Fl Shark Tooth Id

[Ramo]

After he licks it ask him if it taste like urine. No matter how he answers you can always say "How do you know?"

[PaleoRon]

The Chesapeake Bay area, which has extensive middle Miocene marine deposits, has a similar distribution of teeth to south Florida. The majority of the megalodon teeth recovered from the fossiliferous exposures, primarily along the western shore of the bay, are from juvenile megalodons. The incredible abundance and variety of the molluscan biota is indicative of a shallow shelf enviornment. The Miocene Salisbury Embayment, which encompasses the area of the Chesapeake Bay and portions of Delaware, is typically considered to have been a nursery area for juvenile megalodons.

The Paleocene (Thanetian) Aquia formation in Maryland also has an abundant although less varied molluscan assemblage. As in the Miocene formations of the Salisbury Embayment this is indicative of a shallow shelf enviornment. The typical small size of the Otodus teeth found in this formation again support the hypothysis that the larger sharks were using shallow water as a nursery. Considering that megalodon decended from Otodus it is possible that megalodon inherited this behavior from Otodus.

In the Eocene (Ypresian) Nanjemoy formation, which lies above the Aquia formation, there is a very sparse molluscan biota both in number of species and abundance. There is also a noticible lack of ray material which is abundant in the Aquia formation. Specimens of Hercoglossa nautiloids along with the lack of extensive biota and diagnostic clastic deposits are indicative of a deep water deposition. Interestingly, there are very few small Otodus teeth found in this formation but larger specimens, although uncommon, are found in the Nanjemoy with some frequency.

Taken together, collections from the Paleocene, Eocene, and Miocene formations seem to indicate that Otodus and its decendants, regardless of the size differential, preferred shallow water areas for nurseries but not as primary habitat. Even though Otodus was "small" compared to megalodon, some of them were large enough to produce teeth in excess of 4 inches. This was not a small shark.

If you look at the coastline of Morocco you will see that the ocean bottom plunges to a depth of over 4000 meters ( 13,000+ feet) a relatively short distance from the current shoreline. During the Eocene, sealevels were the highest they have been during the Tertiary Period. Increased water depth during this time period in conjunction with a steeply sloping seabottom would have supplied a fairly deep but relatively nearshore enviornment. If this is the case it easily explains the crocodilians, but of course it is also possible that the crocks were fully marine. There is still one species of marine crocodile alive today.

(Whales were just getting started, so to speak, and those large, early whales probably preyed on Otodus, rather than the reverse.)

Yes Harry, whales were just getting started. They were wading around the early Eocene swamps on four legs. Most of the Eocene deposits that are producing the Otodus teeth are around 55 million years old. The earliest "whale" that I have been able to find documentation on shows up about 5 million years later. Even if the earliest whales were contemporary with the latest Otodus, the early whales were not large animals and would have been easy prey for an Otodus.

(This argument becomes even more tenuous when we posit that the deep-water Atlantic deposits that produce adult megalodon teeth might have been the shallow-water nursery for Otodus.)

None of the deposits that produce Otodus teeth that I am familiar with are overlain by deep water deposits that produce megalodon teeth. On the contrary, they are overlain by shallow water deposits that produce primarily juvenile megalodon teeth. Furthermore, the oceans, or land for that matter, are not static. There have been tremendous changes during the past 55 million years and there were tremendous changes during the roughly 25 to 30 million year period between Otodus and megalodon, including the widening and deepening of the Atlantic Ocean which is still occuring today. A good example of land deformation is the Peruvian coast. There are beach deposits 20 or more feet above the current ocean level that are only a few thousand years old. They are there because the land is being uplifted in the continued growth of the Andes Mountains. That is a lot of movement over a short period of time. Multiply that by millions of years and you get a lot of vertical movement. The opposite can also happen and coastlines can go from shallow to very deep given continuous movement and a few million years.

I'm not sure where you got your information, but you might want to consider using another source.

This is the "nursery theory" to explain why there is such a high proportion of small megalodon teeth found in South Florida versus say the Carolinas.

The argument goes like this: The shallow water of a proto-Tampa Bay may have provided a feeding niche that smaller sharks could exploit. Little megalodons grown larger migrated out into the Atlantic waters off the East Coast to hunt whales and walrus and other large prey. This would explain the size distribution of the teeth.

I'm not sure the same theory applies to Moroccan Otodus. For starters, the adult size of Otodus does not approach the adult size of megalodon. Whales were just getting started, so to speak, and those large, early whales probably preyed on Otodus, rather than the reverse.

I don't know enough about the geology of the Oulad Abdoun Basin to talk about water depth. Do you have a reference, Ron? I know that crocodilians are commonly found in the phosphate, and that suggests to me a rather shallow body of water.

This argument becomes even more tenuous when we posit that the deep-water Atlantic deposits that produce adult megalodon teeth might have been the shallow-water nursery for Otodus.

Interesting.

-----Harry Pristis

[PaleoRon]

Sorry I didn't make this more clear... The "hole" is actually a natural thing that's probably been there for a very long time.. You can't tell that it's a hole unless you look at the area on a topographic map, then you can see just how much lower it is than the surrounding area. The contruction site was at the very bottom of the natural "hole"

Hmmm, what do they make these patches out of? I hope it is a patch so I can show it to the guy who had me post this. I tried scratching at that area and it's rock hard... Is there any way to test it to make sure it's not just a discolored area?

The early patch jobs coming out of Morocco years ago were a concoction of flour and milk or cream. They fell apart if it got too humid. Those early specimens often had wax on them as well. The guy I was buying from told me it was because the locals were prepping them at night by candle light. They later moved on to a low grade plaster. The latest repairs I saw were some type of epoxy-like compound.

Most of the repairs are still easy to see but they are definitely getting better at "fixing" the teeth. If you use a decent hand lens you can usually see a change in the texture of the specimen at the juncture of tooth and patch.

The first time I bought a batch of Moroccan Otodus I literally went through several hundred to find around 50 good teeth. That was back in the day when Sahara Seas was located in Florida. The last couple of times I went to Tucson there were thousands of Otodus teeth for sale that had totally fabricated roots. There are still good teeth to be found in Tucson but you have to work to find them.

[Harry Pristis]

Thank you, Ron, for lots of interesting factoids. But, now, let's get to the issue I raised:

I'm not sure the same theory [megalodon nursery] applies to Moroccan Otodus

.

My point about the size of the Otodus was that there wasn't a stark need for a separate and distinct feeding niche between large and small Otodus as there was for megalodon.

Otodus and Archaeocete whales certainly were contemporaneous for a long time, but you are correct to discount their early significance in the Oulad Abdoun Basin (Paleocene-Eocene).

Your first premise is that megalodon favored shallow water nurseries while the adult fish inhabited deeper, near-shore waters.

Your second premise is that since Otodus is related to megalodon, Otodus also must have favored shallow water nurseries while adults inhabited deeper, near-shore waters, i.e. separate habitats or niches as with megalodon.

Your third premise seems to be that a disproportionate number of large Otodus teeth are found in the Oulad Abdoun Basin.

If these premises are true, you argue that the Oulad Abdoun Basin MUST have been a deep-water environment.

What's missing here is any evidence that there is a disproportionate size-gradient in Otodus teeth from these phosphatic beds to support your argument. There is a vast collecting bias in examining these teeth -- the large Otodus teeth get all the attention at every stage. My observation is that there are plenty of smaller teeth which are found with the larger ones.

Here is a description of the Moroccan basin we're discussing:

The sedimentary subbasins of Oulad Abdoun and Timahdit (Morocco) were part of a single marine gulf that extended across Morocco for more than 300 km (west to east) from Late Cretaceous through the Eocene. The differential structural development of this basin resulted in the presence of a stable shelf in Oulad Abdoun and a subsident orogenic zone in Timahdit....

The fact that there is deep water off the coast of Morocco today is simply not germain to this argument because the the phosphate accumulated not in the Atlantic abyss but inland in a gulf. Your example from the coast of Peru, while interesting, is also not dispository in this discussion.

I think that sharks in general prefer shallow-water nurseries for safety and for food resources. Witness the shark pups of multiple species which favor the mangrove shores in the keys. (I don't know what pelagic shark pups do, but some of them may spend their early months in-shore as well -- they have to find safety and food somewhere.)

Megalodon may represent the prime example of this separation of niches/habitats resulting from the enormous size of the adults -- the adults just had to go where the appropriate-size prey was to be found.

We see no evidence that the same stark change in habitat occurred with Otodus in Morocco. If there were a true parallel between Otodus and megalodon, we might find the small Otodus teeth in the gulf (now the Basin) and large Otodus teeth along the Atlantic coast. That is not the distribution we see.

A more cogent parallel might be drawn between the lemon shark and Otodus. Lemon shark pups find safety and food in a few inches of water. As they grow, they venture into deeper and deeper water, though they always live in relatively shallow water, i.e. they are not pelagic sharks. All the evidence (tooth distribution) we see indicates a similar pattern for Otodus.

-----Harry Pristis

[PaleoRon]

Wow Harry, you sure seem to like the word "premise". I don't think 20 years of personally collecting both shallow and deep water deposits that produce Otodus teeth and having purchased several hundred pounds of mixed small Moroccan teeth as well as seeing several thousand larger Moroccan Otodus falls in the realm of "premise". I am not an armchair collector and my information does not only come from published data, but directly from the professional researchers that I have been collecting samples for and also from years of field experience. Anyone with marine science experience who has actually ever collected the U.S. Otodus sites has noticed the direct correlation of shalow water deposits and smaller teeth. There are large teeth found in these deposits occasionally but they are very rare in comparison to the number of smaller teeth that are found.

What's missing here is any evidence that there is a disproportionate size-gradient in Otodus teeth from these phosphatic beds to support your argument. There is a vast collecting bias in examining these teeth -- the large Otodus teeth get all the attention at every stage. My observation is that there are plenty of smaller teeth which are found with the larger ones.

Anyone who has purchased large amounts of bulk small teeth from Morocco, as I did years ago, has noticed that there are relatively few small Otodus teeth in the mix. The Moroccans didn't pull out the small Otodus and throw them away. There are a couple of other types of teeth that would resemble Otodus teeth to someone not overly familiar with shark teeth. Getting your information through reading is a good way to learn, but actual experience is even better, especially since there are many books out there that are not based on actual field work but on other books and "common knowledge".

My point about the size of the Otodus was that there wasn't a stark need for a separate and distinct feeding niche between large and small Otodus as there was for megalodon.

Don't get hung up on the size of the shark. As I said previously Otodus was not a small shark. Modern sharks often have distinct habitats for adults and juveniles. One of the reasons for this is to keep the adults from eating their own young. At least a few types of sharks stop eating a couple of weeks before giving birth and don't resume feeding for several days after. This is presumably to keep the shark from eating the newborn pups. Leaving the birthing area also keeps the female from devouring her young. It's not just the jumbo sharks. Baby sharks are smaller than the parents no matter what species the shark is.

The fact that there is deep water off the coast of Morocco today is simply not germain to this argument because the the phosphate accumulated not in the Atlantic abyss but inland in a gulf. Your example from the coast of Peru, while interesting, is also not dispository in this discussion.

I double checked what I wrote and nowhere did I say the deposit was abyssal. I just pointed out that deep water is relatively close to the coastline. There is presently a fairly steep gradient from the coast to the 4,000 meter level and it is possible that this condition existed during the early Eocene. My example from Peru was to point out that the Earth is not static and yesterday's ocean can be tomorrow's mountain and vice versa. Come on Harry, pay attention.

We see no evidence that the same stark change in habitat occurred with Otodus in Morocco. If there were a true parallel between Otodus and megalodon, we might find the small Otodus teeth in the gulf (now the Basin) and large Otodus teeth along the Atlantic coast. That is not the distribution we see.

When you get a chance e-mail me some photos from your extensive exploration and study of the phosphate deposits in Morocco. They must be interesting. Did you get to ride a camel?

Do you think the reason Otodus doesn't show up on the coast is because the deposits on the coast are too young? Megalodon teeth have been found along the coast of Morocco which would make the deposits Miocene or younger. Changes in sea level as well as tectonic activity have left progressively younger strata west (toward the coast) of the phosphate deposits. You can see the same pattern along the east coast of the U.S. The strata become increasingly younger as you approach the Atlantic Ocean.

Otodus and Archaeocete whales certainly were contemporaneous for a long time, but you are correct to discount their early significance in the Oulad Abdoun Basin (Paleocene-Eocene).

Please let me know where I can find your evidence for this. I can't find any mention of a site that produces both early whales and Otodus. I would like to add that paper to my collection of scientific literature.

What I am finding is that Pakicetus is the oldest "whale" (and probably not fully aquatic) currently known at around 50 million years old. I have personally collected a site in Maryland that has exposures of the transition from Otodus to Carcharocles. Basically the site has teeth that range from typical unserrated Otodus to semi-serrated transitional teeth to fully serrated Carcharocles auriculatus. This site is aproximately 51 to 52 million years old and I have no reason to think that it was just a local occurance. This change was affecting the entire population. I'm no mathematician, but that seems to leave a gap of a million years between the last of the Otodus and the first "whale". If these dates were being applied to terrestrial deposits, a couple of million years might be hard to separate but marine sediment dating is precise in comparison due to the use of foraminifera and other indicator fossils.

[worthy 55]

Sorry I didn't make this more clear... The "hole" is actually a natural thing that's probably been there for a very long time.. You can't tell that it's a hole unless you look at the area on a topographic map, then you can see just how much lower it is than the surrounding area. The contruction site was at the very bottom of the natural "hole"

Hmmm, what do they make these patches out of? I hope it is a patch so I can show it to the guy who had me post this. I tried scratching at that area and it's rock hard... Is there any way to test it to make sure it's not just a discolored area?

Much better Cris, HaHaHa! I see what your talking about now thanks for clearing that up for me. I was about to go on a state road trip to find that hole because it sure would be a fossil gold mine huh .

[Harry Pristis]

Sorry, Ron, bluster is no substitute for logic.

Give us the facts, the numbers, the foram studies, anything scientific to support your assertion that:

The moroccan teeth were deposited in much deeper water than most of the U.S. deposits which is why most of our teeth are juveniles. If they followed the same mechanism as some modern sharks they only entered shallow water to give birth and then immediately left for deep water so they didn't have much of a chance to drop the big adult teeth.

So far, you've expended a lot of words attacking peripheral ideas like word definitions (abyss, 4,000 meters, come on!).

Sometimes you attack me. No, Ron, I didn't ride a camel in Morocco -- I spent my time actually in the Oulad Abdoun Basin with the collectors and brokers of the shark teeth.

You even attack book-learnin' -- what a hoot!

I agreed that we could discount the role of archeocete whales in the Oulad Abdoun gulf. It didn't take much to find an archeocete which may have lived in the gulf contemporaneous with Otodus:

Suborder Archaeoceti,

Himalayecetus subathuensis

- the oldest-known whale fossil, about 53.5 million years old (Ypresian)

Let it go, Ron. Focus on the nursery question.

Otodus was a small shark at a crucial time in its life-cycle -- as a pup. As pups, those Otodus lived with much larger predators, including adult Otodus. The question is, How did those pups protect themselves and/or find food. Did they do that in an environment separate and apart from adult Otodus as did megalodon? If so, where did they go? Or, did the Otodus pups simply retreat to the very shallowest water possible as do lemon sharks.

I don't know how to frame the question any clearer.

This isn't personal, Ron. This is about coming to a clear understanding of a phenomenon -- is it real or not. It's science. Try to keep the discourse on that level.

------Harry Pristis

[PaleoRon]

I agreed that we could discount the role of archeocete whales in the Oulad Abdoun gulf. It didn't take much to find an archeocete which may have lived in the gulf contemporaneous with Otodus:

Suborder Archaeoceti, Himalayecetus subathuensis - the oldest-known whale fossil, about 53.5 million years old (Ypresian)

Good one. A four legged "whale" described from a partial left dentary that was found in India and may have hunted in the shallows. This is the only scientific reference I could find in a quick search. It was written by the researchers of the specimen, Sunil Bajpai and Philip D. Gingerich.

They say:

"Himalayacetus also is significant in showing that some whales probably were partially marine very early in the course of cetacean evolution."

Otodus and Archaeocete whales certainly were contemporaneous for a long time, but you are correct to discount their early significance in the Oulad Abdoun Basin (Paleocene-Eocene).

I saw no mention of Otodus in the article I read, but if you want to get technical I suppose that they were contemporaneous since they both lived at the same time, but I doubt they lived in the same enviornment.

This argument becomes even more tenuous when we posit that the deep-water Atlantic deposits that produce adult megalodon teeth might have been the shallow-water nursery for Otodus.)

I wrote: None of the deposits that produce Otodus teeth that I am familiar with are overlain by deep water deposits that produce megalodon teeth. On the contrary, they are overlain by shallow water deposits that produce primarily juvenile megalodon teeth.

Focus on the nursery question.

Otodus was a small shark at a crucial time in its life-cycle -- as a pup. As pups, those Otodus lived with much larger predators, including adult Otodus. The question is, How did those pups protect themselves and/or find food. Did they do that in an environment separate and apart from adult Otodus as did megalodon? If so, where did they go? Or, did the Otodus pups simply retreat to the very shallowest water possible as do lemon sharks.

I wrote: The moroccan teeth were deposited in much deeper water than most of the U.S. deposits which is why most of our teeth are juveniles. If they followed the same mechanism as some modern sharks they only entered shallow water to give birth and then immediately left for deep water so they didn't have much of a chance to drop the big adult teeth.

I backed it up with this:

The Paleocene (Thanetian) Aquia formation in Maryland also has an abundant although less varied molluscan assemblage. As in the Miocene formations of the Salisbury Embayment this is indicative of a shallow shelf enviornment. The typical small size of the Otodus teeth found in this formation again support the hypothysis that the larger sharks were using shallow water as a nursery.

In the Eocene (Ypresian) Nanjemoy formation, which lies above the Aquia formation, there is a very sparse molluscan biota both in number of species and abundance. There is also a noticible lack of ray material which is abundant in the Aquia formation. Specimens of Hercoglossa nautiloids along with the lack of extensive biota and diagnostic clastic deposits are indicative of a deep water deposition. Interestingly, there are very few small Otodus teeth found in this formation but larger specimens, although uncommon, are found in the Nanjemoy with some frequency.

Researchers place the depth of the shallow deposits in Maryland that produce Otodus at around 300 feet deep. These depths were derived from studies of the marine biota in the deposit. The adult habitat may have only been in 600 to 1000 feet of water but I have seen no data on this subject.

You even attack book-learnin' -- what a hoot!

I wrote:

I am not an armchair collector and my information does not only come from published data, but directly from the professional researchers that I have been collecting samples for and also from years of field experience.

Getting your information through reading is a good way to learn, but actual experience is even better, especially since there are many books out there that are not based on actual field work but on other books and "common knowledge".

You will notice I said many, not all. Something I have learned over the years is that there is no substitute for actual experience. And yes, I have seen manyl books on fossils that were very substandard in their information.

Sometimes you attack me.

Harry, you seen more interested in arguing than anything else. You keep throwing more "bluster" up as your "factoids" get knocked down. You constantly use diversionary tactics instead of evidence. I have seen you do it before on this forum, and frankly I have no interest in dealing with it and I would be shocked if I am the only one who feels that way. I have known many people who operate in this way and I have learned that it is useless to persue a dialog that will never end. You keep pushing the issue and asking for proof, which I have given from my extensive personal experience, yet you have no evidence to the contrary other than evidence that doesn't hold up well under scrutiny. It seems that you argue for the sake of arguing, nothing more. It becomes tiresom quickly.

I have around 30 years experience collecting and studying fossils, but I have only been collecting areas that produce Otodus for about 20 years. I have collected these sites for my own pleasure and knowledge as well as for researchers from the United States Geological Survey and the Smithsonian Institution. I have personally collected hundreds of Otodus teeth over the years. I am not new to this discipline. The knowledge that I have actually comes from doing field research. If you have some concrete evidence from someone who has had half of my field experience in dealing with Otodus please share it with all of us. I am more than willing to change my opinion if I see actual evidence that I am incorrect. Don't badger me with cries of more proof when you have none yourself. I have written my proof and pointed out your fallacies.

I have an extensive base of paleontological knowledge and several friends who are professional paleontologists who I can mine for a wealth of data. The more I learn, the more I realize how much there is to learn and by association how little I truly know. I couldn't learn everything about paleontology if I had a dozen lifetimes to spend on the field.

Even though I do know a lot about paleontology I don't pretend to know everything.

If you have solid data then share it. I will not continue to banter with you for your amusement.

If you want to play games, play with yourself.

[Northern Sharks]

As much as I'm interested in this subject matter, as a moderator here, I think I should step in and say that this seems to be getting a bit too heated. If there are facts to be presented, please do so, but PLEASE, no more "I'm right, you're wrong" type arguing. Thanks.

[PaleoRon]

As much as I'm interested in this subject matter, as a moderator here, I think I should step in and say that this seems to be getting a bit too heated. If there are facts to be presented, please do so, but PLEASE, no more "I'm right, you're wrong" type arguing. Thanks.

I am finished with this conversation or any others with Harry.

[Harry Pristis]

As much as I'm interested in this subject matter, as a moderator here, I think I should step in and say that this seems to be getting a bit too heated. If there are facts to be presented, please do so, but PLEASE, no more "I'm right, you're wrong" type arguing. Thanks.

The real art of conversation is not only to say the right thing at

the right time but also to leave unsaid the wrong thing at the

tempting moment. -----Steven Wright (?)

[non-remanié]

This has been an interesting and heated topic... I will reserve comment on that but I would like to add that Otodus teeth of all sizes have been reported from the Eocene of NJ. "A description of the fossil fish remains of the Cretaceous, Eocene and Miocene formations of New Jersey (1911)" NJGS Publication reports Otodus teeth up to 84mm or 3.3". This is probably not measuring slant height, so I would imagine some might even approach 4" slant. In fact, I have heard from a reliable source of a collector finding a 4" specimen in the past 10 years. Unfortunately, most of the older reports of NJ Otodus come from marl pits in the 1800s and there are very few working exposures of the productive formations.

It is just my opinion, but I would say that the general abundance of large Moroccan Otodus teeth is mostly a function of economics. The decline of supply in recent years would be evidence for this, as prices have significantly dropped except the very few un-repaired pristine specimens. The locals who actually were collecting the fossils probably are paid much less than 5 cents on the dollar (retail). It also seems to me that there are plenty of Otodus of every size available. I have seen 100s or even 1000s of pathologic Otodus for sale and they are mostly small ones. Even considering the fairly large deformity rate in Otodus, there is obviously no short supply of small specimens.

[Uncle Paleo]

Thanks to Ron and Harry for providing us with a spirited discussion on Otodus obliquus. I've been a frequent visitor to the Potomac River Aquia and Nanjemoy sites for several years and have accumulated a fair share of otodus teeth, although probably not as extensive as Ron's. One thing that has always puzzled me is the lack of whale vertebrae from the site. (On the Chesapeake Bay western shoreline you can always find whale, dolphin or porpoise vertebrae in the vicinity of a megalodon tooth.) One could conclude that the vertebrae were absent from otodus' diet simply because there weren't any whales around during the Paleocene and Eocene, except for a stray squalodont in the late Eocene. But, how do you explain the broken tips on the larger otodus teeth? With no whales around, the otodus must have been feeding on something that was large and bony enough to crack those three-inch teeth. The only other marine animal remains from the Paleocene/Eocene that are found along the Potomac are crocodile and turtle. But, it's doubtful that these two creatures ventured far out from the safety of a marsh or bay. Perhaps the otodus was more of a near-shore feeder in the manner of today's orca's or the crocodiles and turtles ranged farther out into the ocean like today's saltwater crocs and loggerhead turtles. What say you two?

[non-remanié]

The Chesapeake Bay area, which has extensive middle Miocene marine deposits, has a similar distribution of teeth to south Florida. The majority of the megalodon teeth recovered from the fossiliferous exposures, primarily along the western shore of the bay, are from juvenile megalodons. The incredible abundance and variety of the molluscan biota is indicative of a shallow shelf enviornment. The Miocene Salisbury Embayment, which encompasses the area of the Chesapeake Bay and portions of Delaware, is typically considered to have been a nursery area for juvenile megalodons.

The Paleocene (Thanetian) Aquia formation in Maryland also has an abundant although less varied molluscan assemblage. As in the Miocene formations of the Salisbury Embayment this is indicative of a shallow shelf enviornment. The typical small size of the Otodus teeth found in this formation again support the hypothysis that the larger sharks were using shallow water as a nursery. Considering that megalodon decended from Otodus it is possible that megalodon inherited this behavior from Otodus.

In the Eocene (Ypresian) Nanjemoy formation, which lies above the Aquia formation, there is a very sparse molluscan biota both in number of species and abundance. There is also a noticible lack of ray material which is abundant in the Aquia formation. Specimens of Hercoglossa nautiloids along with the lack of extensive biota and diagnostic clastic deposits are indicative of a deep water deposition. Interestingly, there are very few small Otodus teeth found in this formation but larger specimens, although uncommon, are found in the Nanjemoy with some frequency.

As far as I know...

Paleocene Aquia fm of Md & Va:

Piscataway member: shallow marine, abundant lignite, slow deposition and known for small Otodus teeth in the range of 1"-2"

Paspotansa member: more offshore deposit as is noted by less lignite and better sorted sediments and the appearance of abundant turritella --- although still fairly rare it is known for larger Otodus teeth of 2"-3" (the Piscataway almost never produces Otodus teeth of this size, but is packed with 1"-2" specimens)

But...

Eocene Nanjemoy fm. of Md & Va:

Potapaco member: near-shore marine, deposited in shallow tropical seas, noted for a very famous collecting locale in Va that uncommonly produces Otodus, but they are always larger, 2"-3"

[non-remanié]

Thanks to Ron and Harry for providing us with a spirited discussion on Otodus obliquus. I've been a frequent visitor to the Potomac River Aquia and Nanjemoy sites for several years and have accumulated a fair share of otodus teeth, although probably not as extensive as Ron's. One thing that has always puzzled me is the lack of whale vertebrae from the site. (On the Chesapeake Bay western shoreline you can always find whale, dolphin or porpoise vertebrae in the vicinity of a megalodon tooth.) One could conclude that the vertebrae were absent from otodus' diet simply because there weren't any whales around during the Paleocene and Eocene, except for a stray squalodont in the late Eocene. But, how do you explain the broken tips on the larger otodus teeth? With no whales around, the otodus must have been feeding on something that was large and bony enough to crack those three-inch teeth. The only other marine animal remains from the Paleocene/Eocene that are found along the Potomac are crocodile and turtle. But, it's doubtful that these two creatures ventured far out from the safety of a marsh or bay. Perhaps the otodus was more of a near-shore feeder in the manner of today's orca's or the crocodiles and turtles ranged farther out into the ocean like today's saltwater crocs and loggerhead turtles. What say you two?

I think it is clear that the crocs and turtles inhabited the same waters as Otodus just from collecting the sites you must have also visited many times. The Piscataway member of the Aquia was deposited in a shallow marine environment, perhaps 1-10 miles offshore according to elasmo.com. I am not sure if that is further than modern types range or not, but I would guess it is not. The Pine cones and abundant lignite in the formation probably indicate the presence of barrier islands as well. The fragmentary and disarticulated nature of the croc and turtle remains are probably a result of the slow deposition and scavenging.

[non-remanié]

bump

[va paleo]

if not Otodus it something like it Otodus did the points at ends of tooths like ones in cris pics