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Crabs, seals and shark bites


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sharkdoctor

In January, @Metopocetus and I met to do some map work and go through some old documents in search of productive exposures of the Eastover Formation (which generally lies on top of the Calvert Formation in Maryland and Virginia). Like all good fossil hunters, we met at dawn to do a little fossil hunting first. The wind chills were below zero (F), but there was a blowout tide. We each found a fossil shell or two and some cool pictures of interesting ice formations along the Chesapeake Bay (below) and then retired, thoroughly frozen to a warmer spot to do our map work. Working with some 50 year-old publications and field notes, we identified a passing mention to a tiny layer within the Eastover Formation that MIGHT have fossil crabs and a concentration of vertebrate material.

 

Ice.thumb.jpg.eb2a4bfb10dd879fcfec45168c4b01a1.jpg

 

Within a few weeks, @Gizmo and I had worked ourselves into a lather over the possibilities. The sites are remote. They are basically not documented in the modern literature and none of us could find any published record of crabs from the Eastover Formation. It sounded like a good chance at finding a new species.

We found ourselves completely convinced that we could do the impossible: 1) drive hours to a waterway that we had no experience with, 2) use 50-year-old information to find the sites and 3) then identify the crabs in anonymous clay beds in shallow, freezing water

 

On February 12, I met @Gizmo at our favorite meet-up in the pouring rain and air temps around 40F. We spent a tense couple of hours on the road wondering if hurricanes, weather or riprap had erased the sites. Just a bit after dawn, we put the boat into the water and set out into a cold and gray day.

 

5c881e9534b69_Rainyriverday.jpg.997c732f255ac5c8081aafc1494774a2.jpg

 

Within an hour we had checked several potential locations and found the sites to be almost exactly as described. Within two hours we identified two nearly complete crabs as well as a pile of other goodies ranging from shark teeth to random fish vertebra. However, we were pretty bummed out that we had only picked up two complete crabs on the beach. While the tide was out, we worked in clay slicks in shallow water to find more. On a hunch, we kept every nodule that we found. We couldn't see through the mud and clay, and the clay was nearly waterproof when wet. Impossible to clean the nodules. Plus, the water was just way too cold.

 

Near the end of the day, Gizmo found a megalodon tooth and several nice makos. Soon after, we found an associated set of vertebra that I kept for trading. Anonymous vertebra and skeletal associations are fairly common in VA, but I hold onto them sometimes to use for trading with other collectors or for donating to classrooms. At the very end of the day, I stumbled on two seal bones, a humerus and metapodial, in the clay underwater. We quarried them quickly in the freezing water and scooted back to the ramp just before sundown.

 

In cleaning up the nodules, I quickly found that the dried marl washed right off. In the course of an hour of cleaning I found 25+ crabs that were largely intact, as well a seal astragalus. In all, we ended up with several coprolites, several pounds of fish, seal and whale bones, a variety of shark teeth, and an ecphora.

 

The little association of dolphin sized vertebra turned out to have some surprises. Three vertebra, with one complete, one with broken processes and one that has been sheared by a large shark bite (on the right). The sheared vertebra was buried in the clay underwater, but came out without any damage. The bitten surface is sheared smooth ( a modern break would be jagged) and has the profile of a large tooth (still trying to figure out how to get a profile+tooth photo).

5c8bc26e5d072_Associated1_resize.thumb.jpg.fcddb7ebb12d305ee62ecde3b90f428b.jpg

 

 

 

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sharkdoctor

Some gnarly chomp marks on the center vertebra5c8bc4a1132e5_InkedAssociated8_LI.thumb.jpg.d6ba0d8c531a989d2cf55b511216ac47.jpg

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Fallingfossils

Great trip writeup and very cool finds.  I could feel your excitement for tracking down a new spot, that's always a great feeling when it pays off.

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Excellent detective work.  Can't wait to see pix of the crabs....  

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crabfossilsteve

Yes, that is a cool trip report on a location from the way back machine.  You especially got my attention when you talked about crab fossils.  As you might guess, I'm a crab fossil collector and look forward to seeing what they look like....perhaps a trade?

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Fossilis Willis

Looking forward to seeing to seeing those crab. Could the bite marks be from land based scavenger chewing on the carcass after it washed ashore? 

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18 hours ago, sharkdoctor said:

The sites are remote. They are basically not documented in the modern literature and none of us could find any published record of crabs from the Eastover Formation.

There is a publication with Eastover Formation crabs in nodules just like you described. Here’s a picture. 

56FD2E7D-6892-4FF1-B499-5979316AB3AC.jpeg

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Great report and pics!

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sharkdoctor
On 3/15/2019 at 2:33 PM, Fallingfossils said:

Great trip writeup and very cool finds.  I could feel your excitement for tracking down a new spot, that's always a great feeling when it pays off.

Thanks! Agreed. Exploring new sites is one of my favorite fossil experiences. Actually making a find is the icing on the cake! :crab:

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sharkdoctor

@Al Dente Excellent! We missed that one! Any chance you'd be willing to send a copy or a reference?

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sharkdoctor
12 hours ago, Fossilis Willis said:

Looking forward to seeing to seeing those crab. Could the bite marks be from land based scavenger chewing on the carcass after it washed ashore? 

Perhaps. Once I figure out how the picture limits work on a post, I'll post some other bite marks that seem very consistent with underwater scavenging.

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sharkdoctor
On 3/15/2019 at 3:09 PM, crabfossilsteve said:

Yes, that is a cool trip report on a location from the way back machine.  You especially got my attention when you talked about crab fossils.  As you might guess, I'm a crab fossil collector and look forward to seeing what they look like....perhaps a trade?

Thanks! We've got a bit more detective work to do at the moment. Hoping to get this assemblage to a researcher here in the next bit. From your location tag, it seems that I am sitting and writing not too far from you near the upper Shenandoah. Sending a PM.

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On 3/16/2019 at 2:06 PM, sharkdoctor said:

Once I figure out how the picture limits work on a post,

There is a size limit of 3.95megabytes per post. You can add additional pictures in a reply.

If You get an over limit flag, refresh the page.

 

Nice story and finds. I am looking forward to seeing what else was found (crabs and meg tooth?)

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Me too, waiting for crab pics.

 

RB

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On 3/18/2019 at 3:22 PM, ynot said:

 

 

Nice story and finds. I am looking forward to seeing what else was found (crabs and meg tooth?)

Here's the meg from this trip. -

 

 

Screen Shot 2019-03-19 at 5.16.38 PM.png

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Nice posterior meg.

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1 hour ago, ynot said:

Nice posterior meg.

Thanks, they're fairly rare at this site and I was happy to find it.

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sharkdoctor

More bite marks. This time on a huge billfish bone:

5c92a1d88cbde_Bittenfishbone1_resize.thumb.jpg.f2484206bf15a5caedecc93d083a06b6.jpg5c92a1eab8ab7_Bittenfishbone2_resize.thumb.jpg.23765cf39527f1d699e56f0313b348e8.jpg

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sharkdoctor

@Gizmo and I just couldn't help going back to find more crabs and do some more exploring in the Eastover Formation. Headed down on March 13 and came away with more goodies, including more crabs. Photos of some finds below. 

Gizmo found this large Eastover Ecphora. It is one of two from these trips that is headed to the Calvert Marine Museum collection. @Metopocetus

Ecphora_cropped.thumb.jpg.c1bb1cdfcfe8d8a448dd2b995d76c463.jpg

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sharkdoctor

A bulla and astragalus. The astragalus seems to be from an artiodactyl. Both pieces are headed to CMM. To be on loan for some current research work.5c952e594ea76_Bullaandastragalus_resize.thumb.jpg.a3545bd266350e2306ae5424e0617832.jpg

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