Articulated Brittle Sea Star and The First Fossil That Looked Back at Me! Pawpaw Formation

[Mikrogeophagus]

The brief visit to the second half of the Pawpaw exposure turned out to be a huge success. I didn't think it was possible, but the finds got even better! There wasn't much of a story to be had with accessing the site, so I'll keep things brief and jump straight into the finds.

 

Once I relocated the productive greyish layer, I was already gathering various claw bits left and right. Their bright white coloration really makes them pop out from the ground. However, I didn't let this lead me into lowering the thoroughness of my search. I still took a close look at every pebble and under every rock. The fruit of my labors came when I locked onto the first shark tooth for the site, a small Leptostyrax macrorhiza. I've found one in the past in the Duck Creek, but never in the Pawpaw. Nine times out of ten I would have missed this guy. Just look at how hidden he is in this photo:

 

Leptostyrax macrorhiza hidden beneath a couple pebbles

 

The vertebrate finds continued with a tiny ~1 cm fish jaw fragment. Let me know if you recognize it:

 

Close up with my new stereo microscope!

 

Not too long after, the crustacean finds began to ramp up. Scattered about were fragments of carapaces. It was only a matter of time before the first complete carapace of the day was found.

 

Steorrosia aspera I want to say

 

I continued finding several more that weren't impressive in situ, but amazing after cleaning. One Steorrosia sp. was pretty banged up on the sides, so I couldn't confidently pin an ID. However, I noticed that it had little black dots where the eyes are usually missing in these crab fossils. Well, my Christmas gift came right on time! I placed it under the digital microscope and almost fell out of my chair. This little crab had preserved compound eyes. I'm not sure how rare such a feature is, but it impressed the hell out of me. I should warn that the pics aren't terribly clear since taking photos requires me to press a button on the microscope that shakes the whole thing. Plus, viewing something so small had the device at its absolute maximum magnification. Hopefully you all can spot the pattern on the compound eyes.

 

Underside of the Steorrosia sp.

 

The face of the Steorrosia sp.

 

A close up of one compound eye. Those faint circles are what I interpret to be the individual eyes.

 

Although not from the grey layer I was hunting in, pyritic cephalopods could be found washed out from the red sandstone above. Most are pretty beat up, but I make sure to collect a little bit of each species I can find. I have enough Engonoceras serpintinum as it stands, but I can't help taking a picture when I find a nice one.

 

Engonoceras serpintinum

 

Mantelliceras sp.

 

The first unorthodox find of the day was very clearly a tiny brittle sea star leg. I've always wanted to find starfish parts, so I was super excited to pick this specimen up.... little did I know. Not sure if it possible to ID beyond genus from just a leg segment:

 

Ophiura sp. in situ

 

Close up of same leg

 

From there, I found a couple more very nice carapaces including a MUCH more complete Texicancer renfroae?. 

 

Face of the Texicancer renfroae?

 

I hate to say I may have already found a Feldmannia wintoni that surpasses the one I submitted to FotM 

 

I need to figure out how to turn off that pesky time stamp on the bottom right. Starting to feel like I'm taking crab mugshots 

 

When I got home, I was able to clean up and analyze a couple of enigmatic specimens that had initially given me starfish vibes. After a bit of research, I believe my hunch was right. These two specimens each have one side covered in "spikes". I found a paper (Blake and Reid 1998) on Pawpaw starfish that had similar structures on the oral sides of the arms. Betelgeusia reidi (cool genus name btw) seemed the closest match, but it's a tough call.

 

 

And to round it off with one of the most legendary finds in my fossil hunting career, a mess of associated brittle sea star chunks including the central disc and several arms fragments. I tried to find more, but these were the only pieces I came up with. It was a massive pain paraloiding this thing together I must admit. There's not much surface area to work with, but it eventually came it alright. Actually looking at it again, I think I put the short arm on upside down, but that will be a headache for another day...

 

The only local brittle star species I know from this period would be Ophiura graysonensis and O. texana. Hard for me to say which it resembles more closely, but I'm leaning towards graysonensis, assuming those exist beyond just the Grayson Marl. 

 

The central disc and a couple of arm bits in situ

 

Oral side?

 

Aboral side?

 

It's safe to say this is my most productive hunt yet! Hopefully you all enjoyed reading through this little report. Here is an overview of the finds:

 

Fish jaw section, Leptostyrax macrorhiza, and xiphactinus? tooth fragment (was hoping it was pterosaur )

 

Crabs of the day L to R: Various Steorrosia, Feldmannia wintoni, Texicancer renfroae?, and Steorrosia reidi?

 

 

Top: Engonoceras serpintinum

Bottom L to R: Mantelliceras sp., Mariella worthensis, Scaphites hilli, and Baculites comanchesnis?

 

Ophiura sp. arm fragment, chunks of Betegeusia reidi?, and a couple of bivalves

 

Thanks for reading!

[RJB]

Small stuff but some really cool stuff.  You take some really good pictures too. 

 

RB

[PaleoPastels]

OH my SEA STARS. You weren’t kidding when you messaged me I’d freak out over what you found in PawPaw the other day!   I would have passed out cold finding that! Yeah, that looks like the aboral side btw! WOW. 
 

I cant get over your little crab having its eyes! It’s so ADORABLE. If you don’t win FOTM that should win this month for sure! According to your in-situ photo it looks like it was just begging you to take it home with you! 

I also love your Leptostyrax! I have yet to come across a nice one with the root. 
 

Save some Engonoceras s. for me!   

[RuMert]

Great finds overall! Crabs, brittle star

[digit]

6 hours ago, EPIKLULSXDDDDD said:

The vertebrate finds continued with a tiny ~1 cm fish jaw fragment. Let me know if you recognize it:

 

With the caveat that I have never hunted for fossils in TX, consider gar (Lepisosteidae) as I think I can detect striations on the bases of the broken-off conical teeth. At least a possibly fruitful avenue for research.

 

 

Cheers.

 

-Ken

[Jared C]

Those crabs are unbelievable. Glad you're saving these from the encroaching development. 

[JohnJ]

Stunning finds, Sir!  Congratulations!

 

Are you sure you are in the Pawpaw and not the Grayson formation?  

[Tales From the Shale]

Guess that brittle star wasn't so brittle after all 

[jpc]

What a great trip and amazing finds. 

I don't think the fish is a gar.  Gar jaws have an external row of big teeth like these and an internal (just inside the big teeth) row of much smaller teeth.

[digit]

3 minutes ago, jpc said:

Gar jaws have an external row of big teeth like these and an internal (just inside the big teeth) row of much smaller teeth.

Do all species in the family follow this form? I though that was just the Alligator Gar, Atractosteus spatula, which has the formidable double row.

 

https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/atractosteus-spatula/

 

 

Cheers.

 

-Ken

[Tidgy's Dad]

Wow! 

That brittle star is sensational. 

[jpc]

4 hours ago, digit said:

Do all species in the family follow this form? I though that was just the Alligator Gar, Atractosteus spatula, which has the formidable double row.

 

https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/atractosteus-spatula/

 

 

Cheers.

 

-Ken

Good question, Ken.  I didn't know there was variety in this trait with the Florida gars.  My knowledge is based on the fossil species of Wyoming.  

[Mikrogeophagus]

@Jared C Yes, it's true I am a hero 

 

@JohnJ I have only dabbled in the Grayson a little bit and I plan on diving deeper soon. I've got a couple really promising sites lined up. I didn't realize such well-preserved crabs could be found in that formation, at least in Waco (hopefully in North Texas too). I always forget you are a bit of a crab guy yourself. Awesome to read through one of your papers! Also cool to see the type specimen for that species is from the Pawpaw. Yet another crab to keep an eye out for. Now I'm down the rabbit hole looking at the post about y'alls top notch finds from the pit that day. Man I wish it would reopen. That was the first legit spot I ever hunted, so I basically didn't known anything about anything. Would love to check it out once more now that I actually know a thing or two about what is out there. 

 

Edit: Looking at the claw on that crab from the paper, I just realized that species could be the ID of an enigmatic fossil I've had from the pit for awhile now. For the longest time I thought it was bryozoan or something. I only recently figured it was crustacean after seeing claw bits from the Pawpaw!

 

@AmmoniteDelight I would probably submit something to FotM if these hadn't been found right at the very end of last month 

 

Edited January 7, 2023 by EPIKLULSXDDDDD
update

[digit]

36 minutes ago, jpc said:

Good question, Ken.  I didn't know there was variety in this trait with the Florida gars.  My knowledge is based on the fossil species of Wyoming.  

I remember finding Cretaceous gar scales while out fossil hunting with you--and they were a really cool dark blue coloration.

 

 

 

I'll try to do some research into the jaws of fossil species. I think there are 3 extant species with only the giant Alligator Gar having the formidable second row of nasty sharp pointy teeth. Always good to find pockets of missing knowledge to research into when questions come up on the forum. 

 

 

 

Cheers.

 

-Ken

[patelinho7]

Amazing finds! I love your photos. So clear. Would the spiky structures on the possible Betelgeusia reidi be the tube feet then?

[Mikrogeophagus]

1 hour ago, patelinho7 said:

Would the spiky structures on the possible Betelgeusia reidi be the tube feet then?

I don't know much about sea stars, but my assumption would be soft things like tube feet wouldn't preserve very well (though not necessarily impossible). I believe the spikes may be the marginal spines. The pieces are a bit mangled, so I'm having trouble telling what region of the animal I am really looking at. Whatever they are, they have an interesting curve to them.

 

After some additional research, I think Alkaidia sumralli is a better ID because of how large and robust these "spines" are, though the ID is still very weakly based! And never know, it could be something undescribed. Not sure if there are any forum members who specialize in a topic as niche as this . If anyone knows a good academic I could send an email to, my PMs are open   

[digit]

5 hours ago, EPIKLULSXDDDDD said:

I don't know much about sea stars, but my assumption would be soft things like tube feet wouldn't preserve very well (though not necessarily impossible).

I'll go with "impossible" on this one. Other than some rare preservation in a slab of matrix where a ghost of the outline of the tube feet leftover as a mere chemical residue, I would not expect tube feet of ophiuroids (or indeed any echinoids) to be preserved in the fossil record. The tube feet are part of the water vascular system and we all know how difficult it is for water to fossilize.

 

https://en.wikipedia.org/wiki/Water_vascular_system

 

 

5 hours ago, EPIKLULSXDDDDD said:

If anyone knows a good academic I could send an email to, my PMs are open   

PM sent.

 

 

Cheers.

 

-Ken