Please Help-Losing Sleep-Shark Tooth I.d.needed

[DE&i]

Shark teeth experts and the like of TFF I seriously need your help I’m losing a lot off sleep with this find I found it on the 19/05/2013 and prepped today the 20/05/2013. This is going to sound like an odd request .I’d like to enter it in this month’s fossil find competion but rules are rules so without knowing the identification of this find I can’t enter it. If I can’t find an i.d. on TFF my search will go on here is as much info I can give you to go with it.

Firstly here is a PDF file titled: Rees, J. and Underwood, C. (2008) Hybodont
Sharks of the English Bathonian and Callovian
(Middle Jurassic).

Of which also has a very detailed description of the all known species of Asteracanthus sharks of which I believe this find is from it is Middle Jurassic, Bathonian of age.

There’s a much more detailed description of these known species with picture plates on pages 132 to 137. But I still can’t find a match at all. Would anyone else have any ideas maby I’m looking in the wrong place or maby we are looking at something completely new?

Kind Regards,

Darren.

[Troodon]

Any chance its a Strophodus sp which is from the same age?

[Terry Dactyll]

Darren.... Thats a very nice specimen.... good luck with the ID...

[Indy]

It's understood you are not seeking someone's "best guess" identifying this tooth.

Crusher shark/fish teeth, with few exceptions, are often real brain busters.

The odds of finding an "exact visual match" on the Net or even in a publication
might be a long shot since there are often several different shapes and sizes in
the palate of the same species.

Hopefully, someone here knows someone who specializes in

crusher shark/fish teeth of the Jurassic and points you in the right direction.

PS: My primary focus is the Mississippian and Pennsylvanian

and the one I turned to for identifying Carboniferous teeth

isn't a member of general Internet fossil discussion forums.

Edited May 20, 2013 by Indy

[Batty]

Myliobatis raouxi??

[DE&i]

Thanks for the great response and taking the time to look….I’ve fine-tuned the tooth down to being Genus Asteracanthus but as yet species unknown.

Darren.

[siteseer]

Darren,

First of all, thanks for the link to that article. I didn't have it.

I don't have a lot of experience with Asteracanthus or other Jurassic teeth. I have picked up specimens in trades over the years, and quite frankly, have depended on the labels provided for the ID. The Rees and Underwood article helps a lot in sorting out the species though they also question a difference between longidens and tenuis.

What site is your tooth from? You noted the age but not the locality.

In any case the tooth is clearly a lateral and shows some wear. It has a "domed area" (sometimes called a cusp) and does not look rectangular enough so we can rule out A. magnus and A.medius. I can see some reticulate patterned ornamentation but without a sign of an occlusal crest eliminating A. ornatissimus. With the "domed area" asymmetrically situated and with the other possibilities set aside, your tooth would seem to be either A. longidens or A. tenuis.

The authors stated that lateral teeth in the A. longidens specimen "seem to be less domed than those of A. tenuis" and left open the possibility that they are showing the range of variation in one species. Your tooth resembles Figure 15-16 in overall shape.

I would try contacting Rees or Underwood or David Ward (or all three) and see who responds. I know David Ward because he goes to the Tucson shows. Unless he's away or otherwise busy, he is always open to helping with identifications.

Jess

P.S. I looked at my own specimens and was able to correct a couple of labels or at least narrow down ID's given as "Asteracanthus sp." Also, I'm not sure if Strophodus is still a valid genus. I believe longidens used to be assigned to it. It appears I have a couple magnus teeth and a few longidens/tenuis.

 

On 5/19/2013 at 7:40 PM, D&E said:

Shark teeth experts and the like of TFF I seriously need your help I’m losing a lot off sleep with this find I found it on the 19/05/2013 and prepped today the 20/05/2013. This is going to sound like an odd request .I’d like to enter it in this month’s fossil find competion but rules are rules so without knowing the identification of this find I can’t enter it. If I can’t find an i.d. on TFF my search will go on here is as much info I can give you to go with it.

Firstly here is a PDF file titled: Rees, J. and Underwood, C. (2008) Hybodont
Sharks of the English Bathonian and Callovian
(Middle Jurassic).

Of which also has a very detailed description of the all known species of Asteracanthus sharks of which I believe this find is from it is Middle Jurassic, Bathonian of age.

There’s a much more detailed description of these known species with picture plates on pages 132 to 137. But I still can’t find a match at all. Would anyone else have any ideas maby I’m looking in the wrong place or maby we are looking at something completely new?

Kind Regards,

Darren.

[DE&i]

Hi Jess,

It took me while to digest your very detailed response, I’m very pleased with the elimination process of narrowing down the species to the GENUS Asteracanthus. And it’s fantastic you were able to take something from that link to help you with the samples you have in your collection.

Sorry I forgot to mention the location of the find was in Lincolnshire, UK.

I took up your advice of contacting David Ward who responded almost immediately and this is what he had to say.

(The Asteracanthus looks much like the common Bathonian species A. Magnus.
There are a number of species that may well represent tooth positions rather than real species.)

So I was thinking Jess how would you suggest I put the possible I.D. too this tooth for future reference.

p.s. Here is a most read two page PDF file report on the geology and potential fossils to be found, written by Alan Dawn the founder of the Stamford geological society.

Kind Regards,

Darren.

[Kosmoceras]

Here are a few museum teeth - Link

Regards,

[siteseer]

Hi Darren,

I would not have thought A. magnus would be a possibility because it does not look very rectangular and a domed area appears to be asymmetrically situated on the crown. I have a flatter, more rectangular specimen (though it is incomplete) so that pushed me to decide against A. magnus. David must see more in your specimen knowing how they wear down from locality to locality. I noticed in the acknowledgements that the authors thanked him for access to his collection. He must have numerous teeth and has probably seen numerous others.

I met David at the Tuscon shows over twenty years ago. When you show him an odd tooth in person and ask him about it, he will often ask you what you think it is. He is not winding you up - just wants you to have an opinion and not simply accept his ID. He will then point out the characters that led him to his determination. It's his way of encouraging collectors to learn to be their own experts. You can learn a lot in five minutes talking with him.

The rectangular tooth I have shows some wear across the crown surface but the root is completely worn away even into the underside of the crown. The site is called "Tetbury,, Glos." which I assume means Glocestershire. Is it common to find them that worn? I got the impression that these teeth are often found incomplete when a friend sent me a cast of a larger, complete tooth (38mm along its greatest dimension). If I had been at the site, I would have likely overlooked it or mistaken it for a small, chipped pebble.

In any case I will have to read more about it. I have another article by Rees and Underwood but will be keeping an eye open for more on the genus. Maybe I'll bring some specimens to Tucson and tell him what I think they are.

Jess

On 5/26/2013 at 4:37 AM, D&E said:

Hi Jess,

It took me while to digest your very detailed response, I’m very pleased with the elimination process of narrowing down the species to the GENUS Asteracanthus. And it’s fantastic you were able to take something from that link to help you with the samples you have in your collection.

Sorry I forgot to mention the location of the find was in Lincolnshire, UK.

I took up your advice of contacting David Ward who responded almost immediately and this is what he had to say.

(The Asteracanthus looks much like the common Bathonian species A. Magnus.
There are a number of species that may well represent tooth positions rather than real species.)

So I was thinking Jess how would you suggest I put the possible I.D. too this tooth for future reference.

p.s. Here is a most read two page PDF file report on the geology and potential fossils to be found, written by Alan Dawn the founder of the Stamford geological society.

Kind Regards,

Darren.

[DE&i]

Here are a few museum teeth - Link

Regards,

Thank you for the link Thomas i went down that road when i first took up the challenge with out much success im afraid.

[DE&i]

Jess....ive been put in contact with apparently one of the leading experts on sharks/fish in this country and will surely be able to advise, his name is E.R Matheau-Raven ive know knowledge of this person but ill give it a shot, personally im not convinced the tooth could be A.magnus.

Darren.

[siteseer]

Darren,

Yes, it's always great to find people who can provide more input on teeth that are not often talked about. I hope you let us know what he says.

Jess

Jess....ive been put in contact with apparently one of the leading experts on sharks/fish in this country and will surely be able to advise, his name is E.R Matheau-Raven ive know knowledge of this person but ill give it a shot, personally im not convinced the tooth could be A.magnus.

Darren.

[DE&i]

Hi Jess,

You were spot on with your i.d. I've had the tooth confirmed by E.R Matheau-Raven as ( partial lateral A.tenius

Thank you for your help.

Regards,

Darren

Edited June 2, 2013 by D&E

[siteseer]

Hi Darren,

You're welcome. Thanks again for that article. In the US there is not a lot of Jurassic marine rocks exposed at the surface (offhand I can think of only the Sundance Formation of Wyoming), so Asteracanthus is not a shark that is often discussed even here on the FF. I have a better understanding of the specimens in my collection now.

I hope you find more stuff.

Jess

Hi Jess,

You were spot on with your i.d. I've had the tooth confirmed by E.R Matheau-Raven as ( partial lateral A.tenius

Thank you for your help.

Regards,

Darren