Some Say Lightning Doesn't Strike the Same Place Twice...

[Mikrogeophagus]

Return to the Badlands of North Texas

 

At long last, rain graced the lands of North Texas this past week. For many of us, that meant it was time to finally crawl out of bed and beat the crowd to that one particular site desperately needing a refresh. In my case, I set on my way to explore a newer spot in the Grayson Marl while the ground was still nice and muddy. I'd been to this place once before, but it had already been thoroughly picked over. It's a popular site, but even then, it managed to pull through and produce some fine specimens for me to take home. With that in mind, I suited up in preparation for a very wet and very, very cold day in the "badlands" of North Texas.

 

As I took my first step out of the car, my foot was immediately enveloped by a Grayson Marl pudding. I don't own boots, so my measly tennis shoe was suctioned off as I tried to wriggle free. Although the moistened marl was a hassle to trudge through, I quickly reassured myself that such a characteristic would be a benefit in terms of eroding new fossils and continued on my way. By the time I reached the spot, I was practically walking atop 6-inch platform shoes made of the stickiest mud known to man. It was no use shaking it off, so I accepted the burden of having to walking like a newborn giraffe for the rest of the day. Out in the distance, I could just make out a person with a bright orange beanie. Clearly, they too were chasing fossils after the rain. Luckily, the site was quite large, so there was plenty of room for both of us to graze. 

 

Still being unfamiliar with the locality, it took a while for me to adjust my eyes to hunting. The ridiculous number of fragmented shell bits and corroded pyrite fossils made it difficult to filter the noise out. However, the knowledge of what could be found kept me motivated. Eventually my efforts were rewarded with the first decent find of the day: A nicely sized Cretalamna

 

Cretalamna catoxodon

 

Soon after, I happened upon an area with a mess of brittle star limb fragments. I searched very thoroughly for a central disk, but nothing could be found, so I decided to swipe only a single piece. Keeping in the theme of weathered finds, I also spotted the most complete Coenholectypus I'd ever come across there. Though it looked nice, I again decided to leave it be. Few fossils are worth that much of a headache to consolidate!

 

Coenholectypus castilloi?

 

Already, a decent chunk of time had elapsed and I was a little discouraged with the lack of weight to my baggie. Meanwhile, the man in the bright orange beanie had steadily made his way closer to the area I had been working. It seemed he was about to finish up his session, so he walked over and introduced himself as Mike. Apparently, he is an admin for the Texas Fossil Hunting group on Facebook. Though he hunts all over the place, the site we were standing in was his main spot he had been visiting for three years! We had a nice conversation about the Grayson Marl as well as a handful of famous places around the state. Since ptychodus was my ultimate goal for the location, I also inquired as to how many he had found here in the badlands. For the span of three years, only two small specimens were to show. With numbers like that, I figured I better not get my hopes up. He showed off a few of his nicer finds from the morning, including dozens of tiny Goniophorus scotti, before saying goodbye and heading out. I still had a final stretch I wanted to check out, so squatted down and quickly got back to work.

 

I think something about seeing his collection helped me to see things more clearly. I rapidly spotted several more C. catoxodon teeth after our encounter. However, I was most excited to find my first Squalicorax from this formation, despite its miniscule size. I know identification for this genus is quite convoluted, but I felt it had a likeness with S. baharijensis because of its broad neck, well developed serrations, and other features. 

 

Squalicorax baharijensis?

 

To round off the day, I looked through one last mound of marl and spotted a very strange and distorted figure. It looked as though some larger fossil had been broken into rubble. I picked up a chunk and observed a texture I was not used to seeing. After taking a moment to process what exactly I was looking at, I realized it was the surface of a heart urchin, likely Hemiaster calvini, with the spines still articulated! I quickly began gathering the pieces in the immediate area in case they were from a single organism I could puzzle back together. At the time they were covered in mud, so I did not realize that they were from many individuals likely eroding from a single layer. At home, I put them under the microscope and found some interesting features generally unobservable in most spatangoid specimens. Have a look:

 

A lot of times it's easy to forget how deeply similar irregular urchins are to their regular counterparts. With the naked eye, it's impossible to observe this level of detail in the tubercles of a spatangoid. However, at the microscopic level, we can see that they are alike. These tubercles, in my amateur opinion, are just like that of a salenia or cidarid species.

 

My favorite observation was the presence of the articulated spines of course. Something I did not expect was their morphology. The bottom 2/3 of the spine appears to be longitudinally ridged and has a black color. The top 1/3 transitions to a yellow coloration while also beginning to flatten out into the shape of a shovel. Also, the spines seem to generally point away from the front of the urchins.

 

I'm sure some of the resident echinoid experts on here are already well familiarized with the shovel shape of these spines, but I was quite intrigued. I already knew that irregular echies travel under substrate, so I began to wonder if these spines perhaps served a function that related to their lifestyle. If you haven't yet had the "aha moment", it appears that spatangoids use these shovel spines to help dig and move their bodies while buried! Hopefully this little tangent helped to enrich your appreciation for irregular echies as it did for me !

 

Anyways, by then I had had enough of the Grayson Marl and was ready to check out some other sites that were preferably a little easier to navigate. So I packed my things and headed for the car.

 

But first, here is an overview of the Grayson Marl Finds:

 

Hemiaster calvini with articulated spines. The one at the top seems to be complete, though completely flattened. The bottom chunks are from many individuals. I have many smaller pieces not pictured. From afar, they have a "fuzzy" texture.

 

Top L to R: Ophiura graysonensis limb frag, Stereocidaris hemigranosus plates, S. hemigranosus spines (cool), and Parasmilia graysonensis solitary corals.

Bottom L to R: Bivalve, bivalve, Neithea texana scallop, unknown fossil with interesting bumpy texture (perhaps decapod), and Mariella bosquensis heteromorph ammonite.

 

Top L to R: Cretalamna catoxodon, Squalicorax baharijensis?,  Cretoxyrhina vraconensis? (more on this at end of the topic), and Cretalamna catoxodon.

Bottom L to R: Various verts, Xiphactinus tooth? (no cutting edges - always wonder if these could be pterosaur), and fishy bits.

 

 

~ ~ ~

 Some Say Lightning Doesn't Strike the Same Place Twice...

 

Well, the original plan was to scope out two new Pawpaw sites in the area, but, in my exhausted state, I decided to say screw it and take a trip to my favorite spot in the Pawpaw. It's been said that you shouldn't go looking for fossils when you've already found them, so what was the point in risking my time and energy when I could see what the rain had swept out at ole reliable.

 

When I got to the exposure, I went straight for the productive layer and instantly had a field day with a plethora of micro ammonites. I'm guessing since they had limited exposure to the atmosphere, they were still shiny and easily spotted. It was definitely the best luck I'd had for cephalopods so far at the place.

 

The first picture-worthy find was an exceptionally preserved central disc to a brittle sea star. I could tell it had eroded from a layer different to the previous starfish I had found. Unfortunately, there was not even a single associated limb fragment in sight.

 

The aboral side appears to differ from that of Ophiura graysonensis. It is difficult to compare with O. texana of the Weno since the only picture I could find of the type specimen is blurry and the fossil itself hard to make out. So, I'll stick with Ophiura sp. for now.

 

Periodically I came across more fantastically preserved crab carapaces. It seems every hunt at this site, I find one beautiful Feldmannia wintoni carapace and this visit was no different. In the past, the better Steorrosia crabs I gathered tended to be S. aspera, but this time, I finally collected a couple great S. pawpawensis specimens including my second carapace with preserved eyes!

 

The fierce compound eye of Steorrosia pawpawensis!

 

Vertebrate fossils are tough to come by, so any shark tooth is a welcome site. The one pictured below had an amazing purple tint that sadly did not stay after being cleaned. It was my first Squalicorax from the Pawpaw, so I knew I was adding a new species to my collection. After some research online, I believe it to be Squalicorax priscoserratus on the basis of its thin neck, dense root, and well-developed serrations.

 

Squalicorax priscoserratus

 

I hadn't been hunting for long when I began to tire. Since the ground was so muddy, I didn't have the chance to sit and hunt like I usually prefer to do. On top of all the squatting, staying right side up on the slippery muck created additional strain. I decided to finish up a little early and save some of the site for a future day when the conditions were drier. I set a location in my mind for where I would call it quits - the area I had found the articulated brittle sea star in my last visit. Of course, I would be crazy to expect a repeat of such a legendary find, but I would be lying if I said the thought wasn't hanging over my head throughout the final 15 minutes of the day.

 

In parts of medieval Europe, heart urchins were once known as "thunderstones" for their supposed creation at the place of a lightning strike sent by a god. They were magical items collected and often cherished by those who hoped to find connection with the heavens. In modern times, such beliefs are easily dismissed, but that isn't to say that the same curiosity and admiration those distant peoples felt for these treasures has eroded away in the slightest. As I approached the location of where the last articulated sea star had been found, I began to wonder if the fossil gods may have cast another bolt in my favor. Kneeling down for one last time, my eyes were embraced with the sight that sent me straight back to my feet.

 

Although the ground didn't show any apparent signs of burn marks sparked by the wrath of Zeus, I was face to face with something I thought I would only find in dreams. A horde of 15 brittle star limb fragments surrounded a single yellow central disc. For reference, my last star had only 4 limb fragments! To any passerby, I looked crazy with the number of fist pumps I was doing. I made sure to gather as much as I could and headed for the car, though I was definitely not in the right head space to be driving .

 

In situ. Doesn't look like much yet!

 

The consolidating process was tedious as expected. Thankfully, my last project had given me some much-needed practice that made the process much easier than it could have otherwise been. With each attachment, the delicate figure of this animal could be more thoroughly appreciated. Once it was complete, I took way too many pictures, but can you really blame me ?

 

Brittle sea stars old and new

 

This is my new favorite in my collection! I'm almost afraid to return to the spot because I know it'll be a let down from this... though on second thought I guess I'm not afraid enough to stay away. 

 

Overview of Pawpaw Formation Finds:

 

Top L to R: Cantabrigites wenoensis, Engonorceras serpintinum, and Stoliczkaia asiatica.

Bottom L to R: Neophlycticeras sp., Enigmaticeras riceae, Scaphites hilli, Stoliczkaia worthense, and Conlinites wrighti.

Not 100% on some of these IDs but based off of overall morphology and suture patterns shown on a publication, these are the names I've somewhat confidently come up with.

 

Top L to R: Steorrosia aspera (the one on the right is oddly shaped and could be something entirely different), Feldmannia wintoni (beautiful blue coloration), and Steorrosia pawpawensis (The one on top has the preserved eyes).

Bottom L to R: Various decapod fragments.

 

A look at the undersides of (L to R) Steorrosia aspera, Feldmannia wintoni, and Steorrosia pawpawensis.

 

A close up of the spines on one of the claw fragments:

 

Top L to R: Squalicorax priscoserratus, and Haimirichia anomensis (Even though this is upper Albian and not Cenomanian, I assume this newly described genus applies to this tooth since Eostriatolamia anomensis/Carcharias anomensis were previously known from the Pawpaw).

Bottom: Fish parts 

 

Brittle stars of the day, oral and aboral sides:

 

 

~~~

Questions

 

Just to round off the post, I have some questions regarding identifying teeth from the Pawpaw and Grayson (Late Albian and Early Cenomanian). Specifically, I have confusion when distinguishing between Cretalamna and Cretoxyrhina. About a month ago, I found a tooth in the Pawpaw that I think strongly resembles Cretoxyrhina vraconensis. During my recent hunt in the Grayson, I picked up a couple of damaged teeth that seem to usually be identified as Cretalamna online, but I think share a resemblance with my Pawpaw Cretoxyrhina specimen (similar tiny splayed cusplets and a large, protruding root). So, I am wondering if any of you can help to clarify. Are these teeth also Cretoxyrhina or simply more Cretalamna? I may even have my Pawpaw tooth misidentified for all I know.

 

L to R: My Pawpaw "Cretoxyrhina vraconensis", two unknown teeth from the Grayson (Cretalamna catoxodon or possibly Cretoxyrhina denticulata/C. vraconensis), and lastly a pretty obvious Cretalamna catoxodon from the Grayson.

 

Feel free to let me know if you would like additional pictures or @ some who might know a thing or two!

 

 

 

Thanks for reading!

[bthemoose]

Great finds, especially that brittle star!
 

The teeth at the end look like Cretalamna anteriors to me. 

[ThePhysicist]

Nice finds! 

12 hours ago, EPIKLULSXDDDDD said:

Just to round off the post, I have some questions regarding identifying teeth from the Pawpaw and Grayson (Late Albian and Early Cenomanian). Specifically, I have confusion when distinguishing between Cretalamna and Cretoxyrhina. About a month ago, I found a tooth in the Pawpaw that I think strongly resembles Cretoxyrhina vraconensis. During my recent hunt in the Grayson, I picked up a couple of damaged teeth that seem to usually be identified as Cretalamna online, but I think share a resemblance with my Pawpaw Cretoxyrhina specimen (similar tiny splayed cusplets and a large, protruding root). So, I am wondering if any of you can help to clarify. Are these teeth also Cretoxyrhina or simply more Cretalamna? I may even have my Pawpaw tooth misidentified for all I know.

I think the basis for your ID of the "C. vraconensis" doesn't distinguish it from anterior C. catoxodon. Comparing their dentitions, Cretalamna has more pronounced cusplets in anteriors. Therefore, I would call all of the teeth in your lineup here Cretalamna. Other positions that might be more easily confused like laterals may be distinguished at least by the shape of the root lobes which are "quadrangular/squared-off" in Cretalamna, and rounded in Cretoxyrhina. 

 

Siversson et al. (2013) state:

"Isolated teeth of Cretalamna are abundant in the Kolbay strata yielding Cretoxyrhina vraconensis (Kennedy et al. 2008b, p. 122) but can be separated from teeth of the latter by generally having more quadrangular root-lobes (especially in the most posteriorly situated teeth), a sharply defined labial crown/root boundary in well-preserved teeth (the rather indistinct labial root/crown boundary in C. vraconensis is a typical Cretoxyrhina character that can also be observed in the type species C. mantelli) and lacking narrow vertical grooves on the basal face of the root in lateroposterior teeth (present on most late Albian–Turonian Cretoxyrhina teeth to some degree...)."

 

C. catoxodon A1:

 

C. vraconensis A1 (juvenile):

 

C. vraconensis A1 (adult):

 

C. vraconensis:

C. catoxodon:

 

Mikael Siverson, David J. Ward, Johan Lindgren & L. Scott Kelley (2013) Mid-Cretaceous Cretoxyrhina (Elasmobranchii) from Mangyshlak, Kazakhstan and Texas, USA, Alcheringa: An Australasian Journal of Palaeontology, 37:1, 87-104, DOI: 10.1080/03115518.2012.709440

 

Mikael Siversson, Johan Lindgren, Michael G. Newbrey, Peter Cederström, and Todd D. Cook

Acta Palaeontologica Polonica 60 (2), 2015: 339-384 doi: http://dx.doi.org/10.4202/app.2012.0137

[JohnJ]

What a report, Sir!  I see many favorites of mine.  

 

 

12 hours ago, EPIKLULSXDDDDD said:

Stereocidaris hemigranosus plates, S. hemigranosus spines (cool),

Not sure where your reference for this name originates....  We used to refer to this species in the Grayson and Pawpaw as Phyllacanthus hemigranosus (Shumard).  The GBIF.org lists it as Leiocidaris hemigranosus.  

 

12 hours ago, EPIKLULSXDDDDD said:

Coenholectypus castilloi?

The HGMS book on Texas Cretaceous Echinoids calls this large Grayson Formation urchin, Holectypus charltoni.  The Echinoid Directory refers to this as a junior synonym of Coenholectypus castilloi.  

[fifbrindacier]

I love your brittle stars man.

[Mikrogeophagus]

1 hour ago, JohnJ said:

Not sure where your reference for this name originates....  We used to refer to this species in the Grayson and Pawpaw as Phyllacanthus hemigranosus (Shumard).  The GBIF.org lists it as Leiocidaris hemigranosus.  

I saw Stereocidaris hemigranosus on a few sites including Smithsonian, so I thought it might be trustworthy enough to go with. Seems this urchin has gone by many names though and Smithsonian may not be very up to date.

 

I'm surprised the Coenholectypus castilloi turned out correct since it took awhile for me to come up with the name and it felt pretty obscure.

 

Thanks!

 

2 hours ago, ThePhysicist said:

I think the basis for your ID of the "C. vraconensis" doesn't distinguish it from anterior C. catoxodon. Comparing their dentitions, Cretalamna has more pronounced cusplets in anteriors. Therefore, I would call all of the teeth in your lineup here Cretalamna. Other positions that might be more easily confused like laterals may be distinguished at least by the shape of the root lobes which are "quadrangular/squared-off" in Cretalamna, and rounded in Cretoxyrhina. 

 

I have pictured below a plate I found online showing C. vraconensis specimens (A-I) from Ukraine which I originally based my ID for the Pawpaw tooth on. After reading through your post and the sources you've shared, I think I'm beginning to see the subtle differences between my tooth and Cretoxyrhina. The root shape for my teeth are a bit "quadrangular" as is expected for Cretalamna and as you've mentioned. Assuming I'm not misunderstanding what an indistinct root crown boundary is, I believe my tooth lacks that which again goes against Cretoxyrhina. So, I think you are correct in your correction of my original ID! Thank you for the very clear and thorough breakdown.

 

 

t

 

[PaleoPastels]

Wow! So nice to read the lore behind that amazing sea star find!  Serious congrats! I would dance around and cartwheel if I found something that insane. You did amazing prep work on fixing it up btw, they don’t call those “brittle stars” for nothing. It looks like it demands a high-five! 

 

Random but I absolutely adore your appreciation for the heart urchin “hair”spines. Im used to the bald Goodland ones so I agree that finding that and seeing the deets under a microscope is worth geeking out on. The same banded patterns of color on all of them are especially interesting! 

 

I agree with ThePhysicist on Cretalamna- looks like he beat me to it! The roots are a very distinct shape Ive become used to, I have a few Turonian teeth of Cretalamna and Cretoxyrhina Ive recently had to ID myself. 
 

You’re going to be a master at PawPaw at this rate. Were you looking for a Ptychodus decurrens there by chance?  

[Mikrogeophagus]

@PaleoPastels

 

I'm always on the look out for ptychodus, especially in the older rocks! Only issue with Pawpaw is I've never heard of ptychodus/paraptychodus being found there. That isn't to say it's impossible though. I'll keep my eyes peeled.

 

I do love micro details. This cheaper end microscope, so far, is worth every penny. Hopefully it manages to last a while. I've looked at so many specimens and taken many pictures already. It came in handy especially for pinning down IDs on the micro ammonites in this thread. No way for me to compare those tiny suture patterns with just the naked eye, that's for sure.

 

Thanks for the compliments too! 

[erose]

Nice Stuff! those urchin spines are really cool and may be important specimens.  Spines are not always known at the time of original species erection.

[MikaelS]

On 1/28/2023 at 2:12 PM, EPIKLULSXDDDDD said:

Return to the Badlands of North Texas

 

 

Questions

 

Just to round off the post, I have some questions regarding identifying teeth from the Pawpaw and Grayson (Late Albian and Early Cenomanian). Specifically, I have confusion when distinguishing between Cretalamna and Cretoxyrhina. About a month ago, I found a tooth in the Pawpaw that I think strongly resembles Cretoxyrhina vraconensis. During my recent hunt in the Grayson, I picked up a couple of damaged teeth that seem to usually be identified as Cretalamna online, but I think share a resemblance with my Pawpaw Cretoxyrhina specimen (similar tiny splayed cusplets and a large, protruding root). So, I am wondering if any of you can help to clarify. Are these teeth also Cretoxyrhina or simply more Cretalamna? I may even have my Pawpaw tooth misidentified for all I know.

 

L to R: My Pawpaw "Cretoxyrhina vraconensis", two unknown teeth from the Grayson (Cretalamna catoxodon or possibly Cretoxyrhina denticulata/C. vraconensis), and lastly a pretty obvious Cretalamna catoxodon from the Grayson.

 

 

 

 

 

Those four teeth are all Cretalamna.