Shark, Ray, Fish And Other Micros From The Miocene Choptank Formation Of Virginia Trip 2

[MarcoSr]

I made a second trip and took out more shelly, brown sandy Choptank Formation matrix from a slide that came down a while back where this layer didn’t mix with the other gray non shelly layers and stayed on top. I had found some really nice micros in my first batch of Choptank matrix (see my other post “Shark, Ray and Fish Micros from the Miocene Choptank Formation of Virginia”) so I decided to take a second batch of the Choptank matrix home during my last trip there.

This time I dry sifted the matrix through a ¼ inch screen into my 1mm sieve. I only found a single nice Hemipristis and a single nice Carcharhinus caught by the ¼ inch sift. I wet sifted the matrix in the 1 mm sieve in the water at the site and brought out 2 gallons of matrix. It took a little over two hours to get these two gallons of matrix. At home I washed the matrix again really well in a 1mm sieve and dried it.

Although I didn’t find much in the ¼ sift at the site, I did find a good number of shark, ray, fish and other micros in the matrix caught by the 1mm sieve that I brought home. There was a nice variety of fish and ray teeth. However, although there were a good number of shark teeth, most were Carcharhinus but I did find several Squalus and a single Mustelus which are not common. I also found a good number of crab claw tips and fish otoliths which don’t often fossilize. The fish otoliths look like they are from mostly the same species of fish. I also found several specimens that I need id help with. I’m posting the nicer and more unusual micros which I found. If you place your cursor on a JPEG image you will see the file name which will have the specimen id as best that I can determine and the specimen size.

Each matrix that I search makes me more of an avid micro tooth collector. If anyone has or can collect good matrix with shark, ray, and fish micros please send me a PM.

The Hemipristis and Carcharhinus sp. from the ¼ inch sift:

The Squalus sp. and Mustelus sp.:

Some of the Carcharhinus sp.:

Some ray teeth and a ray barb including Raja sp., Rhynchobatus sp., and Dasyatis sp. :

(see the next reply)

Marco Sr.

[MarcoSr]

Some ray teeth and a ray barb including Raja sp., Rhynchobatus sp., and Dasyatis sp. Continued:

Some Myliobatis sp. and Rhinoptera sp.:

Some Fish teeth:

Some fish Otoliths:

Close ups of a couple of the Otoliths:

Some crab claw tips:

(See the next reply)

Marco Sr.

Edited August 2, 2013 by MarcoSr

[Bonodog12]

WOW, cool finds

[MarcoSr]

Some specimens that I need id help with. Note a couple of these look very similar to some specimens that I found in Jurassic matrix from the UK which the consensus was were belemnoid hooks. But this is Miocene matrix not Jurassic matrix so I think these are very small crab or shrimp claw tips but one may still be a Miocene cephalopod grasping hook.

Marco Sr.

Edited August 2, 2013 by MarcoSr

[sixgill pete]

Very cool once again Marco. What do you use to take your pictures with?

[Al Dente]

Some specimens that I need id help with. Note a couple of these look very similar to some specimens that I found in Jurassic matrix from the UK which the consensus was were belemnoid hooks. But this is Miocene matrix not Jurassic matrix so I think these are very small crab or shrimp claw tips but one may still be a Miocene cephalopod grasping hook.

Some of these might be scolecodonts (worm jaws).

[MarcoSr]

Very cool once again Marco. What do you use to take your pictures with?

Don

I use a Dino-Lite digital microscope (AM-411T) to take my pictures.

Marco Sr.

[MarcoSr]

Some of these might be scolecodonts (worm jaws).

I don't usually see worm jaws so I'm really not that familiar with them. I need to do some research. Herb had sent to me a bunch of different matrixes a while back that may have had some scolecodonts. I need to look again at what I found in them.

Marco Sr.

[sixgill pete]

Don

I use a Dino-Lite digital microscope (AM-411T) to take my pictures.

Marco Sr.

Thanks Marco, I checked some out on E-Bay. The 411T is little pricey for me right now. However some of the other Dino-Lite's may an option.

[Pagurus]

Nice finds. Thanks for posting all these great photos with the IDs. That really helps me a lot. I appreciate all those otoliths. I remember counting their rings back in school, quite some time ago. If you find out what fish they came from please let us know. Micros are addictive!

[John Hamilton]

Marco,

Those are awsome photos as always. How do get your micros so clean?

[MarcoSr]

Marco,

Those are awsome photos as always. How do get your micros so clean?

John

I use a cheap jewelry ultrasonic cleaner. I only use water in it as the cleaner. If you use one, be very very very careful with delicate micros. Over the years, I've learned, sometimes the hard way, which micros I can leave in the ultrasonic cleaner for minutes to remove bits of sandstone, chalk etc. and which ones I can only give a second or two in the cleaner. I always clean delicate micros individually. To save time, I clean the more robust micros and regular teeth together, sometimes a hundred or more teeth at a time. Sometimes those bits of debris that I am trying to remove are actually holding a cracked or broken micro together. Just recently I disintegrated a real nice Onchopristis dunklei with only a few seconds in the cleaner. That hurts. But 99% of everything usually gets through looking much better if you are careful. If in doubt, don't use it.

Marco Sr.

[John Hamilton]

John

I use a cheap jewelry ultrasonic cleaner. I only use water in it as the cleaner. If you use one, be very very very careful with delicate micros. Over the years, I've learned, sometimes the hard way, which micros I can leave in the ultrasonic cleaner for minutes to remove bits of sandstone, chalk etc. and which ones I can only give a second or two in the cleaner. I always clean delicate micros individually. To save time, I clean the more robust micros and regular teeth together, sometimes a hundred or more teeth at a time. Sometimes those bits of debris that I am trying to remove are actually holding a cracked or broken micro together. Just recently I disintegrated a real nice Onchopristis dunklei with only a few seconds in the cleaner. That hurts. But 99% of everything usually gets through looking much better if you are careful. If in doubt, don't use it.

Marco Sr.

Marco,

I think I'll give the ultrasonic cleaner a try. Thanks for the info.

Edited August 4, 2013 by John Hamilton

[DE&i]

Hi Marco Sr,

Always a pleasure to see what your latest expoits have found . Those Miocene matrix finds sure do resemble my Jurassic macros.

Darren.

[MarcoSr]

Hi Marco Sr,

Always a pleasure to see what your latest expoits have found . Those Miocene matrix finds sure do resemble my Jurassic macros.

Darren.

Darren

My specimen that I labeled Unkown2 especially reminds me of the Belemnoid hooks from the Jurassic UK matrix which you had sent to me.

Marco Sr.

[MarcoSr]

Some of these might be scolecodonts (worm jaws).

I have been checking out pictures of some modern worm jaws. I think that at least two of the specimens are definitely worm jaws.

Marco Sr.

[Just Bob]

I always enjoy looking at your micro's. Please keep them coming.

I am a bit curious as to which two of the specimens you think are worm jaws.

-Bob

[MarcoSr]

I always enjoy looking at your micro's. Please keep them coming.

I am a bit curious as to which two of the specimens you think are worm jaws.

-Bob

I think it is possible that Unkown1 through Unknown5 specimens, my first five pictures of the specimens that I asked for id help, could be worm jaws. However, I now believe Unkown4 and Unknown5 are definitely worm jaws based upon pictures and a video of modern worm jaws that I have seen.

Marco Sr.

Edited August 6, 2013 by MarcoSr