The Cedar Mountain Formation is a geological formation located in the western United States, mostly within the state of Utah, with rocks dating to the early and middle parts of the Cretaceous Period. The Cedar Mountain Formation is most well-known for its dinosaur fossils, in particular Utahraptor. However, the landscape was also populated by other creatures as well, including lungfish, semionotid fish, freshwater hybodont sharks, tuatara-like sphenodonts, turtles, crocodylomorphs, mammals, pterosaurs, and numerous species of dinosaurs.

The “Cedar Mountain Formation” of eastern Utah was first identified in 1949 and dates to the early to middle Cretaceous Period, spanning about 144 to 95 million years ago. It unconformably overlies the Morrison Formation of the late Jurassic Period and it unconformably underlies the Lakota Formation of the middle Cretaceous. It’s the Cedar Mountain Formation which provides our clearest understanding of what prehistoric life was like in North America following the end of the Jurassic Period. This formation is divided into several geological units called “members”. Unfortunately, the same members are not present throughout the entirety of the Cedar Mountain Formation’s geographic range; different members are visible in different areas of the formation. The complete list of geological members are, listed from lowest/oldest to highest/newest with approximate dates: the Buckhorn Conglomerate (ca. 144-140 MYA), the Yellow Cat Member (139-132 MYA), the Poison Strip Member (131-119 MYA), the Ruby Ranch Member (118-105 MYA), the Short Canyon Member (104-98 MYA) (note that some geologists and paleontologists don’t consider this to be a true member), and the Mussentuchit Member (97-95 MYA). The Yellow Cat Member is further sub-divided into “lower” and “upper” layers due to the presence of a “cap rock” of carbonate-rich calcrete dated to 136 MYA which divides the member in half. It is uncertain at the time of this article if these two sub-layers of the Yellow Cat Member are going to be re-classified as two separate members at some point in the future (1).

The famous 20 foot long dromaeosaurid theropod Utahraptor is found exclusively within the upper part of the Yellow Cat Member, dated to around 135-132 million years ago, give or take. It shared its environment with three or four species of iguanodonts, the armored nodosaurid ankylosaurian Gastonia, the brachiosaurid sauropod Cedarosaurus, the turiasaurian sauropod Moabosaurus, the therizinosaurid theropod Martharaptor, and the primitive ornithomimosaurian theropod Nedcolbertia. For a long time, it appeared as though Utahraptor was the top predator of the Cedar Mountain Formation, and the presence of so many prey items within this environment must have presented ample supplies of game for Utahraptor to hunt (2).

Yet as impressive as Utahraptor is, there is evidence that it may not have been the top predator within the Cedar Mountain Formation. Teeth and a handful of bones which have been identified as belonging to a large theropod dinosaur have been recovered from these rock layers. Although the remains of this animal have so far proven sparse, they are nevertheless clear enough to determine that they belonged to a large meat-eating dinosaur measuring perhaps 30 to 35 feet long.

The first evidence that a large theropod dinosaur lived within the Cedar Mountain Formation was uncovered in the late 1980s. Near Castle Dale, Utah, Carlyle Jones of Brigham Young University’s Museum of Paleontology discovered some fossil dinosaur bones. This site where these bones were found was designated as “Long Walk Quarry”, which is located within the lower part of the Ruby Ranch Member, dated to the Aptian Stage of the middle Cretaceous Period, about 118-105 MYA (3). The site was excavated by Frank DeCourten in 1991, where he found sauropod bones which he ascribed to Pleurocoelus (now classified as a junior synonym of Astrodon). In addition to the sauropod bones, two teeth from a large theropod dinosaur were also found at the site (collection ID codes: UUVP 904 and CEU 5107). These teeth were attributed either to Acrocanthosaurus or some other similar animal, largely because no other large carnivorous dinosaur was known to inhabit North America during this time. Acrocanthosaurus was a 35 foot long theropod dinosaur with a prominent ridge running down its back. It was a member of the “carcharodontosaurids”, and as such was a distant relative of Allosaurus, and lived around 115-110 MYA. However, during the late 1980s and early 1990s, Acrocanthosaurus fossils had only been found in Oklahoma (4) and Texas (5) – no fossils of this animal had been found further north (since then, other fossils of this animal have been found in Wyoming (6), Maryland (7), and possibly Arkansas (8)). Yet, since Acrocanthosaurus was the only large theropod dinosaur known to live in North America during the middle Cretaceous, the teeth which had been found at Long Walk Quarry were ascribed to that animal (9).

Allosauroidean tooth, measuring 4 cm long from the crown to the tip (collection ID code: UMNH 0002), discovered at Long Walk Quarry within rocks dated to the lower part of the Ruby Ranch Member. Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Page. 150.

Additionally, an ilium (the bone that forms the upper part of the hip) belonging to a large theropod was also uncovered at Long Walk Quarry (10).

According to an abstract published in 1995, the fossilized remains of a theropod dinosaur were found within the middle part of the Cedar Mountain Formation (i.e., the Ruby Ranch Member) which were classified as “cf. Acrocanthosaurus”, meaning “comparatively similar to Acrocanthosaurus”, although its identity could not be definitively established (11). Kirkland et al (1997) also identified the specimens found at Long Walk Quarry as “cf. Acrocanthosaurus” (12). However, despite similarities to Acrocanthosaurus, Jerald D. Harris stated unequivocally in a 1998 article that the fossils which have been uncovered within the Cedar Mountain Formation do not belong to that animal (13). One of the reasons has to do with the size of the tooth serrations. Acrocanthosaurus teeth have extremely tiny serrations, measuring only half a millimeter in diameter. By contrast the denticles on the teeth found at Long Walk Quarry are twice the size, despite the teeth being the same size overall, although exact measurements weren’t taken (14).

While at first glance it would seem that tooth serration morphology is sufficient enough to warrant classification of this animal as a new species, we should not jump to conclusions. Within Allosaurus, for example, the size and density of the tooth serrations varies from individual to individual. Smith et al (2005) reports that regarding Allosaurus teeth, there can be as few as 6.5 or as many as 17.5 denticles within a length of 5mm along a tooth’s edge. So, a difference in the number of tooth serrations is not enough to state that the teeth recovered from the Cedar Mountain Formation is definitely NOT Acrocanthosaurus (15).

Large carnosaurs didn’t just inhabit the Ruby Ranch Member, either. The oldest evidence that a large carnosaur lived in western North America was uncovered at a site in Utah known as “Doelling’s Bowl”. This locality, which was first identified in 1990, contains rock layers from the base of the Cedar Mountain Formation, within the lower part of the Yellow Cat Member, and is dated 142-136 MYA. Discovered here, along with the fossil bones of several dinosaur species, were several teeth belonging to a large allosauroidean theropod measuring over three inches long. According to a short report published by James Kirkland in 2005, among the fossils which were found within the Yellow Cat Member of the Cedar Mountain Formation (no distinction was made between “lower” and “upper” Yellow Cat rocks) were those belonging to “a large carnosaurid perhaps related to Utah’s state fossil, the Late Jurassic Allosaurus” (16), but no further information was given. Later in 2021, James Kirkland delivered an online lecture in which he said these teeth belonged to a carcharodontosaurid theropod similar in size to Acrocanthosaurus. If true, then this animal would have measured 30-35 feet long, making it the largest carnivorous dinosaur known from North America during the beginning of the Cretaceous Period. Regrettably, only teeth have been found so far at Doelling’s Bowl (17).

Unidentified allosauroidean teeth discovered at Doelling’s Bowl, located 30 miles (49 km) east of Green River, Utah, within rocks dated to the lower part of the Yellow Cat Member. Kirkland, James I.; Madsen, Scott K. (2007). “The Lower Cretaceous Cedar Mountain Formation, eastern Utah: The view up an always interesting learning curve”. Fieldtrip Guidebook, Geological Society of America, Rocky Mountain Section. (May 2007). Page 47.

Unidentified allosauroidean tooth discovered at Doelling’s Bowl. The horizontal scratches located near the tooth’s tip are caused by micro-drills which were used to study the chemical isotopes preserved within the tooth’s enamel. YouTube. Tate Geological Museum. “Tate Geological Museum’s Spring Lecture Series 2021: Cretaceous Dinosaurs- part 3 – The Cedar Mountain Formation of Utah: North America’s Most Complete Early Cretaceous Record, hosted by James I. Kirkland” (May 11, 2021). https://www.youtube.com/watch?v=Thhb6Jy-Acw. Accessed on March 14, 2022.

To date, no teeth or skeletal remains which have been identified as belonging to a large allosauroidean theropod have been found within the upper Yellow Cat Member or throughout the entirety of the Poison Strip Member which lies above it (18). However, this changes when we transition to the Ruby Ranch Member. As mentioned earlier, two teeth were discovered which looked similar to (but not identical to) Acrocanthosaurus. According to Kirkland et al (1997) and Kirkland et al (1999), the principal theropod dinosaurs which inhabited the Ruby Ranch Member were Acrocanthosaurus and “an unidentified large theropod” (19). Within James Kirkland’s 2005 report in the section which discusses the Ruby Ranch Member, he makes reference to the fossils of Acrocanthosaurus being found here as well as the fossils of “a large undescribed carnosaurid” (20). In the 1997, 1999, and 2005 articles, they clearly indicate that the fossils belong to two different species of large theropod which inhabited that landscape at the same time.

In 2009, numerous dinosaur footprint trackways were discovered at a place now known as the Mill Canyon Dinosaur Tracksite. The rock layer that these footprints were deposited in dates to the lower Ruby Ranch Member, about 112 MYA. This was formed along the southern shore of “Lake Carpenter”, a large prehistoric lake which was located on the west side of Arches National Park during the middle Cretaceous Period (21). At least ten different kinds of animals are represented by the footprints here, including a large theropod, which might be Acrocanthosaurus or a species closely related to it. A preliminary report about this site was published in 2014, and a more detailed report was published in 2022. Over 200 footprints have been found which have been ascribed to ten named ichnotaxa, making the Mill Canyon Dinosaur Tracksite the largest and most diverse dinosaur footprint tracksite within the Cedar Mountain Formation. The name ascribed to the large theropod footprints is Irenesauripus, which might be Acrocanthosaurus or a similar animal (22).

Footprint of a large theropod dinosaur, found at the Mill Canyon Dinosaur Tracksite near Moab, Utah. These footprints are dated to 112 MYA, when both Acrocanthosaurus and the Cedar Mountain allosaur co-existed. Photo courtesy of the United States Bureau of Land Management (April 1, 2016).
https://www.flickr.com/photos/blmutah/26177811125/in/album-72157666661422685/.

On November 1, 2013, it was announced at a meeting of the Society of Vertebrate Paleontology that fragmentary remains of a large theropod dinosaur had been discovered near Capitol Reef National Park in central Utah. The rock layer came from the lowest part of the Ruby Ranch Member, dated to around 105 MYA (Note: The dating was made in 2013, and the dates for the lower Ruby Ranch Member have since been revised to 118-110 MYA. Kirkland et al (2016) claimed that the fossils were actually found within the upper Ruby Ranch Member, in which case the original date would be correct (23)). The fossilized bones consisted of one neck vertebra, parts of the sacrum and pelvis, and one femur. It was tentatively classified as an allosauroidean theropod, although a more precise identification could not be made from such scant remains (24). Within this article, the following observations were made concerning this animal’s anatomy:

“The specimen can be placed within Tetanurae based on a convex anterior face of the presacral vertebrae and a femoral head oriented dorsomedially. It appears to be nested within Allosauroidea because the anterior pleurocoel of the cervical vertebra is anteroposteriorly elongate, the parapophysis is located in the middle of the centrum, and there is no articular groove on the proximal surface of the head of the femur. In contrast, unlike other known allosauroids, but similar to megalosaurids, the oblique ligament groove does not extend past the posterior surface of the femoral head. These data suggest that an allosauroid was one of the apex predators during Ruby Ranch time. Intriguingly, though carcharodontosaurians are widespread in other Early Cretaceous assemblages, we have not identified any apomorphies of this clade in the specimen, though this could be due to its incompleteness. These data suggest that allosauroids continued to dominate the apex predator role from the Late Jurassic well into the Early Cretaceous in western North American ecosystems” (25).

Additionally, Kirkland et al (2016) reports that this animal had short neural spines emerging from its vertebrae, in contrast to the elongated neural spines seen in Acrocanthosaurus (26). Interestingly, this aspect of the creature’s anatomy was not mentioned within the 2013 report.

In addition to allosauroidean fossils recovered from the lower Ruby Ranch Member, similar fossils have also been recovered from the upper Ruby Ranch as well, dated to about 105 or 104 MYA (this time is also placed within the “Short Canyon Member”). Most of the finds which come from the upper Ruby Ranch come from the area around the Price River, and as such these localities have been termed the Price River Quarries: PR-2 to PR-4 come from the uppermost part of the Ruby Ranch Member, while PR-1 is the only quarry located within the overlying Mussentuchit Member (27). A large theropod tooth was recovered from the Price River III quarry (PR-3) possessing very fine serrations and seemed most similar to the teeth of Acrocanthosaurus in appearance. For this reason, it was provisionally identified as “cf. Acrocanthosaurus” (28).

On November 22, 2013, just three weeks after it was announced that some bones of a large theropod dinosaur had been found near Capitol Reef National Park, another report was published stating that the fragmentary remains of a large theropod dinosaur had been found within the Mussentuchit Member, the uppermost layer of the Cedar Mountain Formation, dated to the Cenomanian Stage of the middle Cretaceous Period about 98 MYA. It was named Siats, named after a monster in native Ute mythology. Siats was identified as a “neovenatorid”, an allosauroidean more closely related to Neovenator than to Allosaurus or Carcharodontosaurus. The only fossils of the holotype consist of some dorsal and caudal vertebrae, parts of the pelvis, one partial fibula, and three toe bones. The holotype is currently housed within the Field Museum of Natural History in Chicago, Illinois (collection ID code: FMNH PR 2716). Another specimen designated as FMNH PR 3059 consists of one partial caudal vertebra, one partial chevron, and one toe bone. The bones evidently came from a juvenile, since the neural arches on the vertebrae were not fused together, indicating that the animal was immature and still growing (29).

Skeleton of Siats, a neovenatorid allosauroidean from the middle Cretaceous Period of Utah, based upon FMNH PR 2716 and FMNH PR 3059.
https://commons.wikimedia.org/wiki/File:Siats_meekerorum_skeletal_diagram.jpg.

Most of the vertebrae from Siats which were recovered were broken, but a single dorsal vertebra was intact. It was shown that these bones did not belong to Acrocanthosaurus due to the fact that this vertebra had a short neural spine, and the vertebra’s centrum was described as “platycoelous”, meaning that the front and rear faces of the centrum are slightly concave. This is in contrast to the vertebrae of Acrocanthosaurus, which are “opisthocoelous”, meaning that the anterior face of the vertebral centrum is rounded like a ball, but the posterior face is concave (30).

As for the mysterious vertebrae which were uncovered from the Ruby Ranch Member, these were also opisthocoelous in general character. However, there were other differences in the vertebrae’s specific features which showed that they didn’t belong to Acrocanthosaurus or to Siats. This has remarkable implications. It means that during the middle Cretaceous Period, we may have not just one or two but potentially three large carnivorous dinosaurs roaming the landscape at the same time.

It may be tempting to state that the Cedar Mountain allosaur is another fragmentary specimen of Siats. However, due to the difference in the structure of the vertebral centra, it’s safe to assume that Siats and the Cedar Mountain allosaur are not the same animal. But what about Acrocanthosaurus? After all, the specimens which were recovered from the lower Yellow Cat Member and the Ruby Ranch Member were similar enough to Acrocanthosaurus that paleontologists have repeatedly classified them as “cf. Acrocanthosaurus”. The one major difference which was pointed out in Kirkland et al (2016) is that the vertebra recovered from the Ruby Ranch Member possesses short neural spines while Acrocanthosaurus has long neural spines. Due to the similarity of the teeth and the opisthocoelous character of the vertebrae, one hypothesis that may be worth considering is that the Cedar Mountain allosaur might actually be a female Acrocanthosaurus. At present, only four Acrocanthosaurus skeletons are known, and all of them are incomplete (47):

1. OMNH 10146 (holotype): approximately 20% complete (originally MUO8-0-S9; Stovall & Langston, 1950).
2. OMNH 10147 (paratype): approximately 10% complete (originally MUO8-0-S8; Stovall & Langston, 1950).
3. SMU 74646: approximately 70% complete (Harris, 1998).
4. NCSM 14345 (“Fran”): more than 70% complete (originally OMNH 10168; Currie & Carpenter, 2000).

However, it would be a remarkable coincidence if all four of the specimens which were recovered just happened to be males. I’m not saying that it’s impossible, just unlikely. I also must re-iterate that while the vertebrae of both Acrocanthosaurus and the Cedar Mountain allosaur are opisthocoelous, there are many differences in the cervical vertebrae’s physical features which separate them from each other, aside from the length of the neural spines. While it is not outside the realm of possibility that the vertebrae would have sexually dimorphic features, the differences in the cervical vertebrae’s structure further decrease the likelihood that these are simply male and female individuals of the same species.

Another matter which must be addressed is the geological range of all three of these animals. Acrocanthosaurus fossils are known from about 115-110 MYA, although it’s possible that it might have continued onwards a little further to 105 MYA. Siats is known only from fragmentary remains dated to 98 MYA. Finally, the Cedar Mountain allosaur is known from two separated sections within Cretaceous strata: one spanning 142-136 MYA, and another spanning 118-105 MYA, with a gap spanning approximately twenty million years in between where no fossils are currently known. In total, this as-yet-undescribed species existed for thirty-seven million years, which is an extremely long time for a dinosaur species to exist – most usually hang around for five to ten million years.

Chronographic chart of Acrocanthosaurus, Siats, and the Cedar Mountain allosaur.

Fossils of this mysterious allosauroidean theropod have been recovered from the lower Yellow Cat Member, the lower Ruby Ranch Member, and the upper Ruby Ranch Member (48). Interestingly, no remains of this animal have been found in-between within the upper Yellow Cat Member when Utahraptor existed (49), nor have any remains yet been discovered within the entirety of the Poison Strip Member.

Within the scientific paper which named Utahraptor in 1993, Jim Kirkland and his associates made reference to fossil remains of “a large theropod” which had been uncovered by a team from Brigham Young University at a place called Dalton Wells during the 1970s. The Dalton Wells Quarry is a very fossil-rich locality, and excavations were carried out there in 1975 and 1978. The rock layers of both the Dalton Wells Quarry and Gaston Quarry date to the upper Yellow Cat Member. Kirkland et al (1993) reports that the hundreds of fossil specimens which had been excavated at Dalton Wells belonged to several different dinosaur species including a nodosaur (which has since been named Gastonia), a large dromaeosaur (since named Utahraptor), perhaps a smaller dromaeosaur (please read Senter et al (2012) for more info on this), a large theropod, a sauropod with teeth similar to that of Camarasaurus, and an iguanodont (50). Regrettably, the 1993 report does not go into any specifics concerning what exactly was found pertaining to each taxon. As to this enigmatic large theropod, Kirkland et al (1993) states “The presence of a much larger ‘carnosaur’ with Utahraptor at the Dalton Well site raises the question as to how the role of [the] large predator was divided between these two large theropods. A great deal of research will be needed before this question can be approached” (51).

However, no mention has been made in subsequent research papers of the presence of a large carnosaur theropod living within the upper Yellow Cat Member alongside Utahraptor. Detailed research papers about the Dalton Wells Quarry which were published in 2006 and 2009 do not make any reference to any fossil remains belonging to a putative carnosaur theropod. This leads me to suspect that the fossils which were originally ascribed to a large theropod in Kirkland et al (1993) may have been originally mis-identified and have since been classified as something else.

It is possible that Utahraptor out-competed this unknown carnosaur within its particular environment, temporarily driving the carnosaurs out of western North America, until Utahraptor went extinct, thereby allowing the carnosaurs to once again resume their place of dominance in the food chain. A second hypothesis presents the opposite scenario. It’s possible that, for some reason, the carnosaurs temporarily vanished from the Cedar Mountain Formation. This lack of competition would have allowed the smaller dromaeosaurids which lived within the Cedar Mountain Formation to rapidly evolve, becoming larger and more sophisticated, until they occupied the niche of the environment’s top predator. Then, after an absence of just a few million years, the carnosaurs came back and re-established themselves as the rulers of the land, and Utahraptor’s short reign abruptly came to an end. A third hypothesis is much more straight-forward – the carnosaurs never left, we just haven’t found their fossils yet, as it is improbable that such animals could be found within this region, disappear for almost twenty million years, and then suddenly re-appear. If it’s true that there was a large carnosaur similar to Acrocanthosaurus roaming the landscape of the upper Yellow Cat Member alongside Utahraptor, then this dramatically changes the predator-prey dynamics for that ecosystem.

Below is an illustration of what “the Cedar Mountain allosaur” might have looked like. Its appearance is based upon Acrocanthosaurus and Neovenator. The drawing was made with No.2 and No.3 pencil on printer paper.

The Cedar Mountain allosaur. © Jason R. Abdale (March 27, 2022)

Source citations

1. Kirkland, James I.; Madsen, Scott K. (2007). “The Lower Cretaceous Cedar Mountain Formation, eastern Utah: The view up an always interesting learning curve”. Fieldtrip Guidebook, Geological Society of America, Rocky Mountain Section. (May 2007). Pages 2, 7; Suarez, Celina A.; González, Luis A.; Ludvigson, Gregory A.; Kirkland, James I.; Cifelli, Richard L.; Kohn, Matthew J. (2014). “Multi-Taxa Isotopic Investigation of Paleohydrology in the Lower Cretaceous Cedar Mountain Formation, eastern Utah, U.S.A.: Deciphering Effects of the Nevadaplano Plateau on Regional Climate”. Journal of Sedimentary Research, volume 84 (November 2014). Pages 975-978; Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Pages 107-114, 118-147, 154-157; Phillips, Stephen P.; Howell, John A.; Hartley, Adrian J.; Chmielewska, Magda; Hudson, Samuel M. (2021). “Evolution of foreland basin fluvial systems in the mid-Cretaceous of Utah, USA (upper Cedar Mountain and Naturita formations)”. Sedimentology, volume 68 (2021). Page 2,098.
2. Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Pages 127-138.
3. YouTube. Tate Geological Museum. “Tate Geological Museum’s Spring Lecture Series 2021: Cretaceous Dinosaurs- part 3 – The Cedar Mountain Formation of Utah: North America’s Most Complete Early Cretaceous Record, hosted by James I. Kirkland” (May 11, 2021). https://www.youtube.com/watch?v=Thhb6Jy-Acw. Accessed on March 14, 2022.
4. Stovall, J. Willis; Langston, Jr., Wann (1950). “Acrocanthosaurus atokensis, a new genus and species of Lower Cretaceous Theropoda from Oklahoma”. American Midland Naturalist, volume 43, issue 3 (1950). Pages 696-728; Currie, Philip J.; Carpenter, Kenneth (2000). “A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA”. Geodiversitas, volume 22, issue 2 (2000). Pages 207-246.
5. Harris, Jerald David (1998). “A Reanalysis of Acrocanthosaurus atokensis, its Phylogenetic Status, and Paleobiogeographic Implications, Based on a New Specimen from Texas”. New Mexico Museum of Natural History and Science, bulletin 13 (1998). Pages 1-75.
6. D’Emic, Michael D.; Melstrom, Keegan M.; Eddy, Drew R. (2012). “Paleobiology and geographic range of the large-bodied Cretaceous theropod dinosaur Acrocanthosaurus atokensis”. Palaeogeography, Palaeoclimatology, Palaeoecology, 333-334 (March 13, 2012). Pages 13-23.
7. Frederickson, Joseph A.; Lipka, Thomas R.; Cifelli, Richard A. (2018). “Faunal composition and paleoenvironment of the Arundel Clay (Potomac Formation; Early Cretaceous), Maryland, USA”. Palaeontologia Electronica, 21.2.31A (January 2018). Page 9.
8. Suarez​, Celina A.; Frederickson, Joseph; Cifelli, Richard L.; Pittman, Jeffrey G.; Nydam, Randall L.; Hunt-Foster, ReBecca K.; Morgan, Kirsty (2021). “A new vertebrate fauna from the Lower Cretaceous Holly Creek Formation of the Trinity Group, southwest Arkansas, USA”. PeerJ, volume 9: e12242 (October 21, 2021).
9. Harris, Jerald D. (1998). “Large, Early Cretaceous Theropods in North America”. In Lucas, Spencer G.; Kirkland, James I.; Estep, John W., eds. Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science, bulletin no. 14 (1998). Page 226; Mori, Hirotsugu. “Dinosaurian faunas of the Cedar Mountain Formation and LA-ICP-MS detrital zircon ages for three stratigraphic sections and the relationship between the degree of abrasion and U-Pb LA-ICP-MS ages of detrital zircons”. Thesis Paper, Master of Science Degree, Brigham Young University (December 2009). Page 32.
10. Kirkland, James I.; Britt, Brooks; Burge, Donald L.; Carpenter, Kenneth; Cifelli, Richard; DeCourten, Frank; Eaton, Jeffery; Hasiotis, Stephen; Lawton, Tim (1997). “Lower to Middle Cretaceous Dinosaur Faunas of the Central Colorado Plateau: A Key to Understanding 35 Million Years of Tectonics, Evolution, and Biogeography”. Brigham Young University Geology Studies, volume 42, issue 2. Pages 88-89.
11. Kirkland, James I.; Parrish, J. Michael (1995). “Theropod teeth from the lower and middle Cretaceous of Utah”. Journal of Vertebrate Paleontology, volume 15, supplement 3 (November 1995). Page 39A.
12. Kirkland, James I.; Britt, Brooks; Burge, Donald L.; Carpenter, Kenneth; Cifelli, Richard; DeCourten, Frank; Eaton, Jeffery; Hasiotis, Stephen; Lawton, Tim (1997). “Lower to Middle Cretaceous Dinosaur Faunas of the Central Colorado Plateau: A Key to Understanding 35 Million Years of Tectonics, Evolution, and Biogeography”. Brigham Young University Geology Studies, volume 42, issue 2. Page 79.
13. Harris, Jerald D. (1998). “Large, Early Cretaceous Theropods in North America”. In Lucas, Spencer G.; Kirkland, James I.; Estep, John W., eds. Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science, bulletin no. 14 (1998). Pages 225-228.
14. Harris, Jerald D. (1998). “Large, Early Cretaceous Theropods in North America”. In Lucas, Spencer G.; Kirkland, James I.; Estep, John W., eds. Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science, bulletin no. 14 (1998). Page 226.
15. Smith, Joshua B.; Vann, David R.; Dodson, Peter (2005). “Dental morphology and variation in theropod dinosaurs: Implications for the taxonomic identification of isolated teeth”. The Anatomical Record, Part A, 285A (2005). Pages 699-736.
16. Kirkland, James I. (2005). “Utah’s newly recognized dinosaur record from the early Cretaceous Cedar Mountain Formation”. Utah Geological Survey: Survey Notes, volume 37, issue 1 (January 2005). Pages 1-5.
17. YouTube. Tate Geological Museum. “Tate Geological Museum’s Spring Lecture Series 2021: Cretaceous Dinosaurs- part 3 – The Cedar Mountain Formation of Utah: North America’s Most Complete Early Cretaceous Record, hosted by James I. Kirkland” (May 11, 2021). https://www.youtube.com/watch?v=Thhb6Jy-Acw. Accessed on March 14, 2022.
18. YouTube. Tate Geological Museum. “Tate Geological Museum’s Spring Lecture Series 2021: Cretaceous Dinosaurs- part 3 – The Cedar Mountain Formation of Utah: North America’s Most Complete Early Cretaceous Record, hosted by James I. Kirkland” (May 11, 2021). https://www.youtube.com/watch?v=Thhb6Jy-Acw. Accessed on March 14, 2022.
19. Kirkland, James I.; Britt, Brooks; Burge, Donald L.; Carpenter, Kenneth; Cifelli, Richard; DeCourten, Frank; Eaton, Jeffery; Hasiotis, Stephen; Lawton, Tim (1997). “Lower to Middle Cretaceous Dinosaur Faunas of the Central Colorado Plateau: A Key to Understanding 35 Million Years of Tectonics, Evolution, and Biogeography”. Brigham Young University Geology Studies, volume 42, issue 2. Pages 70, 78; Kirkland, James I.; Cifelli, Richard L.; Britt, Brooks B.; Burge, Donald L.; DeCourten, Frank L.; Eaton, Jeffery G.; Parrish, J. Michael (1999). “Distribution of vertebrate faunas in the Cedar Mountain Formation, east-central Utah”. Miscellaneous Publication – Utah Geological Survey 99-1. Pages 201, 211.
20. Kirkland, James I. (2005). “Utah’s newly recognized dinosaur record from the early Cretaceous Cedar Mountain Formation”. Utah Geological Survey: Survey Notes, volume 37, issue 1 (January 2005). Pages 1-5.
21. YouTube. Tate Geological Museum. “Tate Geological Museum’s Spring Lecture Series 2021: Cretaceous Dinosaurs- part 3 – The Cedar Mountain Formation of Utah: North America’s Most Complete Early Cretaceous Record, hosted by James I. Kirkland” (May 11, 2021). https://www.youtube.com/watch?v=Thhb6Jy-Acw. Accessed on March 14, 2022.
22. Lockley, Martin G.; Gierlinski, Gerard; Dubicka, Zofia; Breithaupt, Brent H.; Matthews, Neffra A. (2014). “A preliminary report on a new dinosaur tracksite in the Cedar Mountain Formation (Cretaceous) of eastern Utah”. New Mexico Museum of Natural History and Science, Bulletin 62. Page 279-286; Lockley, Martin G.; Gierlinski, Gerard D.; Houck, Karen; Lim, Jong-Deock; Kim, Kyung Soo; Kim, Dal-Yong; Kim, Tae Hyeong; Kang, Seung-Hyeop; Hunt-Foster, ReBecca; Li, Rihui; Chessser, Christopher; Gay, Rob; Dubicka, Zofia; Cart, Ken; Wright, Christy (2014). “New excavations at the Mill Canyon Dinosaur Track Site (Cedar Mountain Formation, Lower Cretaceous) of Eastern Utah”. New Mexico Museum of Natural History and Science, Bulletin 62 (2014). Pages 287-300; Hunt-Foster, ReBecca K.; Lockley, Martin G.; Milner, Andrew R. C.; Foster, John R.; Matthews, Neffra A.; Breithaupt, Brent H.; Smith, Joshua A. (2016). “Tracking Dinosaurs in BLM Canyon Country, Utah”. Geology of the Intermountain West, volume 3 (October 2016). Pages 73-75; YouTube. Natural History Museum of Utah. “ReBecca Hunt Foster- NHMU DinoFest 2017 – ‘Trailing Dinosaur Tracks in the Early Cretaceous: The Documentation and Public Interpretation of the Mill Canyon Dinosaur Tracksite, Utah’, by ReBecca Hunt-Foster” (January 31, 2017). https://www.youtube.com/watch?v=-Z8flhfevFc. Accessed on March 21, 2022; YouTube. Tate Geological Museum. “Tate Geological Museum’s Spring Lecture Series 2021: Cretaceous Dinosaurs- part 3 – The Cedar Mountain Formation of Utah: North America’s Most Complete Early Cretaceous Record, hosted by James I. Kirkland” (May 11, 2021). https://www.youtube.com/watch?v=Thhb6Jy-Acw. Accessed on March 14, 2022.
23. Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Page 153.
24. Judd, Heather; Irmis, Randall; Kirkland, James I. (2013). “A new large-bodied theropod dinosaur from the Lower Cretaceous Cedar Mountain Formation (Ruby Ranch Member) in Central Utah”. Journal of Vertebrate Paleontology, program and abstracts (November 1, 2013). Page 150.
25. Judd, Heather; Irmis, Randall; Kirkland, James I. (2013). “A new large-bodied theropod dinosaur from the Lower Cretaceous Cedar Mountain Formation (Ruby Ranch Member) in Central Utah”. Journal of Vertebrate Paleontology, program and abstracts (November 1, 2013). Page 150.
26. Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Page 153.
27. Kirkland, James I.; Madsen, Scott K. (2007). “The Lower Cretaceous Cedar Mountain Formation, eastern Utah: The view up an always interesting learning curve”. Fieldtrip Guidebook, Geological Society of America, Rocky Mountain Section. (May 2007). Page 16.
28. Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Page 153; YouTube. Tate Geological Museum. “Tate Geological Museum’s Spring Lecture Series 2021: Cretaceous Dinosaurs- part 3 – The Cedar Mountain Formation of Utah: North America’s Most Complete Early Cretaceous Record, hosted by James I. Kirkland” (May 11, 2021). https://www.youtube.com/watch?v=Thhb6Jy-Acw. Accessed on March 14, 2022.
29. Zanno, Lindsay E.; Makovicky, Peter J. (2013). “Neovenatorid theropods are apex predators in the Late Cretaceous of North America”. Nature Communications, volume 4, article number 2827 (November 22, 2013).
30. Zanno, Lindsay E.; Makovicky, Peter J. (2013). “Neovenatorid theropods are apex predators in the Late Cretaceous of North America”. Nature Communications, volume 4, article number 2827 (November 22, 2013); Stovall, J. Willis; Langston, Jr., Wann (1950). “Acrocanthosaurus atokensis, a new genus and species of Lower Cretaceous Theropoda from Oklahoma”. American Midland Naturalist, volume 43, issue 3 (1950). Pages 696-700.
31. Harris, Jerald David (1998). “A Reanalysis of Acrocanthosaurus atokensis, its Phylogenetic Status, and Paleobiogeographic Implications, Based on a New Specimen from Texas”. New Mexico Museum of Natural History and Science, bulletin 13 (1998). Pages 12-14.
32. Harris, Jerald David (1998). “A Reanalysis of Acrocanthosaurus atokensis, its Phylogenetic Status, and Paleobiogeographic Implications, Based on a New Specimen from Texas”. New Mexico Museum of Natural History and Science, bulletin 13 (1998). Page 14.
33. Harris, Jerald D. (1998). “Large, Early Cretaceous Theropods in North America”. In Lucas, Spencer G.; Kirkland, James I.; Estep, John W., eds. Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science, bulletin no. 14 (1998). Page 226; Judd, Heather; Irmis, Randall; Kirkland, James I. (2013). “A new large-bodied theropod dinosaur from the Lower Cretaceous Cedar Mountain Formation (Ruby Ranch Member) in Central Utah”. Journal of Vertebrate Paleontology, program and abstracts (November 1, 2013). Page 150.
34. Stovall, J. Willis; Langston, Jr., Wann (1950). “Acrocanthosaurus atokensis, a new genus and species of Lower Cretaceous Theropoda from Oklahoma”. American Midland Naturalist, volume 43, issue 3 (1950). Pages 706-707.
35. Judd, Heather; Irmis, Randall; Kirkland, James I. (2013). “A new large-bodied theropod dinosaur from the Lower Cretaceous Cedar Mountain Formation (Ruby Ranch Member) in Central Utah”. Journal of Vertebrate Paleontology, program and abstracts (November 1, 2013). Page 150.
36. Stovall, J. Willis; Langston, Jr., Wann (1950). “Acrocanthosaurus atokensis, a new genus and species of Lower Cretaceous Theropoda from Oklahoma”. American Midland Naturalist, volume 43, issue 3 (1950). Page 706.
37. Zanno, Lindsay E.; Makovicky, Peter J. (2013). “Neovenatorid theropods are apex predators in the Late Cretaceous of North America”. Nature Communications, volume 4, article number 2827 (November 22, 2013).
38. Judd, Heather; Irmis, Randall; Kirkland, James I. (2013). “A new large-bodied theropod dinosaur from the Lower Cretaceous Cedar Mountain Formation (Ruby Ranch Member) in Central Utah”. Journal of Vertebrate Paleontology, program and abstracts (November 1, 2013). Page 150.
39. Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Page 153.
40. Currie, Philip J.; Carpenter, Kenneth (2000). “A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA”. Geodiversitas, volume 22, issue 2 (2000). Pages 230-231.
41. Stovall, J. Willis; Langston, Jr., Wann (1950). “Acrocanthosaurus atokensis, a new genus and species of Lower Cretaceous Theropoda from Oklahoma”. American Midland Naturalist, volume 43, issue 3 (1950). Page 718.
42. Zanno, Lindsay E.; Makovicky, Peter J. (2013). “Neovenatorid theropods are apex predators in the Late Cretaceous of North America”. Nature Communications, volume 4, article number 2827 (November 22, 2013).
43. Judd, Heather; Irmis, Randall; Kirkland, James I. (2013). “A new large-bodied theropod dinosaur from the Lower Cretaceous Cedar Mountain Formation (Ruby Ranch Member) in Central Utah”. Journal of Vertebrate Paleontology, program and abstracts (November 1, 2013). Page 150.
44. Currie, Philip J.; Carpenter, Kenneth (2000). “A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA”. Geodiversitas, volume 22, issue 2 (2000). Pages 242-243.
45. Zanno, Lindsay E.; Makovicky, Peter J. (2013). “Neovenatorid theropods are apex predators in the Late Cretaceous of North America”. Nature Communications, volume 4, article number 2827 (November 22, 2013).
46. Kirkland, James I.; Britt, Brooks; Burge, Donald L.; Carpenter, Kenneth; Cifelli, Richard; DeCourten, Frank; Eaton, Jeffery; Hasiotis, Stephen; Lawton, Tim (1997). “Lower to Middle Cretaceous Dinosaur Faunas of the Central Colorado Plateau: A Key to Understanding 35 Million Years of Tectonics, Evolution, and Biogeography”. Brigham Young University Geology Studies, volume 42, issue 2. Pages 88-89.
47. BrantWorks. “Acrocanthosaurus skeleton”. http://brantworks.com/acro-skeleton.php. Accessed on March 29, 2022.
48. Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Pages 126-127, 150-151, 153; Royo-Torres, Rafael; Upchurch, Paul; Kirkland, James I.; DeBlieux, Donald D.; Foster, John R.; Cobos, Alberto; Alcalá, Luis (2017). “Descendants of the Jurassic turiasaurs from Iberia found refuge in the Early Cretaceous of western USA”. Scientific Reports, volume 7, issue 1 (October 30, 2017). Page 3.
49. Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Pages 126-127, 150-151, 153; Royo-Torres, Rafael; Upchurch, Paul; Kirkland, James I.; DeBlieux, Donald D.; Foster, John R.; Cobos, Alberto; Alcalá, Luis (2017). “Descendants of the Jurassic turiasaurs from Iberia found refuge in the Early Cretaceous of western USA”. Scientific Reports, volume 7, issue 1 (October 30, 2017). Page 3.
50. Kirkland, James Ian; Burge, Donald; Gaston, Robert (1993). “A large dromaeosaur (Theropoda) from the Lower Cretaceous of eastern Utah”. Hunteria, volume 2, issue 10 (June 18, 1993). Pages 2-3; Kirkland, James I.; Britt, Brooks; Burge, Donald L.; Carpenter, Kenneth; Cifelli, Richard; DeCourten, Frank; Eaton, Jeffery; Hasiotis, Stephen; Lawton, Tim (1997). “Lower to Middle Cretaceous Dinosaur Faunas of the Central Colorado Plateau: A Key to Understanding 35 Million Years of Tectonics, Evolution, and Biogeography”. Brigham Young University Geology Studies, volume 42, issue 2. Page 92; Eberth, David A; Britt, Brooks B.; Scheetz, Rod; Stadtman, Kenneth L; Brinkman, Donald B. (2006). “Dalton Wells: Geology and significance of debris-flow-hosted dinosaur bonebeds in the Cedar Mountain Formation (Lower Cretaceous) of eastern Utah, USA”. Palaeogeography, Palaeoclimatology, Palaeoecology, volume 236. Page 218; Britt, Brooks B.; Eberth, David A.; Scheetz, Rod D.; Greenhalgh, Brent W.; Stadtman, Kenneth L. (2009). “Taphonomy of debris-flow hosted dinosaur bonebeds at Dalton Wells, Utah (Lower Cretaceous, Cedar Mountain Formation, USA)”. Palaeogeography, Palaeoclimatology, Palaeoecology, volume 280 (June 2009). Page 18.
51. Kirkland, James Ian; Burge, Donald; Gaston, Robert (1993). “A large dromaeosaur (Theropoda) from the Lower Cretaceous of eastern Utah”. Hunteria, volume 2, issue 10 (June 18, 1993). Page 13.

Bibliography

Articles

Britt, Brooks B.; Eberth, David A.; Scheetz, Rod D.; Greenhalgh, Brent W.; Stadtman, Kenneth L. (2009). “Taphonomy of debris-flow hosted dinosaur bonebeds at Dalton Wells, Utah (Lower Cretaceous, Cedar Mountain Formation, USA)”. Palaeogeography, Palaeoclimatology, Palaeoecology, volume 280 (June 2009). Pages 1-22.

Currie, Philip J.; Carpenter, Kenneth (2000). “A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA”. Geodiversitas, volume 22, issue 2 (2000). Pages 207-246.
http://brantworks.com/resources/Acrocanthosaurus/Currie&Carpenter_2000_Acrocanthosaurus.pdf.

D’Emic, Michael D.; Melstrom, Keegan M.; Eddy, Drew R. (2012). “Paleobiology and geographic range of the large-bodied Cretaceous theropod dinosaur Acrocanthosaurus atokensis”. Palaeogeography, Palaeoclimatology, Palaeoecology, 333-334 (March 13, 2012). Pages 13-23.
https://d1wqtxts1xzle7.cloudfront.net/34214407/DEmic_12_Acro-with-cover-page-v2.pdf?Expires=1648568049&Signature=cQ9IDeJ1aYRdN~ldK-n7mR3oPuGQKll95aRGt3WuC7bJit66mRAP9~tZxvHHooOmHJlm~O0jwP9RzgYAws47x51PnsQELPqpPhJ5PDbL0rav0HQj4y626H5T~KUfBbqh~ietJnw3jIL91vypa8fJuqFR33LttTJCWskyfycdt80qA6JnByuZyqVu34tEQ-~yiE52v6HdqVYhGvPJ5yZWLLcUZXslFkfR9EiRDVeYRregjgQhFWS9FfvL7oVqp7b6RhiWgqeDLukjbMJj54WhLMwZ6NRAKxb9akdgglfglTD~oZm0nGf4ic6w9MlHWKf0QJuqFeammqKWoeoCgMFhSQ__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA.

Eberth, David A; Britt, Brooks B.; Scheetz, Rod; Stadtman, Kenneth L; Brinkman, Donald B. (2006). “Dalton Wells: Geology and significance of debris-flow-hosted dinosaur bonebeds in the Cedar Mountain Formation (Lower Cretaceous) of eastern Utah, USA”. Palaeogeography, Palaeoclimatology, Palaeoecology, volume 236. Pages 217-245.
https://d1wqtxts1xzle7.cloudfront.net/49882404/j.palaeo.2005.11.02020161026-6104-1m6tq92-libre.pdf?1477489419=&response-content-disposition=inline%3B+filename%3DDalton_Wells_Geology_and_significance_of.pdf&Expires=1652625588&Signature=DbIsCQTwiPGd5pNw6kQeggbiB8JbkhFQtMI8DPKD4TcN6t-thxwSM2x1HO8Dx9K20waRgLt7qdluUhGwWXSwj8TBtrs0w4P0t56u6GUZxWRaQMxNxA2SZJTyBwxsn5GPOjhsDffOHPJhxIF4WS9K1vSJQGbbU3dEC51KVIswVm9GSPm1e69DHWCS4oU0px4Z~05gmHnG8Yv-IMEgkyF5EEyUJCmSqsVOGP9HFMQE9sIrEgEdhEPVCInSrlfsQsL-lxPWewZTAq4BdN6UEovm1qVAy6nxXva3kdToDWtVs0BQN0y8iv8Furk7bYcdNklaTMt-Jc52xiVzOQO0Wl83AA__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA.

Frederickson, Joseph A.; Lipka, Thomas R.; Cifelli, Richard A. (2018). “Faunal composition and paleoenvironment of the Arundel Clay (Potomac Formation; Early Cretaceous), Maryland, USA”. Palaeontologia Electronica, 21.2.31A (January 2018). Pages 1-24.
https://www.researchgate.net/publication/327277019_Faunal_composition_and_paleoenvironment_of_the_Arundel_Clay_Potomac_Formation_Early_Cretaceous_Maryland_USA.

Harris, Jerald David (1998). “A Reanalysis of Acrocanthosaurus atokensis, its Phylogenetic Status, and Paleobiogeographic Implications, Based on a New Specimen from Texas”. New Mexico Museum of Natural History and Science, bulletin 13 (1998). Pages 1-75.
http://brantworks.com/resources/Acrocanthosaurus/Harris_1998_Acrocanthosaurus.pdf.

Harris, Jerald D. (1998). “Large, Early Cretaceous Theropods in North America”. In Lucas, Spencer G.; Kirkland, James I.; Estep, John W., eds. Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science, bulletin no. 14 (1998). Pages 225-228.

Hunt-Foster, ReBecca K.; Lockley, Martin G.; Milner, Andrew R. C.; Foster, John R.; Matthews, Neffra A.; Breithaupt, Brent H.; Smith, Joshua A. (2016). “Tracking Dinosaurs in BLM Canyon Country, Utah”. Geology of the Intermountain West, volume 3 (October 2016). Pages 67-100.
https://www.academia.edu/29963998/Tracking_Dinosaurs_in_BLM_Canyon_Country.

Judd, Heather; Irmis, Randall; Kirkland, James I. (2013). “A new large-bodied theropod dinosaur from the Lower Cretaceous Cedar Mountain Formation (Ruby Ranch Member) in Central Utah”. Journal of Vertebrate Paleontology, program and abstracts (November 1, 2013). Page 150.
https://vertpaleo.org/wp-content/uploads/2021/03/SVP-2013-merged-book-10-15-2013.pdf.

Kirkland, James I. (2005). “Utah’s newly recognized dinosaur record from the early Cretaceous Cedar Mountain Formation”. Utah Geological Survey: Survey Notes, volume 37, issue 1 (January 2005). Pages 1-5.
https://geology.utah.gov/map-pub/survey-notes/utahs-newly-recognized-dinosaur-record/.

Kirkland, James I.; Britt, Brooks; Burge, Donald L.; Carpenter, Kenneth; Cifelli, Richard; DeCourten, Frank; Eaton, Jeffery; Hasiotis, Stephen; Lawton, Tim (1997). “Lower to Middle Cretaceous Dinosaur Faunas of the Central Colorado Plateau: A Key to Understanding 35 Million Years of Tectonics, Evolution, and Biogeography”. Brigham Young University Geology Studies, volume 42, issue 2. Pages 69-103.
https://www.researchgate.net/publication/259021967_Lower_to_middle_Cretaceous_dinosaur_faunas_of_the_central_Colorado_Plateau_a_key_to_understanding_35_million_years_of_tectonics_sedimentology_evolution_and_biogeography.

Kirkland, James Ian; Burge, Donald; Gaston, Robert (1993). “A large dromaeosaur (Theropoda) from the Lower Cretaceous of eastern Utah”. Hunteria, volume 2, issue 10 (June 18, 1993). Pages 1-16.
https://www.researchgate.net/publication/285714464_A_large_dromaeosaur_Theropoda_from_the_Lower_Cretaceous_of_eastern_Utah.

Kirkland, James I.; Cifelli, Richard L.; Britt, Brooks B.; Burge, Donald L.; DeCourten, Frank L.; Eaton, Jeffery G.; Parrish, J. Michael (1999). “Distribution of vertebrate faunas in the Cedar Mountain Formation, east-central Utah”. Miscellaneous Publication – Utah Geological Survey 99-1. Pages 201-217.
https://www.researchgate.net/publication/258997949_Distribution_of_vertebrate_faunas_in_the_Cedar_Mountain_Formation_east_-central_Utah.

Kirkland, James I.; Madsen, Scott K. (2007). “The Lower Cretaceous Cedar Mountain Formation, eastern Utah: the view up an always interesting learning curve”. Fieldtrip Guidebook, Geological Society of America, Rocky Mountain Section.
https://www.researchgate.net/publication/40662964_The_Lower_Cretaceous_Cedar_Mountain_Formation_eastern_Utah_the_view_up_an_always_interesting_learning_curve_papers_from_a_symposium_of_the_Geological_Society_of_America_at_the_annual_meeting_in_St_Geo.

Kirkland, James I.; Parrish, J. Michael (1995). “Theropod teeth from the lower and middle Cretaceous of Utah”. Journal of Vertebrate Paleontology, volume 15, supplement 3 (November 1995). Page 39A.

Kirkland, James I.; Suarez, Marina; Suarez, Celina; Hunt-Foster, ReBecca (2016). “The Lower Cretaceous in East-Central Utah—The Cedar Mountain Formation and its Bounding Strata”. Geology of the Intermountain West, volume 3 (October 2016). Pages 101-228.
https://giw.utahgeology.org/giw/index.php/GIW/article/view/11.

Lockley, Martin G.; Gierlinski, Gerard; Dubicka, Zofia; Breithaupt, Brent H.; Matthews, Neffra A. (2014). “A preliminary report on a new dinosaur tracksite in the Cedar Mountain Formation (Cretaceous) of eastern Utah”. New Mexico Museum of Natural History and Science, Bulletin 62. Page 279-286.

Lockley, Martin G.; Gierlinski, Gerard D.; Houck, Karen; Lim, Jong-Deock; Kim, Kyung Soo; Kim, Dal-Yong; Kim, Tae Hyeong; Kang, Seung-Hyeop; Hunt-Foster, ReBecca; Li, Rihui; Chessser, Christopher; Gay, Rob; Dubicka, Zofia; Cart, Ken; Wright, Christy (2014). “New excavations at the Mill Canyon Dinosaur Track Site (Cedar Mountain Formation, Lower Cretaceous) of Eastern Utah”. New Mexico Museum of Natural History and Science, Bulletin 62 (2014). Pages 287-300.
https://www.researchgate.net/publication/358137342_NEW_EXCAVATIONS_AT_THE_MILL_CANYON_DINOSAUR_TRACK_SITE_CEDAR_MOUNTAIN_FORMATION_LOWER_CRETACEOUS_OF_EASTERN_UTAH.

Mori, Hirotsugu. “Dinosaurian faunas of the Cedar Mountain Formation and LA-ICP-MS detrital zircon ages for three stratigraphic sections and the relationship between the degree of abrasion and U-Pb LA-ICP-MS ages of detrital zircons”. Thesis Paper, Master of Science Degree, Brigham Young University (December 2009).
https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=2999&context=etd.

Phillips, Stephen P.; Howell, John A.; Hartley, Adrian J.; Chmielewska, Magda; Hudson, Samuel M. (2021). “Evolution of foreland basin fluvial systems in the mid-Cretaceous of Utah, USA (upper Cedar Mountain and Naturita formations)”. Sedimentology, volume 68 (2021). Pages 2,097-2,124.
https://onlinelibrary.wiley.com/doi/pdf/10.1111/sed.12845.

Royo-Torres, Rafael; Upchurch, Paul; Kirkland, James I.; DeBlieux, Donald D.; Foster, John R.; Cobos, Alberto; Alcalá, Luis (2017). “Descendants of the Jurassic turiasaurs from Iberia found refuge in the Early Cretaceous of western USA”. Scientific Reports, volume 7, issue 1 (October 30, 2017). Pages 1-12.
https://www.researchgate.net/publication/320717437_Descendants_of_the_Jurassic_turiasaurs_from_Iberia_found_refuge_in_the_Early_Cretaceous_of_western_USA.

Smith, Joshua B.; Vann, David R.; Dodson, Peter (2005). “Dental morphology and variation in theropod dinosaurs: Implications for the taxonomic identification of isolated teeth”. The Anatomical Record, Part A, 285A (2005). Pages 699-736.
https://anatomypubs.onlinelibrary.wiley.com/doi/epdf/10.1002/ar.a.20206.

Stovall, J. Willis; Langston, Jr., Wann (1950). “Acrocanthosaurus atokensis, a new genus and species of Lower Cretaceous Theropoda from Oklahoma”. American Midland Naturalist, volume 43, issue 3 (1950). Pages 696-728.
http://brantworks.com/resources/Acrocanthosaurus/Stoval&Langston_1970_Acrocanthosaurus.pdf.

Suarez​, Celina A.; Frederickson, Joseph; Cifelli, Richard L.; Pittman, Jeffrey G.; Nydam, Randall L.; Hunt-Foster, ReBecca K.; Morgan, Kirsty (2021). “A new vertebrate fauna from the Lower Cretaceous Holly Creek Formation of the Trinity Group, southwest Arkansas, USA”. PeerJ, volume 9: e12242 (October 21, 2021).
https://peerj.com/articles/12242/.

Suarez, Celina A.; González, Luis A.; Ludvigson, Gregory A.; Kirkland, James I.; Cifelli, Richard L.; Kohn, Matthew J. (2014). “Multi-Taxa Isotopic Investigation of Paleohydrology in the Lower Cretaceous Cedar Mountain Formation, eastern Utah, U.S.A.: Deciphering Effects of the Nevadaplano Plateau on Regional Climate”. Journal of Sedimentary Research, volume 84 (November 2014). Pages 975-987.
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.724.2968&rep=rep1&type=pdf.

Zanno, Lindsay E.; Makovicky, Peter J. (2013). “Neovenatorid theropods are apex predators in the Late Cretaceous of North America”. Nature Communications, volume 4, article number 2827 (November 22, 2013).
https://www.nature.com/articles/ncomms3827.

Websites

BrantWorks. “Acrocanthosaurus skeleton”. http://brantworks.com/acro-skeleton.php. Accessed on March 29, 2022.

Videos

YouTube. Natural History Museum of Utah. “ReBecca Hunt Foster- NHMU DinoFest 2017 – ‘Trailing Dinosaur Tracks in the Early Cretaceous: The Documentation and Public Interpretation of the Mill Canyon Dinosaur Tracksite, Utah’, by ReBecca Hunt-Foster” (January 31, 2017). https://www.youtube.com/watch?v=-Z8flhfevFc. Accessed on March 21, 2022.

YouTube. Tate Geological Museum. “Tate Geological Museum’s Spring Lecture Series 2021: Cretaceous Dinosaurs- part 3 – The Cedar Mountain Formation of Utah: North America’s Most Complete Early Cretaceous Record, hosted by James I. Kirkland” (May 11, 2021). https://www.youtube.com/watch?v=Thhb6Jy-Acw. Accessed on March 14, 2022.

Categories: Paleontology, Uncategorized

Tags: Acrocanthosaurus, allosauroid, Allosauroidea, Allosaurus, America, art, carcharodontosaurid, Carcharodontosauridae, Cedar Mountain Formation, Cretaceous Period, dinosaur, Early Cretaceous, Late Cretaceous, Mesozoic, Middle Cretaceous, neovenatorid, Neovenatoridae, North America, paleo-art, paleontology, Prehistoric, reptile, theropod, Utah