worn and in no condition comparable to the ones you and others have posted - just some more "river teeth". However, no matter what they may be, such teeth present a most interesting puzzle. If every fossil shark tooth was immediately identifiable and this identity was confirmed by all, the subject of fossil shark teeth would be so much less interesting. I sometimes wonder if Hemipristis serra is the only fossil shark tooth with universal (??) agreement as to identity?

Attached are a few thresher teeth. The two serrated teeth are a little over 2" (Alopias whatensis :P:P . The other pic is of an alopias where the serrations are essentially gone and the other is a very nice non-serrated example from the Morgan River, SC. The serrated teeth don't compare to a few similar teeth posted by others but nevertheless they are of the serrated variety.

FS

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