Shark, Ray, Fish, And Other Micros From A Creek In Florida

[MarcoSr]

I want to thank Jeff for sending me almost three gallons of well washed gravel from Florida. The gravel had a very large diversity of species from recent to the Miocene. There were a lot of specimens in the gravel, some were damaged and/or water worn which is typical with gravel but a lot were in very nice condition. I found a large number of shark, ray and fish fossils, multiple nice shells, a mammal tooth and a snake vertebra. The mammal tooth and the snake vertebra could be recent. I am posting some of the nicer and more unusual specimens which I found which range in size from 2mm to 31mm. I had really hoped to find a nice Isistius (cookie cutter) shark tooth. I had seen in one of Jeff’s post that cookie cutters could be found in the Creek gravel. I was very happy that I found so many really nice specimens. The high density of cookie cutters in this gravel (26 complete and damaged specimens) was very surprising and extremely uncommon. I’ve only seen a similar density in Eocene matrix from Morocco. The second odd thing about the Creek was that even though it cuts through a thick terrestrial Pleistocene layer and macro terrestrial mammal fossils are found by screening in the Creek, I only found one micro terrestrial mammal tooth that may be recent and no bird fossils. 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. If you can identify the specimens further please do so. 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.

Some of the shark teeth including nine of the nicer Isistius, Carcharhinus, Rhizoprionodons etc.:

Continued in the next reply.

Marco Sr.

[MarcoSr]

Shark teeth continued:

Continued in the next reply.

Marco Sr.

Edited November 19, 2013 by MarcoSr

[MarcoSr]

Some of the ray teeth including Rhynchobatus, Dasyatis, Myliobatis, Rhinoptera etc., a ray dermal element and a ray barb:

Continued in the next reply.

Marco Sr.

Edited November 19, 2013 by MarcoSr

[MarcoSr]

Several very nice Gar scales and some of the fish teeth:

Continued in the next reply.

Marco Sr.

Edited November 19, 2013 by MarcoSr

[MarcoSr]

Fish Teeth continued:

A mammal tooth which may be recent:

A snake vertebra which may be recent:

Some of the small shells:

Several specimens which I need id help:

Marco Sr.

Edited November 19, 2013 by MarcoSr

[sixgill pete]

Once again nice micro's; Marco. Seems like a very high density of Isistius, thats amazing.

[John Hamilton]

Marco,

Very nice report as always. The Isitius are awesome hopefully I'll find some with roots in the next batch of matrix I get from Jeff. I think the Mammal tooth might be from a musk rat.

[jcbshark]

Those are very nice pics Marco.I am glad you were able to find so many cookie cutters.Thank you again for the beautiful specimens you sent me as well.

[Sacha]

Jeff, where are you collecting your matrix from? I wanted to check your site vs mine on the state geologic map. My samples apparently had no shells and the condition of the fossils seems to be more warn generally from Marco's description. The first batch of my material was from the Peace under the Rt 17 bridge in Zolfo Springs. The second batch (from yesterday) is from a mile and a half upstream.

[MarcoSr]

Once again nice micro's; Marco. Seems like a very high density of Isistius, thats amazing.

Don

I had told Jeff that I would be happy if I found a cookie cutter in nice condition in his gravel. I was very surprised by and very happy with the number of very nice ones.

Marco Sr.

[busyeagle]

Gotta love those Isistius! And that abundance of them is mind-boggling.

[MarcoSr]

Marco,

Very nice report as always. The Isitius are awesome hopefully I'll find some with roots in the next batch of matrix I get from Jeff. I think the Mammal tooth might be from a musk rat.

John

Thank you for the id help. I very rarely find mammal teeth in the matrix/gravel that I search and am not good at identifying the ones that I find. There is so much similarity with the mammal micro teeth between a lot of the genus/species.

When looking through the gravel, the first 10 or so specimens were just crowns or half a tooth (half a crown, half a root) except for one really nice one with a nice complete root. Then with the last 16 or so that I found about half had complete or nice roots. The nicer ones were larger and maybe a little bit stronger and maybe they somehow sorted in the matrix differently because of the size. You should definitely be able to find some nice complete ones.

Marco Sr.

[MarcoSr]

Those are very nice pics Marco.I am glad you were able to find so many cookie cutters.Thank you again for the beautiful specimens you sent me as well.

Jeff

Thank you again for the gravel. I did so much better than the one nice cookie cutter that I was hoping for.

Marco Sr.

[MarcoSr]

Jeff, where are you collecting your matrix from? I wanted to check your site vs mine on the state geologic map. My samples apparently had no shells and the condition of the fossils seems to be more warn generally from Marco's description. The first batch of my material was from the Peace under the Rt 17 bridge in Zolfo Springs. The second batch (from yesterday) is from a mile and a half upstream.

John

Sometimes the fossils can be already reworked when a formation is forming. However the pristine teeth then get reworked when water like the Peace River cuts through the formation. I've found that the reworking seems a lot less and the micros can be in much better condition in the small size streams and creeks than in the main river branches. Probably because there is much less mixing and force on the fossils.

Marco Sr.

[MarcoSr]

Gotta love those Isistius! And that abundance of them is mind-boggling.

Kyle

It is really odd how certain species can be very uncommon or rare at most sites but then there are a few sites where they are common like this creek site.

Marco Sr.

[CrocodileJen]

Ok, I feel silly for asking this because maybe I should know but your posts are always so intriguing... what exactly is a "micro"? How small do they have to be? Do you need magnifying glasses to find them? I probably have some teeth that would count as micros since they are almost as small as the tip of a ball-point pen. Makes me wonder what else has been hiding in all that material I like to sift through on the island we search. Never occurred to be to bag it and bring it home. I just end up lying face down and poring over the piles to get the tiny ones

[Auspex]

There is, no doubt, an official, formal definition of what is a microfossil, but for me, in casual context, they are whole fossils which are best studied under magnification.

[sixgill pete]

There is, no doubt, an official, formal definition of what is a microfossil, but for me, in casual context, they are whole fossils which are best studied under magnification.

I agree with Auspex's definition 100%. Even if it is a tooth that may also come in giant size.

[jcbshark]

Sacha, I sent you a pm

[PFOOLEY]

Great specimens!

[MarcoSr]

Ok, I feel silly for asking this because maybe I should know but your posts are always so intriguing... what exactly is a "micro"? How small do they have to be? Do you need magnifying glasses to find them? I probably have some teeth that would count as micros since they are almost as small as the tip of a ball-point pen. Makes me wonder what else has been hiding in all that material I like to sift through on the island we search. Never occurred to be to bag it and bring it home. I just end up lying face down and poring over the piles to get the tiny ones

There is, no doubt, an official, formal definition of what is a microfossil, but for me, in casual context, they are whole fossils which are best studied under magnification.

I agree with Auspex that a micro is a fossil that is best studied under magnification. Also to me micros are fossils that you are very unlikely to find while looking at the site itself. You find them by bulk collecting, bringing home material to search under magnification. I've seen various study results of fossil collecting bias based upon fossil size. If you collect by walking alone you can typically collect 1-2% of the teeth based upon size from the fauna. If you crawl on your hands and knees you can collect around 46% of the teeth based upon size in the fauna. If you bulk collect, you can collect 100% of the teeth from a fauna based upon size. I try to show in my posts the teeth that collectors could also be finding if they also bulk collected instead of just walking or crawling on hands and knees. You really should try bringing some material home. From a lot of sites you don't find much because the fossil density is too low. However, some sites are really rich in the really small micro teeth. Trial and error helps you figure out where it is worth taking material home from.

Marco Sr.

[MarcoSr]

thumbs.png

Great specimens!

Mike

I like the giant thumb up. Thanks.

Marco Sr.

[CrocodileJen]

Thanks for the response!~ What sort of magnification do you use? I would also be interested in your process at home, what materials you use, surfaces/containers, etc, if you have time. Also, I think your name should be "MicroSr"

[MarcoSr]

Thanks for the response!~ What sort of magnification do you use? I would also be interested in your process at home, what materials you use, surfaces/containers, etc, if you have time. Also, I think your name should be "MicroSr"

I do like MicroSr. Kind of catchy. But I do find a lot of macro fossils also. I just don't normally post them as they don't add a lot to the other great macro specimens that Forum members are posting.

The matrix I search ranges from river gravel, sand, clay, sandstone, mudstone, limestone, some shale etc. Sometimes it takes weeks of multiple cycles to break down the matrix. Sometimes just hot water. Sometimes just a rinse of river gravel. I have a lot of different sized sifts. Window screen is good for some formations but in others lets a lot of small specimens pass through. In the field when taking micro material I use either a .5mm or 1mm sift. Sometimes the .5mm clogs too easily so I use the 1mm. You can buy fine flour sifts that will do the trick. For washing at home I use .4mm plastic sifts that fit over five gallon buckets which I bought on e-bay.

I use a Luxo 5D (2.25X) Magnifying Lamp desk loupe. I use an additional optional 8 diopter lens (Luxo 50202) with it that gives you around 6.5X magnification. The optional 10X lens doesn't work. These are fairly expensive but I can look at matrix 8 or 9 hours in a day. My son doesn't like the loupe at all so it is not for all people. I can pick out fossils down to around .5mm using this setup. I just pour some matrix on a white paper plate and search it using the desk loupe. I also have a 10X jewelers loupe that I use to look more closely at the small specimens.

I store all of my micros in gem jars in 24 and 50 jar displays. You can see some of these at the below link in the middle of the page. You can see that I also do collect larger teeth and fossils.

http://www.thefossilforum.com/index.php?/topic/40733-show-us-your-display-cases/

I take my pictures with a digital Dino-Lite AM-411T microscope. I typically wash all of my micros in a jewelry ultrasonic cleaner before taking pictures. I don't wash delicate micros or only give them a second or two in the ultrasonic cleaner. I have disintegrated really nice specimens so you have to be extremely careful with this. I normally just take my pictures on a white paper plate. I have additional lighting but rarely use it. I take my pictures in an area of my house with lots of windows and natural light. I do use clay for positioning the micros at times for specific views but have damaged delicate specimens in the past doing so.

Hopefully this helps

MicroSr

I mean

Marco Sr.