Jump to content

Mesaverde Formation Round 2


fossilsonwheels

Recommended Posts

fossilsonwheels

I have been a little bored lately and missing micro matrix searches. It’s been awhile since I’ve gotten to enjoy hunting for tiny shark teeth. I got some more matrix from the Rollins Member of the Mesaverde Formation. My first time through that matrix produced one of my favorite finds, a 1mm Scyliorhinus tooth.

 

This formation doesn’t provide much in the way of complete teeth but it is a fauna that was really quite diverse. The first search was with less matrix but I found enough to want to do it again.  This time I have more matrix and in varying states. Some is broken down, some is in small matrix bits and we have a small piece of untouched matrix. It’s a good chance to practice breaking matrix down and learning a broader approach to collecting. 

 

The first search of the broken down matrix and first look at the small bits has yielded few complete teeth but a much wider diversity which makes it fascinating. The first Squalicorax, Ptychodus, Lissodus, and Rhinobatos. It also produced an Orectolobiformes that doesn’t appear to be Chiloscyllium. It looks much more similar to Restesia. 

 

I am really looking forward to searching more as the breakdown goes forward. I am going to take closer pictures tomorrow but the first time finds are among the teeth in this picture. 

CB389746-FF8D-46E6-B92D-5729D3490AE5.jpeg

Link to post
Share on other sites

Fun stuff.  I know a little about the Mesaverde Fm, but I have never heard of the Rollins Member.  Where is this from?

Link to post
Share on other sites
fossilsonwheels
2 hours ago, jpc said:

Fun stuff.  I know a little about the Mesaverde Fm, but I have never heard of the Rollins Member.  Where is this from?

Colorado. 

Link to post
Share on other sites
will stevenson

Nice finds:) would love to see a close up of the Orectolobiformes tooth

Link to post
Share on other sites
  • 2 weeks later...
fossilsonwheels

The unprepared matrix arrived. A nice but small chunk which is what I wanted. This is an experiment so unlike other micro searches it is less about what we find and more about learning an important process. 

 

 

73479033-401C-458E-BFCE-291F5FA9932F.jpeg

4AB6299F-F759-4264-94AB-4CE1070AABC7.jpeg

Link to post
Share on other sites

What's the matrix chunk soaking in? Vinegar?

 

 

Cheers.

 

-Ken

Link to post
Share on other sites
fossilsonwheels
On 2/24/2021 at 4:10 PM, digit said:

What's the matrix chunk soaking in? Vinegar?

 

 

Cheers.

 

-Ken

Hi Ken

 

Yes. Vinegar. I will probably try a different acid next time. 10% would probably be a bit faster I would think. 

 

Kurt

Link to post
Share on other sites
fossilsonwheels

I’ve taken a few moments to stick the slowly dissolving matrix under the scope to watch the process. It’s pretty cool to watch if a little strong on the vinegar smell lol 

 

I noticed a tiny shark tooth had separated and was able to pick it up cleanly. Not complete but not bad given this is not a formation that yields complete teeth. I do believe it is good enough to probably get an ID. I think it’s possible this is Odontaspis. That’s my lean anyway. It’s on the species list from a publication on a different member of this formation. So is Carcharias so I can’t say for sure.  I will get a better picture tomorrow and maybe we can ID this guy. Either way, not a bad first find from the chunk :) 

4EADB2A6-DDDB-46AB-A14F-61D4BDC9581A.jpeg

Link to post
Share on other sites
fossilsonwheels

Here are a few pictures of some shark teeth. This is what the vast majority of finds are, incomplete teeth. Even though we aren’t finding teeth in great condition it is still very interesting to see pieces of the fauna starting to form the larger picture. 

 

First two pictures are of what I think is a Scapanorhynchus tooth. 

6B31D440-D3B6-4D40-856F-348961CC681F.jpeg

A5B357D6-6DD4-43A7-8CF5-AF8966F7B23F.jpeg

Link to post
Share on other sites
fossilsonwheels

Squalicorax is my best guess on this. I can’t think of any other option. 

7BB16821-6E0E-4345-A165-D4E059811615.jpeg

Link to post
Share on other sites
fossilsonwheels

This is the tooth I thought could be Odontaspis. 3mm. 

69D4A018-E869-492A-A243-2B96947D1E76.jpeg

F353F4E8-D319-4619-B024-D7A8DD5B21B8.jpeg

Link to post
Share on other sites
fossilsonwheels

As the block has slowly dissolves I am getting a sense of just how much matrix we will have to look through and I’ve learned a bit about handling the dissolved matrix. Today I spent about an hour searching the dried out matrix and it turned into some fantastic Cretaceous micro shark picking !! 

 

We got a Scyliorhinus :) Our third total from this formation but the first from the block we broke down. It’s not complete but there is enough to say definitely a Scyliorhinus. No doubt and I am stoked. 

 

We found several more Chiloscyllium, a couple more Rhinobatos, another Orectolobiformes tooth, a Sawfish tooth, a few Goblins, a couple more Squalicorax,  and what could be an Odontaspis. 

 

Even though there a few complete teeth, this is easily the most productive Cretaceous matrix I’ve had. I’ve only searched probably 10% of what we will end up with and I am finding all sorts of shark and batoid teeth. So much fun. 

 

Eventually I will have better pictures but I wanted to post something today. 

 

First pic- the speck on the left is today’s Scyliorhinus lol 

 

Second pic- some of the finds. There are more than what it appears. This tray is loaded with shark goodies. 

47418151-C1EF-4762-8101-E861E07B6860.jpeg

C08E6C1A-CAF6-4530-B943-1FF29385B1D8.jpeg

Link to post
Share on other sites
fossilsonwheels

Pic 1- Chiloscyllium teeth. We’ve found quite a few of these. 

 

Pic 2- some of the Rhinobatos teeth we’ve found. I’d say we have about a dozen so far. 

 

Pic 3- some Lamniformes teeth

92787BB7-AA3D-4903-B82D-7256398470DB.jpeg

7FA2EE7D-40B8-483A-B805-B4957A5D4B7D.jpeg

7975E6EB-4090-4927-9DB1-A7C90D669374.jpeg

Link to post
Share on other sites
fossilsonwheels

I think that I found a Heterodontus tooth in the matrix. I have it an ID thread on here so I’m not saying I’m positive on the ID but I think I am correct. 

 

Outside of the Catshark teeth, I’d say this is my best find if the ID is accurate. It would be, at the very least, the biggest surprise. 

0CB59397-19B1-495E-B6EC-A159E42F2B6B.jpeg

Link to post
Share on other sites
fossilsonwheels

The largest complete tooth we’ve found. It’s a whopper at 12mm lol Complete teeth are rare in this matrix and this is a really nice one. I think Scapanorhynchus but I am not convinced it’s S. texanus. I wonder if it could be one of the other described species. Either way, a solid find. 

FF3D05C9-B719-4A2D-9092-F405194FEF77.jpeg

  • I found this Informative 1
Link to post
Share on other sites
will stevenson

Great stuff :) love the colour of those teeth, and some nice species

  • I found this Informative 1
Link to post
Share on other sites
fossilsonwheels

I’m glad you like them Will because you’re getting a couple lol It has been a great experience, lots of fun and we’ve found some really interesting teeth. 

  • Thank You 1
Link to post
Share on other sites
fossilsonwheels

The block has finally dissolved completely. It took quite awhile but in the end this turned out to be a really fun endeavor. That small piece of limestone was absolutely packed with shark and batoid fossils. Few complete but I couldn’t care less because the diversity found more than makes up for it. I still have some of the matrix to search but we’ve had a few great discoveries lately. 

 

We found a small but complete Cretalamna tooth. I had found a few partial teeth but this one is a beauty. More Goblins and another Squalicorax. I found two small (both around 7mm) but pretty robust crowns. They look similar to some small Russian Cretoxyrhina teeth I have. There are more Chiloscyllium too. 

 

I also found another probable Odontaspis. Elasmo has been a very good tool to use with this fauna and a sub section on Cretaceous Sand Tiger teeth has been super helpful. I’ve been using the labial folding discussed in the section to help me. Using that as my guide, I am pretty confident that I have found at least two Odontaspis teeth. My first such finds in micro matrix. 

 

So far, this is the fauna found. 

Lonchidion

Chiloscyllium

Orectolobiformes indet- my lean is Restesia 

Heterodontus

Squalicorax

Scapanorhynchus

Carcharias

Odontaspis

Cretalamna

Cretoxyrhina- not yet confirmed but possible 

Scyliorhinus- 

Rhinobatos

Ptychotrygon

Myledaphus

 

There are a couple of teeth that could represent different genera from the above too.  

 

The most interesting finds so far are Heterodontus and the Catshark teeth. The Catsharks are so fascinating that I’m going to get another block to dissolve. I strongly suspect that these teeth come from more than one type of Catshark. Cretaceous Catsharks in the United States are not well understood. There are some places ( England, Canada, Lebanon) with multiple catsharks that are well described. If I can find a few more teeth, an informal study could be a fun project. Perhaps a future academic study subject if I do indeed go back to school. 

 

Anyway, that’s the update. The picture shows a couple of today’s finds including the Cretalamna and an Odontaspis, still attached to another fossil. Better pictures in a few days. 

71D9B857-D4D9-418F-B52C-C7973FAF462A.jpeg

Link to post
Share on other sites
  • 4 weeks later...
fossilsonwheels

A very cool and very surprising find that definitely signals this matrix is older than I was told. I found a single Cretomanta tooth. My first of that genus and another example of the fantastic diversity in this fauna. 

20D7890F-7692-477B-A202-0F253D45FB0F.jpeg

  • Enjoyed 1
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.

×
×
  • Create New...