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The Tyrannosaur Dinosaurs (Tyrannosauroidea) inhabited North America from 152 Million Years ago during the Late Jurassic era up until 66 Million Years ago during the Late Cretaceous era. https://www.app.pan.pl/article/item/app20110141.html However, there is a relatively large geologic gap between the time of the Late Jurassic to the Santonian-Campanian stages of the Cretaceous (when the the oldest known Tyrannosaurid Lythronax (Late Creteaceous, 81.9-81.5 Million Years ago) emerged) in terms of the number of Tyrannosauroidae confirmed in North America. However, this doesn't mean they were completely absent from the Continent. Rather, they remained small to mid sized predators under the shadow of Large Carnosaurs up until the Cenomanian-Turnonian extinction event 93-94 Million years ago, which the tyrannosaurs filled the role of Apex Predator in most terrestrial ecosystems by the Campanian stage of the Cretaceous. The Tyrannosaur geologic gap between the Late Jurassic and Santonian Cretaceous is also not completely empty and several confirmed Tyrannosauroidea are known from this time period in North America. I've created a list of known Tyrannosauroidea species and specimens from the Aptian-Santonian Cretaceous of North America which I would like to share on the fourtm (let me know if there are any examples I'm missing or should add): Unnamed Cloverly Formation Tyrannosauroid (Tyrannosaur – Cloverly Formation, Wyoming, US, North America) (Early Cretaceous, 108 Million Years ago) (Based on Specimen FMNH PR 2750, likely grew up to 1.2 meters (3.9 feet) in length) https://www.tandfonline.com/doi/abs/10.1080/08912963.2010.543952 https://www.researchgate.net/profile/Lindsay- Zanno/publication/229287579_On_the_earliest_record_of_Cretaceous_tyrannosauroids_in_western_North_America_Implications_for_an_Early_Cretaceous_Laurasian_interchange_event/links/0fcfd50089dd8f3955000000/On-the-earliest-record-of-Cretaceous-tyrannosauroids-in-western-North-America-Implications-for-an-Early-Cretaceous-Laurasian-interchange-event.pdf Unnamed Wayan Formation Tyrannosauroid (Tyrannosaur – Wayan Formation, Idaho, US, North America) (Early Late Cretaceous, 100.6-97.8 Million Years ago) (Based on Specimen IMNH 2251/53975, grew up to 1.2 meters (3.9 feet) in length) https://bioone.org/journals/journal-of-paleontology/volume-96/issue-6/jpa.2022.42/A-partial-tyrannosauroid-femur-from-the-mid-Cretaceous-Wayan-Formation/10.1017/jpa.2022.42.full Unnamed Lewisville Formation Tyrannosauroid (Tyrannosaur - Woodbine Group Lewisville Formation, Texas US, North America) (Late Cretaceous (100-95 Million Years ago)) (Based on Specimens DMNH 2013-0701701 and SMU 77218, grew up to 2.7-4.8 meters (8.8-15 feet) in length) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8796713/ Moros intrepidus (Tyrannosaur – Cedar Mountain Formation, Utah, US, North America) (Early Cretaceous (96.4 Million Years ago)) (Grew up to 1.2 meters (3.9 feet) in length) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6385174/ Suskityrannus hazelae (Tyrannosaur – Moreno Hill Formation, New Mexico, US, North America) (Early Cretaceous, 93.5-89.3 Million Years ago) (grew up to 3 meters (9.8 feet) in length) https://www.pure.ed.ac.uk/ws/files/82474043/82473554._Brusatte._AAM.pdf

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!

Perhaps the most definitive, lasting project I've had during my short time in paleo is the excavation and study of a basal mosasaur skeleton my step brother and I found in September of 2021 (If you missed it, it's in my blogs on my profile). The site is on a fairly inconspicuous outcrop of the Eagle Ford formation, in a zone that's atypical for the upper eagle ford, as the rock itself is very condensed compared to what is usual for the upper kef. Notably, while Mosasaur material is very, very rare in the kef (kef is an abbreviation for the Eagle Ford formation), it pokes out with greater frequency here - I have found two other Isolated Mosasaur teeth there before. Both @LSCHNELLE, a geologist who is very familiar with the Eagle Ford, and a paleontologist that I'm working with have made this observation about this atypical site. Between the three of us, we weren't sure there was another exposure like it elsewhere. --------------------------------------------------------------------------------------------------------------------------------------------------------- Over spring break, I was in need of some good luck (after losing the transmission in my new car ), so, finding myself back using my parents car, I made a drive to spot I had scouted a year ago, expecting to see the massively steep Ozan exposure I had spotted from a distance before. Upon arrival, I was greeted with those gorgeous grey shales in all their glory. Upon closer inspection though, I was surprised to realize that things weren't as they seemed. The shales were lighter than the Ozan, and physically much harder. I was suppressing exciting pangs of recognition for a few seconds, but it soon became very clear that this massive vertical exposure was an outcrop of that same lithologically atypical zone of the Eagle Ford that produced our Mosasaur. What's more, this site is many miles away, and mapped as a completely different geologic group. It appears that through upfaulting, a cross section of this zone shot through the layers of earth above it, standing as an Island of the Turonian in a sea of much younger rocks. One feature of the Eagle Ford (or any formation for that matter) is that the bulk of the rock is barren, only interrupted by small intervals of great fossiliferous accumulation. This stood to be true at this site as well, so I set about chasing those shelly lenses that caught my eye and changed my path of life over a year ago. It didn't take long before I came to a shell lens a couple inches thick. One con of this site being a vertical cliff is that I can't peel slabs up as I can at its sister site, so I had to slowly chip into the lens, one piece at a time. Here are some finds that resulted: Small shark vertebra Fish vertebra An oddity, insitu in the middle of the shelly lens. Try your guess first Upon removal: A really lovely Ptychodus tooth that I suspect is the unpublished species also found at our mosasaur site. Since the species has not been described yet, I can't fairly quote any exact morphological features to cement my ID, but I've seen enough by now to "know the look", and have had several of these teeth confirmed by Shawn Hamm. This tooth was one of the best fossils I could find to confirm the comparison to the atypical kef mosasaur site. Here's another view: Shortly after, I distracted myself from hammering out small chunks of the lens and took a peak under the one tiny 3D protrusion of the lens that there was. Under a ledge only a few inches wide sat a fossil that made my heart skip a beat: The tip had fallen off, likely from hammer vibrations since I chiseling not far away. But, undeterred, I extracted the slab and was met with an imperfect, though still beautiful sight. To find a mosasaur tooth after removing what was in total less than a gallon bag of slabs made for an exciting day. Though broken, a basal mosasaur is a basal mosasaur, who can complain? I was especially excited that this lightning fast find came from a new site - meaning there might just be what I'll happily nickname a "Kef mosasaur lens" that transcends beyond the boundaries of our original site. Any trip where you walk away pondering those things is a good one

I have problem with this enigmatic shark tooth. Location- Poland, Zabierzów (Cracow Area) Age- Cretaceous. Turonian Size- 2mm

Every year on the christmas holliday we spend a few days at Cap-Blanc-Nez for fossil hunting. This year we found a realy nice ammonite in the Turonian chalk on chrisrmas day to add to the collection A decent sized Lewisicears peramplum ( meaning not to large to carry back to the car) and well preserved. The ammonite is just over 40cm diameter. It was a difficult job to get it out of the boulder since it was near the bottom and hard to acces, but well worth the effort. during extraction It cracked at the base of the living chamber, but I glued it back and restored the crack.