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Giant Thresher Aka Alopias Grandis

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cowsharks

I have about 10 of these shark teeth that have so far been labeled as Giant Thresher's, aka Alopias grandis. All of mine are from Calvert Cliffs; 7 non-serrated, 3 slightly serrated. All of the specimens I have, have recurved crowns, meaning, the crown bends over or leans over toward one of the shoulders, at some angle (see enclosed image as an example). I've never seen one where the crown is mostly, or completely erect or straight "up", implying perhaps that it would come from an Anterior file closer to the mid-line of the jaw. Of course, my going in assumption, if these really are some form of Thresher shark, is that like the extant species of thresher sharks which clearly have anterior files whose crowns point straight up, that these Giant threshers would also possess anterior files with crowns that point straight up.

On Parotodus, you all know how some of those tooth position are really recurved, well, Parotodus also has anterior/symphyseal type of positions where the crown sticks straight up. Look at some of the Parotodus in this link: http://www.ecphora.n...arotodus_lc.jpg (especially in the 3rd and 4th rows down).

If it turns out that none of the anterior (or symphyseal if they exist) Giant thresher teeth exhibit this tooth characteristic, would they still be considered a thresher? I don't know what tooth traits/characteristics must be present for the paleo-scientists to classify or assign a particular tooth to a species. Overall, the Giant thresher teeth do superficially resemble large forms of extant and fossil thresher teeth (A, vulpinus, A. superciliousus), but they don't seem to be proportionally as "thick" as these "smaller" thresher forms. The blades on the Giant thresher teeth seem to be more compressed like those of mako's (I. hastalis). I remember the first time I saw a Giant thresher tooth I thought it was a slightly pathological mako (hastalis).

So, bottom line is, does anyone have any specimens of a Giant thresher tooth where the crown is straight or nearly straight, pointing up instead of leaning over towards one of the shoulders?

Daryl S.

post-2077-0-29572200-1300803850_thumb.jpg

Edited by cowsharks

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Shellseeker
I have about 10 of these shark teeth that have so far been labeled as Giant Thresher's, aka Alopias grandis.....

You are truly fortunate. I am jealous :D

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Auspex

...does anyone have any specimens of a Giant thresher tooth where the crown is straight or nearly straight, pointing up instead of leaning over towards one of the shoulders?

I never even saw one in 15+ years of collecting the Calvert Fm. (back when there was full access).

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Northern Sharks

Taaadaaa

http://www.thefossilforum.com/index.php/gallery/image/106-trigonotodus/

It isn't the largest, but it is the rarest form -a cusped giant thresher. I believe this is a lower anterior. I would think that anterior teeth of the regular giant thresher, if they too have a straight cusp, would be hard to tell apart from Isurus.

Edited by Northern Sharks

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cowsharks

I never even saw one in 15+ years of collecting the Calvert Fm. (back when there was full access).

Yup, I've been blessed with being able to find so many. What's neat is that I have several from one side of the jaw, somewhat in descending order as well, that's what prompted me to think about the other positions like the anteriors.

Daryl S.

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Auspex

Yup, I've been blessed with being able to find so many. What's neat is that I have several from one side of the jaw, somewhat in descending order as well, that's what prompted me to think about the other positions like the anteriors.

Daryl S.

I mean I've never found a straight-crowned one; typical ones I have "a few" of ;)

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cowsharks

Taaadaaa

http://www.thefossil...6-trigonotodus/

It isn't the largest, but it is the rarest form -a cusped giant thresher. I believe this is a lower anterior. I would think that anterior teeth of the regular giant thresher, if they too have a straight cusp, would be hard to tell apart from Isurus.

Thanks NS. Is the "Trigonotodus" the official name? Purdy did not include the Giant threshers from Lee Creek in the Lee Creek vol III book, and Jim B. on elasmo.com still has them listed as Alopias grandis. BTW, is the T. alteri named after Steve Alter of megalodonteeth.com?

The T. alteri in your link looks more like the smaller thresher species, so I can see why it was named or considered to be a type of thresher. In addition, that particular specimen you have illustrated there has the "straight" pointing crown that I was referring to, again, something seen in the species of threshers with small(er) teeth. The T. grandis though in your pic looks so vastly different in comparison though.

So, I'd still be interested in seeing an anterior A. grandis/T. grandis, or one with a straight crown that might indicate it is from the anterior/symphyseal position.

Also, let me know if my logic here is flawed. Meaning, I am pre-supposing that in order for a shark to be a thresher, I figure that it should have similar tooth files as the smaller species of Threshers.

Daryl S.

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Northern Sharks

Thanks NS. Is the "Trigonotodus" the official name? Purdy did not include the Giant threshers from Lee Creek in the Lee Creek vol III book, and Jim B. on elasmo.com still has them listed as Alopias grandis. BTW, is the T. alteri named after Steve Alter of megalodonteeth.com?

The T. alteri in your link looks more like the smaller thresher species, so I can see why it was named or considered to be a type of thresher. In addition, that particular specimen you have illustrated there has the "straight" pointing crown that I was referring to, again, something seen in the species of threshers with small(er) teeth. The T. grandis though in your pic looks so vastly different in comparison though.

So, I'd still be interested in seeing an anterior A. grandis/T. grandis, or one with a straight crown that might indicate it is from the anterior/symphyseal position.

Also, let me know if my logic here is flawed. Meaning, I am pre-supposing that in order for a shark to be a thresher, I figure that it should have similar tooth files as the smaller species of Threshers.

Daryl S.

Steve Alter, who I assume T.alteri is named for, once told me that Trigonotodus was the current name for the giant threshers. Elasmo is leaving the non-cusped version as Alopias for now, it would seem, until someone can say one way or another, exactly what kind of shark these things were. Again, there are probably more than a few "straight" specimens in collections incorrectly labelled as mako. If you found a smaller tooth(>2"), with a straight crown and no serrations, would you call it a common Isurus hastalis, or an uncommon T./A.grandis, a species a lot of people would never have heard of.

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Sharks of SC

So, bottom line is, does anyone have any specimens of a Giant thresher tooth where the crown is straight or nearly straight, pointing up instead of leaning over towards one of the shoulders?

Daryl S.

I've got one that only leans a little - Ill take a few pics. tonight.

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siteseer

The fact that most if not all "Alopias grandis" teeth look like upper laterals prompted Kent (1994) to state that they are upper lateral teeth of I. hastalis (presumably a less common early variant). While many people consider grandis teeth to belong to a distinct species, it is an interesting proposal in that these teeth are found in Early Miocene deposits where "normal" I. hastalis teeth also appear in the fossil record of the east coast of North America. I. hastalis appeared on the west coast in the Middle Miocene (Sharktooth Hill time) but the upper teeth are clearly different from east coast specimens of the same jaw by then.

Without obvious lowers we are left to assume that the upper and lower teeth must look a lot alike, all being curved to some extent. I can't think of another lamniform with uppers and lowers so difficult to distinguish. Esinosa-Arrubarena (1987) considered I. planus to be a species with curved upper and lower teeth though others contend that the curved teeth are all uppers and the lowers are the stouter-rooted straight teeth (often with incomplete cutting edges) from the same deposits.

It could be that apparent lowers are even more rare than the uppers but you would think some would be found among the many thousands of teeth collected and discussed. However, as you noted, Parotodus benedeni is a rare species too but apparent lowers have been found of that (I found a lower anterior once) with the Powell dentition (and the Batesford one) filling in some of the blanks - not many but enough that you can find photos of them or see them in large collections.

I still lean toward grandis being a distinct species perhaps within Alopias or perhaps with a genus of its own.

Espinosa-Arrubarena, L. 1987.

Neogene Species of the Genus Isurus (Elasmobranchii, Lamnidae) in southern California, U.S.A. and Baja California Sur, Mexico. Master's Thesis. California State University, Long Beach. 153p.

Kent, B.W. 1994.

Fossil sharks of the Chesapeake Bay Region. Egan, Rees, and Boyer, Inc. 146p.

I have about 10 of these shark teeth that have so far been labeled as Giant Thresher's, aka Alopias grandis. All of mine are from Calvert Cliffs; 7 non-serrated, 3 slightly serrated. All of the specimens I have, have recurved crowns, meaning, the crown bends over or leans over toward one of the shoulders, at some angle (see enclosed image as an example). I've never seen one where the crown is mostly, or completely erect or straight "up", implying perhaps that it would come from an Anterior file closer to the mid-line of the jaw. Of course, my going in assumption, if these really are some form of Thresher shark, is that like the extant species of thresher sharks which clearly have anterior files whose crowns point straight up, that these Giant threshers would also possess anterior files with crowns that point straight up.

On Parotodus, you all know how some of those tooth position are really recurved, well, Parotodus also has anterior/symphyseal type of positions where the crown sticks straight up. Look at some of the Parotodus in this link: http://www.ecphora.n...arotodus_lc.jpg (especially in the 3rd and 4th rows down).

If it turns out that none of the anterior (or symphyseal if they exist) Giant thresher teeth exhibit this tooth characteristic, would they still be considered a thresher? I don't know what tooth traits/characteristics must be present for the paleo-scientists to classify or assign a particular tooth to a species. Overall, the Giant thresher teeth do superficially resemble large forms of extant and fossil thresher teeth (A, vulpinus, A. superciliousus), but they don't seem to be proportionally as "thick" as these "smaller" thresher forms. The blades on the Giant thresher teeth seem to be more compressed like those of mako's (I. hastalis). I remember the first time I saw a Giant thresher tooth I thought it was a slightly pathological mako (hastalis).

So, bottom line is, does anyone have any specimens of a Giant thresher tooth where the crown is straight or nearly straight, pointing up instead of leaning over towards one of the shoulders?

Daryl S.

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siteseer

That cuspleted tooth is a different genus but gives us an idea of what a lower might look like. I would lean against alteri belonging to Trigonotodus because it doesn't compare well to the type species, T. tusbairicus, known from the Middle Eocene of Kazakhstan. I wonder if T. tusbairicus is just another one of those oddball Eocene lamniforms (perhaps more closely related to threshers than to makos) that didn't leave any Oligocene descendants. I think alteri might be the ancestor or close relative of grandis (perhaps even a separate unnamed genus).

Alopias is rare but present by the Middle Eocene.

Yeah, those cuspleted threshers are rarer than grandis or the serrated form. They come out of an unnamed "hard layer" (considered probably Late Oligocene) in the Ashapoo River and perhaps sites elsewhere.

Taaadaaa

http://www.thefossilforum.com/index.php/gallery/image/106-trigonotodus/

It isn't the largest, but it is the rarest form -a cusped giant thresher. I believe this is a lower anterior. I would think that anterior teeth of the regular giant thresher, if they too have a straight cusp, would be hard to tell apart from Isurus.

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MikeDOTB

Ok, I know this is an old topic, but I was curious about Alopias Grandis teeth and am bringing it back. I have never actually seen an alopias grandis tooth from Lee Creek and was wondering if anyone had any examples if they wouldnt mind posting some pictures. I have other alopias shark teeth from Lee Creek (PCS) but not Grandis. The only places I have seen pictures of Alopias Grandis Teeth are from South Carolina and Calvert Cliffs and Virginia. Any responses are much appreciated!

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bmorefossil

Ok, I know this is an old topic, but I was curious about Alopias Grandis teeth and am bringing it back. I have never actually seen an alopias grandis tooth from Lee Creek and was wondering if anyone had any examples if they wouldnt mind posting some pictures. I have other alopias shark teeth from Lee Creek (PCS) but not Grandis. The only places I have seen pictures of Alopias Grandis Teeth are from South Carolina and Calvert Cliffs and Virginia. Any responses are much appreciated!

they are around i have seed pictures on elasmo of aurora/lee creek specimines

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bmorefossil

they are around i have seed pictures on elasmo of aurora/lee creek specimines

http://www.elasmo.com/frameMe.html?file=genera/cenozoic/sharks/parotodus.html&menu=bin/menu_genera-alt.html

click lee creek at the top then on the side go to shark-1 scroll down to you see "alopias grandis" and click the second picture to read about and see some examples from the mine.

Edited by bmorefossil

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MikeDOTB

http://www.elasmo.com/frameMe.html?file=genera/cenozoic/sharks/parotodus.html&menu=bin/menu_genera-alt.html

click lee creek at the top then on the side go to shark-1 scroll down to you see "alopias grandis" and click the second picture to read about and see some examples from the mine.

You know, I think thats the first time I saw that page, and I thought I had previously seen the entire site. Guess I have more digging to do on there. Thanks BMore. Has anyone found or obtained specimens from there? I guess they are rare.

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bmorefossil

You know, I think thats the first time I saw that page, and I thought I had previously seen the entire site. Guess I have more digging to do on there. Thanks BMore. Has anyone found or obtained specimens from there? I guess they are rare.

i was talking to NCJack while was down there for the festival and his friend(not sure if they are a forum member) found one first trip into the mine..... really wish i had that luck. Finding my favorite tooth first time in....geeze.

here are the few i have been lucky enough to find or aquire over my few fossiling years :) Im pretty sure all of the ones i have either traded or bought are from SC.

enjoy

post-1554-0-80969600-1309149104_thumb.jpg

Edited by bmorefossil

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MikeDOTB

i was talking to NCJack while was down there for the festival and his friend(not sure if they are a forum member) found one first trip into the mine..... really wish i had that luck. Finding my favorite tooth first time in....geeze.

No kidding, that would have been awesome. But first time in, anything good would have been exciting for me. My best finds were 1.5" makos my first trip in.

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Paleoc

http://www.elasmo.com/frameMe.html?file=genera/cenozoic/sharks/parotodus.html&menu=bin/menu_genera-alt.html

click lee creek at the top then on the side go to shark-1 scroll down to you see "alopias grandis" and click the second picture to read about and see some examples from the mine.

Here is a better link: http://www.elasmo.com/frameMe.html?file=heim/leecreek/lc-alopias.html&menu=bin/menu_topics-alt.html

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ncjack99

No kidding, that would have been awesome. But first time in, anything good would have been exciting for me. My best finds were 1.5" makos my first trip in.

That would have been a guy named Hank. I'm actually better aquainted with his buddy Al, but anyways, Hank found what I thought to be a giant thresher and also a cowshark still in the matrix. The cowshark was the perfect display piece with the rock being about the size of a computer mouse and the tooth itself perfectly mounted within. Hank said he was going to have a little rock sawed off the back so it would lay at just the right angle in the curio case.

Sorry got a little side tracked remembering the cowshark tooth...lol

The "Thresher" was perfect with classic Lee Creek colors. If I remember correctly, it was about 2 1/2 inches in length. But the mind may sometimes exagerrate with time so I'll see if I can find out the actual measurement and what the actual ID of the tooth is.

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Prognathodon saturator 101

thats epic when/if i become a paleontologist im thinking of studying this shark more apparently its the second biggest shark ever 13 meters long

alopias_grandis_by_teratophoneus-d8w41j6.png

teumessian_thresher_by_hodarinundu-d9s6mvj.jpg

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