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  1. Jaybot

    Cretoxyrhina sp.

    From the album: Neutache Shoreline - Sharks & Fish

    A partial tooth, possibly Cretoxyrhina. Glacial deposits, E Kansas #VM18 4/12/24

    © CC BY-NC

  2. ThePhysicist

    Texas sharks

    From the album: Eagle Ford Group

    A handful of Cretaceous sharks (and fish vert) from an outing in the Kamp Ranch Limestone. Not particularly plentiful, but great preservation.
  3. ThePhysicist

    Cretoxyrhina in situ

    From the album: Eagle Ford Group

    A razor-sharp Cretoxyrhina in plain sight.
  4. isurus90064

    Extraordinary Common Teeth

    Hey guys, I've been off the radar for awhile .. work you know .. been working on Siggraph for those of you who are familiar with software development. Just wanted to start a new topic here .. This one is right at 3.00" - 7.62cm C. carcharias Bahia Inglesa Formation South of Caldera Provincia Copiapo III Regio de Atacama Chile
  5. Hey all, Here are four teeth from the Gault Formation, Albian stage of Folkstone, Kent, UK. Am I correct that the left two teeth are Dwardius siversoni? The right two teeth have somewhat relatively bigger cusplets and they are more round. Could they be Dwardius or possible Cretoxyrhina sp.? I noticed that the book chapter of Ward (2010), https://www.researchgate.net/publication/280316422_Chapter_21_Sharks_and_Rays, also mentions Cretoxyrhina aff. vraconensis from the formation. Any thoughts? If you need better pictures, just let me know.
  6. Fullux

    Cretoxyrhina?

    These came from a Cretaceous site in Mississippi. One looks like it could be Scapanorhynchus and the other looks like Cretoxyrhina, am I correct?
  7. Mikrogeophagus

    Cretoxyrhina agassizensis, Bouldin Flags

    From the album: Eagle Ford Group

    Cretoxyrhina agassizensis, Central TX Cenomanian, Cretaceous Dec, 2022
  8. This month I decided to take on the challenge of finding my first Kamp Ranch sites. It's not the easiest thing to do since, to my knowledge, the elusive layer is not mapped anywhere. I spent a lot of time scouring the waterways of North Texas and by the end, I came up with two distant potential spots for a couple days worth of hunting. I traveled to the first site one sunny morning and after a long walk, I finally made it to the water's edge where I met endless limestone slabs filled with Collignoniceras woollgari impressions, meaning I was just in the right place. I readied my rock hammer and began the search. It was mostly just oyster fragments initially, but soon enough I started picking some nice Squalicorax and tiny Ptychodus anonymous. The Kamp Ranch was pretty hard, and that meant that the Squalicorax rarely survived extraction. Even the Ptychodus, which are usually quite resilient, ended up shattering more than I'd like to admit. I built up a steady flow of Ptychodus anonymous before spotting an enigmatic crusher tooth. I was excited since it appeared to be very large and of a rare species, but it turned out only to be a fragment. What's strange about it is the flat crown and few yet thick transverse ridges on top. The only species I know of this nature is Ptychodus latissimus, but in Texas those are better known to begin in the Basal Atco (Early Coniacian). I did some research at home and found that P. latissimus has been observed in Middle Turonian outside of Texas, so I suppose it is a possibility here. Possible Ptychodus latissimus After some more finds like a huge Xiphactinus tooth and Cretoxyrhina cusp, I at last flipped the slab that would yield the definitive best find of the day. In perfect condition was the biggest Ptychodus anonymous I had laid eyes on. I was familiar with the fact that the Turonian P. anonymous morphotype was supposed to be larger, but it's always different seeing it in person. Initially, I wasn't totally sure if it was P. marginalis instead, but the taller crown and anonymous-esque marginal area led me to believe it was the former. P. anonymous A couple weeks later, I ventured out to my second site. This locality had a smaller exposure on timid waters, so I was looking forward to being able to hunt for freshly eroding fossil from the limestone wall. When I first showed up, I was once again greeted with limestone slabs containing Collignoniceras woollgari impressions, however I was struggling to even find a single shark tooth among them. I recalled reading in the past that the Kamp Ranch can be spotty, so the possibility that this locality might be barren was looming in my head as I traversed the creek. Once I reached the exposure, I pulled out the probe and danced my way through the limestone blocks. I skimmed through the whole exposure pretty quickly, but only came out with a few Squalicorax teeth and a big Cretoxyrhina from the gravel. I was a bit disheartened. This was such a nice looking location, how could that be all there was to offer? Cretoxyrhina mantelli in the gravel Desperate to salvage the day, I got down low and searched the under side of the lowest slabs. After dodging a spider, I spotted the outline of a Ptychodus sticking out from a shaley layer cemented to the underside of the limestone. The matrix was soft enough I could dig it out with my fingers. Then I noticed another... and another. This layer was extremely productive and soon I pried off a slab of it to process atop a boulder. I could not believe the number of teeth I was finding. Pristine teeth from just ONE slab Not only were the Ptychodus numerous, they were also diverse. Shawn Hamm in a recent paper listed six species of Ptychodus occurring in the Kamp Ranch. I didn't know it at the time, but after some cleaning, I have EVERY one of those species represented from only a day's worth of hunting! Some of the more special ones included P. mammillaris which was a new species for me. Also, I found an upper medial file tooth of P. marginalis(?) which are always a neat tooth position with their unique proportions. P. decurrens is one I usually don't associate with the Turonian in Texas, but they made it through and I managed to snag a textbook one. Ptychodus mammillaris Upper medial file Ptychodus marginalis(?) Ptychodus decurrens The Lamniformes were also plentiful, though difficult to bust out in one piece. Dallasiella willistoni, a common smaller tooth from the Turonian Huge Cretoxyrhina mantelli One of the coolest finds was not a tooth at all or even from a vertebrate for that matter. The Kamp Ranch is a bit famous its fossil pearls. When I spotted a perfectly spherical curvature from the slab I put in 110% effort to pop it out cleanly and not have it fly away into the flowing water below. It came out in one piece and after looking through the microscope, it has the polygonal structure expected for a Kamp Ranch pearl. Inoceramid Pearl. That rock it came from also had two Ptychodus anonymous and a Cretoxyrhina mantelli as well Towards the end of my slab-splitting, I found an enigmatic fossil. Its flat and a fishy bone look with a bunch of holes on one side. The other side is completely smooth. My best guess is it's from a Plethodid fish, but it looks pretty different from the South Bosque (also Turonian) Plethodid fragments I have in my collection. Possible Plethodid After a long and rewarding day hitting the slabs, I turned around to head for the car. Of course, my eyes were locked on the gravel anything I had missed on the way in. No teeth were to be had, but I did find a thin shale ammonite entirely separate from matrix. I have no idea how it managed to survive in the gravel. It's so delicate and even has the tubercles of the shell intact on both sides. It's obviously not from the limestone, but would this still be Collignoniceras woollgari? It was a great day. I'll be visiting both of these sites again in the future for sure! Finds at the second site: Top L to R: P. marginalis, P. mammillaris, and Undescribed species Bottom L to R: P. anonymous, P. whipplei, and P. decurrens Top: Cretoxyrhina mantelli Bottom L to R: Plethodid?, Dallasiella willistoni, Inoceramid Pearl, Cretalamna sp., and Squalicorax sp. Thanks for reading!
  9. ThePhysicist

    Cretoxyrhina tooth

    Identification Cretoxyrhina teeth are simple in design, having a triangular crown with smooth enamel and non-serrate edges, a thin lingual dental band, rounded root lobes, a lingual root protuberance, and no nutrient groove.1,2 Comments This tooth is from a latero-posterior position, given the crown's distal curvature. The chalk preserved this tooth very well - the enamel retains a sharp gloss comparable to that on modern sharks' teeth. References 1. Bourdon, Jim, and Michael J. Everhart. “Analysis of an Associated Cretoxyrhina Mantelli Dentition from the Late Cretaceous (Smoky Hill Chalk, Late Coniacian) of Western Kansas.” Transactions of the Kansas Academy of Science (1903-), vol. 114, no. 1/2, 2011, pp. 15–32. JSTOR, http://www.jstor.org/stable/41309622. 2. Shimada, Kenshu. “Dentition of the Late Cretaceous Lamniform Shark, Cretoxyrhina Mantelli, from the Niobrara Chalk of Kansas.” Journal of Vertebrate Paleontology, vol. 17, no. 2, 1997, pp. 269–79. JSTOR, http://www.jstor.org/stable/4523806.
  10. Apologies for the dramatic title. I thought it sounded cool and stuck with it even though 90 + 80 + 80 is only 250 . Anyways... This past 30 days, I decided to make it a point to check out some new spots. I won't be living in Austin soon, so I thought it would be good to branch out and scout some new locations with potential. I've found lots of creek-worn mosasaur bits and pieces over the past year. I'm ready to find things in situ, and, one day, something articulated. It's a tall order, I know, but I feel like it's the next step and really the ultimate goal I've always had. So, the first step towards this objective was to find locations and, of course, take a look. This is what I saw! Location 1. Austin Chalk: In my usual Ozan stomping grounds, I've come across a variety of fossils ranging from the Eagle Ford to the Ozan itself. Included, was an assortment of spectacular Austin Chalk invertebrates along with the occasional and highly sought-after mosasaur vertebra. They can be readily distinguished from their Ozan counterparts by their yellow-orange preservation and lack of pyritic elements. Honestly, I come across them just as commonly as I do Ozan verts, so I took this to be a sign that the Austin Chalk could be a good bet. In Austin, it's a pretty wide formation with lots of members to look into. I did some research and found a place with some potential. When I arrived, it was a hot afternoon. I picked up my backpack and swapped my school notes out for a rock hammer and a couple of icy bottled waters. Walking down a little trail, I came across the first large exposure of Austin Chalk in what I believe to be the Dessau member. Literally within the first minute, I had to take a double-take at a white glint on the ground. "Surely there couldn't already be a shark tooth," I thought to myself as I kneeled for a closer inspection. Sure enough, it wasn't just a shiny piece of shell; it was indeed the enamel to a bleached tooth from the king shark of the Late Cretaceous seas, the infamous Cretoxyrhina mantelli! Thankfully, it popped out in one piece. A recreation of the tooth in situ and after extraction. I poked around the rest of the surrounding exposure. There were a couple of mangled echinoid bits and gastropods, but not much else, so I continued on to search the main creek. Unfortunately, the only apparent path forward was along a narrow and steeply banked feeder stream. Many of you will know that navigating through these can be a real pain. The brush was densely packed and smelly stagnant water had to be avoided with every step. There were thorny vines dangling from each limb and I was constantly tasked with picking off the burrs that snagged onto my clothing and in my hair. Last year, I was in a similar situation when I was suddenly attacked by a hive of wasps (don't worry, I managed to avoid getting stung too much). It's a fun story to tell friends now, but I must admit that the thought always crawls back into my mind when I am in a position that's a bit difficult to get out of in a hurry. Anyways, after about twenty minutes, I took the final hop over a fallen tree to get to the main creek. It was nice to breathe in the fresh, open air as I sat my backpack down and took a rest, of course, with my eyes perusing along the limestone bed. After the brief sit-down, I began to notice the beauty of the area I was in. The air was filled with the drip-drop of water leaking from the fern-covered bank and the reflection of the greenery was simply mesmerizing. I couldn't help but snap a quick photo. A beautiful, hidden place away from the city. Though, not too far... there's a shopping cart wedged in the gravel just out of frame. In terms of fossils, this place was loaded. Just about everywhere I stepped, I was standing over piles of clams and oysters along with the occasional baculites segment. I didn't bother taking any of these with me, however, as I have plenty already. I noticed there was a decent amount of chert as well, so artifacts were on my radar when I came across a preform. A little farther down the creek, I found a nice ammonite fragment. I didn't intend on keeping it, but sometimes it's nice to have something to hold so I took it along with me. By now, much of the afternoon had come and went. It was about time I turned around and faced the prospect of navigating my way through the dreaded feeder creek in reverse. As I was coming to a stop, I saw a girl walking along the slanted banks of the creek who almost certainly did not enter the way I did. I tried my best to get her attention without spooking her (keep in mind I look and smell like a swamp monster at the moment). She was nice enough to come close to the limestone ledge and introduce herself as I trudged my way through knee deep waters towards dry land. Turns out, she's a local who often hikes by the creek. We chatted for some time and I ended up giving her the preform and ammonite fragment, hopefully inspiring a future hobbyist. After explaining the situation I was in, she laughed and pointed out a trail that led back to the road. When I climbed out and exited the trail sore and tired, I kicked myself. My car was right in front of me. I could have taken this path from the beginning, but instead I took the road never traveled and boy did it make all the difference. Location 2. Ozan Formation: Although many of the mosasaur verts I come across are from the Austin Chalk, a significant portion are still from the good ole Ozan. With that in mind, I took a trip to a creek I usually don't hunt that had a decently-sized exposure. Something in a book tipped me off to this particular site, so I had high hopes. The trip from the road to the waterway wasn't as troublesome as the feeder creek from the week before, but it was still a challenge. I worked my way along the dirt bank to a place I could safely enter the waters when I saw what I was more so wary of. Across the lazy stream was a tent set up along a slope with a clothesline and shopping carts around it. On the initial drive to this spot, I did take notice of the pronounced homeless presence in the area. From the cover of the trees, I took a moment to scope out the tent and the surrounding area. The last thing I wanted was to have an unexpected encounter in a secluded place like this. Luckily, it seemed nobody was home, so I entered the creek, though making sure to have my rock hammer visibly in hand. When I approached the first gravel bar, I was greeted with tons of broken down blocks of Ozan shale and various Austin Chalk fossils. Curious, I started splitting the blocks open to see what the area had to offer. Each one was filled with heart urchin spines and plates! Most were fragmented and all were extremely fragile. Still, I took this to be a good sign. After hours of splitting the loose slabs, I finally found a complete irregular urchin. It's a definite upgrade from the half of one I had found a while back in the Ozan (though that one did have a nice red color). A compressed heart urchin. Looks to be Pliotoxaster/Hemiaster? It may appear round, but it is totally flat! The slab splitting continued with some compressed ammonites and enchodus teeth, but not much more, so it was time to move on to the main event. As I walked the rest of the gravel bar, however, I was forced to once again stop in my tracks. Lying in the mud right in front of me was, by far, the largest mosasaur vertebra I had ever seen in person. It had the preservation of what I assume to be Austin Chalk (of course as soon as I return to the Ozan). The underside of the vert was badly weathered, but it was, nevertheless, far heavier than any others in my collection. Plus, I only need one decent side to show in my picture . Gargantuan mosasaur vertebra. I wonder how long the whole lizard was. Welp, there's really no better motivator than something like that, so I took the short walk to the main exposure. A large expanse of creek bed was Ozan shale ripe for the picking. I got straight to working chiseling out every strange thing just poking out of the ground. Most of them were only oddly shaped pyritic accumulations, I'm guessing originally bivalves and poop. Now and then I would come across a Hamulus squamosus worm tube or piece of fish bone. The bed was a little difficult to see as the lack of recent rain meant that the detritus and algae had yet to be washed away. I didn't find much in the water. Thankfully, the dry parts of the bed were easy to probe. Eventually, I came upon something unmistakably bony. Before I could stop myself to snap a photo, I was already digging. It popped out easily and was instantly apparent of being mosasaur, the very thing I was seeking most. Frantically searching for a continuation of the vertebral column, I spotted what I thought was the head of the next vertebra behind. In my mind, I could see it all right in front of me. The ultimate prize was right there! Just some minor excavating and I'll have done it! Perhaps in theme with fool's gold, I was fooled by the imprint of the very fossil I had just pulled out . I was bummed out for a second, until I had time to realize that this was my first ever mosasaur vert found in situ! Out popped my first in situ mosasaur vert! Cleaned up, it is a real beauty. The color of the cuboidal pyrite outgrowths looks amazing when moved under the light. "Fool's gold" is a real disservice as far as names go. And with that, the sun was already starting to set. The finds of the day. 2 mosies, a flattened echinoid, a Hamulus squamosus tube, an Austin Chalk ammonite, and an Austin Chalk Exogyra tigrina. Location 3. Ozan Formation: After crossing such a major milestone, I had no choice but to head out for the Ozan again once a brief rain had passed. This new location was similar to number 2 in that it was a large expanse of Ozan creek bed. Unfortunately, the route to reach it from the road was a treacherous one. I didn't intend on swimming across a sudden deepening of the creek waters, so I had to search along the steep banks for ways to traverse the barrier. There was somewhat of a flattened trail along a slope with various obstacles that seemed the most doable to me. For the most part, I side-stepped my way across, hugging the dirt and tree limbs to avoid losing balance or putting too much weight on the unstable ground. Now and then, I'd have to cross through a bush that would replenish the population of burrs covering every part of me. By that point, I couldn't have complained too much as things were going relatively smoothly. That is until I made one misstep and had to quickly catch myself by snagging an exposed tree root. Regaining my composure, I heard the rustling and sliding of a plastic bag followed by a loud splash of water from underneath my feet. I usually carry my dirty pair of tennis shoes in a plastic bag since I swap between them and water shoes on my excursions. Now they were just a white shimmer far beyond reach. I hopped off the bank and landed on firm ground. Most of the bed was readily exposed to the air. There was a high density of deer and raccoon tracks. I was entertained most by the shale claw marks I saw at the bottom of shallow pools that I interpreted to be raccoons taking a refreshing swim. From way up the creek, I even caught a glimpse of a coyote jumping from out of the foliage. He sniffed around a bit before noticing me and darted off the other way. I settled down to catch my breath and inspected broken bits of Ozan shale nearby. Pretty soon I spotted the first regular echinoid I've seen in the Ozan. Unfortunately, it was too fragile and didn't survive the journey home. A regular echinoid and a mess of urchin spines surrounding. This portion of the Ozan is rich in echinoid material, though heavily compressed and often very fragile. Denture clams are the other most common find of which fragments can also be seen here. After some rehydration, I got up to start looking for bone. It took some time, but I eventually found a peculiar specimen sticking out of the shallows. It was too suspect to ignore, so I began excavating. Spongey thing as originally found. I was hoping it would be a rib or something, but it just didn't look right. The pores of the cancellous bone were much larger than what I was familiar with for reptiles and the thing didn't seem like fish at all. Typical for fossils in this layer, there was pyrite all over. However, there was an additional mineral I hadn't encountered before. Encrusting the entirety of the underside were selenite(?) crystals in prismatic shapes. As I dug deeper and deeper, the form continued on. The spongey thing was long and had curvature. There was another short one layered just underneath it intersecting close to the hammer. If it's vertebrate, I have no idea what bone it would be. I suspect it's invertebrate in nature. Revealing more of it showed that a separate, shorter piece was present just underneath. Both structures were flattened, fragile, and had to be removed in chunks. From what I could tell, their spongey structure remained consistent across the entirety of their lengths. Once extracted, I searched the surrounding space, but found no sign of continuation. Post extraction I was completely stumped by what I had found. All I could think was spongey, pores, spongey, pores. I am embarrassed to admit it took me way too long to cut off the "y" and realize that it's likely a sponge. Pore bearing (porifera) is about as accurate as you can get when describing it. So, I settled with that as my final guess for what this mystery structure could be. Though, this is still up for debate, so let me know if there are any opposing opinions. From there, I took a couple of paces before stumbling upon the next thing of interest. It was a robust black protrusion with some apparent symmetry. Okay, if the last thing was pseudo-bone, surely this had to be the real thing. As per usual, there was pyritic encrusting on it. From how it was positioned, it was hard to say how long it could be - if there was much more to try and dig out. I got to chiseling and it popped right out within the first few swings. Instantly, I knew I had once again fallen for some pseudo-bone. That being said, it was the first time I had found carbonized wood in the Ozan. I don't usually keep fossil wood, but this guy is interesting enough to warrant it. A pyritized deposit of coal, pretending to be a mosasaur rostral. The fossil wood with a pyritized denture clam and Serratolamna(?) tooth on top. A piece of an artifact and irregular urchin on top. The clam on the right is a cool optical illusion. It's only 3/4 of an inch tall. Here and there I made some other nice smaller finds. A fragment of an artifact, some shark teeth, and an even better flattened irregular urchin to name a few. Though, I had spent a lot of the recent weeks hammering away at things in creeks, so I thought it would be best to call it early and head home to have a nice meal and reflect on my prizes. No articulated mosasaur bits, but a great many lessons learned and special memories to reminisce upon in the future. I know I'm preaching to the choir with this one, but there are few things as magical as traveling alone and exploring a side of the outdoors you hadn't encountered before. It's hard to explain, but I love just parking somewhere and walking into a part of the brush where few people go, if ever. It's freeing in a sense. But for now, I've creek walked way too much. I'm gonna go hunt a roadcut or something
  11. Egrigg

    Texas shark tooth ID

    I cannot for the life of me figure out what this tooth is. When I first found it I was sure it was Cretoxyrhina but with further inspection I doubt that’s the case. Does anyone have a clue what shark this mysterious tooth belongs to? (Found in alluvium/ozan)
  12. It's been over a month now since @Jared C and I found the Eagle Ford Xiphactinus. In the weeks that followed our discovery I was able to get in touch with the right people at Baylor University where I go to school and start to organize a retrieval project. Unfortunately I haven't been able to make it back to the site since then as all involved will have to wait for the wheels of bureaucracy to turn enough for us to have the proper permission necessary to return. So I was left with a problem: my first visit to the Eagle Ford turned out so well that I wanted nothing more than to go back, but I couldn't! Of course, that was just because I only knew of one exposure. And so I turned to more old literature in the hopes that I could locate another productive site the same way I had the first one. After many hours of reading papers that were filled to the brim with so much scientific jargon that they often went completely over my head, it seemed like I had finally struck gold when I found directions to a specific locality. Several days later I found myself with enough free time to make a scouting trip. The woods that I traveled through to get to the creek that was my ultimate destination were not making my job easy for me. Anyone who's spent even a little time outdoors in the eastern half of Texas knows that any given stretch of woods is about 80% brambles and thorns. This particular area was absolutely covered in them. I made slow progress - every fifteen minutes that passed would find me moving roughly the same number of feet. Eventually I got lucky and stumbled onto a trail through the thorns made by the local hogs. It's probably the only time I've ever been grateful for an invasive species! Following the trail led me to a steep bank and the creek I had been looking for. Peering over the ledge, I could see that the sides were lined with shale almost from top to bottom. All that shale had to mean fossils and so I wasted no time in making my way down to the creekbed. The paper I was referencing told me that I was within the Lake Waco and South Bosque formations of the Eagle Ford group, but it didn't take long for me to realize that there were probably others present as well. Massive slabs of limestone had fallen from the ledges at the top of the bank and littered the creekbed. Here's a picture of probably the biggest one I saw: My best guess is that this was some of the nearby Austin Chalk making a surprise appearance. From there I made my way westward. Fragments and impressions of giant inoceramid bivalves were visible on almost every scrap of rock I passed. I was so focused on inspecting the broken pieces of shale and limestone I was picking my way through that I failed to notice the pack of wild hogs I had inadvertently cornered! The creek dead-ended just beyond a fallen log, behind which were the makers of the trail I had followed through the woods. A limestone ledge formed a now-dry waterfall and below it was a pool of stagnant water and mud that the local hogs were obviously using as a place to wallow and escape the Texas summer heat - I can't say I blame them! I made sure to give them enough space to escape up the side of the bank and once I was sure they were gone I moved to inspect the pit they had been so kind to leave me. The shale I had been walking alongside further up the creek was exposed in all its many-layered glory here. For a mudhole used by a bunch of pigs it was surprisingly beautiful, and I found my breath briefly taken away when I got my first good look at it. Interpreting what I was seeing using the paper that had led me here proved to be a challenge at this point. At first I believed that everything below the waterfall ledge was the Lake Waco formation and everything above it was the South Bosque, but after a LOT of research since my first visit I'm now fairly confident in saying that almost everything I saw was just one particular member of the Lake Waco formation: the Cloice. The first finds of the day were located on the right side of the picture above in a layer just above a bentonite seam and just below the thick layer represented by the waterfall ledge. See how fast you can figure out what they are: The tooth on the left turned out to be a species of Ptychodus that was super common here (maybe anonymous?) while the tooth on the right was a perfect anterior Cretoxyrhina mantelli, my first of that species! Unfortunately I still don't own a rock hammer and even if I did I would have forgotten to bring it. I'm so used to just walking around at a site and surface collecting that the most I ever pack on fossil hunting trips is a garden trowel. At first I told myself I'd leave the teeth for a return trip when I had proper tools, but my impatience got the better of me as the hours wore on and I ended up using my trowel as an impromptu chisel and a rock as a hammer. The root of the Cretoxyrhina tooth broke in one place but I saved it for reattachment later. My troubles weren't over when I finally got the tooth out of the rock, however. My attempts to pry it out with a screwdriver on my walk back to my car were far from successful and actually caused my thumb to slip at one point, forcing the the tip of the tooth up and underneath my nail. Ninety million years since it was alive and this particular Ginsu shark finally got to taste blood again (even if it was only because of my stupidity ). Rewinding back a little bit to when I first found the site, I was able to follow the layer that I first spotted the Ptychodus and Cretoxyrhina in to the left where it was better exposed. It turned out that although there were obviously teeth in the grey/tan, fine-grained layers roughly three to four inches above the bentonite seam (the two teeth I just mentioned being examples), the vast majority were to be found within the red-stained "contact layer" immediately above the bentonite. A super thin lense was sandwiched between the bentonite and the dense shale/siltstone above. Here's a picture of the lense as I first saw it: Over the course of the next couple of hours I had my hands full pulling out shark tooth after shark tooth. There were so many in such close proximity that just a single small four by five inch slab of the red contact lense contained three decent sized Squalicorax teeth, a small Ptychodus, a fish vertebra, and an uncountable amount of microscopic fish teeth and other vertebrate detritus. I personally love in-situ photos, so I took a couple to show off. First up, a nicely-preserved Ptychodus anonymous. With the stratigraphy of the site more or less ironed out now, I'm pretty sure that the majority of Ptychodus teeth I found were P. anonymous with a couple of the much less common P. decurrens mixed in for variety. An incredibly small palatine bone from an Enchodus with the trademark fang intact, surrounded by a jumble of fragmented bone and teeth detritus. The blade of a Squalicorax falcatus peeking out from the contact lense. This specific tooth turned out to be the largest example of the species I've ever found (just barely bigger than those from Post Oak Creek!). How it looked once it was cleaned up: My blurry attempt at using an iPhone camera to take a closeup of the incredible serrations of a different Squalicorax tooth sticking out of a piece of the contact lense: One of the bigger fish scales I saw at the site. Every piece of shale was absolutely covered in them. Yet another Ptychodus tooth (probably P. anonymous). A second large Cretoxyrhina mantelli anterior tooth. This one still required some time spent with a dental pick but it proved to be much easier to retrieve than the first one I found. A before and after: And just to show how abundant the teeth were at this site, here's a picture showing the result of only four minutes' worth of digging and picking around: The best find of the day turned out to not be one of the shark teeth, but a tiny little bone that I didn't find particularly interesting when I first pulled it out of the shale. Any guesses as to what it might be? (Hint: this is a view from the bottom side) If you guessed vertebra, you're right! And you're also a lot smarter than I me - my lack of interest was because I thought I was looking at part of a crab carapace. This particular vertebra is from a Coniasaurus (an ID provided by @Jared C) - and it wouldn't be the only one I'd find here. But I'll leave that for the next post since I'm running out of space for pictures and I've already rambled for too long. I'll leave you all with a group picture of the finds from that first day: - Graham
  13. fossilsonwheels

    Cretoxyrhina ???

    .7” tooth, Blue Hill Member, Carlile Shale, Jewell Co Kansas. I am not super familiar with the Carlile Shale fauna and I think this is a Cretoxyrhina but I’m not 100% sure I’m correct so I thought I seek other opinions.
  14. ThePhysicist

    Cretaceous sharks

    From the album: Sharks

    Just a handful of Cretaceous species, most from North Texas. The sea that bisected North America ~85 million years ago played host to a diverse and burgeoning ecosystem that supported many species of sharks. It was likely due to specialization that allowed these sharks to all live in the same place and time.
  15. I've recently become very interested in the sharks of the Cretaceous. The largest of all sharks during this time period was supposedly Cretoxyrhina mantelli, or the "Ginsu Shark". It likely would've highly resembled the modern Great White. I looked up a few images of their teeth, but I was wondering if anyone who hunts the Cretaceous here on the forum has any of their own? If so, I'd love to see them! Hoppe hunting!
  16. ThePhysicist

    Cretoxyrhina tooth (3)

    From the album: Sharks

    A gorgeous tooth from one of my favorite sharks! The enamel isn't polished - the chalk preserves its shine extremely well - it's as shiny as when it fell out of the animal's mouth!
  17. ThePhysicist

    Cretoxyrhina tooth (2)

    From the album: Sharks

    A beautiful tooth from one of my favorite sharks. This one is extra special because of the self-inflicted bite mark - a gash seen on the left in lingual view. Apparently their bite was strong enough to cut their own teeth!
  18. ThePhysicist

    Cretoxyrhina tooth

    From the album: Sharks

    One of my favorites - the "ginsu" shark. This one was found at the DFW airport in the 80's.
  19. Chase_E

    Cretoxyrhina vraconensis

    From the album: Cenomanian Shark Teeth and other Marine Fauna, Ryazan Oblast, Russia

    Cretoxyrhina vraconensis. I believe this is a lower anterior, but I could be mistaken.
  20. Hi, Recently, I had the good fortune to acquire this set of Cretoxyrhina (vraconensis) teeth from the Britton Fm., Texas. I have a detailed account of it’s discovery which describes almost all of these teeth being found together in an area about 18” x18”, with a few stragglers found just outside the main pile of teeth. It’s not complete, but It looks like most of the positions are represented. Some of the larger anteriors were not recovered and I suspect at least one or two positions are missing. I have arranged these teeth into positions that look close to me, but there is no doubt that it needs to be adjusted. I am hoping someone here might know something about these early Cretoxyrhina dentitions and might be able to advise or comment on how I can make this accurate. Some other noteworthy finds recovered from the same 18” square were 2 suspected Cretoxyrhina vertebrae, 5 small Squalicorax (falcatus) teeth, a possible Archeolamna tooth, another very small unidentified cusped shark tooth, and some small fish vertebrae and bones. Thanks for looking. R~
  21. bthemoose

    Texas Cretaceous shark teeth

    I have here two shark teeth from the Cretaceous of Texas that I'm hoping to ID. #1: Dwardius ?woodwardi? The first tooth below is from Dallas, TX, from a buffer zone between the Eagle Ford and Woodbine formations (i.e., late Cretaceous, ~90-96 mya). I previously posted this tooth in the mailbox score thread and the @ThePhysicist tentatively IDed it as Dwardius (woodwardi?) but recommended posting it in the ID forum. I'm finally getting around to doing that! This tooth measures 25 mm on the slant. #2: Cretoxyrhina ?mantelli? I don't have as much info on the next tooth below. I acquired it last year from the estate of a Dallas, TX, fossil collector. I don't have any other details, but it was most likely collected from a site in North Texas. I've tentatively IDed this as Cretoxyrhina mantelli teeth; if that's the correct ID, it would be the first one in my collection with cusplets. This tooth measures 29 mm on the slant. Thanks in advance for any help you can provide!
  22. ThePhysicist

    A Physicist's Collection

    While my prime focus is essentially learning how to accurately describe Nature in the precise language of mathematics, I've always been intrigued by natural history - it's actually what started me on the path to physics. The sort of interrogation that paleontology practices provoked me to think and question even further, down to the fundamental science which makes it all work. Collecting fossils has brought a large amount of enjoyment to my life, and is often a welcome distraction from what can sometimes be straining work. The knowledge that I accumulate along the way is also part of the fun. Here is my collection, which will always be a work-in-progress. There's still many things I haven't photographed yet, but I feel comfortable saying this is the majority. I don't have many big things, but I'm certainly pleased with the many small things I have so far. Links to albums: Dinosaurs Sharks North Sulphur River Post Oak Creek Permian Aguja Formation Harding Sandstone Devonian Galveston Fossils Miscellaneous Highlights / Personal Favorites: The ones underlined are linked to their respective fossil page in the Fossil Forum Collections, which has more information and photos. Infant Tyrannosaurus rex posterior tooth If I could keep only one fossil, it would be this one. It's from my favorite animal that has ever lived, and being from a young'un is just so darn cool. A true crowning jewel in my eyes. Juvenile Tyrannosaurus rex maxillary tooth Again, you can't go wrong with T. rex. It doesn't have the best preservation but regardless, there's a lot more to love. Tylosaurus proriger tooth (self-found) Undoubtedly my favorite find to-date. Finding fossils yourself adds that extra value to its place in your collection. I'll remember the moment I first saw it for a long time. Triceratops prorsus tooth Triceratops is another one of my favorite dinosaurs, I think we all grew up playing with toys of T. rex and Triceratops. Unique circumstances also allow for me to say it's Triceratops and not Torosaurus with some confidence. It's not perfect, but still a significant part of the collection. Avisaurus archibaldi tooth A bird tooth? Doesn't get much cooler or more uncommon. Dimetrodon cf. limbatus tooth I've always been drawn to "icons of life," since those are the ones we remember from childhood. Dimetrodon is definitely an icon, and I'm glad to have found one of these uncommon treasures (in micromatrix - it was a very nice surprise). Cretoxyrhina mantelli tooth One of my favorite shark species, the "ginsu" had sleek-looking teeth, ate mosasaurs and dinosaurs, and was overall a formidable animal worthy of admiration. Cretodus crassidens tooth (self-found) Another one of my favorite sharks. It's not big or complete, but the preservation is so rare for the locality (POC) - the gloss on the enamel is as if it fell out of the shark's mouth yesterday. Saurornitholestes langstoni tooth I'm currently working on growing the dinosaur component of my collection, and this is my first Dromaeosaurid. Dromaeosaur tooth (Hell Creek Fm.) My most recent addition (as of Sept. 4, 2021), and it's my best dinosaur tooth for sure. Unfortunately it will be labeled as only a Dromaeosaurid tooth for now, but it still is just a great tooth from a cool family of dinosaurs. Shark Tooth Riker Display I've got one riker that I've tried to squeeze as many teeth into as possible. I need to get a couple more, probably; there's a lot of teeth that deserve a riker, but are just lying around. I'll try to update this thread semi-regularly as I make acquisitions in the future.
  23. ThePhysicist

    Cretoxyrhina mantelli (6)

    From the album: Sharks

    Nearly flawless lateral "ginsu" from the Smoky Hill Chalk of Kansas, USA.
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