Lower Eagle Ford jaw droppers

[Shaun-DFW Fossils]

The last 30 days have been great. Not the largest numbers of fossils, but high quality. I went to a highway median lower Eagle Ford exposure in South Grand Prairie, Texas, and another nearby Tarrant formation exposure on 3 occasions in the last few weeks. I have a lot of firsts from these excursions:

unknown gastropod

absolute unit of an ammonite, a 5.1 pound acanthoceras amphibolum with huge spikes

concretion with conlinoceras tarrantense with original shell and septarian veins

mosasaur vertebra

partial (?) lobster in a pre-broken concretion

metiococeras ammonite (rough one but my first)

numerous conlinoceras tarrantense ammonites 2-4 inches diameter 

 

 

 

 

Edited June 28 by Shaun-DFW Fossils
Duplicated photos

[Jaybot]

Wow!  Nice to see that your finding great stuff.  That partial lobster/crustacean looks interesting; might be worth prepping out?

[Shaun-DFW Fossils]

28 minutes ago, Jaybot said:

Wow!  Nice to see that your finding great stuff.  That partial lobster/crustacean looks interesting; might be worth prepping out?

Thanks Jaybot! I hope you’ve been doing well! I’m definitely going to try and prep the crustacean. I bought a $14 dremel 290 and I’ve gotten pretty good about doing what I can with that noisy sucker, but I’m at the point where I need air abrasive to finish it out. I plan to get my own system soon, so in the meantime, I’ll have to wait until I either get that or I can use my friends abrasive tool. I’ll post updates in fossil prep when done!

[Ludwigia]

Great finds! I'm already looking forward to seeing the prepped out crustacean.

[Jaybot]

12 hours ago, Shaun-DFW Fossils said:

Thanks Jaybot! I hope you’ve been doing well! I’m definitely going to try and prep the crustacean. I bought a $14 dremel 290 and I’ve gotten pretty good about doing what I can with that noisy sucker, but I’m at the point where I need air abrasive to finish it out. I plan to get my own system soon, so in the meantime, I’ll have to wait until I either get that or I can use my friends abrasive tool. I’ll post updates in fossil prep when done!

Thank you, I have been doing pretty well.  Looks like both of us have had some good finds lately.  Looking forward to the prep updates!

Have a great day

[gwestbrook]

Very nice!

 

[hadrosauridae]

Awesome finds!

[Jared C]

Can you send quite a few more angles of the vertebra? I do not think it's mosasaur, and that you have a different reptile there. More views will be helpful

[PaleoNoel]

I agree the vert is not mosasaur. Lower Eagle Ford is around the Cenomanian-Turonian Boundary, which means some of the last ichthyosaurs were still around, and the apparent concavity of the vert could point toward that identification, we just need a few more pics to determine that.

[PaleoPastels]

Very lovely ammonites! Im actually pretty jealous of those! I should also let you know that vert is most likely either icthyosaur, shark, or plesiosaur, def post pics of it cleaned  Ive seen a few icthyosaurs from Lyme Regis in person recently and although jurassic… that very reminds me of theirs a bit. (I actually cant wait to go back to the North Atlantic jurassic for more adventures!!!!) 

 

I recommend varnish B-72ing that crustacean carapace and make sure its super dry as you clean it to prevent breakage. Warm water and a paint brush might help a lot with matrix removal but be careful. I saved a few Albian aged sea urchins from here in TX that way prepping them manually with hand tools (by tools i mean a thumb tack/pushpin and a paint brush) 

[Shaun-DFW Fossils]

3 hours ago, PaleoPastels said:

Very lovely ammonites! Im actually pretty jealous of those! I should also let you know that vert is most likely either icthyosaur, shark, or plesiosaur, def post pics of it cleaned  Ive seen a few icthyosaurs from Lyme Regis in person recently and although jurassic… that very reminds me of theirs a bit. (I actually cant wait to go back to the North Atlantic jurassic for more adventures!!!!) 

 

I recommend varnish B-72ing that crustacean carapace and make sure its super dry as you clean it to prevent breakage. Warm water and a paint brush might help a lot with matrix removal but be careful. I saved a few Albian aged sea urchins from here in TX that way prepping them manually with hand tools (by tools i mean a thumb tack/pushpin and a paint brush) 

 

8 hours ago, PaleoNoel said:

I agree the vert is not mosasaur. Lower Eagle Ford is around the Cenomanian-Turonian Boundary, which means some of the last ichthyosaurs were still around, and the apparent concavity of the vert could point toward that identification, we just need a few more pics to determine that.

 

10 hours ago, Jared C said:

Can you send quite a few more angles of the vertebra? I do not think it's mosasaur, and that you have a different reptile there. More views will be helpful

Thanks for your help! I went with the input of a more experienced friend, but I gladly invite your expertise to help me get it right. Here are the rest of what was on my camera roll, I can take more in a little while and post them as well:

[Jared C]

In the last image you sent: is the vertebral face completely flat? Slightly convex? Slightly concave? hard to tell from pics. This is a very important detail for ID 

@pachy-pleuro-whatnot-odon @GPayton

 

There are no mosasaurs known from the lower eagle ford. The oldest known mosasaurs currently are Tethysaurus and Sarabosaurus, both early Turonian in age. The tarrant is cenomanian if I remember correctly. 

[Shaun-DFW Fossils]

19 hours ago, Jared C said:

In the last image you sent: is the vertebral face completely flat? Slightly convex? Slightly concave? hard to tell from pics. This is a very important detail for ID 

@pachy-pleuro-whatnot-odon @GPayton

 

There are no mosasaurs known from the lower eagle ford. The oldest known mosasaurs currently are Tethysaurus and Sarabosaurus, both early Turonian in age. The tarrant is cenomanian if I remember correctly. 

Thanks Jared. It slopes upward toward a rounded point, sorry I edited this because I originally thought you meant the face (my mistake). I should clarify the concretions, gray shale color, big concretions full of dark clay and crystals, and presence of metiococeras ammonites (certainly not a hard and fast scientific checklist) makes me think it must be where the lower eagle ford meets the next layer up, could be wrong though

Edited July 4 by Shaun-DFW Fossils
Misread question

[Andúril Flame of the West]

As always I love reading your trip reports even if I do not always have the expertise to leave a comment! I envy how easily you can stumble upon ammonites down there in Texas considering their relative rarity up here in the DMV. I have very limited experience with marine reptile fossils from viewing this forum and from my explorations in the Cretaceous of Maryland, but I had a lingering feeling that the vertebra may not be mosasaur. As others have mentioned, they usually have a notable convex bulge at one end along with a concave end. I am very curious to see what @pachy-pleuro-whatnot-odon and @Praefectus might have to say about this piece. 

[pachy-pleuro-whatnot-odon]

Nice finds! Those are some good-looking ammonites! 🥳

 

As for the vertebra, that looks distinctly plesiosaurian...! Their vertebra can range all the way from amphiplatean, through amphicoelous to amphicoelous, with both faces being able to have different degrees of concavity. You can even make out the keel and subcentral foramina in the below photograph (unfortunately, they appear to be infilled with matrix):

 

22 hours ago, Shaun-DFW Fossils said:

 

 

 

Setting as the lack of visible parapophyses and zygapophyses, this would've been a dorsal vertebra. Excellent find!

[Shaun-DFW Fossils]

3 hours ago, pachy-pleuro-whatnot-odon said:

Nice finds! Those are some good-looking ammonites! 🥳

 

As for the vertebra, that looks distinctly plesiosaurian...! Their vertebra can range all the way from amphiplatean, through amphicoelous to amphicoelous, with both faces being able to have different degrees of concavity. You can even make out the keel and subcentral foramina in the below photograph (unfortunately, they appear to be infilled with matrix):

 

 

 

Setting as the lack of visible parapophyses and zygapophyses, this would've been a dorsal vertebra. Excellent find!

Thank you for lending me your depth of knowledge! Next time I will post bones for ID before running with the verdict of one person in my local sphere. I’m learning a lot and I appreciate it!

[Euhoplites]

Isn't ealge ford formation also partial turonain? Because that acanthoceras looks a lot like mammites nodosoides to me.
The sutures could confirm that.

Very nice finds!! Quality is indeed fantastic!

[Jared C]

3 hours ago, Euhoplites said:

Isn't ealge ford formation also partial turonain? Because that acanthoceras looks a lot like mammites nodosoides to me.
The sutures could confirm that.

Very nice finds!! Quality is indeed fantastic!

In dfw it ranges from at least middle Cenomanian up to the latest Turonian. Fortunately, it’s distinct members make ID’ing time ranges easier