Jump to content

Recommended Posts

siteseer

Your program sounds interesting.  About 20 years ago, I gave a talk on the history of sharks at the Buena Vista Museum in Bakersfield.  There was an overview of Paleozoic chondrichthyans and how the end-Permian mass extinction nearly wiped them all out.  I covered the Mesozoic groups with the establishment of the modern orders by the Cretaceous (early carcharhiniforms by the late Cretaceous).  I discussed the orders as part of a mini-review of the Middle Miocene Sharktooth Hill fauna.

 

The thing I wanted to get across and it seems like what you are doing is that sharks have been like any other group that has managed to survive a decent stretch of geologic time.  They have suffered minor losses along the way and major ones a couple of times followed by times of recovery - new forms.  The large predators of the Cretaceous did not survive into the Cenozoic and the ones of the Early Cenozoic are not the ones we know today.  Meanwhile, many smaller sharks of the Cretaceous (sixgills, angel sharks, horn sharks, soupfin sharks, dogfish, etc.) still live today.  It's tough to stay top dog for any length of time no matter how big your teeth are.

 

 

Share this post


Link to post
Share on other sites
fossilsonwheels
13 minutes ago, siteseer said:

Your program sounds interesting.  About 20 years ago, I gave a talk on the history of sharks at the Buena Vista Museum in Bakersfield.  There was an overview of Paleozoic chondrichthyans and how the end-Permian mass extinction nearly wiped them all out.  I covered the Mesozoic groups with the establishment of the modern orders by the Cretaceous (early carcharhiniforms by the late Cretaceous).  I discussed the orders as part of a mini-review of the Middle Miocene Sharktooth Hill fauna.

 

The thing I wanted to get across and it seems like what you are doing is that sharks have been like any other group that has managed to survive a decent stretch of geologic time.  They have suffered minor losses along the way and major ones a couple of times followed by times of recovery - new forms.  The large predators of the Cretaceous did not survive into the Cenozoic and the ones of the Early Cenozoic are not the ones we know today.  Meanwhile, many smaller sharks of the Cretaceous (sixgills, angel sharks, horn sharks, soupfin sharks, dogfish, etc.) still live today.  It's tough to stay top dog for any length of time no matter how big your teeth are.

 

 

That is really interesting. I wish you had a video of that talk. Yes you understand exactly what we are aiming for. We hit the adaptation science standards for 3rd/4th grade and do so by explaining that bigger or flashier is part of shark evolution but it is often the small and simple design that survives the longest. Sharks are something kids know and they will be able to grasp the concepts. If we do our job right, they also have a much deeper appreciation for sharks and their importance to the planet.

 

STH is very important to our programs. Our marine mammal program will be 90% STH species and it is really important to our Miocene sharks too. I grew up in Fresno and my only fossil hunting trips have been to that area. It will be fun to connect kids to an important fossil area at the other end of the Great Valley !

Share this post


Link to post
Share on other sites
fossilsonwheels

I thought I would add this as well. Carter's first Scapnorhynchus drawing. This is a copy. The original was given to his grandparents. This is the type of stuff he is working on for our program.

20190112_210607.jpg

Share this post


Link to post
Share on other sites
siteseer
On 2/5/2019 at 11:13 PM, fossilsonwheels said:

That is really interesting. I wish you had a video of that talk. Yes you understand exactly what we are aiming for. We hit the adaptation science standards for 3rd/4th grade and do so by explaining that bigger or flashier is part of shark evolution but it is often the small and simple design that survives the longest. Sharks are something kids know and they will be able to grasp the concepts. If we do our job right, they also have a much deeper appreciation for sharks and their importance to the planet.

 

STH is very important to our programs. Our marine mammal program will be 90% STH species and it is really important to our Miocene sharks too. I grew up in Fresno and my only fossil hunting trips have been to that area. It will be fun to connect kids to an important fossil area at the other end of the Great Valley !

 

Right, the bigger you are, the more surprisingly more vulnerable you become.  You need to eat more and you tend to get specialized. It's tougher to find shelter during a storm.  If you're smaller and aren't too picky about what you eat, you can get by with less.  Generalists do better through tough times than specialists.

 

The STH Bonebed is my favorite layer.  If you dig it long enough, you can build a nice sample of sharks, rays, bony fishes, and marine mammals.  You can find parts of sea turtles and learn about what bird bones tend to preserve.  You can learn general anatomy from Allodesmus, the extinct pinniped, and how its limb proportions are different from humans and what that says about how it moved around.  You can learn about how different the whales were at that time from what we see today.

 

Yeah, kids like sharks and dinosaurs.  From either of those subjects you can teach a lot of science - geology and deep time, climate, biology, ecology, etc.  Even better, you can draw a dinosaur eating a shark or a shark eating a dinosaur.

 

Share this post


Link to post
Share on other sites
fossilsonwheels
5 hours ago, siteseer said:

 

Right, the bigger you are, the more surprisingly more vulnerable you become.  You need to eat more and you tend to get specialized. It's tougher to find shelter during a storm.  If you're smaller and aren't too picky about what you eat, you can get by with less.  Generalists do better through tough times than specialists.

 

The STH Bonebed is my favorite layer.  If you dig it long enough, you can build a nice sample of sharks, rays, bony fishes, and marine mammals.  You can find parts of sea turtles and learn about what bird bones tend to preserve.  You can learn general anatomy from Allodesmus, the extinct pinniped, and how its limb proportions are different from humans and what that says about how it moved around.  You can learn about how different the whales were at that time from what we see today.

 

Yeah, kids like sharks and dinosaurs.  From either of those subjects you can teach a lot of science - geology and deep time, climate, biology, ecology, etc.  Even better, you can draw a dinosaur eating a shark or a shark eating a dinosaur.

 

That is exactly what we want to get across. Generalists survive and specialist can end up being far more vulnerable.  It is an important idea to talk about what when doing adaptation education.

 

I am fascinated by whale evolution and I am really looking forward to building a lab about it. STH stuff is the cornerstone of this one. From what I can gather by looking at research that is out there, the Miocene is a time of rapid evolution in whales and important adaptations begin appearing as species transition toward our modern whales, like the development of sonar and migration to avoid mega sharks. The fun part of that lab is it is about classification so we will have some known species but also some undescribed species. I have a few teeth and bones from at least one, maybe two, undescribed odontoceti species. They might be Kentriodon which is a link to modern dolphins. We have species that link to modern sperm whales and modern baleen whales but are very different from those. I am still putting this program together but it may end up being my favorite. Allodesmus and Desmostylus will be in the program too.

 

It is funny that you mention that. I was talking to my son yesterday about drawing the theropd Richardoestesia gilmorei as looking like a cormorant or merganser and chasing after a little Lissodes. I have read that it is believed to have been a fish eater so we discussed drawing it as such. Having it chase a little shark would be a way to further describe the fauna of Hell Creek which included tiny freshwater sharks. I doubt kids realize that tiny sharks were living with the giant dinosaurs. My son also wanted to depict Cretoxyrhina doing battle with a marine reptile of the age. Endless artistic possibilities.

Share this post


Link to post
Share on other sites
ynot
On 2/5/2019 at 11:14 PM, fossilsonwheels said:

Carter's first Scapnorhynchus drawing.

Nice rendition! Your son is a nice artist.

 

One thing though... whales and marine reptiles have a tail that spreads out to the sides and fish or shark tails spread out top and bottom.

The shark has the wrong tail type.:D

Share this post


Link to post
Share on other sites
fossilsonwheels
23 minutes ago, ynot said:

Nice rendition! Your son is a nice artist.

 

One thing though... whales and marine reptiles have a tail that spreads out to the sides and fish or shark tails spread out top and bottom.

The shark has the wrong tail type.:D

Excellent observation. This was his first rendition of a goblin. He drew this one in about an hour while he was at the museum we work for. We have discussed the tail and also rounding off the snout. The holotype of S. lewisii has a much more rounded snout. I think one of the renderings I gave him had the tail wrong and it seems that is what he based it on. He is still in the rough draft phase with the art and is still in high school so we will not have the full array of finished art until the fall of this year.

Share this post


Link to post
Share on other sites
siteseer
10 hours ago, ynot said:

Nice rendition! Your son is a nice artist.

 

One thing though... whales and marine reptiles have a tail that spreads out to the sides and fish or shark tails spread out top and bottom.

The shark has the wrong tail type.:D

 

 

Oh, c'mon Tony.  Can't you let the kid have a little artistic license?  He doesn't adhere to photorealistic views of the natural world in his art.  It reminded me of the kind of tail in those sea monster drawings on old maps back when they thought California was an island or even before that.  I think it's a brilliant interpretation.  Thought provoking.

 

Jess

Share this post


Link to post
Share on other sites
siteseer
On 2/5/2019 at 4:55 PM, fossilsonwheels said:

After the Hybodontids, our program starts to transition toward the modern sharks. We introduce lamniform sharks and the cow sharks. We will not be able to spend much time at all on the Cow and Crow Sharks. They only get a brief introduction and a look at the teeth. Squalicorax is an important species for us even though we do not spend a lot of time on it. The students in first few classes we do presentations for will be going home with Squalicorax teeth from Morocco. We would like to spend more time on the Cow sharks eventually but we only have one tooth to show them and we will have to edit content to free up space for them but I will work on that down the road.

 

The primary focus in this section is Scapanorhynchus. The first shark art Carter did was a Goblin and we do give them a lot of time in the presentaton. They look cool and have been around for a long time. We present the kids with a nice assortment of teeth and some cool science. The teeth were important adaptations for catching fish and the snout had the ampullae of Lorenzini for sensing changes in the electro magnetic fields around them. We compare this to the modern hammerhead which we do not cover in the program but gives the kids a sense of how the adaptations of hammerheads work. We also talk about fin structure and being able to tell they were slow swimmers. The extend-o-matic jaw is another adaptation we cover with this species.

 

I am happy with the fossil representations for now though I really want to add more Cow Shark fossils at some point and Anomotodon would also be a good addition.

 

The fossils for the presentation..

 

Pic 1 Hexanchus andersoni from STH. I know H. andersoni should chronologically fit later but Cow Sharks fit here and this is the only one we have for now.

Pic 2- Squalicorax pristodontus from Morocco. This is our largest Squalicorax tooth. The kids will get these teeth to take home so while we do not spend a lot of time on them, the teeth are very important to the program.

Pic 3- Scapnorhynchus texanus and Scapanorhynchus puercoensis. Our nice little Goblin Shark display with some of our best teeth. Two of the texanus teeth are over 1.5 inches and the puercoenisis teeth are uncommon I believe and pretty super cool.

20190205_163910.jpg

 

 

 

Yes, H. andersoni is a good example for the order Hexanchiformes.  You can usually find an identifiable tooth or two within 4 hours of digging the STH Bonebed so it's probably the easiest low-cost option for the group.  Cretaceous hexanchid teeth tend to be uncommon wherever they occur.

 

The nice thing about the bonebed is that you can find examples of 6 of the 7 modern shark orders and the two modern ray orders in that.  A Low-cost example of the Orectolobiformes would be Nebrius teeth from the Early Eocene of Morocco unless you know someone who finds related forms in their own neck of the woods.

 

Jess

 

 

 

Share this post


Link to post
Share on other sites
fossilsonwheels
7 hours ago, siteseer said:

 

Yes, H. andersoni is a good example for the order Hexanchiformes.  You can usually find an identifiable tooth or two within 4 hours of digging the STH Bonebed so it's probably the easiest low-cost option for the group.  Cretaceous hexanchid teeth tend to be uncommon wherever they occur.

 

The nice thing about the bonebed is that you can find examples of 6 of the 7 modern shark orders and the two modern ray orders in that.  A Low-cost example of the Orectolobiformes would be Nebrius teeth from the Early Eocene of Morocco unless you know someone who finds related forms in their own neck of the woods.

 

Jess

 

 

 

That is super helpful information. Ideally we get teachers to go for a two part presentation and lab in the fall because I want to expand on the number of species we cover including the cows so I need to start learning more about Hexanchiformes teeth.

Share this post


Link to post
Share on other sites
ynot
21 hours ago, fossilsonwheels said:

I need to start learning more about Hexanchiformes teeth.

Have You seen these websites...

http://elasmo.com/   and   http://naka.na.coocan.jp/

 

They have some good information on shark and ray species.

Share this post


Link to post
Share on other sites
fossilsonwheels
1 hour ago, ynot said:

Have You seen these websites...

http://elasmo.com/   and   http://naka.na.coocan.jp/

 

They have some good information on shark and ray species.

I use Elasmo.com frequently. I love that site. I have had not heard of the other site you mentioned. I will check that out. Thank you.

Share this post


Link to post
Share on other sites
siteseer

Just to get back to the idea of low-cost examples, you will likely run into problems coming up with a constant supply of shark teeth if you tie yourself to particular genera and species.  Back in the 90's a friend taught 5th grade in Orange County, CA and her husband was a mineral/fossil dealer.  Her budget for science materials was $50 for the whole school year.  Fortunately, her husband made it his mission to find extra stuff for her class.  I used to make displays with 8 x 12 Riker Mounts.  I think I made two different ones of Oligocene mammal teeth, jaw sections, and bones from the Badlands of SD, NE, and WY.  There are a few of those animals that are very cheap and are substantial enough to get a kid's attention, the Oligocene being a time when many modern mammal orders were becoming more significant members of their faunas around the world.

 

By that time in my own collecting, I was primarily a shark tooth collector so I made one of "sharks through time" display as well using extras from my collection.  I also made one for my uncle so cousins would have something for science class.  I wanted the displays to have a decent amount of diversity (all seven modern orders represented plus the two ray orders plus a few extinct ones) with the goal to sample different parts of the world across the evolution of sharks.

 

What you run into is it's difficult to find cheap Paleozoic teeth that are also complete enough to see how different or similar they are to Mesozoic or Cenozoic teeth especially if you want to give some away and then there's also loss and breakage in the classroom.  For the Paleozoic I found these to be the low-cost examples I could replace:

 

Petrodus sp - this is a name given to dermal denticles (scales that cover the skin) found in Carboniferous deposits in spots in North America and Europe.  I was able to get a small quantity from an Indiana site and from the UK.  You might be able to get collectors to give you some of these because they have little monetary value (maybe 25 cents each?) especially if it's for a school.  The educational value comes from the fact that the earliest sharks are represented by dermal denticles.  While Petrodus came later, it's good to have an example of a Permian dermal denticle andthose of Petrodus are big enough to see without magnification (though you might want a magnifier to examine one in detail).  You might be able to find Devoniana-age teeth and dermal denticles but they tend to be tiny - not a great visual aid as it is.  Blow-ups of photos could help and you can get some dermal denticles from the Cenozoic (STH, Bone Valley Fm, Florida to see the diversity in shapes).

 

Orthacanthus or other xenacanth teeth, Permian of Texas and Oklahoma.  If you look around you can get a quantity of these especially if you're not too picky about condition.  Most teeth have one broken cusp but you can see how different they are from modern shark groups.

 

You might be able to get examples of some of the crusher-type teeth (Deltodus, Chomatodus, etc.) from the Paleozoic but an incomplete tooth doesn't look like and even a complete tooth isn't that flashy.  It might not be easy to come up with a supply of those anyway.  It would be the kind of thing to have one or two of for the classroom.  It might be nice to have a Petalodus just to further illustrate the range in tooth shapes but that is a tough genus to find cheap (not commonly found complete).  You might find a few near-complete teeth and then draw what a complete tooth looks like to give the kids a clearer idea.

 

For the Mesozoic getting Triassic teeth is not easy.  In recent years some Reticulodus teeth have been coming out of New Mexico but you tend to find just partials when you go through matrix and even a complete tooth is quite small.  Not that flashy for kids.  If you look around, you can get other hybodonts from Germany and Belgium, but again, not really the kind of thing you can get a bunch of.

 

Jurassic teeth are tough to get though you can come up with some hybodonts and the occasional Sphenodus (when found, the tooth is usually missing part of the crown and part of the root).  A complete Asteracanthus or Sphenodus is a collector level tooth and is unlikely to be cheap.  Sphenodus belongs to another extinct order.

 

The news gets better for the Cretaceous because it was largely a time of high sea level so there are a lot of marine formations with the more shark-rich ones that are also commonly collected slated toward the Late Cretaceous.  Rays have appeared by the Early Cretaceous so you can get specimens of extinct forms.  You already have an idea of what you can get but here's a summary of what I've found cheap:

 

Onchopristis numidus - rostral spine of a sawfish from a group that died out at the end of the Cretaceous.  These tend to come of Morocco and small ones tend to be cheap.  You can find rostral spines of related forms like Ischyrhiza (sites in TX, NJ, and NC) too.  

 

Squalicorax - sites in TX, KS, NJ, Morocco.  This is an extinct shark known from the Early to Late Cretaceous.  You can find lots of these especially from Morocco.

 

Cretoxyrhina - sites in TX, KS mostly.  This might not be an easy one to keep getting examples of but you should be able to pick up a few examples.  Someone might sell a weathered tooth that is otherwise complete for a good price.

 

Ptychodus - You might be able to get a supply of these over time especially the smaller species from Texas. An example of an extinct shark that died out before the end of the Cretaceous. 

 

Scapanorhynchus - most teeth come from NJ, TX, and NC but I've seen dealers with specimens from MS, AL, and NM.

 

Myledaphus - an extinct ray found in Late Cretaceous river deposits where dinosaurs are also known.  You should be able to find these cheap but not in large numbers.  It's an example of an extinct ray genus.

 

Rhombodus - an extinct ray perhaps best known commercially from Morocco.  You might be able to buy these by the small bagful as I once saw a dealer do.  You can find these from NJ and TX but the Moroccan ones tend to be bigger.

 

You might be able to pick up some smaller teeth best viewed with a magnifier (rays like Protoplatyrhina, Ptychotrygon) to provide a little more diversity.

 

For the Cenozoic you start seeing modern genera in the early part of the era.  Sand tiger shark teeth are common so you should be able to find numerous examples of Striatolamia, Carcharias, and Odontaspis especially from the Early Eocene of Morocco.  At this point you start thinking about assembling a collection of specimens from the modern orders.  Here is a rundown of the orders and the low-cost genera and species you can find:

 

Hexanchiformes - We talked about this before.  You can find collectors with numerous partial specimens from the STH Bonebed, Calvert Cliffs, and maybe Peru or Chile.  You can find relatively cheap complete teeth from the Early Eocene of Morocco.  They are small but a large partial next to it from a more recent deposit is a good visual aid.

 

Squaliformes - The dogfish teeth of Squalus occidentalis from the STH Bonebed might be your best low-cost example.

 

Pristiophoriformes - this is a tough one.  You might be able to get a few Pristiophorus rostral spines from Chile but they are harder to find now since Chile outlawed the export of fossils about twenty years ago.  This is the group that includes sawsharks (not sawfish) which prefer deepwater and apparently have always preferred deepwater because they are uncommon fossil finds.

 

Squatiniformes - Your best low-cost example is probably Squatina sp. from the STH Bonebed though you  might be able to find someone who can supply several from elsewhere and maybe even some Cretaceous ones.

 

Heterodontiformes - the teeth of the Heterodontus from the STH Bonebed would be the easiest to find unless you have a friend who can supply some from elsewhere.  They tend to be uncommon.  The anterior teeth have a different shape than a lateral tooth and a juvenile anterior tooth looks different from an adult one.  These are very small teeth so you might not push for examples of all that - not flashy.

 

Orectolobiformes - You can find Nebrius teeth available from Moroccan fossil dealers.  Some sell matchboxes full of smaller teeth from the Moroccan phosphates and you can find teeth like Nebrius and Ginglymostoma in them.  They would likely be tough to replace regularly unless you go to the Tucson shows (early February) or Denver shows (mid-September).  You can also find various nurse shark teeth from the Late Cretaceous of Texas, the Late Paleocene of Maryland, and Early Eocene of Virginia. 

 

Lamniformes - one of the easiest orders to stay stocked up on as it includes sand tiger sharks, makos, and great whites along with extinct forms like Scapanorhynchus, Cretodus, Squalicorax, Otodus, and Carcharocles.

 

Carcharhiniformes - another of the easier orders to find examples of.  The most common teeth would be of Carcharhinus but you can find examples of Hemipristis, Sphyrna, Galeocerdo, and Negaprion.  Cretaceous examples are more rare and tend to be very small.  You can find Eocene carcharhiniform teeth like Abdounia among the smaller Moroccan teeth.  In the STH Bonebed you can find lots of Carcharhinus teeth plus some Physogaleus teeth and even the smaller Galeorhinus teeth.

 

As for the modern ray orders:

 

Rajiformes - these tend to be tiny teeth.  You can find examples of the various groups like guitarfishes (Rhinobatos, Rhychobatus) and skates (Raja and relatives).  The Cretaceous sawfishes belong to this order too as well as the unrelated family of Cenozoic sawfishes.

 

Order Torpediniformes - this might be the toughest order to obtain samples of.  The teeth are uncommon and tiny anyway but you might be able to get an Eocene representative (Eotorpedo) or a later one (Torpedo from the Miocene of France).

 

Myliobatiformes - you can find a lot of Dasyatis (one of the stingray genera) teeth if you screen STH matrix as well as some caudal sting sections and dermal denticles.  You can also get some Myliobatis teeth (the wider-than-long medial teeth and smaller lateral teeth) as well as examples of tooth plates that include some of both tooth forms from that bonebed.  You can also find tooth plates of that and other genera from other sites.  A partial tooth plate can be surprisingly cheap for as uncommon as they tend to be as fossils.

 

My advice to you is to go to a major mineral/fossil show like the ones in Tucson or Denver.  You might find a dealer with similar stuff at a local gem/mineral society show like the Castro Valley show, or the Santa Clara Valley Gem and Mineral Society or one of the larger ones in southern California.  The Tucson show ended a couple of weeks ago.

 

Jess

 

 

 

 

Share this post


Link to post
Share on other sites
fossilsonwheels
On 3/3/2019 at 9:54 PM, siteseer said:

Just to get back to the idea of low-cost examples, you will likely run into problems coming up with a constant supply of shark teeth if you tie yourself to particular genera and species.  Back in the 90's a friend taught 5th grade in Orange County, CA and her husband was a mineral/fossil dealer.  Her budget for science materials was $50 for the whole school year.  Fortunately, her husband made it his mission to find extra stuff for her class.  I used to make displays with 8 x 12 Riker Mounts.  I think I made two different ones of Oligocene mammal teeth, jaw sections, and bones from the Badlands of SD, NE, and WY.  There are a few of those animals that are very cheap and are substantial enough to get a kid's attention, the Oligocene being a time when many modern mammal orders were becoming more significant members of their faunas around the world.

 

By that time in my own collecting, I was primarily a shark tooth collector so I made one of "sharks through time" display as well using extras from my collection.  I also made one for my uncle so cousins would have something for science class.  I wanted the displays to have a decent amount of diversity (all seven modern orders represented plus the two ray orders plus a few extinct ones) with the goal to sample different parts of the world across the evolution of sharks.

 

What you run into is it's difficult to find cheap Paleozoic teeth that are also complete enough to see how different or similar they are to Mesozoic or Cenozoic teeth especially if you want to give some away and then there's also loss and breakage in the classroom.  For the Paleozoic I found these to be the low-cost examples I could replace:

 

Petrodus sp - this is a name given to dermal denticles (scales that cover the skin) found in Carboniferous deposits in spots in North America and Europe.  I was able to get a small quantity from an Indiana site and from the UK.  You might be able to get collectors to give you some of these because they have little monetary value (maybe 25 cents each?) especially if it's for a school.  The educational value comes from the fact that the earliest sharks are represented by dermal denticles.  While Petrodus came later, it's good to have an example of a Permian dermal denticle andthose of Petrodus are big enough to see without magnification (though you might want a magnifier to examine one in detail).  You might be able to find Devoniana-age teeth and dermal denticles but they tend to be tiny - not a great visual aid as it is.  Blow-ups of photos could help and you can get some dermal denticles from the Cenozoic (STH, Bone Valley Fm, Florida to see the diversity in shapes).

 

Orthacanthus or other xenacanth teeth, Permian of Texas and Oklahoma.  If you look around you can get a quantity of these especially if you're not too picky about condition.  Most teeth have one broken cusp but you can see how different they are from modern shark groups.

 

You might be able to get examples of some of the crusher-type teeth (Deltodus, Chomatodus, etc.) from the Paleozoic but an incomplete tooth doesn't look like and even a complete tooth isn't that flashy.  It might not be easy to come up with a supply of those anyway.  It would be the kind of thing to have one or two of for the classroom.  It might be nice to have a Petalodus just to further illustrate the range in tooth shapes but that is a tough genus to find cheap (not commonly found complete).  You might find a few near-complete teeth and then draw what a complete tooth looks like to give the kids a clearer idea.

 

For the Mesozoic getting Triassic teeth is not easy.  In recent years some Reticulodus teeth have been coming out of New Mexico but you tend to find just partials when you go through matrix and even a complete tooth is quite small.  Not that flashy for kids.  If you look around, you can get other hybodonts from Germany and Belgium, but again, not really the kind of thing you can get a bunch of.

 

Jurassic teeth are tough to get though you can come up with some hybodonts and the occasional Sphenodus (when found, the tooth is usually missing part of the crown and part of the root).  A complete Asteracanthus or Sphenodus is a collector level tooth and is unlikely to be cheap.  Sphenodus belongs to another extinct order.

 

The news gets better for the Cretaceous because it was largely a time of high sea level so there are a lot of marine formations with the more shark-rich ones that are also commonly collected slated toward the Late Cretaceous.  Rays have appeared by the Early Cretaceous so you can get specimens of extinct forms.  You already have an idea of what you can get but here's a summary of what I've found cheap:

 

Onchopristis numidus - rostral spine of a sawfish from a group that died out at the end of the Cretaceous.  These tend to come of Morocco and small ones tend to be cheap.  You can find rostral spines of related forms like Ischyrhiza (sites in TX, NJ, and NC) too.  

 

Squalicorax - sites in TX, KS, NJ, Morocco.  This is an extinct shark known from the Early to Late Cretaceous.  You can find lots of these especially from Morocco.

 

Cretoxyrhina - sites in TX, KS mostly.  This might not be an easy one to keep getting examples of but you should be able to pick up a few examples.  Someone might sell a weathered tooth that is otherwise complete for a good price.

 

Ptychodus - You might be able to get a supply of these over time especially the smaller species from Texas. An example of an extinct shark that died out before the end of the Cretaceous. 

 

Scapanorhynchus - most teeth come from NJ, TX, and NC but I've seen dealers with specimens from MS, AL, and NM.

 

Myledaphus - an extinct ray found in Late Cretaceous river deposits where dinosaurs are also known.  You should be able to find these cheap but not in large numbers.  It's an example of an extinct ray genus.

 

Rhombodus - an extinct ray perhaps best known commercially from Morocco.  You might be able to buy these by the small bagful as I once saw a dealer do.  You can find these from NJ and TX but the Moroccan ones tend to be bigger.

 

You might be able to pick up some smaller teeth best viewed with a magnifier (rays like Protoplatyrhina, Ptychotrygon) to provide a little more diversity.

 

For the Cenozoic you start seeing modern genera in the early part of the era.  Sand tiger shark teeth are common so you should be able to find numerous examples of Striatolamia, Carcharias, and Odontaspis especially from the Early Eocene of Morocco.  At this point you start thinking about assembling a collection of specimens from the modern orders.  Here is a rundown of the orders and the low-cost genera and species you can find:

 

Hexanchiformes - We talked about this before.  You can find collectors with numerous partial specimens from the STH Bonebed, Calvert Cliffs, and maybe Peru or Chile.  You can find relatively cheap complete teeth from the Early Eocene of Morocco.  They are small but a large partial next to it from a more recent deposit is a good visual aid.

 

Squaliformes - The dogfish teeth of Squalus occidentalis from the STH Bonebed might be your best low-cost example.

 

Pristiophoriformes - this is a tough one.  You might be able to get a few Pristiophorus rostral spines from Chile but they are harder to find now since Chile outlawed the export of fossils about twenty years ago.  This is the group that includes sawsharks (not sawfish) which prefer deepwater and apparently have always preferred deepwater because they are uncommon fossil finds.

 

Squatiniformes - Your best low-cost example is probably Squatina sp. from the STH Bonebed though you  might be able to find someone who can supply several from elsewhere and maybe even some Cretaceous ones.

 

Heterodontiformes - the teeth of the Heterodontus from the STH Bonebed would be the easiest to find unless you have a friend who can supply some from elsewhere.  They tend to be uncommon.  The anterior teeth have a different shape than a lateral tooth and a juvenile anterior tooth looks different from an adult one.  These are very small teeth so you might not push for examples of all that - not flashy.

 

Orectolobiformes - You can find Nebrius teeth available from Moroccan fossil dealers.  Some sell matchboxes full of smaller teeth from the Moroccan phosphates and you can find teeth like Nebrius and Ginglymostoma in them.  They would likely be tough to replace regularly unless you go to the Tucson shows (early February) or Denver shows (mid-September).  You can also find various nurse shark teeth from the Late Cretaceous of Texas, the Late Paleocene of Maryland, and Early Eocene of Virginia. 

 

Lamniformes - one of the easiest orders to stay stocked up on as it includes sand tiger sharks, makos, and great whites along with extinct forms like Scapanorhynchus, Cretodus, Squalicorax, Otodus, and Carcharocles.

 

Carcharhiniformes - another of the easier orders to find examples of.  The most common teeth would be of Carcharhinus but you can find examples of Hemipristis, Sphyrna, Galeocerdo, and Negaprion.  Cretaceous examples are more rare and tend to be very small.  You can find Eocene carcharhiniform teeth like Abdounia among the smaller Moroccan teeth.  In the STH Bonebed you can find lots of Carcharhinus teeth plus some Physogaleus teeth and even the smaller Galeorhinus teeth.

 

As for the modern ray orders:

 

Rajiformes - these tend to be tiny teeth.  You can find examples of the various groups like guitarfishes (Rhinobatos, Rhychobatus) and skates (Raja and relatives).  The Cretaceous sawfishes belong to this order too as well as the unrelated family of Cenozoic sawfishes.

 

Order Torpediniformes - this might be the toughest order to obtain samples of.  The teeth are uncommon and tiny anyway but you might be able to get an Eocene representative (Eotorpedo) or a later one (Torpedo from the Miocene of France).

 

Myliobatiformes - you can find a lot of Dasyatis (one of the stingray genera) teeth if you screen STH matrix as well as some caudal sting sections and dermal denticles.  You can also get some Myliobatis teeth (the wider-than-long medial teeth and smaller lateral teeth) as well as examples of tooth plates that include some of both tooth forms from that bonebed.  You can also find tooth plates of that and other genera from other sites.  A partial tooth plate can be surprisingly cheap for as uncommon as they tend to be as fossils.

 

My advice to you is to go to a major mineral/fossil show like the ones in Tucson or Denver.  You might find a dealer with similar stuff at a local gem/mineral society show like the Castro Valley show, or the Santa Clara Valley Gem and Mineral Society or one of the larger ones in southern California.  The Tucson show ended a couple of weeks ago.

 

Jess

 

 

 

 

Thanks Jess. That is very helpful information. I am not real worried about adding more paleozoic material as that is my primary area of interest with my own collecting. We put a number of our Paleozoic teeth in one large riker mount and it worked well with the kids. We are pretyt much open to using what ever teeth we can get for the give away stuff and between a donation and a couple of purchases, we have about 500 more teeth coming for give ways :)

 

We are working on obtaining more Orthocanthus teeth and some denticles to perk up that display. The Eel sharks were really quite popular. Thanks to a donation, we added two Cretoxyrhina teeth to the one we had so that display is coming along nicely. I picked up a lot of 50 Scapanorhynchus and Anomotodon teeth becasue the goblin sharks were so popular. Ptychodus is one I am always trying to pick up and that was another one that the kids really dug.

 

I just purchased a 2 inch Angustidens tooth, it was super cheap, and it adds another tooth of size. Plus it is another link in the chain of Megalodon evolution. I am also going to add an Alopias grandis tooth at some point. I love Thresher sharks so a giant one would be fun to talk about with the kids. Cretodus is another add on in the near future.

 

They rays I am just starting to learn but we will be adding matertial. Same with Sawfish. The goal now is to round out the basic presentation and develop a second companion presentation that gets deeper into sharks. So far, so good.

 

I will be consulting your list again in the near future as I work on building this up. Thank you for all of the super helpful information.

 

Kurt

Share this post


Link to post
Share on other sites
siteseer

Hi Kurt,

 

One thing I should have added is that Cretalamna teeth would be a lot easier to get in quantity than something like Cretoxyrhina.  You get a ton of them from Morocco and some extra specimens from Texas and New Jersey if you make the right connections.

 

Jess

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Recently Browsing   0 members

    No registered users viewing this page.

×