Search the Community

Took a short visit today to my Basal Atco site for the third time. Seems like every visit yields something new and totally unexpected (first visit = Acrotemnus prearticular tooth, second visit = huge assoc. fish verts, and now these). I'm fairly confident both of these are reptilian, but unfortunately I don't know much about identifying tetrapods. The first specimen I found is now my only non-Campanian mosasaur tooth. It's quite small (1 cm tall) and broke into 3 pieces, but the b72 seems to have done the job in making it presentable. Not amazing quality as expected for the Basal Atco, where much of the material is reworked. I'm not completely familiar with the genera present in the earliest Coniacian. I have read about a chunk of Tylosaurinae maxilla being found near if not in the Basal Atco of Grayson county and the subfamily is thought to have started in the Lower Coniacian altogether. I want to say Russellosaurus made it to the Atco although I believe my tooth is a little large for this ID. I think Clidastes was also around in the Coniacian, although not sure how early. And there's a lot of genera I am not mentioning, so hopefully someone in the know can fill in. The tooth itself seems to have both a mesial and distal non-serrated carina. The enamel isn't faceted as far as I can tell. I know it's not much to go off of and a precise ID is unlikely, but my hope is to at least cross off some of the genera that don't fit the description with yall's help. Mosasaur tooth (1 cm tall) Going from a relatively old mosasaur, the second specimen is a surprisingly young Coniasaurus (or so I think). This might be surprising to some, but Conisaurus is found beyond the Cenomanian. It actually has been documented to extend through the Coniacian all the way into the Middle Santonian (though the documentation is few and far between I must admit)! In other words this is a rare sort of find, but not necessarily unheard of. I don't believe any species have been named extending past the Turonian, so this may be an undescribed species. My specimen has that classic bulbous shape as well as textured enamel. It sure pays to look closely at every chunk of matrix. Coniasaurus sp.? (3 mm tall) One thing I would like to note is that I have since found a paper that helped to clarify the geology of this site which was a point of confusion in my previous trip reports. I made the mistake of referring to this place as the "Fish Bed Conglomerate" when it turns out that title has been used for at least a couple different layers, namely the base of the Austin Chalk and a phosphatic pebble bed that exists a short ways below the base documented by Taff and Leverett way back in 1893. This mixup has caused some confusion it seems in old academia. Anyways the stratigraphic chart (Fig. 2) in the source below shows these two phosphatic layers and some info on them. I kinda had a mind blown moment as I have actually visited both of these layers while looking for the Basal Atco at a couple of locations. The site where these teeth were found along with all my other written Atco adventures did actually in fact occur in the Atco or earliest Coniacian. However, the "second location" noted in the report I've linked below was actually at this Arcadia Park phosphatic pebble bed. These two layers are quite distinct and my "Atco" site definitely better fits the base. The sea levels paper specifically notes the layer as being ripple bedded which I coincidentally took a picture of in my old report! So satisfying when everything clicks into place... Hancock, Jake M., and Ireneusz Walaszczyk. “Mid-Turonian to Coniacian Changes of Sea Level around Dallas, Texas.” Cretaceous Research 25.4 (2004): 459–471. Web. As a bonus for reading through this, here are a couple of nice sharks teeth I found from the same layer. They are my first larger complete Cretalamna from the location and a new species on top of that. They compare best with Cretalamna ewelli which Siversson notes as being present in the Late Coniacian. I have some less impressive Cretalamna from the location that I previously identified as C. gertericorum, but I may have to double check those since it would be weird for two species to show up on top of one another in my opinion. They are very similar-looking species so I wouldn't be surprised if I was mistaken before. Cretalamna ewelli with beautifully splayed cusplets Looking forward to hearing yall's opinions! Thanks

OK, I have read the posts about croc tooth versus mosasaur and croc versus alligator. Based on what I read, this could be a mosasaur tooth given the sort of “prismatic” ribbing and lack of any carinae or at least the lack of the two that are equidistant from each other. Anyway, I’m not an expert but would love some help from those more learned. Check out the pics. This is basically from the Calvert formation - but more specifically Horsehead Cliffs area from the water. Thanks for looking!

The first mosasaur tooth I found in Pierre shale sd. 2in long poorly preserved. Was wondering if it was a shedded tooth or part of jaw? Also what species might it be? thanks!

The only thing I know about this specimen is that's from Morocco and it's probably some mosasaur tooth. Is it possible to tell anything more about it?

Hello All, First time posting. Joined up due to a fellow fossil hunter's request that I do so. Went out to Big Brook Preserve this past Sunday (4-23-23) and came away with a good selection of the usual suspects but one stood out. A nice Mosasaur tooth seen at the top of the pics below and in my hand in the following pics. Thanks for looking and thank you Sam for the company, the friendly conversation and helping with the fossil id. Happy Hunting everyone!

Hi guys, wondering if any of these teeth are from carinodens (they are from a seller online so I don’t have more pics) thanks @pachy-pleuro-whatnot-odon

I already wrote about in a previous trip report back in September, but I thought it worth posting here as well (I'll link the original trip report below). I'm proud to say that as of last October I was able to donate my first fossil to science - a life-long goal of mine since I was a kid! The mosasaur vertebra I found has the potential to be one of the oldest known to science, or at the very least one of the oldest found in North America. I donated it to SMU's collection after correspondence with Dr. Mike Polcyn as it only seemed right that one of the leading experts on early mosasaurs should have it. Alongside the vertebra I also donated two Ptychodus teeth found within the same shale layer to assist in the dating process. Basal Mosasaurid (anterior caudal vertebra) Upper Cretaceous (Middle Cenomanian) Lake Waco Formation Central Texas - found on September 15, 2022 Donated October 14, 2022 to Southern Methodist University ^ @Jared C and I recently returned to the site to collect unweathered bentonite to assist in the dating process. I haven't taken the several bags we filled up to SMU to deliver to Dr. Polcyn yet but plan to do so soon.

Hi guys I’ve got a few more mosasaur teeth here I think this is the last few! Thanks again for your help @Praefectus @pachy-pleuro-whatnot-odon 1. This one’s in a bit of jaw bone, the striations aren’t so pronounced but maybe still gavialimimus 2. a more posterior or pterygoid gavialimimus? 3. yet another one! This one is a bit more angular though 4. reminds me more of a croc tooth actually!

Hi guys got a few more for idenitification thanks for your help 1. this was broken in shipment and is completely hollow even the root is this normal? The rounded cross section makes me think T.atrox 2. slightly more compressed, eramiasaurus? 3. gavialiminus? 4. another gavialiminus, any idea why both of these are so compressed? Preservation?

Hello, I'd love to know your opinion about these reptilian vertebrae coming from the lower santonian of northern Spain. Fisrt photo is view from above and second from beneath I've made some guesses about this piece, and I hope some of you could give me your opinion about them. Here come muy guesses: -Taken that it comes from clear ancient marine strata, its general morfphology and its Santonian age, I think it probably is a mosasaur vertebrae. The problem is that there hasn' been any mosasaur reports in these places, basically because vertebrate remains are really rare and fragmented -Supposing that the mosasaur ID is correct, the next logical step would be trying to discover which kind of vertebrae it is. In the second photo, its beneath view, you can see a big spherical gap (it is highlighted in picture 3), and from it, I'veguessed this vertebra cannot be a dorsal, nor a caudal, because the chevrons there are conected to the vertebrae by a symetrical paired haemal arches (so not a big notch in the center) I have related this spherical gap with the small chevron like bones which kind of appear beneath some mosasaur cervicals. To show clearer what a I refering to, picture 4 is a higlighted image of this bone I am refering to So, so far, I've guessed I'm dealing with a mosasaur cervical vertebra I would love to know what are your opinions about these guesses and, also, if there's a detalied mosasaur vertebrae monograph I could go for Thanks in advance!!!! Cheers

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

Found these 3 fossils 1ft apart from each other at bottom of a hill. Are the 2 vertebrae from the same area of the body as the mosasaur paddle arm bone? What's the chance this is all from same 1 animal? If so I might try looking for where they came from. Is there a technique to removing a side of a hill to find the source? Thanks

Hello, I have found in a shop this "mosasaur spine" fossil. Is it a mosasaur? For what I see the vertebras are procoelous which is what you would expect, but I would like some expertise council on this. And moreover is it possible to identify the which type of vertebras are those? And to which mosasaur they belong? The full plate measures 55cm x 20cm and each vertebra measures 8-9cm more or less. It's from Thanks! Edit: It's from morocco.

Hi guys got a few more mosasaur teeth with unconfirmed identities 1. slightly pathological M,beaugi ? 2. faceted, eramiasaurus?

Hi, this is being sold as a mosasaur vertebra. Is it? Taging @Praefectus and @pachy-pleuro-whatnot-odon are you are my mosasaur guys .

Here are the two fragments I found in Ramanessin of what i believe to be mosasaur. the right one im unsure of, i still think its a cretaceous reptile. the left one, I am more certain is a mosasaur. but let me know what you think!

Hi guys I have these 3 similiar mosasaur teeth that I was wondering if it was possible to identify, are they prognathodon thanks! 1. 2. 3.

Hi all, me again, I wanted to share a closeup of the bone fragments that I found in Ramanessin to see if I could get them ID'd further since I know how the brook tends to make fake fossil bones i want to check that the ones I found are real fossil bone 1) the big one, i think it might be a cretaceous turtle shell, it passed the burn, and the lick test. 1A) I believe these are also enchodus jaw fragments. 2) 2A)