Time for the Bullheads ! Show us your Heterodontus fossils

[fossilsonwheels]

The next shark on the list to start a thread for are the Bullhead Sharks. The order is represented by a lone extant genus, Heterodontus, and a few extinct genera. Heterodontus is a cute little shark. One of my personal favorites partially because they look like they should not be a rugged survivor but they really are. They have been around since the early Jurassic and basically have not had to change much to survive. They are not the torpedo shaped super shark for sure. They are small, sluggish bottom feeders but they are incredibly well adapted to their environment. They have very powerful jaws designed for crushing shelled prey but they are also opportunistic feeders that will also eat small fish. Some are strictly nocturnal and some are capable of "walking"along the sea floor using pelvic fins. Extant genera are limited to the Pacific and Indian Oceans though the fossil record shows they used to live in the Atlantic Ocean.

 

Heterodontus has been proven to be a bit of collecting challenge. The small size of the teeth and the rather unshark-like appearance probably contribute to this. They are not common despite the long history of the order.  There are a few locations where they appear to be pretty common.  They are common in the Round Mountain Silt if you are willing to do micro matrix searches. I see a pretty fair number of teeth from the Eocene of the UK too. Lateral teeth are larger and pretty easy to identify. The anterior teeth are usually pretty small. I used to confuse them with ray teeth on occasion lol Fin spines can be found as well. We have one from STH and I have seen one from Chile as well.

 

The hope with all of these posts is to encourage TFF members to show off their fossils and build knowledge. I am really curious to see what Bullhead fossils are lurking the collections here and what interesting information is shared !!!

[fossilsonwheels]

Our collection begins in the Jurassic. We have to different genera from the same location. 

 

Heterodontus cf semirugosus

Jurassic 

Ringstead Bay

Weymouth UK

[fossilsonwheels]

Paracestracion falcifer 

Jurassic 

Ringstead Bay

Weymouth UK 

[fossilsonwheels]

We recently found a tooth from the Atco Formation that is a dead ringer for the Heterodontus tooth in Hamm’s paper on that formation. Very happy find. Only our second Cretaceous tooth. It is a tiny tooth at 1mm 

 

Heterodontus sp

Cretaceous

Atco Formation 

Texas

 

 

[fossilsonwheels]

Another tooth from the Cretaceous of Texas. A real beauty. A large lateral tooth. 

 

Heterodontus granti

Cretaceous 

Kemp Clay

South Sulphur River

Texas

[fossilsonwheels]

I’m skipping ahead on the time line and I’ll get to some Eocene examples later but I wanted to get to some of really cool STH stuff we have. 

 

Heterodontus sp 

Miocene 

Round Mountain Silt

Kern Co California 

 

Some anterior teeth

[fossilsonwheels]

Some lateral and anterolateral teeth. 

[fossilsonwheels]

Fin spine. I should take a better picture but I’ll do it later. A hair over 2”. 

[caterpillar]

Heterodontus sp from aptian of southeast France

 

 

Heterodontus sp from lower thanetian of southwest France

 

[fossilsonwheels]

17 minutes ago, caterpillar said:

Heterodontus sp from aptian of southeast France

 

 

Heterodontus sp from lower thanetian of southwest France

 

Awesome teeth. I’ve never seen any from France myself so thanks for posting. Really excellent teeth from a cool location. 

[DatFossilBoy]

Heterodontus sp.

Late Cenomanian

Ryazan Oblast

Russia

 

[digit]

Just recently found the first recorded Heterodontus sp. lateral crushing tooth from the late Miocene (~5.5 Ma) while picking micro-matrix from the Montbrook site in north-central Florida (scale=0.5 mm).

 

Cheers.

 

-Ken

 

 

 

 

[fossilsonwheels]

9 hours ago, DatFossilBoy said:

Heterodontus sp.

Late Cenomanian

Ryazan Oblast

Russia

 

Very nice tooth and great location! Thanks for posting 

[fossilsonwheels]

6 hours ago, digit said:

Just recently found the first recorded Heterodontus sp. lateral crushing tooth from the late Miocene (~5.5 Ma) while picking micro-matrix from the Montbrook site in north-central Florida (scale=0.5 mm).

 

Cheers.

 

-Ken

 

 

 

 

Hi Ken 

 

Fantastic find. Scientifically relevant and a really beautiful tooth to boot. That particular location yields some great teeth. I loved the Catshark teeth you posted plus this one. Great stuff 

 

Kurt

[digit]

Of course, Cookiecutter Creek gave up some nice Heterdontus sp. as well--mostly lateral crushing teeth but at least one tiny gripping anterior tooth.

 

Cheers.

 

-Ken

 

 

 

[fossilsonwheels]

5 minutes ago, digit said:

Of course, Cookiecutter Creek gave up some nice Heterdontus sp. as well--mostly lateral crushing teeth but at least one tiny gripping anterior tooth.

 

Cheers.

 

-Ken

 

 

 

Those are fantastic. It didn’t give up any to us but I’m glad you found some. Those Florida finds raise some questions as to why they are absent from other East Coast locations. So cool and thanks for sharing Ken  

[digit]

The Heterodontus sp. teeth are actually much rarer than the Cookiecutter Shark  (Isistius triangulus) teeth at this site. It was having the search image from finding these lateral crushing teeth at Shark Tooth Hill (STH) that enabled me to recognize these when they turned up in my picking plate of CC Creek micro-matrix.

 

I do know that a Heterodontus species is found in the Muddy Creek matrix (Nanjemoy Formation, Eocene) from Virginia as a friend send me some which I donated to the FLMNH for comparative material.

 

 

Cheers.

 

-Ken

[fossilsonwheels]

I put this cool and tiny tooth in an ID thread here but I got neither a confirmation of ID or another suggestion so I’m going with my ID. I believe I found an anterior Heterodontus from the Cretaceous micro matrix I’ve been searching. The second such find recently but a different formation and state. I am using the geological information I was given. 

 

Heterodontus sp 

Late Cretaceous 

Rollins Member 

Mesaverde Formation 

Colorado

 

Just over 1mm so it’s tiny but looks quite similar to the Atco tooth only more complete. I may have found a second one just yesterday. 

[siteseer]

On 3/10/2021 at 3:11 PM, fossilsonwheels said:

Those are fantastic. It didn’t give up any to us but I’m glad you found some. Those Florida finds raise some questions as to why they are absent from other East Coast locations. So cool and thanks for sharing Ken  

 

Hi Kurt,

 

Horn sharks like warm-temperate waters and particular habitats and are never particularly common.  It is not a particularly common tooth from any of its known fossil sites (we're lucky to find some in the STH Bonebed when screening) and the lateral teeth might evade detection as Ken suggests because they don't look like the stereotypical shark tooth.  It evolved in shallow tropical seas of the Jurassic and spread to its modern distribution as the continents drifted apart.  It is known from the Aquia (late Paleocene) and Nanjemoy Formation (early Eocene) as we might expect as that was an interval of warm worldwide climates but it becomes harder to find across the Oligocene-Miocene of the east coast of North America as climates cooled.  Florida would have been the last refuge of the genus along that coast.  I'm not sure why it is not known from Florida today but it must have something to do with habitat as much as temperature.  You don't see horn sharks in the Atlantic.

 

I've seen Heterodontus from the Oligocene-Miocene of Argentina but you don't see them that far south off South America today.

 

Jess

 

 

[digit]

Splendid primer on the family.

 

 

Cheers.

 

-Ken

[siteseer]

Yeah but I just noticed that it's basically a restatement of what Kurt already said.  I'll try to get some photos of what I have.  As Kurt said, some of the anteriors are quite small so they are tough to photograph but I have some lateral teeth from scattered sites and a couple of fin spines.

 

I can add that the H. granti tooth is rare and that the Kemp Clay is latest Cretaceous age.  There was a time when a few collectors were hunting for the tiny teeth from the river site(s) but I haven't heard about fresh material being available.  What you see for sale tends to come from someone letting go of something from an old collection.

 

Because horn shark material is a little more common from the STH Bonebed, it takes less time for one person to collect a wider variation in tooth shape though it involves a lot of screening.  Sometimes you see more development of the transverse ridge in a lateral tooth with cusp-like projections extending from it. 

 

Jess

[digit]

I learned about Heterodontus laterals from STH material allowing me to have the search image burned into my memory banks which enabled me to spot (and instantly recognize) the Heterodontus from Cookiecutter Creek here in Florida. There are usually 1-3 Heterodontus teeth (usually partials but frequently complete) per 5-gallon bucket (25 kg) of micro-matrix from the CC Creek site. They are not as rare as catshark (Scyliorhinidae) teeth at this location (maybe 1 every other 5-gallon bucket if you are lucky).

 

I spotted a most unusual "Heterodontus" tooth a couple years back from CC Creek which had the longitudinal ridge but none of the perpendicular wrinkly ridges from the longitudinal ridge to the edge of the teeth. It also had a root that was bilobed (if weakly so). This was a minor mystery till I showed photos to Richard Hulbert who recognized it from a similar find in Alabama some years back. Turns out it is the lateral (also crushing) tooth of the smallest member of the hammerhead shark family--Bonnethead Shark (Sphyrna tiburo). The fact that hard-shelled invertebrates feature prominently in the diet of this species of shark explains the convergent evolution of tooth form and function.

 

    

 

The front teeth are grasping (like Heterodontus) but shaped significantly different from their anteriors.

 

        

 

Cheers.

 

-Ken

 

[fossilsonwheels]

32 minutes ago, digit said:

I learned about Heterodontus laterals from STH material allowing me to have the search image burned into my memory banks which enabled me to spot (and instantly recognize) the Heterodontus from Cookiecutter Creek here in Florida. There are usually 1-3 Heterodontus teeth (usually partials but frequently complete) per 5-gallon bucket (25 kg) of micro-matrix from the CC Creek site. They are not as rare as catshark (Scyliorhinidae) teeth at this location (maybe 1 every other 5-gallon bucket if you are lucky).

 

I spotted a most unusual "Heterodontus" tooth a couple years back from CC Creek which had the longitudinal ridge but none of the perpendicular wrinkly ridges from the longitudinal ridge to the edge of the teeth. It also had a root that was bilobed (if weakly so). This was a minor mystery till I showed photos to Richard Hulbert who recognized it from a similar find in Alabama some years back. Turns out it is the lateral (also crushing) tooth of the smallest member of the hammerhead shark family--Bonnethead Shark (Sphyrna tiburo). The fact that hard-shelled invertebrates feature prominently in the diet of this species of shark explains the convergent evolution of tooth form and function.

 

    

 

The front teeth are grasping (like Heterodontus) but shaped significantly different from their anteriors.

 

        

 

Cheers.

 

-Ken

 

Hi Ken 

 

 I found an STH tooth that was really odd. Multiple ridges that really look like cusps but the tooth looked like a lateral. Jess explained that it was a transitional tooth from juvenile to adult. Remains the oddest Heterodontus tooth I’ve found. I agree with Jess that STH is a place that you can find a wide variety of teeth from different positions and different aged sharks. It greatly expanded my understanding of the complexity of their teeth. 

 

I love that Bonnethead tooth. Super cool. 

 

Kurt

[fossilsonwheels]

1 hour ago, siteseer said:

Yeah but I just noticed that it's basically a restatement of what Kurt already said.  I'll try to get some photos of what I have.  As Kurt said, some of the anteriors are quite small so they are tough to photograph but I have some lateral teeth from scattered sites and a couple of fin spines.

 

I can add that the H. granti tooth is rare and that the Kemp Clay is latest Cretaceous age.  There was a time when a few collectors were hunting for the tiny teeth from the river site(s) but I haven't heard about fresh material being available.  What you see for sale tends to come from someone letting go of something from an old collection.

 

Because horn shark material is a little more common from the STH Bonebed, it takes less time for one person to collect a wider variation in tooth shape though it involves a lot of screening.  Sometimes you see more development of the transverse ridge in a lateral tooth with cusp-like projections extending from it. 

 

Jess

Hi Jess 

 

Thank you so much for stopping by to drop knowledge on us ! Always new information from you. 

 

I have only seen a couple of the Kemp Clay teeth pop up. I was lucky to get one and it’s pretty large to boot. I found several anteriors in the Cretaceous matrix I have from Colorado.  Last count was 5. Also found one in some Atco matrix. No lateral teeth yet. Very exciting finds. 

 

Kurt

[digit]

21 minutes ago, fossilsonwheels said:

I found an STH tooth that was really odd. Multiple ridges that really look like cusps but the tooth looked like a lateral.

Would love to see a photo (or two) of that tooth if you can easily lay your mitts on it.

 

 

Cheers.

 

-Ken