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Philip Currie

Philip Currie

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Papers by Philip Currie

Research paper thumbnail of New material reveals the pelvic morphology of Caenagnathidae (Theropoda, Oviraptorosauria)
Cretaceous Research, Oct 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... moreThis is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Research paper thumbnail of A small caenagnathid tibia from the Horseshoe Canyon Formation (Maastrichtian): Implications for growth and lifestyle in oviraptorosaurs
Cretaceous Research, Dec 1, 2018
Caenagnathid elements are exceptionally rare in the Horseshoe Canyon Formation, and a small tibia... moreCaenagnathid elements are exceptionally rare in the Horseshoe Canyon Formation, and a small tibia constitutes only the fourth record from the formation. The tibia is elongate and gracile, with a semi-circular cross-section. A representative survey of Late Cretaceous, North American theropod tibiae suggests that cross-sectional shape can be useful for distinguishing theropod superfamilies. Caenagnathid tibiae can be distinguished from those of other theropods by the combination of their elongation, semi-circular cross-sections, and absence of extensive contact between the fibula and distal ends of the tibia. Histological sections reveal that the individual represented by the tibia was likely just over one year old and was increasing its growth rate at the time of death. However, the cyclical growth mark is unusual, consisting of a zone of parallel-fibered bone, rather than a distinct line of arrested growth-similar to annuli of rapidly-growing young ornithischians. A transition in vasculature orientation and osteocyte lacunae size and density prior to the growth mark may represent a physiological change within the first year of life. It is possible that this represents fledging, ontogenetic niche shift, or an environmental change, but more evidence from other individuals is required to test this. The presence of endosteal lamellae suggests that the tibia already experienced significant mechanical loads, despite the young age of the individual. Together with evidence from other caenagnathids, it suggests that they were active early in life, consistent with a precocial lifestyle.
Research paper thumbnail of Two braincases of <i>Daspletosaurus</i> (Theropoda: Tyrannosauridae): anatomy and comparison<sup>1</sup>
Canadian Journal of Earth Sciences, Sep 1, 2021
For sheer complexity, braincases are generally considered anatomically conservative. However, rec... moreFor sheer complexity, braincases are generally considered anatomically conservative. However, recent research on the braincases of tyrannosaurids have revealed extensive morphological variations. This line of inquiry has its root in Dale Russell's review of tyrannosaurids in which he established Daspletosaurus torosusa large tyrannosaurine from the Campanian of southern Alberta. In the wake of systematic revisions to tyrannosaurines previously assigned to Daspletosaurus, one potentially distinct species remains undescribed. This paper describes and compares a braincase referable to this species with that of the holotype for Daspletosaurus torosus using computerized-tomography-based reconstructions. The two braincases have numerous differences externally and internally. The specimen of Daspletosaurus sp. has a bottlenecked olfactory tract, short and vertical lagena, and a developed ascending column of the anterior tympanic recess. The holotype of Daspletosaurus torosus has many unusual traits, including an anteriorly positioned trochlear root, elongate common carotid canal, distinct chamber of the basisphenoid recess, asymmetry in the internal basipterygoid aperture, and laterally reduced but medially expanded subcondylar recess. This comparison also identified characters that potentially unite the two species of Daspletosaurus, including deep midbrain flexures in the endocasts. However, many character variations in the braincases are known in other tyrannosaurids to correlate with body size and maturity, or represent individual variations. Therefore, taxonomic and phylogenetic signals can be isolated from background variations in a more comprehensive approach by using additional specimens. New information on the two braincases of Daspletosaurus is consistent with the emerging view of tyrannosaurid braincases as highly variable, ontogenetically dynamic character complexes.
Research paper thumbnail of Birdlike growth and mixed-age flocks in avimimids (Theropoda, Oviraptorosauria)
Scientific Reports, Dec 11, 2019
Avimimids were unusual, birdlike oviraptorosaurs from the Late Cretaceous of Asia. Initially enig... moreAvimimids were unusual, birdlike oviraptorosaurs from the Late Cretaceous of Asia. Initially enigmatic, new information has ameliorated the understanding of their anatomy, phylogenetic position, and behaviour. A monodominant bonebed from the Nemegt Formation of Mongolia showed that some avimimids were gregarious, but the site is unusual in the apparent absence of juveniles. Here, a second monodominant avimimid bonebed is described from the Iren Dabasu Formation of northern China. Elements recovered include numerous vertebrae and portions of the forelimbs and hindlimbs, representing a minimum of six individuals. Histological sampling of two tibiotarsi from the bonebed reveals rapid growth early in ontogeny followed by unexpectedly early onset of fusion and limited subsequent growth. This indicates that avimimids grew rapidly to adult size, like most extant birds but contrasting other small theropod dinosaurs. The combination of adults and juveniles in the Iren Dabasu bonebed assemblage provides evidence of mixed-age flocking in avimimids and the onset of fusion in young individuals suggests that some of the individuals in the Nemegt Formation bonebed may have been juveniles. Regardless, these individuals were likely functionally analogous to adults, and this probably facilitated mixed-age flocking by reducing ontogenetic niche shift in avimimids. Avimimidae was an enigmatic, monogeneric family of oviraptorosaurs from China and Mongolia (Fig. 1). Avimimus was first described by Kurzanov 1 and its bird-like morphology immediately confused palaeontologists. Although regarded as a non-avian theropod by Kurzanov 1 , other workers interpreted its mosaic of features as similar to those of a flightless avian 2 , a sauropod 3 , and even an ornithopod dinosaur 3. These apparently contradictory hypotheses led several authors 4,5 to suggest that the holotype may have been a chimaera, a possibility Kurzanov considered himself 4. However, Vickers-Rich et al. 5 argued this claim, and the subsequent discovery of an articulated skeleton 6 indicated that the material did indeed belong to a single taxon. The oviraptorosaurian affinities of Avimimus were first recognized by Maryanska et al. 7 , although their analysis also placed oviraptorosaurs within Avialae, a conclusion no longer supported by broad-scale theropod phylogenies 8,9. Recent analyses 10-12 have recovered Avimimus as an intermediate oviraptorosaur, sister to Caenagnathoidea (=Caenagnathid ae + Oviraptoridae). The rarity of avimimid material and its poor history of description has led to several problems in the understanding of these animals. A series of detailed descriptions of Avimimus portentosus in Russian by Kurzanov 13-17 , and their translations, comprise most of the literature on avimimids. Despite the discovery of numerous additional specimens in the intervening years, few of these have been described until recently. An expedition led by the Hayashibara Museum of Japan collected a nearly complete skeleton including cranial material (MPC-D 100/129) from Shar Tsav in the eastern Gobi Desert of Mongolia, but it has not been described beyond conference abstracts 6. In 2006, the same organization discovered a second skeleton in the Nemegt Formation at Bugiin Tsav, in western Mongolia, the cranium of which was recently described 18. A bonebed of disarticulated avimimids from the Nemegt Formation of Mongolia was discovered in 2006 19 , but was not described until ten years later 20. Subsequent examination of that material determined that it represents a new species, Avimimus nemegtensis, based on a suite of cranial and postcranial differences from the holotype of Avimimus portentosus 21. A second bonebed from the Iren Dabasu Formation of China was briefly described by Ryan et al. 22 , but has not received further attention until now. The general age of the Iren Dabasu Formation is widely accepted as Late Cretaceous, but its precise age is debated. Granger and Berkey 23 indicated a Cretaceous age, but did not speculate
Research paper thumbnail of Cranial Anatomy of New Specimens of <i>Saurornitholestes langstoni</i> (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta
Cranial Anatomy of New Specimens of <i>Saurornitholestes langstoni</i> (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, Sep 9, 2019
ABSTRACTThe holotype of the dromaeosaurid Saurornitholestes langstoni was described in 1978 on th... moreABSTRACTThe holotype of the dromaeosaurid Saurornitholestes langstoni was described in 1978 on the basis of fewer than 30 associated cranial and postcranial bones of a single individual from Dinosaur Provincial Park. Four additional partial skeletons of Saurornitholestes were recovered from Campanian (Upper Cretaceous) beds of Alberta and Montana over the next 25 years, although reasonably complete skeletons remained elusive, and virtually nothing was known about the skull. The lack of truly diagnostic material has been problematic, and the relationships of Saurornitholestes to other dromaeosaurids have been difficult to resolve because of the incomplete knowledge of its anatomy. In 2014, an almost complete skeleton, including the skull, was collected less than a kilometer from where the holotype had been found. Although similar in body size to Velociraptor, the facial region of the skull is relatively shorter, taller, and wider. The nasals are pneumatic. The premaxillary teeth are distinctive, and teeth previously identified in the Dinosaur Park Formation as Zapsalis abradens can now be identified as the second premaxillary tooth of S. langstoni. Morphology and wear patterns suggest that these may have been specialized for preening feathers. Many traits define a Campanian North American clade, Saurornitholestinae, that is distinct from an Asian clade that includes Velociraptor (Velociraptorinae). This new information on the skull allows a more complete evaluation of its systematic position within the Dromaeosauridae and supports the suggestion of at least two major faunal interchanges between Asia and North America during the Cretaceous. Anat Rec, 303:691–715, 2020. © 2019 American Association for Anatomy
Research paper thumbnail of PISCIVORY IN THE FEATHERED DINOSAUR<i>MICRORAPTOR</i>
Evolution, Apr 19, 2013
The largest specimen of the four-winged dromaeosaurid dinosaur Microraptor gui includes preserved... moreThe largest specimen of the four-winged dromaeosaurid dinosaur Microraptor gui includes preserved gut contents. Previous reports of gut contents and considerations of functional morphology have indicated that Microraptor hunted in an arboreal environment. The new specimen demonstrates that this was not strictly the case, and offers unique insights into the ecology of nonavian dinosaurs early in the evolution of flight. The preserved gut contents are composed of teleost fish remains. Several morphological adaptations of Microraptor are identified as consistent with a partially piscivorous diet, including dentition with reduced serrations and forward projecting teeth on the anterior of the dentary. The feeding habits of Microraptor can now be understood better than that of any other carnivorous nonavian dinosaur, and Microraptor appears to have been an opportunistic and generalist feeder, able to exploit the most common prey in both the arboreal and aquatic microhabitats of the Early Cretaceous Jehol ecosystem.
Research paper thumbnail of The first pterosaur pelvic material from the Dinosaur Park Formation (Campanian) and implications for azhdarchid locomotion
Facets, May 1, 2017
A partial pterosaur pelvis from the Campanian Dinosaur Park Formation of Canada adds to our knowl... moreA partial pterosaur pelvis from the Campanian Dinosaur Park Formation of Canada adds to our knowledge of Late Cretaceous pterosaurs. The pelvis is tentatively referred to Azhdarchidae and represents the first pelvic material from a North American azhdarchid. The morphology of the ilium is bizarre compared with other pterosaurs: it is highly pneumatized, the preacetabular process tapers anteriorly, and muscle scars show that it would have anchored strong adductor musculature for the hindlimb. The acetabulum is deep and faces ventrolaterally, allowing the limb to be positioned underneath the body. These features support previous suggestions that azhdarchids were well adapted to terrestrial locomotion.
Research paper thumbnail of <i>Albertosaurus</i> (Dinosauria: Theropoda) material from an <i>Edmontosaurus</i> bonebed (Horseshoe Canyon Formation) near Edmonton: clarification of palaeogeographic distribution
<i>Albertosaurus</i> (Dinosauria: Theropoda) material from an <i>Edmontosaurus</i> bonebed (Horseshoe Canyon Formation) near Edmonton: clarification of palaeogeographic distribution
Canadian Journal of Earth Sciences, Nov 1, 2014
Research paper thumbnail of A non-avian dinosaur with a streamlined body exhibits potential adaptations for swimming
Communications Biology
Streamlining a body is a major adaptation for aquatic animals to move efficiently in the water. W... moreStreamlining a body is a major adaptation for aquatic animals to move efficiently in the water. Whereas diving birds are well known to have streamlined bodies, such body shapes have not been documented in non-avian dinosaurs. It is primarily because most known non-avian theropods are terrestrial, barring a few exceptions. However, clear evidence of streamlined bodies is absent even in the purported semiaquatic groups. Here we report a new theropod, Natovenator polydontus gen. et sp. nov., from the Upper Cretaceous of Mongolia. The new specimen includes a well-preserved skeleton with several articulated dorsal ribs that are posterolaterally oriented to streamline the body as in diving birds. Additionally, the widely arched proximal rib shafts reflect a dorsoventrally compressed ribcage like aquatic reptiles. Its body shape suggests that Natovenator was a potentially capable swimming predator, and the streamlined body evolved independently in separate lineages of theropod dinosaurs.
Research paper thumbnail of Calibrating geologic strata, dinosaurs, and other fossils at Dinosaur Provincial Park (Alberta, Canada) using a new CA-ID-TIMS U–Pb geochronology
Calibrating geologic strata, dinosaurs, and other fossils at Dinosaur Provincial Park (Alberta, Canada) using a new CA-ID-TIMS U–Pb geochronology
Canadian Journal of Earth Sciences
The 100 m thick stratigraphic section exposed at Dinosaur Provincial Park (DPP, southern Alberta)... moreThe 100 m thick stratigraphic section exposed at Dinosaur Provincial Park (DPP, southern Alberta) contains bentonites that have been used for more than 30 years to date DPP&#39;s rocks and fossils using the K-Ar decay scheme. Limited reproducibility among different vintages of K-Ar and 40Ar/39Ar ages inhibited the development of a high resolution chronostratigraphy. Here we employ and further test a recently completed CA-ID-TIMS U–Pb geochronology and associated age-stratigraphy model to update temporal constraints on the Park’s bentonites, formational contacts, and other markers. In turn, we document rock accumulation rates, and calibrate ages and durations of informal megaherbivore dinosaur assemblage zones and other biozones. Weighted mean 206Pb/238U ages from five bentonites range from 76.718 ± 0.020 Ma to 74.289 ± 0.014 Ma (2σ internal uncertainties) through an interval of 88.75 m, indicating a duration of ~2.43 Myr and an overall rock accumulation rate of 3.65 ± 0.04 cm/ka. An...
Research paper thumbnail of Celebrating dinosaurs: their behaviour, evolution, growth, and physiology
Canadian Journal of Earth Sciences
Dinosaurs have attracted varying degrees of scientific and public interest since their initial de... moreDinosaurs have attracted varying degrees of scientific and public interest since their initial description in 1824. Interest has steadily increased, however, since the late 1960s when the Dinosaur Renaissance began, and when the Canadian Journal of Earth Sciences started to publish. Since then, there has been a feedback system (international in scope) promoting increased scientific activity and ever-increasing public attention. This has led to ever more dinosaur discoveries internationally; increased numbers of museums and parks displaying dinosaurs; more publications, blogs, and other media on dinosaurs; and (most importantly) increased numbers of people and institutions doing research on dinosaurs. About 30 new species of dinosaurs are now being described every year, adding to the more than 1000 species already known. Furthermore, it is now acknowledged by most biologists and palaeontologists that modern birds are the direct descendants of dinosaurs, and that they are classified a...
Fig. 2. Fukui Prefectural Dinosaur Museum, Japan (opened in 2000) is one of the largest museums devoted to dinosaurs. The Museum, shaped like a gigantic dinosaur egg, is about 25 km from the Katsuyama dinosaur site. Photo by P.J. Currie. Fig. 1. Royal Tyrrell Museum of Palaeontology (opened in 1985) as seen from the west side of the Red Deer River Valley. The badlands surrounding the museum expose strata of the Horseshoe Canyon Formation, and dinosaur skeletons have been recovered within several hundred metres of the building. Photo by P.J. Currie.
Russell 1969, 1970, 1972; Waldman 1969) as the “Dinosaur Renaissance” gained a foothold. There was nothing about d t d t inosaurs in the eighth volume (1971) of CJES. On average hen, there was less than one dinosaur article per year dur- ing the first decade of publication. In contrast, the current ecade of issues (Volumes 51-60) is not finished but the number of dinosaur-related papers already numbers more han 40. In part, this is because of special issues of CJES (Fig. 3) that are mostly (Burns et al. 2014; Currie 1993, 1996, 2001; Currie and Koppelhus 2010) or partially (Gardner et Interestingly, his article was preceded by one by Russel (1967a), who succeeded Langston as the dinosaur researcher at the National Museum of Canada (now the Canadian Museum of Nature). The latter article (Russell 1967a) did not have anything to do with dinosaurs, although it was about Cretaceous vertebrates. A different man with the same surname, Loris Shano Russell, published the second dinosaur article in CJES the following year (Russell 1968). For the next few years, the journal published up to two dinosaur articles per year (Heaton 1972, 1973; Norford 1973;
Fig. 3. Two special issues of the Canadian Journal of Earth Sciences that were largely focussed on dinosaur research. The issu to the left is Volume 33, Number 4 from 1996, and was titled “Results from the Sino-Canadian Dinosaur Project, Part 2”. Th cover art is by Donna L. Sloan, and shows a nesting oviraptorid burying her eggs as a sandstorm approaches. The artwork wa done before the first feathered dinosaur fossil was found, and would be drawn differently today. Volume 47, Number 9 (201(¢ on the right was “A century of discoveries in the Late Cretaceous Albertosaurus sarcophagus bonebed of Alberta”. The Albertosauru painting by Michael W. Skrepnick shows the aftermath of a different storm, where numerous bodies of the tyrannosaur hav accumulated at the bottom of a stream after a catastrophic death event. al. 2015; Mallon et al. 2021) focussed on dinosaurs or related topics. ics were given the larger rooms. However, everything turned around at that 1988 meeting, and more people wanted to lis- ten to the dinosaur talks. Consequently, we needed to change the auditorium for the dinosaur session to accommodate the largest audience of the conference. And since that year, the dinosaur sessions at the SVP meetings have steadily increased in the numbers of talks and attendance. In most recent meet- ings, almost a third of the talks (two of the six scientific ses- sions) have been focussed on dinosaurs.
Fig. 6. Synchrotron X-ray microtomography of MOR 268 (left dentary from the lower jaw of a hatchling-sized tyrannosaurid from Montana). (A) Medial view of jaw; (B) Dorsal view of jaw. Abbreviations: mg, Meckelian groove; pit, pit at the anterior end of the Meckelian groove; spl, splenial. Teeth are numbered d4—-d10 and have been coloured blue. Modified from fig. 7 of Funston et al. (2020). ‘ig. 5. Portable XRF machine for reading the geochemical composition of fossils and the surrounding sediments. This was ised to “fingerprint” dinosaur bones in the Nemegt Formation of Mongolia to help determine what sites poached specimens which never have locality data when they are seized by authorities) may have come from (Bell et al. 2018). Photograph by PJ. vurrie.
in that they allowed the reader to see 3D features that could not be seen well on 2D photographs. However, they were a problem to photograph and print properly, and many peo- ple could not see the 3D qualities without special equipment. Anaglyph stereo imaging was a variant that used colours to distinguish the right and left images of a stereo pair that were superimposed (Gatesy et al. 2005). Although easier for the reader to see the images in three dimensions, neverthe- less they still had to be printed in colour and required having the coloured stereo-glasses. Digital photos were not widely used until shortly after the year 2000. Digital photography has now surpassed the resolution of imagery possible with conventional (film) cameras by being able to layer and merge images to eliminate depth of field problems, or even produce 3D models that can be studied, measured, or manipulated on computer screens. Photogrammetry has been used to record
Fig. 7. The badlands of Dinosaur Provincial Park (Alberta, Canada) are one of the richest dinosaur sites known. They were declared as the first UNESCO World Heritage Site established for palaeontological resources, have produced hundreds of orig- inal skeletons that are in more than thirty institutions internationally, and have exposed millions of bones and teeth from bonebeds and microvertebrate sites. Photograph by PJ. Currie. whole fossil sites to map the distribution of footprints or bones, or simply as a way to study and illustrate individual footprints, bones, and teeth.
Fig. 10. Oval clusters of polygonal basement scales on the neck an Edmontosaurus regalis (UALVP 53722) from the Wapiti For- mation of Alberta. Photograph by Phil Bell. Fig. 9. An almost complete skeleton of the tyrannosaurid Gorgosaurus libratus found in Dinosaur Provincial Park in 1991. The head was pulled back over the hips, and the tail was pulled forward, as the muscles and ligaments dried out along the top of the backbone. This is the typical “death pose” that a lot of dinosaurs are found in, and can also be evident in carcasses of modern animals as well (particularly those with long necks). Photograph by P.J. Currie.
More focussed studies of anatomy examined the direction and range of movements possible at the joints. Dinosaur trackways revealed the sequence of how the animals were actually stepping when they were alive, and gave a sense of how fast they may have been walking or even running. ments in ceratopsians, hadrosaurs (Williams et al. 2009), theropods, and other types of dinosaurs), vertebral support and flexion, centres of gravity (Alexander 1989; Henderson 1999, 2006), and limb mechanics (Senter 2006; Senter and Robins 2005; Moore et al. 2022). Ceratopsian front limb pos- ture is a great example of a long-standing debate of a biome- chanical problem (Russell 1935; Bakker 1987; Johnson and
Fig. 11. The Flaming Cliffs (Bayan Zag) of Mongolia have produced hundreds of specimens of Protoceratops, in the past 100 years. The Protoceratops skull was found 30 km away at Togrégiin Shiree in 1986, and represents what Brown and Schlaikjer (1940) referred to as a large male individual. Photos by Philip J. Currie. relatively small compared to body size with the eggs of mod- ern birds (Varricchio and Jackson 2003), they are large com- pared with those of living reptiles. There are changes (such as changing the shape of an egg from a simple sphere to an elongate oval, or resorbing the eggshell from the inside of the shell as the embryo gets larger) that push the limits of theoretical egg size, but the largest known dinosaur eggs are only half a metre long (Pu et al. 2017).
Fig. 13. The Nemegt Formation of Mongolia has interbedded levels that either preserve dinosaur skeletons or dinosaur foot prints. The dinosaurs in each of these two types of levels suggest two different compositions for the dinosaur fauna living i1 that area during the Late Cretaceous. In the footprint levels, hadrosaurs (lower left) greatly outnumber the ichnites of carniv orous dinosaurs (lower right). In the levels between the footprint layers, however, the tyrannosaur Tarbosaurus is much mor common than the hadrosaur Saurolophus. Multiple lines of evidence suggest that there is some kind of preservational bias tha favours the recovery of tyrannosaurid skeletons between the footprint concentrations. Photos by Philip J. Currie. debate continued to intensify about whether they were re- ally feathers, or whether the animals were dinosaurs or birds, more feathered dinosaurs were discovered and described. For me, the turning point was the discovery of several speci- mens of Caudipteryx, a turkey-sized dinosaur with long, bird- like feathers behind the arms and at the end of the tail (Ji et al. 1998; Currie 1998). It did not matter whether it was classified as a nonavian or avian dinosaur because it had all of the characters expected for a transitional form. And unlike Sinosauropteryx, which had relatively simple feathers that some argued were not feathers at all, Caudipteryx had feathers that were indistinguishable from those of modern birds. Although some persist in arguing that birds are not derived from nonavian dinosaurs, their arguments have in- creasingly fallen on deaf ears as ever more species and spec- imens of feathered dinosaurs were discovered in other parts
Research paper thumbnail of A new hypothesis of eudromaeosaurian evolution: CT scans assist in testing and constructing morphological characters
A new hypothesis of eudromaeosaurian evolution: CT scans assist in testing and constructing morphological characters
Journal of Vertebrate Paleontology
Research paper thumbnail of 3D model related to the publication: Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs
3D model related to the publication: Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs
MorphoMuseuM, 2022
Research paper thumbnail of Head-biting behavior in theropod dinosaurs: Paleopathological evidence
Cranial material of Sinraptor dongi (Upper Jurassic, Xinjiang, China), Gorgosaurus libratus, Dasp... moreCranial material of Sinraptor dongi (Upper Jurassic, Xinjiang, China), Gorgosaurus libratus, Daspletosaurus torosus (Upper Cretaceous, Alberta, Canada), and other large theropod dinosaurs exhibit similar paleopathological anomalies indicative of aggressive intraor interspecific biting. Tooth strike trauma includes osseous lesions caused by solitary or multiple tooth punctures, or by dragging or gouging the tooth tips across the surfaces of cranial elements. Many of these lesions were undergoing active healing at the time of death. One isolated tyrannosaurid dentary bears a broken off and embedded tooth tip of another tyrannosaur. Comparison with unhealed large theropod tooth marks on prey bone suggests that sublethal wounds ofthese types were caused by other large theropods, possibly rival conspecifics. This may indicate aggressive head or face-biting behavior in certain theropod families. Other associated traumatic osteopathy typified as localized rib and fibula fractures were obse...
Research paper thumbnail of Baby hadrosaurid material associated with an unusually high abundance of Troodon teeth from the Horseshoe Canyon Formation, Upper Cretaceous, Alberta, Canada
A new microvertebrate site (»72 Ma) in the Horseshoe Canyon Formation, southcentral Alberta, is a... moreA new microvertebrate site (»72 Ma) in the Horseshoe Canyon Formation, southcentral Alberta, is a deflational lag in interbedded silty shales. The site represents deposition on a waterlogged coastal plain »100 km to the west of the Bearpaw Sea. Approximately two-thirds (n=224) of the 388 elements recovered from this site belong to indeterminate hadrosaurids. Forty of these are from baby-sized individuals, suggesting that a nesting site of unknown size was located nearby. These fossils are notable for being the first occurrence of baby dinosaurs in the formation and the geologically youngest occurrence of baby dinosaurs in Canada. The next most common taxon (17% of elements) is the small theropod Troodon, represented by abundant teeth (n=65). Troodon teeth are normally rare in Upper Cretaceous sites in southern Alberta. The large number of Troodon teeth at the new site suggests a non-random association with the baby hadrosaurid elements, and is potentially indicative of predation. Elements of other dinosaurs are less common at the site, and include 45 teeth or tooth fragments from at least four other theropod taxa, and rare ankylosaurid and ceratopsid elements.
Research paper thumbnail of Three new skulls of the Late Cretaceous armored dinosaur Talarurus plicatospineus Maleev, 1952
Three new skulls of the Late Cretaceous armored dinosaur Talarurus plicatospineus Maleev, 1952
Research paper thumbnail of Lithobiotopes of the Nemegt Gobi Basin1
Lithobiotopes of the Nemegt Gobi Basin1
Canadian Journal of Earth Sciences, 2021
Three distinct but overlapping dinosaur-dominated faunas characterize the Upper Cretaceous Djadok... moreThree distinct but overlapping dinosaur-dominated faunas characterize the Upper Cretaceous Djadokhta, Baruungoyot, and Nemegt formations of the Nemegt Basin of Mongolia. Documented faunal differences cannot be explained easily by temporal succession, but can be understood in light of the physical processes controlling the life, death, and burial of taxa. The stratigraphy of the Gobi Desert region records tectonically driven geometries, clearly documenting preservational processes that differ from those acting in most other dinosaur-dominated beds worldwide. Small, asymmetric tectonic grabens were filled with Upper Cretaceous dinosaur-bearing deposits showing asymmetric distributions of facies, here termed lithobiotopes. The water-lain fluvial and alluvial plain facies of the Nemegt lithobiotope supported and preserved a fauna dominated by gigantic dinosaurs, but had a preservational bias against smaller animals. The Nemegt passed laterally into the interdune facies of the Baruungoyo...
Research paper thumbnail of Dental anatomy of the apex predator Sinraptor dongi (Theropoda: Allosauroidea) from the Late Jurassic of China
Canadian Journal of Earth Sciences, 2020
The dental morphology of the holotype of the theropod Sinraptor dongi from the Jurassic Shishugou... moreThe dental morphology of the holotype of the theropod Sinraptor dongi from the Jurassic Shishugou Formation of China is comprehensively described. We highlight a combination of dental features that appear to be restricted to Sinraptor: (i) crowns with denticulated mesial and distal carinae extending from the root and an irregular surface texture on the enamel; (ii) a D- to salinon-shaped cross-sectional outline at the crown base in mesialmost teeth; (iii) mesial crowns with mesial carinae spiraling mesiolingually and lingually positioned longitudinal groove adjacent to the mesial carina; and (iv) particularly labiolingually compressed lateral teeth with weakly labially deflected distal carinae, flat to concave basocentral surfaces of the labial margins of the crowns, and horizontally elongated distal denticles showing short to well-developed interdenticular sulci. Using cladistic, multivariate, discriminant, and cluster analyses, we demonstrate that the dentition of Sinraptor is rel...
Research paper thumbnail of Neuroanatomy of the ankylosaurid dinosaurs Tarchia teresae and Talarurus plicatospineus from the Upper Cretaceous of Mongolia, with comments on endocranial variability among ankylosaurs
Palaeogeography, Palaeoclimatology, Palaeoecology, 2018
Ankylosaur braincase and endocranial morphologies are poorly known. Furthermore, cranial endocast... moreAnkylosaur braincase and endocranial morphologies are poorly known. Furthermore, cranial endocasts have been described for fewer than ten taxa so far. The complete inner ear morphology is known for only three species-Euoplocephalus tutus, Kunbarrasaurus ieversi, and Pawpawsaurus campbelli. Here, the first cranial endocast morphologies are presented for the Mongolian Cretaceous ankylosaurids Talarurus plicatospineus and Tarchia teresae. The study of paleoneurological features of these Mongolian taxa adds novel anatomical information to both species allowing the first comparison with ankylosaurids from North America. The development of a cerebellar flocculus that leaves an impression on the vestibular eminence-floccular recess-is observed in Euoplocephalus, Talarurus and T. teresae. Because this structure hasn't been identified in any nodosaurid so far, its presence in ankylosaurid cranial endocasts may represent a possible synapomorphy with unknown paleobiological implications.
Research paper thumbnail of New material reveals the pelvic morphology of Caenagnathidae (Theropoda, Oviraptorosauria)
Cretaceous Research, Oct 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... moreThis is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Research paper thumbnail of A small caenagnathid tibia from the Horseshoe Canyon Formation (Maastrichtian): Implications for growth and lifestyle in oviraptorosaurs
Cretaceous Research, Dec 1, 2018
Caenagnathid elements are exceptionally rare in the Horseshoe Canyon Formation, and a small tibia... moreCaenagnathid elements are exceptionally rare in the Horseshoe Canyon Formation, and a small tibia constitutes only the fourth record from the formation. The tibia is elongate and gracile, with a semi-circular cross-section. A representative survey of Late Cretaceous, North American theropod tibiae suggests that cross-sectional shape can be useful for distinguishing theropod superfamilies. Caenagnathid tibiae can be distinguished from those of other theropods by the combination of their elongation, semi-circular cross-sections, and absence of extensive contact between the fibula and distal ends of the tibia. Histological sections reveal that the individual represented by the tibia was likely just over one year old and was increasing its growth rate at the time of death. However, the cyclical growth mark is unusual, consisting of a zone of parallel-fibered bone, rather than a distinct line of arrested growth-similar to annuli of rapidly-growing young ornithischians. A transition in vasculature orientation and osteocyte lacunae size and density prior to the growth mark may represent a physiological change within the first year of life. It is possible that this represents fledging, ontogenetic niche shift, or an environmental change, but more evidence from other individuals is required to test this. The presence of endosteal lamellae suggests that the tibia already experienced significant mechanical loads, despite the young age of the individual. Together with evidence from other caenagnathids, it suggests that they were active early in life, consistent with a precocial lifestyle.
Research paper thumbnail of Two braincases of <i>Daspletosaurus</i> (Theropoda: Tyrannosauridae): anatomy and comparison<sup>1</sup>
Canadian Journal of Earth Sciences, Sep 1, 2021
For sheer complexity, braincases are generally considered anatomically conservative. However, rec... moreFor sheer complexity, braincases are generally considered anatomically conservative. However, recent research on the braincases of tyrannosaurids have revealed extensive morphological variations. This line of inquiry has its root in Dale Russell's review of tyrannosaurids in which he established Daspletosaurus torosusa large tyrannosaurine from the Campanian of southern Alberta. In the wake of systematic revisions to tyrannosaurines previously assigned to Daspletosaurus, one potentially distinct species remains undescribed. This paper describes and compares a braincase referable to this species with that of the holotype for Daspletosaurus torosus using computerized-tomography-based reconstructions. The two braincases have numerous differences externally and internally. The specimen of Daspletosaurus sp. has a bottlenecked olfactory tract, short and vertical lagena, and a developed ascending column of the anterior tympanic recess. The holotype of Daspletosaurus torosus has many unusual traits, including an anteriorly positioned trochlear root, elongate common carotid canal, distinct chamber of the basisphenoid recess, asymmetry in the internal basipterygoid aperture, and laterally reduced but medially expanded subcondylar recess. This comparison also identified characters that potentially unite the two species of Daspletosaurus, including deep midbrain flexures in the endocasts. However, many character variations in the braincases are known in other tyrannosaurids to correlate with body size and maturity, or represent individual variations. Therefore, taxonomic and phylogenetic signals can be isolated from background variations in a more comprehensive approach by using additional specimens. New information on the two braincases of Daspletosaurus is consistent with the emerging view of tyrannosaurid braincases as highly variable, ontogenetically dynamic character complexes.
Research paper thumbnail of Birdlike growth and mixed-age flocks in avimimids (Theropoda, Oviraptorosauria)
Scientific Reports, Dec 11, 2019
Avimimids were unusual, birdlike oviraptorosaurs from the Late Cretaceous of Asia. Initially enig... moreAvimimids were unusual, birdlike oviraptorosaurs from the Late Cretaceous of Asia. Initially enigmatic, new information has ameliorated the understanding of their anatomy, phylogenetic position, and behaviour. A monodominant bonebed from the Nemegt Formation of Mongolia showed that some avimimids were gregarious, but the site is unusual in the apparent absence of juveniles. Here, a second monodominant avimimid bonebed is described from the Iren Dabasu Formation of northern China. Elements recovered include numerous vertebrae and portions of the forelimbs and hindlimbs, representing a minimum of six individuals. Histological sampling of two tibiotarsi from the bonebed reveals rapid growth early in ontogeny followed by unexpectedly early onset of fusion and limited subsequent growth. This indicates that avimimids grew rapidly to adult size, like most extant birds but contrasting other small theropod dinosaurs. The combination of adults and juveniles in the Iren Dabasu bonebed assemblage provides evidence of mixed-age flocking in avimimids and the onset of fusion in young individuals suggests that some of the individuals in the Nemegt Formation bonebed may have been juveniles. Regardless, these individuals were likely functionally analogous to adults, and this probably facilitated mixed-age flocking by reducing ontogenetic niche shift in avimimids. Avimimidae was an enigmatic, monogeneric family of oviraptorosaurs from China and Mongolia (Fig. 1). Avimimus was first described by Kurzanov 1 and its bird-like morphology immediately confused palaeontologists. Although regarded as a non-avian theropod by Kurzanov 1 , other workers interpreted its mosaic of features as similar to those of a flightless avian 2 , a sauropod 3 , and even an ornithopod dinosaur 3. These apparently contradictory hypotheses led several authors 4,5 to suggest that the holotype may have been a chimaera, a possibility Kurzanov considered himself 4. However, Vickers-Rich et al. 5 argued this claim, and the subsequent discovery of an articulated skeleton 6 indicated that the material did indeed belong to a single taxon. The oviraptorosaurian affinities of Avimimus were first recognized by Maryanska et al. 7 , although their analysis also placed oviraptorosaurs within Avialae, a conclusion no longer supported by broad-scale theropod phylogenies 8,9. Recent analyses 10-12 have recovered Avimimus as an intermediate oviraptorosaur, sister to Caenagnathoidea (=Caenagnathid ae + Oviraptoridae). The rarity of avimimid material and its poor history of description has led to several problems in the understanding of these animals. A series of detailed descriptions of Avimimus portentosus in Russian by Kurzanov 13-17 , and their translations, comprise most of the literature on avimimids. Despite the discovery of numerous additional specimens in the intervening years, few of these have been described until recently. An expedition led by the Hayashibara Museum of Japan collected a nearly complete skeleton including cranial material (MPC-D 100/129) from Shar Tsav in the eastern Gobi Desert of Mongolia, but it has not been described beyond conference abstracts 6. In 2006, the same organization discovered a second skeleton in the Nemegt Formation at Bugiin Tsav, in western Mongolia, the cranium of which was recently described 18. A bonebed of disarticulated avimimids from the Nemegt Formation of Mongolia was discovered in 2006 19 , but was not described until ten years later 20. Subsequent examination of that material determined that it represents a new species, Avimimus nemegtensis, based on a suite of cranial and postcranial differences from the holotype of Avimimus portentosus 21. A second bonebed from the Iren Dabasu Formation of China was briefly described by Ryan et al. 22 , but has not received further attention until now. The general age of the Iren Dabasu Formation is widely accepted as Late Cretaceous, but its precise age is debated. Granger and Berkey 23 indicated a Cretaceous age, but did not speculate
Research paper thumbnail of Cranial Anatomy of New Specimens of <i>Saurornitholestes langstoni</i> (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta
Cranial Anatomy of New Specimens of <i>Saurornitholestes langstoni</i> (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, Sep 9, 2019
ABSTRACTThe holotype of the dromaeosaurid Saurornitholestes langstoni was described in 1978 on th... moreABSTRACTThe holotype of the dromaeosaurid Saurornitholestes langstoni was described in 1978 on the basis of fewer than 30 associated cranial and postcranial bones of a single individual from Dinosaur Provincial Park. Four additional partial skeletons of Saurornitholestes were recovered from Campanian (Upper Cretaceous) beds of Alberta and Montana over the next 25 years, although reasonably complete skeletons remained elusive, and virtually nothing was known about the skull. The lack of truly diagnostic material has been problematic, and the relationships of Saurornitholestes to other dromaeosaurids have been difficult to resolve because of the incomplete knowledge of its anatomy. In 2014, an almost complete skeleton, including the skull, was collected less than a kilometer from where the holotype had been found. Although similar in body size to Velociraptor, the facial region of the skull is relatively shorter, taller, and wider. The nasals are pneumatic. The premaxillary teeth are distinctive, and teeth previously identified in the Dinosaur Park Formation as Zapsalis abradens can now be identified as the second premaxillary tooth of S. langstoni. Morphology and wear patterns suggest that these may have been specialized for preening feathers. Many traits define a Campanian North American clade, Saurornitholestinae, that is distinct from an Asian clade that includes Velociraptor (Velociraptorinae). This new information on the skull allows a more complete evaluation of its systematic position within the Dromaeosauridae and supports the suggestion of at least two major faunal interchanges between Asia and North America during the Cretaceous. Anat Rec, 303:691–715, 2020. © 2019 American Association for Anatomy
Research paper thumbnail of PISCIVORY IN THE FEATHERED DINOSAUR<i>MICRORAPTOR</i>
Evolution, Apr 19, 2013
The largest specimen of the four-winged dromaeosaurid dinosaur Microraptor gui includes preserved... moreThe largest specimen of the four-winged dromaeosaurid dinosaur Microraptor gui includes preserved gut contents. Previous reports of gut contents and considerations of functional morphology have indicated that Microraptor hunted in an arboreal environment. The new specimen demonstrates that this was not strictly the case, and offers unique insights into the ecology of nonavian dinosaurs early in the evolution of flight. The preserved gut contents are composed of teleost fish remains. Several morphological adaptations of Microraptor are identified as consistent with a partially piscivorous diet, including dentition with reduced serrations and forward projecting teeth on the anterior of the dentary. The feeding habits of Microraptor can now be understood better than that of any other carnivorous nonavian dinosaur, and Microraptor appears to have been an opportunistic and generalist feeder, able to exploit the most common prey in both the arboreal and aquatic microhabitats of the Early Cretaceous Jehol ecosystem.
Research paper thumbnail of The first pterosaur pelvic material from the Dinosaur Park Formation (Campanian) and implications for azhdarchid locomotion
Facets, May 1, 2017
A partial pterosaur pelvis from the Campanian Dinosaur Park Formation of Canada adds to our knowl... moreA partial pterosaur pelvis from the Campanian Dinosaur Park Formation of Canada adds to our knowledge of Late Cretaceous pterosaurs. The pelvis is tentatively referred to Azhdarchidae and represents the first pelvic material from a North American azhdarchid. The morphology of the ilium is bizarre compared with other pterosaurs: it is highly pneumatized, the preacetabular process tapers anteriorly, and muscle scars show that it would have anchored strong adductor musculature for the hindlimb. The acetabulum is deep and faces ventrolaterally, allowing the limb to be positioned underneath the body. These features support previous suggestions that azhdarchids were well adapted to terrestrial locomotion.
Research paper thumbnail of <i>Albertosaurus</i> (Dinosauria: Theropoda) material from an <i>Edmontosaurus</i> bonebed (Horseshoe Canyon Formation) near Edmonton: clarification of palaeogeographic distribution
<i>Albertosaurus</i> (Dinosauria: Theropoda) material from an <i>Edmontosaurus</i> bonebed (Horseshoe Canyon Formation) near Edmonton: clarification of palaeogeographic distribution
Canadian Journal of Earth Sciences, Nov 1, 2014
Research paper thumbnail of A non-avian dinosaur with a streamlined body exhibits potential adaptations for swimming
Communications Biology
Streamlining a body is a major adaptation for aquatic animals to move efficiently in the water. W... moreStreamlining a body is a major adaptation for aquatic animals to move efficiently in the water. Whereas diving birds are well known to have streamlined bodies, such body shapes have not been documented in non-avian dinosaurs. It is primarily because most known non-avian theropods are terrestrial, barring a few exceptions. However, clear evidence of streamlined bodies is absent even in the purported semiaquatic groups. Here we report a new theropod, Natovenator polydontus gen. et sp. nov., from the Upper Cretaceous of Mongolia. The new specimen includes a well-preserved skeleton with several articulated dorsal ribs that are posterolaterally oriented to streamline the body as in diving birds. Additionally, the widely arched proximal rib shafts reflect a dorsoventrally compressed ribcage like aquatic reptiles. Its body shape suggests that Natovenator was a potentially capable swimming predator, and the streamlined body evolved independently in separate lineages of theropod dinosaurs.
Research paper thumbnail of Calibrating geologic strata, dinosaurs, and other fossils at Dinosaur Provincial Park (Alberta, Canada) using a new CA-ID-TIMS U–Pb geochronology
Calibrating geologic strata, dinosaurs, and other fossils at Dinosaur Provincial Park (Alberta, Canada) using a new CA-ID-TIMS U–Pb geochronology
Canadian Journal of Earth Sciences
The 100 m thick stratigraphic section exposed at Dinosaur Provincial Park (DPP, southern Alberta)... moreThe 100 m thick stratigraphic section exposed at Dinosaur Provincial Park (DPP, southern Alberta) contains bentonites that have been used for more than 30 years to date DPP&#39;s rocks and fossils using the K-Ar decay scheme. Limited reproducibility among different vintages of K-Ar and 40Ar/39Ar ages inhibited the development of a high resolution chronostratigraphy. Here we employ and further test a recently completed CA-ID-TIMS U–Pb geochronology and associated age-stratigraphy model to update temporal constraints on the Park’s bentonites, formational contacts, and other markers. In turn, we document rock accumulation rates, and calibrate ages and durations of informal megaherbivore dinosaur assemblage zones and other biozones. Weighted mean 206Pb/238U ages from five bentonites range from 76.718 ± 0.020 Ma to 74.289 ± 0.014 Ma (2σ internal uncertainties) through an interval of 88.75 m, indicating a duration of ~2.43 Myr and an overall rock accumulation rate of 3.65 ± 0.04 cm/ka. An...
Research paper thumbnail of Celebrating dinosaurs: their behaviour, evolution, growth, and physiology
Canadian Journal of Earth Sciences
Dinosaurs have attracted varying degrees of scientific and public interest since their initial de... moreDinosaurs have attracted varying degrees of scientific and public interest since their initial description in 1824. Interest has steadily increased, however, since the late 1960s when the Dinosaur Renaissance began, and when the Canadian Journal of Earth Sciences started to publish. Since then, there has been a feedback system (international in scope) promoting increased scientific activity and ever-increasing public attention. This has led to ever more dinosaur discoveries internationally; increased numbers of museums and parks displaying dinosaurs; more publications, blogs, and other media on dinosaurs; and (most importantly) increased numbers of people and institutions doing research on dinosaurs. About 30 new species of dinosaurs are now being described every year, adding to the more than 1000 species already known. Furthermore, it is now acknowledged by most biologists and palaeontologists that modern birds are the direct descendants of dinosaurs, and that they are classified a...
Fig. 2. Fukui Prefectural Dinosaur Museum, Japan (opened in 2000) is one of the largest museums devoted to dinosaurs. The Museum, shaped like a gigantic dinosaur egg, is about 25 km from the Katsuyama dinosaur site. Photo by P.J. Currie. Fig. 1. Royal Tyrrell Museum of Palaeontology (opened in 1985) as seen from the west side of the Red Deer River Valley. The badlands surrounding the museum expose strata of the Horseshoe Canyon Formation, and dinosaur skeletons have been recovered within several hundred metres of the building. Photo by P.J. Currie.
Russell 1969, 1970, 1972; Waldman 1969) as the “Dinosaur Renaissance” gained a foothold. There was nothing about d t d t inosaurs in the eighth volume (1971) of CJES. On average hen, there was less than one dinosaur article per year dur- ing the first decade of publication. In contrast, the current ecade of issues (Volumes 51-60) is not finished but the number of dinosaur-related papers already numbers more han 40. In part, this is because of special issues of CJES (Fig. 3) that are mostly (Burns et al. 2014; Currie 1993, 1996, 2001; Currie and Koppelhus 2010) or partially (Gardner et Interestingly, his article was preceded by one by Russel (1967a), who succeeded Langston as the dinosaur researcher at the National Museum of Canada (now the Canadian Museum of Nature). The latter article (Russell 1967a) did not have anything to do with dinosaurs, although it was about Cretaceous vertebrates. A different man with the same surname, Loris Shano Russell, published the second dinosaur article in CJES the following year (Russell 1968). For the next few years, the journal published up to two dinosaur articles per year (Heaton 1972, 1973; Norford 1973;
Fig. 3. Two special issues of the Canadian Journal of Earth Sciences that were largely focussed on dinosaur research. The issu to the left is Volume 33, Number 4 from 1996, and was titled “Results from the Sino-Canadian Dinosaur Project, Part 2”. Th cover art is by Donna L. Sloan, and shows a nesting oviraptorid burying her eggs as a sandstorm approaches. The artwork wa done before the first feathered dinosaur fossil was found, and would be drawn differently today. Volume 47, Number 9 (201(¢ on the right was “A century of discoveries in the Late Cretaceous Albertosaurus sarcophagus bonebed of Alberta”. The Albertosauru painting by Michael W. Skrepnick shows the aftermath of a different storm, where numerous bodies of the tyrannosaur hav accumulated at the bottom of a stream after a catastrophic death event. al. 2015; Mallon et al. 2021) focussed on dinosaurs or related topics. ics were given the larger rooms. However, everything turned around at that 1988 meeting, and more people wanted to lis- ten to the dinosaur talks. Consequently, we needed to change the auditorium for the dinosaur session to accommodate the largest audience of the conference. And since that year, the dinosaur sessions at the SVP meetings have steadily increased in the numbers of talks and attendance. In most recent meet- ings, almost a third of the talks (two of the six scientific ses- sions) have been focussed on dinosaurs.
Fig. 6. Synchrotron X-ray microtomography of MOR 268 (left dentary from the lower jaw of a hatchling-sized tyrannosaurid from Montana). (A) Medial view of jaw; (B) Dorsal view of jaw. Abbreviations: mg, Meckelian groove; pit, pit at the anterior end of the Meckelian groove; spl, splenial. Teeth are numbered d4—-d10 and have been coloured blue. Modified from fig. 7 of Funston et al. (2020). ‘ig. 5. Portable XRF machine for reading the geochemical composition of fossils and the surrounding sediments. This was ised to “fingerprint” dinosaur bones in the Nemegt Formation of Mongolia to help determine what sites poached specimens which never have locality data when they are seized by authorities) may have come from (Bell et al. 2018). Photograph by PJ. vurrie.
in that they allowed the reader to see 3D features that could not be seen well on 2D photographs. However, they were a problem to photograph and print properly, and many peo- ple could not see the 3D qualities without special equipment. Anaglyph stereo imaging was a variant that used colours to distinguish the right and left images of a stereo pair that were superimposed (Gatesy et al. 2005). Although easier for the reader to see the images in three dimensions, neverthe- less they still had to be printed in colour and required having the coloured stereo-glasses. Digital photos were not widely used until shortly after the year 2000. Digital photography has now surpassed the resolution of imagery possible with conventional (film) cameras by being able to layer and merge images to eliminate depth of field problems, or even produce 3D models that can be studied, measured, or manipulated on computer screens. Photogrammetry has been used to record
Fig. 7. The badlands of Dinosaur Provincial Park (Alberta, Canada) are one of the richest dinosaur sites known. They were declared as the first UNESCO World Heritage Site established for palaeontological resources, have produced hundreds of orig- inal skeletons that are in more than thirty institutions internationally, and have exposed millions of bones and teeth from bonebeds and microvertebrate sites. Photograph by PJ. Currie. whole fossil sites to map the distribution of footprints or bones, or simply as a way to study and illustrate individual footprints, bones, and teeth.
Fig. 10. Oval clusters of polygonal basement scales on the neck an Edmontosaurus regalis (UALVP 53722) from the Wapiti For- mation of Alberta. Photograph by Phil Bell. Fig. 9. An almost complete skeleton of the tyrannosaurid Gorgosaurus libratus found in Dinosaur Provincial Park in 1991. The head was pulled back over the hips, and the tail was pulled forward, as the muscles and ligaments dried out along the top of the backbone. This is the typical “death pose” that a lot of dinosaurs are found in, and can also be evident in carcasses of modern animals as well (particularly those with long necks). Photograph by P.J. Currie.
More focussed studies of anatomy examined the direction and range of movements possible at the joints. Dinosaur trackways revealed the sequence of how the animals were actually stepping when they were alive, and gave a sense of how fast they may have been walking or even running. ments in ceratopsians, hadrosaurs (Williams et al. 2009), theropods, and other types of dinosaurs), vertebral support and flexion, centres of gravity (Alexander 1989; Henderson 1999, 2006), and limb mechanics (Senter 2006; Senter and Robins 2005; Moore et al. 2022). Ceratopsian front limb pos- ture is a great example of a long-standing debate of a biome- chanical problem (Russell 1935; Bakker 1987; Johnson and
Fig. 11. The Flaming Cliffs (Bayan Zag) of Mongolia have produced hundreds of specimens of Protoceratops, in the past 100 years. The Protoceratops skull was found 30 km away at Togrégiin Shiree in 1986, and represents what Brown and Schlaikjer (1940) referred to as a large male individual. Photos by Philip J. Currie. relatively small compared to body size with the eggs of mod- ern birds (Varricchio and Jackson 2003), they are large com- pared with those of living reptiles. There are changes (such as changing the shape of an egg from a simple sphere to an elongate oval, or resorbing the eggshell from the inside of the shell as the embryo gets larger) that push the limits of theoretical egg size, but the largest known dinosaur eggs are only half a metre long (Pu et al. 2017).
Fig. 13. The Nemegt Formation of Mongolia has interbedded levels that either preserve dinosaur skeletons or dinosaur foot prints. The dinosaurs in each of these two types of levels suggest two different compositions for the dinosaur fauna living i1 that area during the Late Cretaceous. In the footprint levels, hadrosaurs (lower left) greatly outnumber the ichnites of carniv orous dinosaurs (lower right). In the levels between the footprint layers, however, the tyrannosaur Tarbosaurus is much mor common than the hadrosaur Saurolophus. Multiple lines of evidence suggest that there is some kind of preservational bias tha favours the recovery of tyrannosaurid skeletons between the footprint concentrations. Photos by Philip J. Currie. debate continued to intensify about whether they were re- ally feathers, or whether the animals were dinosaurs or birds, more feathered dinosaurs were discovered and described. For me, the turning point was the discovery of several speci- mens of Caudipteryx, a turkey-sized dinosaur with long, bird- like feathers behind the arms and at the end of the tail (Ji et al. 1998; Currie 1998). It did not matter whether it was classified as a nonavian or avian dinosaur because it had all of the characters expected for a transitional form. And unlike Sinosauropteryx, which had relatively simple feathers that some argued were not feathers at all, Caudipteryx had feathers that were indistinguishable from those of modern birds. Although some persist in arguing that birds are not derived from nonavian dinosaurs, their arguments have in- creasingly fallen on deaf ears as ever more species and spec- imens of feathered dinosaurs were discovered in other parts
Research paper thumbnail of A new hypothesis of eudromaeosaurian evolution: CT scans assist in testing and constructing morphological characters
A new hypothesis of eudromaeosaurian evolution: CT scans assist in testing and constructing morphological characters
Journal of Vertebrate Paleontology
Research paper thumbnail of 3D model related to the publication: Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs
3D model related to the publication: Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs
MorphoMuseuM, 2022
Research paper thumbnail of Head-biting behavior in theropod dinosaurs: Paleopathological evidence
Cranial material of Sinraptor dongi (Upper Jurassic, Xinjiang, China), Gorgosaurus libratus, Dasp... moreCranial material of Sinraptor dongi (Upper Jurassic, Xinjiang, China), Gorgosaurus libratus, Daspletosaurus torosus (Upper Cretaceous, Alberta, Canada), and other large theropod dinosaurs exhibit similar paleopathological anomalies indicative of aggressive intraor interspecific biting. Tooth strike trauma includes osseous lesions caused by solitary or multiple tooth punctures, or by dragging or gouging the tooth tips across the surfaces of cranial elements. Many of these lesions were undergoing active healing at the time of death. One isolated tyrannosaurid dentary bears a broken off and embedded tooth tip of another tyrannosaur. Comparison with unhealed large theropod tooth marks on prey bone suggests that sublethal wounds ofthese types were caused by other large theropods, possibly rival conspecifics. This may indicate aggressive head or face-biting behavior in certain theropod families. Other associated traumatic osteopathy typified as localized rib and fibula fractures were obse...
Research paper thumbnail of Baby hadrosaurid material associated with an unusually high abundance of Troodon teeth from the Horseshoe Canyon Formation, Upper Cretaceous, Alberta, Canada
A new microvertebrate site (»72 Ma) in the Horseshoe Canyon Formation, southcentral Alberta, is a... moreA new microvertebrate site (»72 Ma) in the Horseshoe Canyon Formation, southcentral Alberta, is a deflational lag in interbedded silty shales. The site represents deposition on a waterlogged coastal plain »100 km to the west of the Bearpaw Sea. Approximately two-thirds (n=224) of the 388 elements recovered from this site belong to indeterminate hadrosaurids. Forty of these are from baby-sized individuals, suggesting that a nesting site of unknown size was located nearby. These fossils are notable for being the first occurrence of baby dinosaurs in the formation and the geologically youngest occurrence of baby dinosaurs in Canada. The next most common taxon (17% of elements) is the small theropod Troodon, represented by abundant teeth (n=65). Troodon teeth are normally rare in Upper Cretaceous sites in southern Alberta. The large number of Troodon teeth at the new site suggests a non-random association with the baby hadrosaurid elements, and is potentially indicative of predation. Elements of other dinosaurs are less common at the site, and include 45 teeth or tooth fragments from at least four other theropod taxa, and rare ankylosaurid and ceratopsid elements.
Research paper thumbnail of Three new skulls of the Late Cretaceous armored dinosaur Talarurus plicatospineus Maleev, 1952
Three new skulls of the Late Cretaceous armored dinosaur Talarurus plicatospineus Maleev, 1952
Research paper thumbnail of Lithobiotopes of the Nemegt Gobi Basin1
Lithobiotopes of the Nemegt Gobi Basin1
Canadian Journal of Earth Sciences, 2021
Three distinct but overlapping dinosaur-dominated faunas characterize the Upper Cretaceous Djadok... moreThree distinct but overlapping dinosaur-dominated faunas characterize the Upper Cretaceous Djadokhta, Baruungoyot, and Nemegt formations of the Nemegt Basin of Mongolia. Documented faunal differences cannot be explained easily by temporal succession, but can be understood in light of the physical processes controlling the life, death, and burial of taxa. The stratigraphy of the Gobi Desert region records tectonically driven geometries, clearly documenting preservational processes that differ from those acting in most other dinosaur-dominated beds worldwide. Small, asymmetric tectonic grabens were filled with Upper Cretaceous dinosaur-bearing deposits showing asymmetric distributions of facies, here termed lithobiotopes. The water-lain fluvial and alluvial plain facies of the Nemegt lithobiotope supported and preserved a fauna dominated by gigantic dinosaurs, but had a preservational bias against smaller animals. The Nemegt passed laterally into the interdune facies of the Baruungoyo...
Research paper thumbnail of Dental anatomy of the apex predator Sinraptor dongi (Theropoda: Allosauroidea) from the Late Jurassic of China
Canadian Journal of Earth Sciences, 2020
The dental morphology of the holotype of the theropod Sinraptor dongi from the Jurassic Shishugou... moreThe dental morphology of the holotype of the theropod Sinraptor dongi from the Jurassic Shishugou Formation of China is comprehensively described. We highlight a combination of dental features that appear to be restricted to Sinraptor: (i) crowns with denticulated mesial and distal carinae extending from the root and an irregular surface texture on the enamel; (ii) a D- to salinon-shaped cross-sectional outline at the crown base in mesialmost teeth; (iii) mesial crowns with mesial carinae spiraling mesiolingually and lingually positioned longitudinal groove adjacent to the mesial carina; and (iv) particularly labiolingually compressed lateral teeth with weakly labially deflected distal carinae, flat to concave basocentral surfaces of the labial margins of the crowns, and horizontally elongated distal denticles showing short to well-developed interdenticular sulci. Using cladistic, multivariate, discriminant, and cluster analyses, we demonstrate that the dentition of Sinraptor is rel...
Research paper thumbnail of Neuroanatomy of the ankylosaurid dinosaurs Tarchia teresae and Talarurus plicatospineus from the Upper Cretaceous of Mongolia, with comments on endocranial variability among ankylosaurs
Palaeogeography, Palaeoclimatology, Palaeoecology, 2018
Ankylosaur braincase and endocranial morphologies are poorly known. Furthermore, cranial endocast... moreAnkylosaur braincase and endocranial morphologies are poorly known. Furthermore, cranial endocasts have been described for fewer than ten taxa so far. The complete inner ear morphology is known for only three species-Euoplocephalus tutus, Kunbarrasaurus ieversi, and Pawpawsaurus campbelli. Here, the first cranial endocast morphologies are presented for the Mongolian Cretaceous ankylosaurids Talarurus plicatospineus and Tarchia teresae. The study of paleoneurological features of these Mongolian taxa adds novel anatomical information to both species allowing the first comparison with ankylosaurids from North America. The development of a cerebellar flocculus that leaves an impression on the vestibular eminence-floccular recess-is observed in Euoplocephalus, Talarurus and T. teresae. Because this structure hasn't been identified in any nodosaurid so far, its presence in ankylosaurid cranial endocasts may represent a possible synapomorphy with unknown paleobiological implications.

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