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Showing results for tags 'brachauchenius lucasi'.
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From the album: Eagle Ford Group
Brachaucheninae Pliosaur, North TX Turonian, Cretaceous Jul, 2023 Within the subfamily Brachaucheninae, it is unclear whether this tooth belonged to the genus Brachauchenius or Megacephalosaurus, both of which are regarded as some of the final pliosaurs to exist altogether. It is unclear whether convergently adapted Polycotylid plesiosaurs brought about this extinction or simply filled the niche as it opened up.- 3 comments
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My Best Tooth Yet; On My Final North TX Hunt No Less! Kamp Ranch
Mikrogeophagus posted a topic in Fossil Hunting Trips
Even after having a night to sleep on the fact, I'm still in shock. I was tempted to not even go on this trip since part of me wanted my plesiosaur tooth from last week's Woodbine adventure to be my final impression on North TX. The other part of me wanted one last crack at the Kamp Ranch and a new potential site. It's fine to return to already known locations, but I was thirsting for one more journey into unknown territory where the risk of failure is greater, but the taste of victory is sweeter. After swimming/wading a ways, I found the first small outcrop of Kamp Ranch. I've had some previous experience with this layer in the past, and the knowledge I picked up from then proved useful. While most of the outcrop was relatively devoid of vertebrate material, there was a thin pasty layer cemented to the underside of the thickest limestone that proved to be rich in teeth. I pried out the odd Ptychodus tooth here and there, but pretty soon I was out of real estate. The thick limestone slab looked precarious and the rest of the pasty matrix I was after was nestled deep in the crumbly wall. Noticing the slick shale beneath my feet, I decided jumping away from an avalanche was out of the question and it was time to move on. Ptychodus from the outcrop. All P. anonymous except the top right which may be a P. marginalis(?) lateral. On the walk over to the next outcrop, I made sure to scan the loose pieces of Kamp Ranch matrix scattered about. Most of them were only comprised of oyster bits and Collignoniceras woollgari impressions, but once in awhile there would be some shark. I went for a rock with a shiny black Ptychodus anonymous that had caught my eye. As I dug it out to have a closer look, I saw there was a tiny tan mosasaur situated next to it! Unfortunately it's cracked and in super hard material. If I try to bust it out, it will probably explode! Ptychodus anonymous and mosasaur tooth (Russelosaurine?) Just a few feet further I found an absolute heartbreaker. I could see black striations coming from the edge of a slab and my hopes shot up. As I turned the rock, I realized it was a shattered piece of a pliosaur tooth . Don't even think it's worth keeping... Pliosaur tooth, likely Brachauchenius lucasi I picked up my pack and headed to the last outcrop of Kamp Ranch. I was relieved to see the thick limestone was much more secure. As I examined underneath, I had my mind set on small Ptychodus teeth when I almost fell on my back from surprise. Cemented to the slab was a truly astonishing sight: Pliosaur Tooth! If that wasn't crazy enough, just centimeters below was a limb bone jutting out. I got out my excavating gear and carefully went to work. I don't carry b72 in the field, so each tooth fragment was extracted separately. Afterwards, the bone slid out pretty cleanly. I didn't find other similar material, so I'm not sure if the two are associated or it's just coincidence. Maybe someone familiar with reptile anatomy can say if the bone came from a pliosaur. The tooth came in 6 pieces Once I was home, I got straight to cleaning and gluing. The fragments had held up alright along the journey thankfully and the prep went smoothly. By the end, I was holding up the newest and greatest tooth in my collection! It is most likely Brachauchenius lucasi although Megacephalosaurus eulerti is also a rarer possibility (I don't have access to the paper distinguishing their dentition). Both of these pliosaurs represent the youngest pliosaurids in the fossil record which adds some extra coolness factor. That Woodbine plesiosaur tooth (possible basal Polycotylid) I found last week is interestingly tied evolutionarily with the demise of pliosaurs such as B. lucasi. Polycotylids had traditionally been placed in Pliosauridae until more recent findings moved them to Plesiosauroidea instead. This confusion is likely due to convergent evolution. As pliosaurs disappeared in the aftermath of the Cenomanian-Turonian Anoxic Event, it seems some Polycotylids evolved to fill a similar niche, moving away from gracile dentition (like my Woodbine specimen) and into a more robust form similar to B. lucasi. At least that is how I understand it. Brachauchenius lucasi most likely The second half of the neat discoveries is this reptile bone I found several centimeters below the tooth. I'm not sure it's associated. The high energy nature of the Kamp Ranch makes me wonder if it was just coincidence. Anyways, it seems to be a limb bone. If you look closely, you can see toothy scrapes that are probably from scavenging sharks. I tried to look for signs of serrated teeth, but I didn't see anything obvious. Some of the attached matrix is vertebrate rich with tons of little fish verts and other goodies. Anyone know if this is pliosaur in origin? @pachy-pleuro-whatnot-odon Reptile Limb Bone So glad I decided to have one last exploration before my move. I guess it's not like I will never hunt in North TX again, it's just that it will be much, much more rare. I've added so many new, fun, and interesting sites to my list this past half year, I'm a bit sad to leave them all behind. At the same time, I'm itching with excitement to make new discovers in the southern half of our big state. It won't be easy though! Look forward to more trip reports in the not-so-distant future . Thanks for reading- 14 replies
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Can anyone help to identify whether this is a pliosaur tooth? The seller listed it as a Brachauchenius lucasi tooth, and its locality is Eutaw Formation, Mississipp.
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From the album: Proudest finds
If I am to exclude the articulated finds, this tooth is my vertebrate pride and joy, on par with my Hadrodus tooth- 2 comments
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