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almach

Otoliths near Aquasco, Prince George's Co., Md

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almach

The Chesapeake Group has at least 16 different species of otoliths (from bony fish) that fossilized.  I still have at least a thousand otoliths left to sort.  So far I only have five different species (I think).  I have already searched over a thousand otoliths in material brought back in just four trips to this middle Miocene (Calvert formation) site.  Here are pictures of the five.  If I find any additional species I will post them.

 

1. Micromesistius cognatus (a genus of cods)

2. Trisopterus sculptus (a genus of cods)

3. Genyonemus sp. (a croaker)

4. Pogonias sp. (a black drum fish)

5. Sciaenops sp. (a red drum fish)  

PSAQ00586 MICROMESISTIUS COGNATUS.JPG

PSAQ00587 TRISOPTERUS SCULPTUS.JPG

PSAQ00588 GENYONEMUS SP..JPG

PSAQ00589 POGONIAS SP..JPG

PSAQ00590 SCIAENOPS SP..JPG

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SailingAlongToo

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ynot

Nice!

@Coco might like these.

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Coco

Hi,

 

Nice otoliths, but I never dared to determine them. I am more familiar with current otoliths than with fossilized ones. I am interested in any PDF dealing with fossilized otoliths.

 

How do you tell the difference between the first and second pics ? Can you put a photo with one of each species side by side to show the differences ?
 
Coco

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almach
9 hours ago, Coco said:

Hi,

 

Nice otoliths, but I never dared to determine them. I am more familiar with current otoliths than with fossilized ones. I am interested in any PDF dealing with fossilized otoliths.

 

How do you tell the difference between the first and second pics ? Can you put a photo with one of each species side by side to show the differences ?
 
Coco

Hi,

 

There is a new book called The Geology and Vertebrate Paleontology of Calvert Cliffs Maryland edited by Dr. Godfrey published in 2018. I think I got the otoliths right, but if you disagree, please let me know.  I will send a picture later today or tomorrow, per your request. Here is a link to that book, the otoliths are on page 205.   https://opensi.si.edu/index.php/smithsonian/catalog/book/107  

 

Almach

 

 

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Al Dente
On 4/11/2019 at 11:46 PM, almach said:

So far I only have five different species (I think). 

I think you have more than five species. These two are clearly different. 

2042F95E-D8D3-40EA-9AD4-34DC4AE62514.jpeg

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Al Dente

I tried comparing these two to a publication I have (Muller 1999). Here’s the closest I found for the two otoliths above. Take this with a grain of salt as I don’t have much experience identifying these. The first is identified as “Sciaenops species 1”, the second as “genus aff. Sciaenops paraeastmani”.

 

 

A473A014-8484-4D2E-A42C-ADDD4CDA123A.jpeg

7A2CAF65-2997-483E-8FD9-E1EA02C46BB3.jpeg

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almach
1 hour ago, Al Dente said:

I think you have more than five species. These two are clearly different. 

2042F95E-D8D3-40EA-9AD4-34DC4AE62514.jpeg

I see what you mean.  The one on the right is  Pogonias sp.  I will forward the photo to Dr. Godfrey to see if he knows what the one on the left is.  Thank you. 

 

Almach

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almach
13 hours ago, Coco said:

Hi,

 

Nice otoliths, but I never dared to determine them. I am more familiar with current otoliths than with fossilized ones. I am interested in any PDF dealing with fossilized otoliths.

 

How do you tell the difference between the first and second pics ? Can you put a photo with one of each species side by side to show the differences ?
 
Coco

 

3 hours ago, almach said:

Hi,

 

There is a new book called The Geology and Vertebrate Paleontology of Calvert Cliffs Maryland edited by Dr. Godfrey published in 2018. I think I got the otoliths right, but if you disagree, please let me know.  I will send a picture later today or tomorrow, per your request. Here is a link to that book, the otoliths are on page 205.   https://opensi.si.edu/index.php/smithsonian/catalog/book/107  

 

Almach

 

 

 

 

Hi Coco,

 

Here is a photo of two of the otoliths.  I believe the upper photo (Proximal side) is Trisopterus and the lower photo is Micromesistius the more streamlined of the two.  I understand you are excellent on otoliths, so I could be wrong.  Please let me know your thoughts as I am no longer sure.

 

Almach

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almach
Just now, almach said:

 

 

 

Hi Coco,

 

Here is a photo of two of the otoliths.  I believe the upper photo (Proximal side) is Trisopterus and the lower photo is Micromesistius the more streamlined of the two.  I understand you are excellent on otoliths, so I could be wrong.  Please let me know your thoughts as I am no longer sure.

 

Almach

Oops, here is the photo!

Otoliths.JPG

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Coco

Hi,

 

As I said earlier, I know more about today’s otoliths than fossils, and I never dared to identify my fossilized otoliths.

 

That said, here is my opinion. On the PDF document, page 205, we see the otoliths of these two species. I notice that both have a "serrated" side. Can you see these indentations on your samples, with a magnifying glass for example ?
 
In your last photo (not quite clean), I get the impression that the one at the top is flatter than the other one, is it ? Can we get a picture of the other side of the two otoliths, and their profile if possible ? In the same order please.
 
Coco

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almach
12 hours ago, Coco said:

Hi,

 

As I said earlier, I know more about today’s otoliths than fossils, and I never dared to identify my fossilized otoliths.

 

That said, here is my opinion. On the PDF document, page 205, we see the otoliths of these two species. I notice that both have a "serrated" side. Can you see these indentations on your samples, with a magnifying glass for example ?
 
In your last photo (not quite clean), I get the impression that the one at the top is flatter than the other one, is it ? Can we get a picture of the other side of the two otoliths, and their profile if possible ? In the same order please.
 
Coco

Hi Coco,

I have rephotographed the proximal surface (photo 1) (I agree, it wasn't very clear).  I have photographed the distal surface as well (photo 2)  and two profile photos Micromesistius (photo 3) and Trisopterus (photo 4).   Hope these help.

 

Almach

Proximal.JPG

Distal.JPG

Profile Micromesistius.JPG

Profile Trisopterus.JPG

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Coco

Sorry, can't say more... :(

 

On the PDF document, page 205, we see the otoliths of these two species. I notice that both have a "serrated" side. Can you see these indentations on your samples, with a magnifying glass for example ?

 

Coco

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almach
1 hour ago, Coco said:

Sorry, can't say more... :(

 

On the PDF document, page 205, we see the otoliths of these two species. I notice that both have a "serrated" side. Can you see these indentations on your samples, with a magnifying glass for example ?

 

Coco

Yes I see the "serrations" on both of my otoliths on the same side as shown on page 205, but neither is obvious as on page 205. 

 

Almach 

ProximalA.jpg

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Coco

Hi,

 

OK, I think they could be these 2 species :dinothumb:

 

 

Coco

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Daleksec

What rescources are you using for identification?

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almach
22 hours ago, Coco said:

Hi,

 

OK, I think they could be these 2 species :dinothumb:

 

 

Coco

Hi

 

I just signed in, it's 2:50 AM, Tuesday, been busy.  If I post about a dozen otoliths that I can't determine, would you like to take a crack at id's?

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almach

Hi, 

 

There was a new book published by the Smithsonian on the Geology and Vertebrate Paleontology of Calvert Cliffs, Md (late 2018).   If you go to the Smithsonian's website you can search for a lot of their fossil publications from other areas as well.   I tried to post the link to the PDF file here (that you can download, for free) but it won't work, sorry.  Now these otoliths I posted on this thread are from a site near Aquasco, Md.  They are the same formation (Calvert) as in this publication.  The otoliths are on page 205.  Hope this helps!

 

Almach

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Al Dente

Almach-

The otoliths are nice. What else are you finding in the material you are searching through? Also, was size mesh are you screening with?

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Coco

Hi,

 

Almach, I can try...

 

Coco

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almach
13 hours ago, Al Dente said:

Almach-

The otoliths are nice. What else are you finding in the material you are searching through? Also, was size mesh are you screening with?

Hello,

 

Only four trips to this site back in 2001-2002.  I do not remember what mesh size I used (have several sifter mesh sizes), but I usually used window screen material under my sifter at many sites (including Aquasco).  Some of the finds at this site and material brought home:  C. Megalodon (one small, one over 2 centimeters)  C. hastalis, A. grandis (only one), H, serra, C. Taurus, Carcharhinus species, G. aduncus, Squatina (only one), other small shark teeth, Dasyatis sp., Myliobatis sp., a handful of bony fish teeth,  possible small crocodile tooth.  Shells include: A. cuneiformis, M. Staminea, C. thallus (tusk shell), D. attenuatum (tusk shell), T. indenta, T. exaltata, T. plebia, C. inaequaus, F. alticosta (Limpet shell (about 50 of these), C. granulate,  P. americana, Retusa sp., Chesapectens, S. foremanni, C. costaum, Epitonium sp. E. quadriscostata? (only one), E. Tricostata, and many unidentified shells.   Even found some tiger eye (mineral), and over 3,000 otoliths).  This is more of a shell site than shark teeth site.  Fossils are found at the bottom of a 6 meter ravine (20 ft).  Shell preservation is excellent.

Site is posted no trespassing, so one must track down the current owner for permission to enter for fossil hunting.  Can post some photos if you like.

 

Almach

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Coco

Hi,

 

I am interested in shell pics ! :wub: :popcorn:

 

Coco

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almach
7 hours ago, Coco said:

Hi,

 

I am interested in shell pics ! :wub: :popcorn:

 

Coco

Hi,

I will send photos of teeth and shells to this thread.  I may need some time (a few days).

 

Almacn

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almach
On 4/13/2019 at 4:03 PM, Al Dente said:

I tried comparing these two to a publication I have (Muller 1999). Here’s the closest I found for the two otoliths above. Take this with a grain of salt as I don’t have much experience identifying these. The first is identified as “Sciaenops species 1”, the second as “genus aff. Sciaenops paraeastmani”.

 

 

A473A014-8484-4D2E-A42C-ADDD4CDA123A.jpeg

7A2CAF65-2997-483E-8FD9-E1EA02C46BB3.jpeg

Hi,

I got an answer back from Dr. Godfrey, the editor of the new book.  The person who wrote that section says they are both Pogonias sp.  I am going to post about a dozen or so otoliths in a few days.  Coco is going to try to id them.  I would appreciate your feedback as well, if you like.

 

Almach  

 

 

 

 

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almach
On 4/16/2019 at 7:01 AM, Coco said:

Hi,

 

Almach, I can try...

 

Coco

Hi Coco

 

Here are some of the otoliths that I am not sure about.  You may reference the number below the MM ruler in ID's.  Thank you in advance for any help.

 

Almach

8 Otoliths.JPG

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