Eagle Ford Hunt With a Fellow FF Member! Loads of Shark Teeth With Some Unexpected Micro Surprises!

[Mikrogeophagus]

A couple of weeks ago, @Jackito, his son, and I took a trip out to one of his favorite Eagle Ford sites. For those of you who are familiar with Carter's posts, this was once the famed location of the so-called "giving rock", so the bar was set high for the day. I've come across some of Austin's eagle ford material in the past, but it was always only the leftovers of what had been washed through miles of rushing creek water. This was my first time getting to poke through the source material, so I was eager to see what could be found. The water was low and the temperature mild. I was thankful I wouldn't have to suffer trudging around in soggy shoes. As we walked beside the creek, Carter explained the various layers and where the best stuff could be found. He pointed out the notable spots where things like pseudomegachasma and pliosaur teeth had been dug up. I knew to not get my hopes THAT high up, but it was certainly a good motivator to stay attentive and expect the unexpectable.

 

It took me a while to get the hang of pinpointing which slabs were best to open and how. Carter was nice enough to share some of his finds, and I must admit, not everything pictured below was necessarily first spotted by me . I was quickly surprised by the sheer number of shark teeth we started finding. Being the completionist that I am, I would immediately try to excavate every tooth I found. Carter advised me that simply bringing the matrix home and processing it there would be the most efficient use of time which I have come to agree with. Every tooth had fantastic preservation and would often pop right out of the shale (though not necessarily in one piece). The Ptychodus teeth were the most mesmerizing. They basically broke off without a speck of matrix still attached and had a beautiful shine. Thankfully, they were also robust and rarely fell apart.

 

A decently sized Ptychodus still in matrix

 

The amount of Cretoxyrhina to be found was also staggering. Unfortunately, they required a little bit more delicate prep than what I had to offer in the field, so my ratio of broken to unbroken teeth was higher than I'd like to admit. In my defense, I managed to lower that ratio as the day progressed. Squalicorax was also a common sight along with various fish teeth. Carter's son managed to find some turtle material... that was still alive and may or may not have come from out of the stream . For most of the hunt, Carter and I had some nice discussions on things to be found here in Austin along with various chats about life. The hours seemed to fly by so fast, it wasn't long until Carter and Jack had to head on out. They'd been wanting to find some mosasaur material for a while, so I sent info on one of my favorite sites (the place where I came out with 4 mosasaur verts in a day). Hopefully we'll get to hunt together over there some time in the near future. I stuck around as I had a couple hours to kill before needing to drive to a friend's birthday.

 

The rest of the time was spent doing more of the same. I managed to come across a huge Cretodus tooth, but the root was unfortunately nowhere to be found. I also started gathering some of the leftover matrix for later processing for microfossils. The layer was just so rich, how could there not be something cool to find? I filled up a couple Ziploc bags with the stuff and made my way out, thinking of ways I could clean this while residing in a college dorm.

 

The richness of fossils in the matrix. This piece was a little too stony to break down though. Might try vinegar.

 

Suffice it to say, I figured out a way to clean it without clogging the communal sinks, but it's a slow process. Though, I must admit, it's nice to come home each day to a cup's worth of dried micro matrix ready for screening. In only my first batch, I found something I think is pretty amazing. What was at first just a shiny little speck, upon closer analyzing, may, in fact, be a tiny coniasaur tooth! It has that characteristic bulging crown that is instantly recognizable. Hopefully I'm not jumping the gun on this one. A couple rounds later, and many many puny Ptychodus teeth, I managed to spot what appeared to be the tooth plate to a Pycnodont fish or something similar. After some delicate cleaning and lots of paraloid, it's still a little bit scuffed, but there are definitely some little round bulbous teeth in close association. 

 

The tooth plate before and after cleaning. Can anyone confirm if it's Pycnodont?

 

There was plenty bony fish and shark material. Interspersed within them were some that eluded my identification (including mayyybe Paraisurus?). I've got plenty of matrix to still go through, so I will post updates if anything cool is found. For now, here are some pictures summarizing the finds:

 

Please excuse the hand pics. It's just that the details come out better on a slightly darker surface as opposed to white paper.

 

Closeups of Coniasaur(?) Tooth

 

L to R: Bony bits, "Coniasaur" tooth, and "Pycnodont" tooth plate

 

The best of the Ptychodus and a close up of the smallest one. The bottom left is smoothed over. Is this maybe feeding damage? Also, any ID for species is much appreciated :

 

Cretoxyrhina mantelli. My favorite is the fat one on the left 

 

Best of the Squalicorax falcatus. Right two are a little strange. Possibly symphyseal?

 

Best of Scapanorhynchus and huge rootless Cretodus (hard to see in pic, but its got the wrinkling):

 

Paraisurus? I saw that genus mentioned in a Shawn Hamm publication on the Atco and thought it could be a match. The roots are very skinny on both specimens and the teeth seem vertically stretched. The larger tooth on the left initially appears to be missing half the root, but it is actually nearly complete. The only break is a tiny portion of the root at the very top. The right specimen is very fragmented. No signs of cusps nor nutrient groove on either one.

 

Cantioscyllium orals and Sawfish Rostral Teeth:

 

L to R: Enchodus, Protosphyraena, and Pachyrhizodus

 

Some oddballs. The left is a fragment of some sort of multi-cusped shark tooth. The middle is a a segment of some barbed material that seems similar in appearance to the fishy bits found in the matrix. The right specimen is a shiny crescent shaped thing that I have found in other micro matrixes from Moss Creek and POC. Never kept them, but now I'm curious after finding them again:

 

 

Thanks for reading!

[Manticocerasman]

great finds  

That's a lot of Ptychodus, here in the late cretaceous I'am lucky if I find 1 per year.

[Jared C]

awesome report, I agree with coniasaur. Glad you and Carter had success!!

[Uncle Siphuncle]

The sawtooth specimen deserves comparison with an Onchopristis dunklei rostral.

 

[Al Dente]

Some of the teeth in this photo look like Cretomanta.

 

 

 

[Mikrogeophagus]

1 hour ago, Uncle Siphuncle said:

Onchopristis dunklei rostral.

I think this solves the mystery of the barbed specimen. I've heard of Onchopristis before, but was not familiar with their teeth. It's a shame it's so fragmented. Not sure if it was already broken or if my processing was too rough. Oh well, maybe there will be a better one in the next batch. Thanks for the ID! 

[Mikrogeophagus]

4 minutes ago, Al Dente said:

Cretomanta.

What the... how have I never seen these before. A quick Google images search shows some pretty wild concept art. There are some definite similarities, especially with the leftmost tooth. Though, I know absolutely nothing about these guys and if they are even present in the Eagle Ford or even Texas. That's a pretty exciting! 

[Uncle Siphuncle]

12 minutes ago, EPIKLULSXDDDDD said:

I think this solves the mystery of the barbed specimen. I've heard of Onchopristis before, but was not familiar with their teeth. It's a shame it's so fragmented. Not sure if it was already broken or if my processing was too rough. Oh well, maybe there will be a better one in the next batch. Thanks for the ID! 

I've only found one whole one over the years and it wasn't much over 1/2" incl the root.

[Mikrogeophagus]

@Uncle Siphuncle Was it also from the Eagle Ford or different fm? 

[ThePhysicist]

17 hours ago, EPIKLULSXDDDDD said:

Closeups of Coniasaur(?) Tooth

Definitely possible, but I'd like to see the little guy under a microscope to be sure. If you don't have one, might as well invest in a cheap one if you plan on sorting through that matrix (super jealous, it looks awesome!).

17 hours ago, EPIKLULSXDDDDD said:

Cretoxyrhina mantelli. My favorite is the fat one on the left 

My favorite is all of them 

17 hours ago, EPIKLULSXDDDDD said:

Paraisurus? I saw that genus mentioned in a Shawn Hamm publication on the Atco and thought it could be a match. The roots are very skinny on both specimens and the teeth seem vertically stretched. The larger tooth on the left initially appears to be missing half the root, but it is actually nearly complete. The only break is a tiny portion of the root at the very top. The right specimen is very fragmented. No signs of cusps nor nutrient groove on either one.

These look like symphyseal teeth, or at least the left one for sure, I can't see enough detail on the right. Leaning towards it being goblin.

[Uncle Siphuncle]

9 hours ago, EPIKLULSXDDDDD said:

@Uncle Siphuncle Was it also from the Eagle Ford or different fm? 

Kef

[MarcoSr]

11 hours ago, ThePhysicist said:

 

These look like symphyseal teeth, or at least the left one for sure, I can't see enough detail on the right. Leaning towards it being goblin.

 

I agree that the tooth is a symphyseal tooth.  I've found many similar sandtiger symphyseal teeth in the Eocene of Virginia.

 

Marco Sr.

[LSCHNELLE]

On 10/24/2022 at 12:52 AM, EPIKLULSXDDDDD said:

The best of the Ptychodus and a close up of the smallest one. The bottom left is smoothed over. Is this maybe feeding damage? Also, any ID for species is much appreciated :

Nice finds @EPIKLULSXDDDDD!

 

It would be best for me to see the sides of these to be sure of the species. Top left & 3rd from top left appear to be P. anonymous. Many of the others appear to either be P. decurrens or P. occidentalis. The best way to tell is the number of ridges and the height of the crown. If they are pretty flat crowns, then they are probably P. decurrens - especially if the ridges branch out toward the margins. Like in second from the top left. The smallest lateral or posterior file teeth (look like raisins) are more likely P. occidentalis (if they have a small bump) or P. decurrens (if they don't have a small bump) and have three or more ridges. The one on the far upper right is an anomaly. On first glance it appears to be a P. marginalis. But I don't think that lines up to the lower Bouldin Flags area that you were hunting. It could be P. decurrens - especially if it has a low crown.

Edited October 27, 2022 by LSCHNELLE
Correction

[Mikrogeophagus]

@LSCHNELLE Here's a couple of side views for the top 2 rows. They follow the same from left to right as in the original post's picture.

Top Row:

I agree with 1-3 going anonymous, decurrens, likely anonymous. For number 3, my noob opinion is that it could also be occidentalis since the crown's incline is less steep than 1's and more closely fits what I tend to associate with occidentalis. 4 does look a bit strange. After looking more closely at decurrens pics online, I think it may be decurrens as well. Though, marginalis would be pretty cool if it were the case .

 

2nd Row:

1 and 3 seem to be decurrens and 2 looks like anonymous.

 

I'm gonna pass on doing the smaller ones. I've got tons of them and am satisfied with just grouping them as either decurrens or occidentalis to be honest. 

 

Also, just a quick question on the geology. You say this is from the lower bouldin flags (I honestly had no idea what part of the eagle ford this came from prior). Did you reach that conclusion based off of the fossils/preservation I included or did you say that because all of the Eagle Ford around Austin from the same lower Bouldin Flags layer? I know there are many spots where the Kef is exposed. Do they all yield the same stuff?

 

Thanks for the informative reply!

[LSCHNELLE]

5 hours ago, EPIKLULSXDDDDD said:

@LSCHNELLE Here's a couple of side views for the top 2 rows. They follow the same from left to right as in the original post's picture.

Top Row:

I agree with 1-3 going anonymous, decurrens, likely anonymous. For number 3, my noob opinion is that it could also be occidentalis since the crown's incline is less steep than 1's and more closely fits what I tend to associate with occidentalis. 4 does look a bit strange. After looking more closely at decurrens pics online, I think it may be decurrens as well. Though, marginalis would be pretty cool if it were the case .

 

2nd Row:

1 and 3 seem to be decurrens and 2 looks like anonymous.

 

I'm gonna pass on doing the smaller ones. I've got tons of them and am satisfied with just grouping them as either decurrens or occidentalis to be honest. 

 

Also, just a quick question on the geology. You say this is from the lower bouldin flags (I honestly had no idea what part of the eagle ford this came from prior). Did you reach that conclusion based off of the fossils/preservation I included or did you say that because all of the Eagle Ford around Austin from the same lower Bouldin Flags layer? I know there are many spots where the Kef is exposed. Do they all yield the same stuff?

 

Thanks for the informative reply!

I think the second one on the first row definitely does look to be P. occidentalis based on the height of the crown. The fourth one is still questionable. On the second row the middle one is definitely P. anonymous. And the other two do have low enough crowns to be P. decurrens.

 

I based the location in the formation on the types of Ptychodus that you were finding. I have not seen P. decurrens in the Lower Bouldin Flags (LBF) - only the Upper (UBF). But it is possible. Marginalis is rare in UBF but not found in LBF. P. occidentalis is usually only found in the LBF, but it may be rarely found in UBF. It is extinct by the Turonian in the South Bosque Member.

 

So, I admit that it is possible that you were hunting both the lower and the upper parts of that member. But, note that a pliosaur tooth is more likely in the LBF.

[Mikrogeophagus]

@LSCHNELLE Ah ok thanks for clearing those up. You are probably right about this just being LBF. Everything here came straight out of one pretty thin layer, so I doubt there's a mix of two members. All the faulting around the Eagle Ford makes this stuff confusing for me, but I think I'm starting to understand it a bit better!

 

I'll keep a hold on this fourth specimen from the top row in case I meet a ptychodus expert who can analyze it in person. I'll be at fossil fest in a couple weeks, so there's probably someone who could help there.

 

While I'm making this reply I might as well also ask: Are there any comprehensive papers that list which species can be found in which EF members? I kinda doubt it exists, but if it does, I'd love to read through it.

 

Thanks!

[LSCHNELLE]

Not that I am aware of. I compiled a list of Ptychodus species grouped by Central Texas formations. But, I am kind of waiting on Shawn Hamm to publish a paper first to do an update to it.

[sharko69]

Great finds!! Has been on my list to hunt Austin Eagle ford but have yet to get that chance. 

[erose]

Nice variety of teeth.  Any time you get to hunt the Eagle Ford is good.  Were you seeing anything other than teeth? 

[Mikrogeophagus]

@sharko69 The EF in Austin is great, though it takes some time and research to locate. I'm thankful Carter and his son showed me to their spot!

 

@erose Vertebrate-wise there were some unidentifiable flakes of possibly reptilian bone and a mish-mash of fish verts/bones. Invertebrate-wise I saw lots of shells mostly from oysters and clams. Don't think there were any cephalopods or echinoids. Perhaps they are out there.

[LSCHNELLE]

Quote

Don't think there were any cephalopods or echinoids. Perhaps they are out there.

 

I have found some of both but they are fairly uncommon compared with shark teeth. I think the echinoids are a rarer find usually found in the South Bosque Member.

 

To more easily find an ammonite, you will need a more widespread aerial outcrop or construction site. I find them sometimes in the thin limestone layers of the Bouldin Flags member and in the South Bosque near the Atco Basal member.

 

Usually, the ammonites specimens are incomplete unless they are juveniles. I think they might be more common in the Britton Member of the Eagle Ford in North Texas.

 

Here's my largest and one of my best molds from a construction site Kef excavation pile - now developed over residential neighborhood.

[Mikrogeophagus]

18 minutes ago, LSCHNELLE said:

To more easily find an ammonite, you will need a more widespread aerial outcrop or construction site. I find them sometimes in the thin limestone layers of the Bouldin Flags member and in the South Bosque near the Atco Basal member.

Carter and I plan on checking out a potential Kef site this weekend that looks pretty spacious. An ammonite from this time period would certainly be a prize. We'll have to keep a lookout!

[erose]

11 hours ago, EPIKLULSXDDDDD said:

Carter and I plan on checking out a potential Kef site this weekend that looks pretty spacious. An ammonite from this time period would certainly be a prize. We'll have to keep a lookout!

Years ago there was a great exposure in Round Rock while a large golfing community was being built. I believe. it exposed the South Bosque and maybe the Waco. There was a great deal of invert stuff as well as vert. Lots of small ammonites (mostly fragments) as well as other molluscs. And a smattering of echinoids.