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Hi there. I have this Triassic tooth from the Bull Canyon formation sold to me a good few years back as belonging to Coelophysis. I'd tentatively labeled it cf.Coelophysis (due to the locality) but now that I'm going through and re-evaluating everything I'm not sure it is an accurate description considering the curvature (though I'm not knowledgeable on ontogenic variation in this genus). I'm aware of a great thread posted by Troodon about this particular area but I'd like some input on the possibility it could belong to other Archosaurian taxa. My knowledge of this area is minimal so I'd appreciate any help. I counted about 26 denticles/5mm on both carinae.

@Gary Stradling and I had an incredible visit to Ghost Ranch yesterday. This is a large dude ranch/convention center/museum about an hour and a half north of where I live, on the highway from Abiquiu to Chama, New Mexico, in the extreme southeastern part of the Colorado Plateau (Chama Basin). I believe it's the type location for Coelophysis bauri; in any case, the mass kill beds of Coelophysis here are pretty famous, and there are a number of other fossil quarries in the general area, including some that were fought over by Cope and Marsh during the Bone Wars. They have a small but very nice paleontology museum, and a permanent paleontologist on staff, Gretchen Gürtler. Perhaps because we came on a winter week day during COVID slowdown, or perhaps because Gary is just such a charming guy, she ended up giving us the grand tour, including her workshop and latest work. It was a real treat. Gretchen, Gary, and bones. The slab she's currently preparing. This is part of a mass kill of Vancleavea, from the Chinle Group (most likely Rock Point Formation). Various paleontologists have been working on this slab for almost two decades. There are at least three distinct animals in this section. Left of the pointing finger is the palate of a Vancleavea skull, and you can see scutes of its armored skin at upper left. A skull, with orbit just above and to the right of the center of the photograph. Teeth along the jaw in the lower part of the photograph. The full slab again. You can see a string of vertebrae. This section came out of a much larger slab on display in the museum. You can see the work tool stand in the background. This museum seems to have a tradition of letting visitors see the work of the paleontologists close up -- visitors can come right up to the surrounding wall and see the slab and (at the right times) the paleontologist and her students working on the slab. Complete Coelophysis in death attitude. I was aware that the dead tendons tend to contract and pull the skeleton into this curved shape, with tail and neck curled back. I didn't know, until Gretchen told us, that the contracting tendons have such force that they can partially disarticulate the skeleton -- pulling the jaw off, for example. Pes of a Vancleavea in the big slab. The sharp bend is the ankle joint. There is still some debate whether the animal walked flatfooted or on its toes; there are at present no trace fossils from this area to tell us. Alas, there is not an equally striking manus from this slab. Display for Vancleavea Pesky reflection. Gretchen opened the display for us to get a better photograph. The skull at left is a metoposaurid, a temnospondyl (amphibian). A phytosaur. Looks a lot like a crocodile, doesn't it? But it's not that closely related; in fact, birds are more closely related to crocodiles than this critter. It's considered a good example of convergent evolution. Yeah, and the mask. That's where its nostrils were. This critter inhabited very much the same niche as modern crocodiles. The hospitality we were shown was incredible. An absolutely wonderful visit.

A number of collectors are very interested in Triassic Dinosaur tooth material, however, lots of misinformation exists, partially because little is known and dealers want to sell product. My knowledge is very limited so I tried to put together an assemblage of current information that has been published so that we can all become better versed on this topic. I'm not saying its complete but its the best I can do with my limited knowledge. Most technical papers on this subject are outdated, difficult to read for a novice and not complete enough. Fortunately a recent, legible paper was published in 2015 by Heckert & Lucas that has helped me. I've tried to extract the pertinent information, associated with teeth, since that what most collectors are interested in. First let me get on my sandbox and say that we should NOT assume that what is being sold is accurately described regardless who is selling it or how much you like a dealer. Very little is known and even less is described. If a seller insists what he has identified is accurate, have him show you the technical documents that supports his diagnosis. There are a number of theropods and archosaurs in these assemblages that have serrated teeth so identification is difficult. Triassic dealers similar to those in the Kem Kem which label everthing Spinosaurus like to label everything Coelophysis. Just be cautious..its your money. Almost all the teeth you see sold come from New Mexico so I will focus in that region. A Map of New Mexico with the Triassic outcrops shown below as well as the associated Counties. The numbers correlate to the stratigraphic formations shown below in Figure 4. Figure 4 The Zuni Mountains in West-Central NM are from the lower Chinle Group (Bluewater Creek Fm) and contain Tetrapod fossils amphibians and phytosaurs and aetosaurs. Dinosaurs are possible but nothing is diagnostic. Faunal List of the lower Chinle Group Zuni Mountains Northern/West Central New Mexico has yielded some of the most interesting Vertebrate Fossils most associated with Coelophysis at Ghost Ranch. Included in this group are the Petrified Forest and Rock Point Formation of the western counties. Chindesaurus bryansmalli, Tawa hallae and Daemonosaurus chauliodus are considered valid a dinosaurs in the Petrified Forest Fm. Coelophysis bauri is valid from the Rock Point Formation. Faunal List of the Petrified Forest and Rock Point Formation - Key on this list is Coelophysis bauri in the Rock Point Fm Northeasten New Mexico (Bull Canyon and Redonda Formations). Heckerts 2015 paper comments that dinosaur fossils remains are rare in the Bull Canyon Formation. The coelophysoid Gojirasaurus quayi has been described but its taxonomic placement is uncertain. Herrerasauridae tooth fragments have been found but nothing has been assigned to a taxon. Heckerts & Lucas 2015 Paper on Triassic Vertebrate Paleontology in New Mexico https://libres.uncg.edu/ir/asu/f/Heckert_Andrew_triassic.pdf Bull Canyon Formation 2001 Paper on Vertebrate Fauna https://nmgs.nmt.edu/publications/guidebooks/downloads/52/52_p0123_p0151.pdf Latest placement ( Hans-Dieter Sues et al 2011 ) Coelophysis bauri Formation: Petrified Forest (Chinle Formation) Location: New Mexico, USA Other occurrences: cf Coelophysis may be found in other late Triassic exposures Characteristics: Most all the teeth are recurved Lots of variation is seen in these dentition Some mesial teeth have only distal denticles. Fluted ridges can be see on juveniles The enamel surface texture is braided Marginal and transverse undulations appear to be absent on most crowns.. Premaxillary teeth: rounded cross-section, smaller teeth are ribbed but smooth on larger ones. None show serrations. Maxillary Teeth: the first tooth is recurved with no serrations, second tooth has serrations only on the posterior carina. All the other maxillary teeth have serrations on both edges. Some of the teeth the serrations may be limited to the upper part of the anterior (mesial) edge. Dentary Teeth: the first seven teeth lack serrations, eight tooth serrations only on the posterior edge. Subsequent teeth have serrations on both edges. The first four teeth are elliptical (rounded) in cross-section being compressed after that. Measurements: (From Hendrickx 2019 study) (2 Premax, 15 Maxillary, 3 Dentary) (Not all crowns had serrations) Dentary Density: 40 to 45 / 5mm (Avg 40.0 / 5mm) Maxillary Density: 35 to 50 / 5mm (Avg 15 / 5mm) Average Ratio's: Premax CHR: 3.6, CBR: 0.4 Maxillary CHR: 1.6, CBR: 0.4 Dentary CHR: 2.4, CBR: 0.5 The Museum of Northern Arizona publication Coelophysis describes the teeth as follows: Distal Carina Denticles (Source on colored images C. Hendrickx) Skull characterized by fluted teeth in juveniles, procumbent mesial dentary and maxillary teeth. Also some unserrated mesial crowns Some mesial teeth have only distal denticles. The mesial carina is straight and extends well above the root in lateral teeth. The enamel surface texture is braided and marginal and transverse undulations appear to be absent on most crowns.. (2 photos) Fluted ridges can be see on juveniles Additional images Premaxillary, Maxillary and Dentary teeth shown - Striations visible Anterior maxillary tooth #2 Maxillary Tooth #4 Maxillary tooth #10 Maxillary denticles M#5 Dentary tooth Posterior Maxillary Tooth Paper on Coelophsis Teeth by Currie and Buckley Coelophisis.pdf Additional images of the teeth with no supporting info Good overall paper on C. bauri but does nothing to increase our knowledge on how to describe its teeth https://www.researchgate.net/publication/292525024_The_paleobiology_of_Coelophysis_bauri_Cope_from_the_Upper_Triassic_Apachean_Whitaker_quarry_New_Mexico_with_detailed_analysis_of_a_single_quarry_block Ken Carpenter described these teeth from the Bull Canyon fm as cf Coelophysis. A few skulls Other Theropods Gojirasaurus quayi : one tooth was described with the holotype however it was found isolated and cannot be positively assigned to this species. (Added a few pages below) Chindesaurus bryansmalli : not aware of any skeletal material Daemonosaurus chauliodus Characteristics: Characterized by 3 large premaxillary teeth, first 2 dentary teeth are procumbent, longitudinal ridges on the crowns, some constricted teeth, and hooked mesial denticles A Premaxillary Teeth #3 B Maxillary Teeth C Posterior most Maxillary Teeth Reference on Daemonosaurus: The osteology of the early-diverging dinosaur Daemonosaurus chauliodus (Archosauria: Dinosauria) from the Coelophysis Quarry (Triassic: Rhaetian) of New Mexico and its relationships to other early dinosaurs STERLING J. NESBITT and HANS-DIETER SUES http://rspb.royalsocietypublishing.org/content/royprsb/278/1723/3459.full.pdf Tawa hallae : http://www.thefossilforum.com/applications/core/interface/file/attachment.php?id=503864 Characteristics All preserved premaxillary, maxillary and dentary teeth seem to be fluted on both sides Premaxillary are unserrated Maxillary teeth with a mesial denticulated carina reaching the root Interdenticular sulci present on both mesial and distal edges Teeth are very pointy Fifth? left maxillary tooth Scale: 1 cm images from C. Hendrickx twitter feed

Recently acquired a Triassic Theropod Dinosaur Tooth from New Mexico, USA Coelophysis bauri tooth Location: Bull Canyon Formation, Norian, Upper Triassic, San Miguel County, New Mexico, USA 210 Million Years Old Obtained from Palaeontologist Byron Blessed Below are some sample photos, I am looking around for a small device in order to try magnify the serrations on the tooth as there are so many and it is very hard to count the number per mm. I have read the books and journals on Coelophysis bauri that were linked on this forum previously and they are so interesting! Will try to post some close-ups of the serrations, the other side of the tooth and the bottom of the tooth soon. Wiki Link: https://en.wikipedia.org/wiki/Coelophysis_bauri Journal is called 'Acritical re-evaluation of the Late Triassic dinosaur taxa of North America'