Posterior Cretalamna Or Otodus Or . . .

[non-remanié]

Kent says divergent cusps so there ya go, label them whatever you like! I'm really not trying to be a jacka$ Harry I did help you get on the track of pachyrhiza track in the first place. I admit that you are an absolute asset to this forum and THE MAN with mammal fossils, but in my opinion, not so much with sharks teeth. Thats as far as I will take this because no matter what, you will keep trying to find new species to call your morroccan shark teeth so you can sell them as such rather than "morroccan shark tooth, late cretaceous - eocene, khourigba" and murder my own words over and over again. Just like you wouldn't accept when I informed you that you were ACCIDENTALLY selling DYED morroccan sharks teeth. Instead you chose the much less simple explanation of the very odd preservation to say that they must have come from moroccan oil shales or something and it just happens that you are one of the few people to have seen these oil shale Moroccan teeth. I mean come on, the dye seaped into the cracks in the enamel, how much mroe obvious could it be? They are dang good at forgery in Morocco we know that. The dye is good whatever it was. You got fooled and instead of accept it you denied and came up with some crazy explanation instead of giving an ounce of thought to what I was saying and decide maybe the simple explanation is better. Why dont you post some of those shark tteeth pictures again or did you get rid of all of those teeth. If so, WHY get rid of them if they had a really cool and UNIQUE preservation for Morocco? hmmmm

You say now that no one but me sees the distinctiveness of the three teeth that I have labeled "pachyrhiza." I respectfully point to your earlier post about these teeth:

Your judgement about some of the teeth being "pachyriza" depended then on their being Cretaceous in age (although Kent cites reports of Cretolamna appendiculata pachyrhiza from the Maastrichtian and Early Paleocene of Europe and North America).

Since we've already agreed that the actual age of the teeth is unknowable, I choose to rely on what your eyes were telling you when you made this December 7 post.

I have only these three teeth that I would call C. a. pachyrhiza. I will certainly be on the lookout for others.

[Harry Pristis]

Kent says divergent cusps so there ya go, label them whatever you like! I'm really not trying to be a jacka$ Harry I did help you get on the track of pachyrhiza track in the first place. I admit that you are an absolute asset to this forum and THE MAN with mammal fossils, but in my opinion, not so much with sharks teeth. Thats as far as I will take this because no matter what, you will keep trying to find new species to call your morroccan shark teeth so you can sell them as such rather than "morroccan shark tooth, late cretaceous - eocene, khourigba" and murder my own words over and over again. Just like you wouldn't accept when I informed you that you were ACCIDENTALLY selling DYED morroccan sharks teeth. Instead you chose the much less simple explanation of the very odd preservation to say that they must have come from moroccan oil shales or something and it just happens that you are one of the few people to have seen these oil shale Moroccan teeth. I mean come on, the dye seaped into the cracks in the enamel, how much mroe obvious could it be? They are dang good at forgery in Morocco we know that. The dye is good whatever it was. You got fooled and instead of accept it you denied and came up with some crazy explanation instead of giving an ounce of thought to what I was saying and decide maybe the simple explanation is better. Why dont you post some of those shark tteeth pictures again or did you get rid of all of those teeth. If so, WHY get rid of them if they had a really cool and UNIQUE preservation for Morocco? hmmmm

I'm disappointed, 'Toothpuller.' The fun ends when participants get pissy during an argument. And, more important, the learning stops.

You've accused me before of stirring up attention to these teeth in order to sell them; but, I've sold only a half-a-handful of these Moroccan teeth in the past five years. And even then, I sold that few teeth 'cause they were surplus in my effort to learn more about them.

If anyone dyed those few dark-colored teeth that I have, it wasn't a Moroccan. The Moroccans who would have access to dyes would not be those who collect the teeth. The collectors are the farmers and children who glue the teeth and repair the roots. The brokers and dealers don't think twice about these little teeth, and are unlikely to experiment with dying a few. But, once those teeth get into the hands of a retailer here, anything is possible. I think we've discussed this in another thread where I offered possible alternatives. I didn't realize you were brooding about it.

You seem to be a smart fellow, an educated fellow, I'm sorry you don't seem to be a happy fellow. I try not to brood or hold a grudge when my arguments don't hold sway. I always learn something from a brisk exchange of ideas, even (especially) if it's that my ideas could be incomplete or mis-informed. That happens to the smartest among us once in a while. Cheer up!

[non-remanié]

Harry I said nothing when you basically decided to belittle me when I mentioned your moroccan teeth being dyed and that I paid a few bucks for a few similar ones myself on ebay from a blurry 150x150 pixel image. I am 99% positive I am correct, but you defended yourself to the bitter end in which you said basically said "well I gots the teeth in hand and I'm sure I'm right and youre full of it". Post a new thread and see if anyone has seen similar moroccan teeth or has an opinion and you will see the facts. You have great images and references, but sometimes you are just thick headed and most definitely obnoxious. Theres a reason you get in so many heated discussions on here. And for your claim about having only sold a couple.... conveniently I guess it was all the dyed ones, eh? I dont give a snarge about your selling them but when you have a high and mighty attitude and won't admit your mistakes (like selling dyed teeth for good money) then its annoying. I would have been happy to continue in a civil manner with the pachyrhiza debate but you just dont listen to anything anyone has to say so its impossible. So continue to post your canned response when you can't open someones elses pictures when its really YOUR problem and stick to mammal topics

I'm disappointed, 'Toothpuller.' The fun ends when participants get pissy during an argument. And, more important, the learning stops.

[PaleoRon]

The dyed Moroccan teeth have been around for several years. The one I posted was purchased in Tucson, directly from a Moroccan dealer, about five years ago. The guy had a large sticky pile of them. I bought a few to hand out as examples of yet another way the Moroccan dealers like to manipulate fossils in order to generate sales. There was another fossil collector there at the time and he purchased several pounds of the black teeth which were selling at a premium. I warned him that the teeth had been dyed and he brushed my warning off. I suggested that he the soak the teeth in alcohol and check the results. He later called me to tell me that he should have listened to my advice and that the teeth were now worthless to him. The samples I purchased had small gobs of a black substance attached to them and they smelled just like black shoe polish. After several years of military service the scent of black polish sticks with you. I soaked a couple of the teeth in alcohol and a couple more in acetone and although some of the color remained, the smell was nearly eliminated. If the color was natural neither alcohol nor acetone should have removed the color from the teeth.

Just for the record, the fun stops when one person tries to make others look bad in an attempt to try to make himself look good. It isn't working.

Luckily, nearly all of the people on this forum are intelligent enough to see through the smoke screen.

It is quite amusing to see an antagonist impaled and squirming upon his own weapon.

[Harry Pristis]

Harry I said nothing when you basically decided to belittle me when I mentioned your moroccan teeth being dyed and that I paid a few bucks for a few similar ones myself on ebay from a blurry 150x150 pixel image. I am 99% positive I am correct, but you defended yourself to the bitter end in which you said basically said "well I gots the teeth in hand and I'm sure I'm right and youre full of it". Post a new thread and see if anyone has seen similar moroccan teeth or has an opinion and you will see the facts. You have great images and references, but sometimes you are just thick headed and most definitely obnoxious. Theres a reason you get in so many heated discussions on here.

And for your claim about having only sold a couple.... conveniently I guess it was all the dyed ones, eh? I dont give a snarge about your selling them but when you have a high and mighty attitude and won't admit your mistakes (like selling dyed teeth for good money) then its annoying. I would have been happy to continue in a civil manner with the pachyrhiza debate but you just dont listen to anything anyone has to say so its impossible. So continue to post your canned response when you can't open someones elses pictures when its really YOUR problem and stick to mammal topics

Golly! You're not merely unhappy, you're angry. I'm sorry if I belittled you in an earlier manifestation; I do know how to do that (my bad!). In the past, that has been a final recourse after learning stops and ad hominem arguments have been directed at me. I try to avoid that behaviour these days 'cause it's just not productive.

As for "so many heated discussions on here," if there's any heat, I assure you it's one-sided. I get coldly rational in a clash of ideas (as I am as I write this). I have learned that he who loses his temper, loses the argument.

Anyone who's really interested can see all of the Moroccan shark teeth I've sold in the past five years, including the four shark teeth 'Toothpuller' finds so annoying.

[Harry Pristis]

Just for the record, the fun stops when one person tries to make others look bad in an attempt to try to make himself look good. It isn't working.

Luckily, nearly all of the people on this forum are intelligent enough to see through the smoke screen.

It is quite amusing to see an antagonist impaled and squirming upon his own weapon.

Now that's a creepy metaphor . . . yet . . . . . . Uhhhhhhh . . . . . . . YESSS!! It's exhilarating to see the crimson flood, and to hear the screams and pleas for mercy!! NO MERCY!! Disembowel him! Twist that weapon until his guts fall out and the antagonist is on the floor twitching in his own offal !!

ROFT

[non-remanié]

Thanks Ron, I knew someone had to know what I was talking about. Sharks teeth value depends on preservation and locality and if someone has a new and unique color and preservation for sale, people will pay a premium for them sometimes.

Harry, I have seen you do it to others on here and it just gets old. It was no big deal or else I would have said something at the time. Just stop making personal judgements. This is an internet forum, Harry. You know nothing of the disposition of a poster from a single comment. But when it is systemic like your attitude I do think we can draw some conclusions and I tried to get some paybacks for us all , thats all I've spent way too much time chatting on the internet to let a few comments get under my skin, but I will take note and point it out if it reaches a certain level. I will continue to read your posts and try to learn but it would be nice to not see the same things over and over. </flame war>

[Guest bmorefossil]

Thanks Ron, I knew someone had to know what I was talking about. Sharks teeth value depends on preservation and locality and if someone has a new and unique color and preservation for sale, people will pay a premium for them sometimes.

Harry, I have seen you do it to others on here and it just gets old. It was no big deal or else I would have said something at the time. Just stop making personal judgements. This is an internet forum, Harry. You know nothing of the disposition of a poster from a single comment. But when it is systemic like your attitude I do think we can draw some conclusions and I tried to get some paybacks for us all , thats all I've spent way too much time chatting on the internet to let a few comments get under my skin, but I will take note and point it out if it reaches a certain level. I will continue to read your posts and try to learn but it would be nice to not see the same things over and over. </flame war>

look guys i think we are getting a little of topic, lets all calm down and shake hands.

[hybodus]

I personally would still like to see better information on the delta between Cretalamna and Otodus, relevant to both genera existing in the same deposit(s), whether it be Morocco or the Mid-Atlantic.

It seems like everyone keeps refering to Kent - are you refering to the 1994 publication "Fossil Sharks of the Chesapeake Bay Region"? If so, why would this be the default/definitive publication for tooth descriptions of these genera? I think Kent did a poor job in this one...

Just out of curiosity, has anyone refered to "Early Eocene Vertebrates and Plants from the Fisher/Sullivan Site" 1999? Kent has also authored the shark section of this publication, but his descriptions of tooth and root design for both Cretalamna appendiculata and Otodus obliquus are much better - seems 5 years makes a difference. If you do not have this reference, I provide the text below:

Cretalamna appendiculata: "Anterior teeth with a compresed, moderately tall and wide crown with complete, smooth cutting edges. There is a single pair of triangular, weakly divergent primary cusplets. The enameloid on both the crown and the cusplets is completely smooth. The basal grove is relatively narrow and inconspicuous. The root is moderately robust and has a comparitively small lingual protruberance. The protuberance contains a cluster of several nutrient pores, but has at best, only a weak nutrient grove. In many specimens, the nutrient grove is completely lacking. The root lobes are short and have rectilinear tips. The basal margin of the root consists of the roughly aligned margins of the lobes, seperated by a distinctly U-shaped medial notch. Maximum tooth height about 30mm.

Lateral teeth are similar to anterior teeth, but are shorter and wider. Both the crown and cusplets are lower and broader. The root is less robust and more compressed. The root lobes are abbreviated, with vertical mesial and distal margins. The basal root margin is nearly horizontal, except for a broad, shallow based concavity. The nutrient pores and nutrient grove are comparable to those of the anterior teeth."

Otodus Obliquus: The anterior teeth are massive, with tall, compressed, lanceolate crowns and complete cutting edges. A pair of large, triangular and divergent cusplets are also present and in some specimens, a pair of reduced secondaries may also occur. The basal grove is medially very broad, but becomes narrower toward the mesial and distal margins of the tooth. On well preserved specimens, the basal grove may be covered with a thin layer of pallial dentine. The root is robust with prominent lingual protruberance that lacks a nutrient grove. Nutrient pores are clustered on the most elevated portion of the protruberance, with a few additional pores scattered in an arch onto each root lobe. These pores are are frequently permineralized and can be difficult to observe. The root lobes are relatively short with rounded tips. The basal margin of the root is deeply notched, rather than angled.

Lateral teeth have crowns that are shorter, broader and more inclined than those of anterior teeth. As with anterior teeth, the cutting edges are complete, and a pair of large, divergent cusplets are present. Lateral teeth are more likely to have a pair of secondary cusplets than anterior teeth, although they are still considerably reduced in size when compared to the primary cusplets. The basal grove is similar to that of anterior teeth, but is longer and slightly narrower. The root is robust, although the lingual protuberance is reduced. The distribution of nutrient pores resembles that of anterior teeth, although the number of pores may be reduced. The root lobes are short and have rounded tips"

(please forgive any typos as I was in a hurry)

What do you tease out of the above that is relevant to the quest? I think we began by trying to distinguish between potentialy worn and small lateral teeth which could be Cretalamna or Otodus. Certainly the above descriptions are for Early Eocene teeth - but seem to be the best descriptions of any of the numerous references I have...

[Harry Pristis]

look guys i think we are getting a little of topic, lets all calm down and shake hands.

Yes! Yes! I'm calming down . . . . . . . . . . . the blood-lust is subsiding.

[non-remanié]

Agreed. There are too many loose ends to tie up but this is one of my big issues. Harry is using Kent 1994 as if it were the bible and its not. I think an aid in the confusion seems to be inconsistent usage of pachyrhiza subspecies in the Cretalamna line literature and amongst Cretalamna in general. I only have a couple other references to pachyrhiza in my literature and they don't really help much either. I'd like to see Arambourg 19xx, but its hard to obtain and I am not even sure any relevant info is in there. Generally I don't pay much attention to specifics of the Moroccan teeth for the same reasons I told Harry, but he insists on using them even though we have no good stratigraphic information available on them. It seems like Cretolamna appendiculata descriptions are site specific in the literature while in general over time & place quite a bit of variation is noted, as in the subspecies.

I have the fisher sullivan publication as well and I have seen a decent sample of both types of teeth from the site. The otodus tend to be large ones, 2+" range but are generally QUITE rare... oddly no juvenile teeth seem to be present. Cretolamna is also less common there, but not nearly as much as Otodus and matches well with the model paleoron gave in his images from Maryland's paleocene Aquia. They are also generally much smaller than the ones shown by Harry. They tend to match well with the sizes seen in late cretaceous specimens from the atlantic coastal plain... many images can be seen on blackriverfossils.org. I bet paleoron has some good spceimns from the fisher sullivan site.

I personally would still like to see better information on the delta between Cretalamna and Otodus, relevant to both genera existing in the same deposit(s), whether it be Morocco or the Mid-Atlantic.

It seems like everyone keeps refering to Kent - are you refering to the 1994 publication "Fossil Sharks of the Chesapeake Bay Region"? If so, why would this be the default/definitive publication for tooth descriptions of these genera? I think Kent did a poor job in this one...

[Guest bmorefossil]

look both of you guys are right in your own way. Tooth if Harry wants to posts his teeth let him post his teeth, i can remember when i posted a tooth so many times trying to get someone to see what i thought i was seeing. Harry, tooth is not wrong in saying what he is saying, he did help you out in coming to identifying some of your teeth. So lets all just calm down and be respectful of other peoples opinions. You two are great members of the forum, and we dont want you guys to go and set a bad example to some of the new members

steve

[Guest bmorefossil]

Agreed. There are too many loose ends to tie up but this is one of my big issues. Harry is using Kent 1994 as if it were the bible and its not. I think an aid in the confusion seems to be inconsistent usage of pachyrhiza subspecies in the Cretalamna line literature and amongst Cretalamna in general. I only have a couple other references to pachyrhiza in my literature and they don't really help much either. I'd like to see Arambourg 19xx, but its hard to obtain and I am not even sure any relevant info is in there. Generally I don't pay much attention to specifics of the Moroccan teeth for the same reasons I told Harry, but he insists on using them even though we have no good stratigraphic information available on them. It seems like Cretolamna appendiculata descriptions are site specific in the literature while in general over time & place quite a bit of variation is noted, as in the subspecies.

I have the fisher sullivan publication as well and I have seen a decent sample of both types of teeth from the site. The otodus tend to be large ones, 2+" range but are generally QUITE rare... oddly no juvenile teeth seem to be present. Cretolamna is also less common there, but not nearly as much as Otodus and matches well with the model paleoron gave in his images from Maryland's paleocene Aquia. They are also generally much smaller than the ones shown by Harry. They tend to match well with the sizes seen in late cretaceous specimens from the atlantic coastal plain... many images can be seen on blackriverfossils.org. I bet paleoron has some good spceimns from the fisher sullivan site.

i dont think that kents book is that great of a book to be using for otodus teeth, heck i really dont know one that is, i myself know very little about otodus teeth, i have only hunted in an area one time where otodus teeth can be found so i am no help in that issue, i do have a few Moroccan otodus teeth and a few look similar to the ones Harry and others have been posting, but other than 1 or 2 teeth i have all deformed teeth, bringing me to another question from harry, he asked about a otodus tooth that had a back curve, he wanted to know if it was deformed. Im going to say no, but i do have an otodus tooth that im sure Harry would like to see showing what a deformed tooth with a back curve looks like

[Harry Pristis]

I personally would still like to see better information on the delta between Cretalamna and Otodus, relevant to both genera existing in the same deposit(s), whether it be Morocco or the Mid-Atlantic.

It seems like everyone keeps refering to Kent - are you refering to the 1994 publication "Fossil Sharks of the Chesapeake Bay Region"? If so, why would this be the default/definitive publication for tooth descriptions of these genera? I think Kent did a poor job in this one...

Just out of curiosity, has anyone refered to "Early Eocene Vertebrates and Plants from the Fisher/Sullivan Site" 1999? Kent has also authored the shark section of this publication, but his descriptions of tooth and root design for both Cretalamna appendiculata and Otodus obliquus are much better - seems 5 years makes a difference. If you do not have this reference, I provide the text below:

<snip>

What do you tease out of the above that is relevant to the quest? I think we began by trying to distinguish between potentialy worn and small lateral teeth which could be Cretalamna or Otodus. Certainly the above descriptions are for Early Eocene teeth - but seem to be the best descriptions of any of the numerous references I have...

Thank you for something constructive, 'Hybodus'! I have not seen reference to this paper. Where is the Fisher/Sullivan Site? Does the author deal with subspecies of C. appendiculata? I think that's the core of the problem, the subspecies.

Kent does address subspecies in his 1994 guide, but the Elasmo.com authors don't want to go there. PaleoRon's C. appendiculata don't appear to be the same as the three teeth I think are C. a. pachyrhiza. If I put some of PaleoRon's teeth in my drawer, I think I would label them C. a. lata.

It's a can of worms, but it will become better sorted out. The safest thing to do for the nonce -- despite my foray to explore this problem -- is to stick to the genus and trivial designators.

As for the small, posterior teeth that JBStedman asked about, we have descriptions you've just transcribed plus a check-list of diagnostic characters in Kent (1994) to help distinguish between Cretalamna ssp. and Otodus, though mistakes are likely when dealing with the similarities.

Were there any useful images in the 1999 paper?

[fossilselachian]

Thank you for something constructive, 'Hybodus'! I have not seen reference to this paper. Where is the Fisher/Sullivan Site?

The Fisher/Sullivan site is in Stafford County, Virginia. The fauna of this site is described in Publication No. 152 of the Virginia Division of Mineral Resources. The exact title of the publication is:

Early Eocene Vertebrates and Plants from the Fisher/Sullivan Site (Nanjemoy Formation) Stafford County, Virginia.

The site is also known as Muddy Creek

[tracer]

3/4ths way down the page...

l'arbre cache la forêt

[Harry Pristis]

The Fisher/Sullivan site is in Stafford County, Virginia. The fauna of this site is described in Publication No. 152 of the Virginia Division of Mineral Resources. The exact title of the publication is:

Early Eocene Vertebrates and Plants from the Fisher/Sullivan Site (Nanjemoy Formation) Stafford County, Virginia.

The site is also known as Muddy Creek

Thank you! I just bought it.

[hybodus]

Harry, it's a pretty good reference, though Kent only provides a couple of photos for Cretalamna and Otodus.... no references to subspecies, but some coverage of Serratolamna.

In all, it has been a decent reference for me, and does include reptile and mammal sections.

[jbstedman]

Kent has also authored the shark section of this publication, but his descriptions of tooth and root design for both Cretalamna appendiculata and Otodus obliquus are much better - seems 5 years makes a difference. If you do not have this reference, I provide the text below:

What do you tease out of the above that is relevant to the quest? I think we began by trying to distinguish between potentialy worn and small lateral teeth which could be Cretalamna or Otodus. Certainly the above descriptions are for Early Eocene teeth - but seem to be the best descriptions of any of the numerous references I have...

hypodus -- thank you for the extensive quotation from this other Kent piece. It forced me to be a bit more systematic about what this thread has covered. I went through it and then went back to our discussion (skipping the one difficult tangent) to see what we confirmed and if we had come up with anything to add. Here's my take on it (I don't intend to rekindle the discussion, just give you what I came away with):

1) Boxier root in C. appendiculata. Emerged in the thread; Kent seems to agree with his description of root differences.

2) More prominent lingual protuberance in O. obliquus. Clear to Kent; I guess for us, too.

3) Forget nutrient pores. Not helpful in our examination; Kent says the holes likely to mineralize.

4) Crown curved in O. obliquus; slanted in C. appendiculata. This was put forward by toothpuller and PaleoRon. I think it's clear from the pictures; but not identified in Kent.

5) Basal groove in O. obliquus, broad, narrowing at margins. Not present in C. appendiculata. It was mentioned in the thread, but didn't emerge from the examination of specimens in the thread.

6) Cusplets divergent in O. obliquus; less so in C. appendiculata. This is from Kent; not sure we came out that way.

(I skipped the subspecies question.)

This thread has covered an amazing amount of ground. Where this thread began was with the question of distinguishing posterior teeth from these two sharks. I find Kent's descriptions of lateral Otodus and Cretalamna teeth only mildly helpful in that regard -- sort of, "more the same but shorter and wider." And that may just be the best we can do. Small posteriors may always be a snarge shoot.

[non-remanié]

http://74.125.93.104/translate_c?hl=en&amp...MnKylvO804Gy6Sw

my favorite line is "i do not believe in enchodus" :>

3/4ths way down the page...

l'arbre cache la forêt

[tracer]

"my favorite line is "i do not believe in enchodus" :>"

yeah, ain't it grand how translation is like classifying fossils? you find words, or an expression that doesn't fit exactly, and you pound that sucker in the nearest size hole you find.

that's why it should be a felony to try to translate poetry.

[tanzi]

Interesting discussion. Herman's pachyrhiza "form" is a mid-Campanian taxon. I have not seen any examples in the Paleogene.

[Still_human]

On 12/2/2008 at 10:48 PM, hybodus said:

Tracer - not as out there as you think... and I agree! So, as you well know, the fossil record as far as extinct sharks goes is pretty poor - LOTS of teeth, and some occasional skeletal remains - and luckily, a very occassional articulated skeleton or so... but nothing that can be compared to the fossil skeletal record of extinct animals with bones.

So ok... it sucks to have cartilage - and some isolated shark teeth can be pretty diagnostic if you are able to reference one of those few articulated specimens, or a fair fossilized portion of jaw with teeth, or even an associated tooth set - but not a whole lot of them exist.

Below is an example of Hybodus basanus - a skull, with preserved teeth - I can certainly understand the Hybodont naming due to many Hybodont remains with well defined characteristics that match this skull and teeth - I have several of these, and I can pretty much get down to species level for a bunch of Hybodont sharks, but for the vast majority of them, the ID is based on a reference to a fossil horizon that someone smarter than I found some teeth and gave them a name - the number of genera and species is pretty mind boggling in the shark fossil record. I think we have more dang extinct sharks than any other type of organism... seems pretty funny to me...

Extinct fossil sharks do seem to be the poster child for what the _)(*(^^%^! And MANY genera have been named solely on the basis of isolated teeth, fin spines or dermal denticles. Some of them are very funny. I personally like the Listracanthus and Petrodus dermal denticle issue: ok, so we have these fossils which are restricted to the Paleozoic, and found in many places, often associated with shark remains, but a fossil shark has never been found with deffinitive Listracanthus or Petrodus like denticles - so how in the world can we give a name to something that we say is a shark when we have no idea? Zangerl (1981) dedicates a good amount of discussion to the topic and contends that based on known remains, Petrodus was likely a large animal covered only with petrodi, and possibly come from Carcharopis, a Paleozoic shark with teeth similar to Edestus. He further elaborates that Listracanthus is likely a shark with a dermal skeleton consisting of large numbers of both listracanthi and petrodi.... ok....so I do not get it.... Listracanthus and Petrodus dermal denticles below:

Wow - quite a ramble for me - the short of it is we have a few associated tooth sets for both Otodus and Cretalamna, and very little skeletal material - And again, folks seem to be able to create great taxonomic designations based on tooth design alone - not everyone buys into the Cretalamna - Otodus lineage, but hey, they are cool teeth!

What on earth is that skull?!?! Those are definitely shark teeth, but the jaws seem to be placed oddly(upward pointing teeth on the upper jaw, pointing up into the gums??).  Is that actually the head of a shark?!?!?!?!