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These are fossils from the early Campanian of northwestern New Mexico, collected on BLM-managed land as part of the Menefee Expedition. The Menefee Expedition, which has run yearly since 2011, is a multi-institutional effort combining the talents of the Southwest Paleontological Society, Western Science Center, Zuni Dinosaur Institute for Geosciences, and formerly the University of Pennsylvania, permitted under the Bureau of Land Management in New Mexico. Fossils collected as part of the Menefee Expedition are prepared and stored at the Western Science Center in Hemet, California. If you'd like to watch the day-by-day of the expedition, be sure to check out the Expedition Video logs on YouTube! Baenid turtle shell- my find! Dinosaur limb end- my find! Large croc tooth, likely Deinosuchus- volunteer find! Leaf and stem- my find! Gar scale- my find! Dinosaur tibia- volunteer find! Brachychampsa tooth- my find! Bivalve, which I think is a unionid- my find! Crocodilian tooth in matrix- my find! Finally, a dinosaur toe bone- volunteer find!

Good afternoon! My name is Benjamin Mohler, and I'm an 24-year-old early career paleontologist born and raised in Arizona, USA. I have lived in the southern city of Tucson for the past 5 years, choosing to stick around town even after graduating with my bachelor's of science from the University of Arizona. The story of how I got here after 15 years of experience in the field of paleontology is quite long, which you can read about on my blog if you're so inclined. In short, I've searched for fossils across the American west, including Arizona, New Mexico, Utah, Colorado, and Wyoming. Much of my fieldwork experience has come from working in the Campanian-aged Menefee Formation since 2011, though I have also spent time in the Chinle, Naco, Fort Crittenden, Cedar Mountain, Atarque, Morrison, Cliff House, Fruitland, and Moreno Hill formations (among others). I have been published twice so far, including most recently a paper describing the first Deinosuchus fossils from the Menefee Formation. My upcoming research involves describing additional crocodylomorphs from the Menefee Formation and evaluating the ecology of crocodylomorphs throughout southern Laramidia during the Campanian. While I'm in the field, I record expedition videos so that the experience of discovering fossils can be shared far and wide. You can watch my latest Menefee Expedition videos now on YouTube! In order to support myself in this rather unforgiving industry, I run a patreon page called the Parent-Teacher Guide to Paleontology. This is the home for all of my original science writing and photography, including research notes, Q&As, bonus blogs, and more. The aim of my work, besides paying my rent and student debt, is to create paleo content that a once and future student like myself sought after for years: well-researched, mature, and unafraid to explore complex topics. I'll be sure to share much more of my open access work here, both peer-reviewed and self-published, and I look forward to meeting all of you and learning everything I can! -Benjamin Mohler

Hello Folks! I want to get better at identifying fossilized teeth. My family and I spend a lot of time hiking through Jurassic and Cretaceous deposits in the western US that contain largely vertebrate terrestrial fossils. We've found a lot of fragmentary bone, and over the course of picking up a few thousand bone fragments, have developed a pretty good eye for telling what is bone and what's just pretending to be bone until you bend down to pick it up. Teeth, however, we're far less adept at identifying. Wandering around the desert, without training wheels, how am I to tell what a fossilized tooth looks like if I've not seen a tooth? Hm... Luckily, we've stumbled upon enough obvious examples of teeth that we do have some data on what they look like - but precious little data. We've only ever found a handful of easily identified teeth, so we're not so good at identifying the poor quality stuff. Sometimes the tooth structure just looks like chert/chalcedony, and sometimes there are similarities to the structure of bone. What are some key features I can look for that are unique to teeth? Below is an example where the Allosaurid ID is only given away by the serration imprints left behind - the "meat" of the tooth just looked like fracture chert/chalcedony. I wouldn't be able to prove it was tooth material without the serrations. Allosaurid tooth (Brushy Basin) - ~1.5inch length Another tooth (~half inch diamter), this one from the Cretaceous Menefee, found nearby crocodile type scutes (Deinosuchus?), but whose core has porosity similar to fossilized bone. Very different structure from the Allosaurid tooth, but the texture of the outer layers tell me this isn't just a bone. I believe this could be up in the root of the tooth, and these hollow channels are what is left of the blood vessels that supply nutrients to the teeth. I've had a hard time finding any example pictures online of a cross section looking into the root of a fossilized tooth to confirm. Opinions? Anyone have good example pictures of tooth root cross section? In situ in the same boulder as the above tooth. More porous core. Another example from the same boulder. Cast remnants of another crocodilian tooth (Osteoderm was in situ in the same boulder) from the same layer a mile away from the above examples Another example I suspect is a tooth from the Menefee, found in float. Porous structure within looks similar to decayed haversian canal structure we find in bone, but the structure as a whole doesn't strike me as bone. Small <1cm Goniopholid tooth from Jurassic Brushy Basin. Without fluting and external material, I'd have a hard time convincing myself this was anything but some small chalcedony inclusion or other in the sandstone Another 1cm (tooth?) I would brush off as inconclusive if not for the context of being next to the above tooth Does anyone have any wisdom to give to help discern bone fragments from teeth? Thanks for taking a look! Ben

The attached paper describe six osteoderms, two vertebrae, and a partial tooth discovered in the Menefee Formation of New Mexico and representing one of the earliest occurrences of Deinosuchus on the Laramidian subcontinent. https://peerj.com/articles/11302/

Hey everyone There's this new bit of research from PeerJ, describing the partial remains of a new tyrannosaurid, Dynamoterror dynastes (pretty cool name, huh? ). The remains were from the Menefee Formation (Upper Cretaceous) of New Mexico, and are a valuable addition to our knowledge of North American tyrannosaurids. Partial cranial material of D. dynastes. McDonald et al. (2018). A new tyrannosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Menefee Formation of New Mexico. Abstract: The giant tyrannosaurids were the apex predators of western North America and Asia during the close of the Cretaceous Period. Although many tyrannosaurid species are known from numerous skeletons representing multiple growth stages, the early evolution of Tyrannosauridae remains poorly known, with the well-known species temporally restricted to the middle Campanian-latest Maastrichtian (∼77–66 Ma). The recent discovery of a new tyrannosaurid, Lythronax argestes, from the Wahweap Formation of Utah provided new data on early Campanian (∼80 Ma) tyrannosaurids. Nevertheless, the early evolution of Tyrannosauridae is still largely unsampled. We report a new tyrannosaurid represented by an associated skeleton from the lower Campanian Allison Member of the Menefee Formation of New Mexico. Despite fragmentation of much of the axial and appendicular skeleton prior to discovery, the frontals, a metacarpal, and two pedal phalanges are well-preserved. The frontals exhibit an unambiguous autapomorphy and a second potential autapomorphy that distinguish this specimen from all other tyrannosaurids. Therefore, the specimen is made the holotype of the new genus and species Dynamoterror dynastes. A phylogenetic analysis places Dynamoterror dynastes in the tyrannosaurid subclade Tyrannosaurinae. Laser-scanning the frontals and creation of a composite 3-D digital model allows the frontal region of the skull roof of Dynamoterror to be reconstructed. You can download (for free!) the paper from this link: McDonald et al. 2018 Dynamoterror dynastes Hope you like this! -Christian

I went to the Menefee Formation... ...