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Earlier this month I got the opportunity to return to one of my Permian fossil sites that I haven't visited since around April. The site is located in McClain County in central Oklahoma south of OKC. According to a geological map the majority of the area consists of the Wellington Formation, however the bottom of the exposed area is shown to be apart of the Stillwater Formation. According to scientific publications the only fossil producing layer is mentioned as belonging to the Wolfcamp (296.4 to 268 Ma) particularly the Gearyan strata. I've spent multiple trips earlier this year searching the layer mentioned as being the fossil producing layer but have only found plant impressions. Which I'll post some time in the future. Out of the entire outcrop though, I have only been able to find vertebrate remains in one particular spot. An area that appears to be below the known fossil producing layer. On this trip though, I only spent about 4 hours searching the site because I also had plans to visit family for dinner. Overall, I feel I had a pretty good half day trip. Below are some pictures of the vertebrate remains I surface collected on this trip. I must admit I haven't dedicated any real time to trying to identify the various species from the site yet and have only cleaned the material upon returning back home. But just looking through them while laying them out for pictures, there appears to be Eryops, Edaphosaurus, Diplocaulus, a small Captorhinid as well as an Xenacanthus shark. I've been collecting and cleaning the vertebrate remains from this particular site since March of this year but have focused the majority of my attention towards collecting, prepping and identifying fossils from a different site/formation here with in Oklahoma. All the following pictures are from my most recent fossil hunting trip. ⬆️ Overall view of the site. ⬆️ Quick separation of the bone fragments into various piles. ⬆️ Teeth, mostly Eryops megacephalus. ⬆️ Xenacanthus shark teeth. ⬆️ Jaw fragments, larger fragments appear to be Eryops megacephalus. ⬆️ Small jaw fragment with 2 or 3 teeth, possibly belonging to Diplocaulus. ⬆️ Large vertebrae fragments. ⬆️ Small sized vertebrae, the top row appear to be Diplocaulus. ⬆️ Edaphosaurus sail spine sections, a couple fragments might not be from an Edaphosaurus but were placed in the grouping during a quick sort of all the fragments. ⬆️ Various skull fragments, Eryops megacephalus, Diplocaulus and possibly Diadectes along the top row. Diadectes were one of the two species initially identified from the site along with a temnospondyl according to the research papers I read. I have had a difficult time finding clear close up images of the surface of a Diadectes skull. That is, at least from a legitimate scientifically described specimen that hasn't had the majority of the skull restored. ⬆️ These two pieces are the largest of the fragments that I suspect might belong to a Diadectes. ⬆️ Small limb bone fragments. ⬆️ Possible coprolites. ⬆️ Last but not least, concretions with bone fragments. At least one of the larger pieces has multiple vertebrae and portions of ribs. One small piece has what appears to be a section of jaw with 2 teeth still in place. One piece even has the exposed bases of a small Captorhinid jaw, showing atleast 3 rows of teeth. Interestingly, not all that far away in the next county over in Cleveland county near Norman there's a site that has produced the remains of Captorhinikos chozaensis and Captorhinikos parvus. Exactly what species this particular jaw fragment is from I have no idea. But I'm hoping when I do dedicate the time to identifying the species from this site, I will be able to find enough bone fragments from similar sized Captorhinid remains that I can get a general idea of what species inhabited the site. ⬇️ For these next pictures I used my loop and did the best I could at holding the specimen while also holding the loop still and then also holding my phone up to the loop and still managing to press the take a picture button on my phone. All while trying to hold still so the pictures did not come out blurry. The picture quality is poor but I hope in the future to invest in a digital microscope with a viewing screen. ⬆️ I suspect this might be the exterior of a jaw with two teeth still remaining in the jaw. The possible teeth are along the bottom of the fragmented red/white bone. ⬆️ Captorhinid fragment showing just the base of at least 3 rows of teeth. The broken teeth are the reddish and black donut shapes. ⬆️ This is the small concretion with the Captorhinid teeth. The teeth are located in the bottom goldish blurry blob. You can kinda make out one broken tooth in the top right corner of the goldish blur blob.

Hi all, Recently I was collecting at a locality that exposes the Duquesne Limestone and shale, which if you’ve seen any of my previous posts you’ll know that I’ve collected extensively. But for those of you that have not, the Duquesne shale is a layer of black, carbonaceous shale found in areas where the Conemaugh group is exposed. This layer is chalk full of disarticulated vertebrate remains, but some of the most recognizable are the teeth of Orthacanthus and Xenacanthus. These were eel-like sharks that existed from the Devonian-Triassic and had bicuspid or tricuspid teeth. They grew to be about 10-12 feet at the largest and thrived in the swampy lakes of the late Pennsylvanian. It’s somewhat uncommon for me to find a large Orthacanthus tooth (which are tiny compared to Otodus sp. )and it is even rarer for me to find a tooth with feeding damage. It seems to me that, understandably, many collectors of Cenozoic shark teeth are disappointed when they find shark teeth with feeding damage, but for me at least when I find Paleozoic shark teeth with feeding damage it makes it even more special. Last time I was collecting I did just that. Interestingly enough this Orthacanthus compressus tooth is my largest yet and has a very unusual break. The cusp that is missing is not broken cleanly at the enamel, rather, when it broke off it took a good chunk of the rooth with it. To me at least this would indicate that the shark was using quite a bit of force when it bit down, and whatever it bit in to must have been very hard and made for a painful meal for the shark. It’s important to note that the other cusp was damaged recently and isn’t feeding damage. I’m not one to heavily speculate but I’d imagine that it had to have bit in to one of the heavily armored Paleoniscoids for damage of this nature to take place. Or, who knows, the tooth might have just been old. Whatever happened to break the cusp is lost to time, I guess. Regardless, I think it’s a wonderful find and reminds me that these animals were truly alive and had imperfections. Hopefully you all find this as interesting as I do .

Hello everyone, Curious if anyone knows the difference between Xenacanthus and Orthacanthus shark teeth? Particularly as it concerns shark teeth from the Permian site in Waurika, Oklahoma? Have quite a few shark teeth from there and am unsure how to determine which is which. There's also Barbclabornia, to complicate matters! Any help would be appreciated (and yes, I have seen the rhynie chert website on them, but it doesn't show/tell the difference between the three kinds)

Here are my best fossils of Xenacanthiformes. All are from the British Coal Measures (Upper Carboniferous). The first one I suspect may be Orthacanthus due to the width of the cusps, though Xenacanthus teeth sometimes have quite wide cusps. I think all of the other teeth are Xenacanthus. The second one seems very large for Xenacanthus (I suspect around 14-15mm though it’s difficult to tell how far under the rock the cusps go) but I’m fairly sure it’s Xenacanthus rather than Orthacanthus. The third photo is what I believe to be a Xenacanthus denticle.

Hi all, I have seen and heard from multiple different sources that the cephalic spines of Xenacanthid sharks are considered to have been venomous. This is usually supported by the serrated nature of these spines and a canal that runs down the middle of them. Has any research been done to prove or disprove this hypothesis. I know that we can never know for sure but I am curious if there is any scientific support to these claims. Thanks in advance, Zach

This head spine has just reappeared in my collection - I must have found it about 20 years ago in Linton. Is that an Orthacanthus or Xenacanthus head spine? The length is about 8 cm / 3". Thanks Thomas

Found this last Sunday. And i can't seem to narrow down who lost it, Xenacanthus or Orthacanthus. To my knowledge neither has been formally described from the location it was found. And, no, i will not say where. I'll simply say LaSalle county, IL. Still not sure if my site is Permian or Carboniferous. I'm 90% convinced it's Carboniferous. Any ID help is much appreicated. I'm leaning more towards Orthacanthus. Sorry, i'll add mm later. As found: After some needle prep:

First off, I apologize for the poor image quality... The pictures were taken quickly with my phone camera through a microscope. If anyone is interested I'll get out a proper camera later and try again. I found this while searching some Widder formation matrix collected in Arkona ontario. It is roughly 1 mm across. I am fairly certain the tooth belonged to a Xenacanth. Has anyone found these in the area before or did it migrate from somewhere else? Note: the tooth is smooth. The serrated look is caused by pixels in #2