Philip J. Currie

University of Alberta | UAlberta · Department of Biological Sciences

Understanding the extent to which tyrannosaurid cranial morphology changed through ontogeny is essential to correctly refer tyrannosaurid specimens at varying life stages to taxa. However, taxonomically diagnostic immature tyrannosaurid bones remain exceedingly elusive. Over the last century, the University of Alberta has collected three isolated i...

Edmontosaurus regalis is a hadrosaurid represented by abundant fossil material from the late Campanian-early Maastrichtian of what is now Alberta, Canada. Despite its prevalence, juvenile craniomandibular elements of E. regalis are poorly known. A newly collected partial skeleton from the Horseshoe Canyon Formation, UALVP 60425, represents a small...

The Horseshoe Canyon Formation has provided a wealth of vertebrate skeletal fossils over the past 100years of collection. Vertebrate trace fossils such as footprints and trackways, however, have been markedly underrepresented. Trackways can provide a wealth of information regarding behaviour and soft tissues reflective of autopodial anatomy. Discov...

Tyrannosaurid dinosaurs dominated as predators in the Late Cretaceous of Laurasia, culminating in the evolution of the giant Tyrannosaurus rex, both the last and largest tyrannosaurid. Where and when Tyrannosaurini (T. rex and kin) originated remains unclear. Competing hypotheses place tyrannosaurin origins in Asia, or western North America (Larami...

Albertosaurus sarcophagus Osborn, 1905 specimens from the Danek Bonebed of Edmonton, Alberta, Canada were first described in 2014. Since this initial report, the University of Alberta's annual field work has continued to yield additional tyrannosaurid material from the Danek Bonebed. In addition to nearly 200 tyrannosaurid shed teeth, five diagnost...

Tyrannosaurids were large carnivorous dinosaurs that underwent major changes in skull robusticity and body proportions as they grew, suggesting that they occupied different ecological niches during their life span. Although adults commonly fed on dinosaurian megaherbivores, the diet of juvenile tyrannosaurids is largely unknown. Here, we describe a...

The 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’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 chron...

Since the beginning of the 1990s, palaeontologists have been interested in understanding biological processes recorded within the bone microstructure of deinonychosaurian theropods, the group comprising Troodontidae and Dromaeosauridae. Several studies were published on this subject, and the growing database requires the first revision of used term...

Isolated teeth, previously referred to Aves, are more common than other bird fossils from the Late Cretaceous of Alberta. However, there are no known morphological synapomorphies that distinguish isolated bird teeth, and features of these teeth are generally shared with those of non-avian theropods and crocodilians. Here, specimens ranging from Lat...

The osteology of Pilmatueia faundezi Coria, Windholz, Ortega & Currie, 2019, a dicraeosaurid sauropod from the Lower Cretaceous of Patagonia, is reassessed from the perspective of a new specimen (MLL-Pv-010) that provides additional information on the axial skeleton and the pectoral girdle. The specimen MLL-Pv-010 is composed of three articulated a...

Streamlining 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...

Tyrannosaurid dinosaurs were ecologically unique vertebrates as the sole clade of large terrestrial carnivores (adults >400 kg) in their continent-spanning habitats. Expanded ligaments between metatarsals, inferred by gross morphology of attachment correlates, have been hypothesized to have strengthened their specialized arctometatarsus. We tested...

Dromaeosaurids (Theropoda: Dromaeosauridae), a group of dynamic, swift predators, have a sparse fossil record, particularly at the end of the Cretaceous Period. The recently described Dineobellator notohesperus, consisting of a partial skeleton from the Upper Cretaceous (Maastrichtian) of New Mexico, is the only diagnostic dromaeosaurid to be recov...

In this study, we use an exceptional skeleton of the pachycephalosaur Stegoceras validum (UALVP 2) to inform a comprehensive appendicular muscle reconstruction of the animal, with the goal of better understanding the functional morphology of the pachycephalosaur postcranial skeleton. We find that S. validum possessed a conservative forelimb muscula...

The Middle–Late Jurassic transition period is a critical period for the evolution of terrestrial vertebrates, but the global fossil record from this time is relatively poor. The Shishugou Fauna of this period has recently produced significant fossil remains of dinosaurs and other vertebrate groups, some representing the earliest known members of se...

Counts of the number of skeletal specimens of “adult” megaherbivores and large theropods from the Morrison and Dinosaur Park formations—if not biased by taphonomic artifacts—suggest that the big meat‐eaters were more abundant, relative to the number of big plant‐eaters, than one would expect on the basis of the relative abundance of large carnivore...

Known from dozens of specimens discovered since the early 20th century, Gorgosaurus libratus has arguably contributed more than any other taxon to our understanding of the life history of tyrannosaurids. However, juvenile material for this taxon is rare. Here, we describe two small, articulated Gorgosaurus specimens (skull lengths of ca. 500 mm) th...

Dromaeosaurids are poorly known in Europe and their fossil records are mostly postcranial remains. To date, the French faunal records of the family Dromaeosauridae include two taxa: Pyroraptor olympius and Variraptor mechinorum. Nevertheless, their taxonomic validity and phylogenetic relationships as dromaeo-saurids are controversial. Here, we repo...

Eudromaeosauria is a clade of derived dromaeosaurids that typifies the common perception of ‘raptor’ dinosaurs. The evolutionary history of this clade has been controversial due to conflicting views of taxonomic identity, and because, due to taphonomic bias, several species were diagnosed primarily or solely by the maxilla. The maxilla is therefore...

A total of 227 theropod teeth have so far been recovered from the upper Campanian Laño site (northern Iberian Peninsula). The teeth were studied for their qualitative and quantitative features. From the theropod sample found at Laño, seven morphotypes attributed to five taxa are identified: a medium to large abelisaurid (Arcovenator sp.) and four s...

Modern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in the group of theropod dinosaurs (Maniraptoriformes) that include crown Aves. Squamous or scaly reptilian-like skin is, however, considered the plesiomorphic condition for theropods and dinosaurs more broadly. Here, we review the m...

Michael Benton and colleagues reminisce about the discovery of Sinosauripteryx, the first feathered dinosaur.

Small herbivorous dinosaurs of the clades Pachycephalosauridae and Thescelosauridae occur in multiple Cretaceous formations in North America, their coexistence likely made possible by differences in feeding style. Fossils of these taxa are generally rare, but isolated pachycephalosaurid and thescelosaurid teeth are common at microfossil sites, and...

Intraspecific aggression, or agonism, is a widespread intrasexual selective behavior important to understanding animal behavioral ecology and reproductive systems. Such behavior can be studied either by direct observation or inferred from wound/scar frequency in extant species but is difficult to document in extinct taxa, limiting understanding of...

For 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 torosus — a large tyrannosaurine from...

The Nemegt Formation of the Gobi Desert of Mongolia has produced one of the most abundant and diverse oviraptorosaur records globally. However, the caenagnathid component of this fauna remains poorly known. Two caenagnathid taxa are currently recognized from the Nemegt Formation: Elmisaurus rarus and Nomingia gobiensis. Because these taxa are known...

The Dinosaur Park Formation (DPF) of Alberta, Canada, has produced one of the most diverse dinosaur faunas, with the record favouring large-bodied taxa, in terms of number and completeness of skeletons. Although small theropods are well documented in the assemblage, taxonomic assessments are frequently based on isolated, fragmentary skeletal elemen...

The question why non-avian dinosaurs went extinct 66 million years ago (Ma) remains unresolved because of the coarseness of the fossil record. A sudden extinction caused by an asteroid is the most accepted hypothesis but it is debated whether dinosaurs were in decline or not before the impact. We analyse the speciation-extinction dynamics for six k...

Recent studies have identified numerous pathologies in the cranial domes of pachycephalosaurid dinosaurs. These studies utilized CT images of domes to identify secondary woven bone and sclerosis associated with the pathologies. These features were critical for diagnosing post-traumatic osteomyelitis, which supported the head-butting behaviour hypot...

A new articulated postcranial specimen of an indeterminate ankylosaurid dinosaur from the Upper Cretaceous (middle-upper Campanian) Baruungoyot Formation from Hermiin Tsav, southern Gobi Desert, Mongolia includes twelve dorsal vertebrae, ribs, pectoral girdles, forelimbs, pelvic girdles, hind limbs, and free osteoderms. The new specimen shows that...

Locomotion is a fundamental aspect of palaeobiology and often investigated by comparing osteological structures and proportions. Previous studies document a stepwise accumulation of avian-like features in theropod dinosaurs that accelerates in the clade Maniraptora. However, the soft tissues that influenced the skeleton offer another perspective on...

A characteristic fauna of dinosaurs and other vertebrates inhabited the end-Cretaceous European archipelago, some of which were dwarves or had other unusual features likely related to their insular habitats. Little is known, however, about the contemporary theropod dinosaurs, as they are represented mostly by teeth or other fragmentary fossils. A n...

Three 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 the light of physical processes controlling life, death, and burial of taxa...

Abstract: Tyrannosaurids were the apex predators of Late Cretaceous Laurasia and their status as dominant carnivores has garnered considerable interest since their discovery, both in the popular and scientific realms. As a result, they are well studied and much is known of their anatomy, diversity, growth, and evolution. In contrast, little is know...

We review the distinguished and varied career of our friend and colleague, palaeontologist Dr. Dale A. Russell, following the recent news of his death. Dale relished his work, and approached his research—whether it be on mosasaur systematics, dinosaur extinction, or the evolution of animal intelligence—with great gusto. A deep and contextual thinke...

Late Cretaceous trends in Asian dinosaur diversity are poorly understood, but recent discoveries have documented a radiation of oviraptorosaur theropods in China and Mongolia. However, little work has addressed the factors that facilitated this diversification. A new oviraptorid from the Late Cretaceous of Mongolia sheds light on the evolution of t...

The Cretaceous birds of Alberta are poorly known, as skeletal elements are rare and typically consist of fragmentary postcranial remains. A partial avian coracoid from the upper Campanian Dinosaur Park Formation of Alberta, Canada can be referred to the Ornithurae, and is referred to here as Ornithurine G (cf. Cimolopteryx). Its structure is simila...

Microraptorine dromaeosaurids are characterized by a lateral pubic tubercle or process on the midshaft of the pubis. Initially proposed as a tubercle for muscle attachment, this structure has since received little attention beyond identifying its presence or absence in theropods. Examination of this tubercle reveals inconsistencies in texture and t...

In recent years, several papers have claimed that soft tissue can preserve within bone matrix of extinct vertebrates, some dating back over 100 million years. Work conducted on specimens from Montana suggested sediment type may influence preservation of original tissues and proteins. An alternative hypothesis is that soft tissue preservation may be...

Caenagnathids were oviraptorosaur theropods characterized by elongate hind limbs that are proposed as adaptations for either wading or enhanced cursoriality. A lack of well preserved pelvic material, however, has thus far prevented reconstruction of both the hind limb and girdle for verification of these hypotheses. Here we describe an abundance of...

The taxonomy of caenagnathids from the Dinosaur Park Formation of Alberta, Canada, has remained problematic because of incomplete, partial skeletons that do not overlap anatomically. This is particularly problematic for referring mandibular remains, which are the most abundant caenagnathid fossils recovered, but cannot be confidently tied to taxa k...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Avimimids 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 appa...

Despite being known from every continent, the geological record of pterosaurs, the first group of vertebrates to develop powered flight, is very uneven, with only a few deposits accounting for the vast majority of specimens and almost half of the taxonomic diversity. Among the regions that stand out for the greatest gaps of knowledge regarding thes...

Hadrosaurian dinosaurs were abundant in the Late Cretaceous of North America, but their habitats remain poorly understood. Cretaceous amber is also relatively abundant, yet it is seldom found in direct stratigraphic association with dinosaur remains. Here we describe an unusually large amber specimen attached to a Prosaurolophus jaw, which reveals...

Daspletosaurus is a large tyrannosaurine found in upper Campanian deposits of Alberta and Montana. Although several large subadult and adult individuals of this taxon are known, only one juvenile individual, TMP 1994.143.1, has been identified. This specimen has played a key role in the idea that juvenile tyrannosaurid individuals are difficult to...

The ceratopsid Styracosaurus albertensis is an important component of the herbivorous dinosaur fauna preserved in the Campanian-aged Dinosaur Park Formation in Alberta, Canada. A new skull (UALVP55900) exhibits previously unobserved variability and asymmetry in this species. As in the type, the right lateral parietal bar bears seven epiossification...

A new carcharodontosaurid taxon, Lajasvenator ascheriae gen. et sp. nov. is described. The new taxon is based on two specimens: MLL-PV-Pv-005 is a partial skeleton represented by a portion of the snout, partially articulated presacral vertebral series, four articulated caudal vertebra and fragments of the pelvic girdle; MLL-PV-Pv-007 includes the a...

Preserved labile tissues (e.g., skin, muscle) in the fossil record of terrestrial vertebrates are increasingly becoming recognized as an important source of biological and taphonomic information. Here, we combine a variety of synchrotron radiation techniques with scanning electron and optical microscopy to elucidate the structure of 72 million-year...

Dinosaur Provincial Park has been a popular site for palaeontological digs for many years. Over time, the many quarries and bone beds uncovered have had their locations marked on large paper topography maps. Unfortunately, many dig sites have been lost due to poor documentation. Some sites have been abandoned for years. The high erosion levels of t...

The fossil record of caenagnathid oviraptorosaurs consists mainly of their fused, complexly sculptured dentaries, but little is known about the growth and development of this diagnostic structure. Previous work has suggested that the ridges and grooves on the occlusal surface are either the vestiges of teeth and their alveoli or were adaptations to...

Over the last two decades, paleontologists have pieced together the early evolutionary history of feathers. Simple hair‐like feathers served as insulating pelage, but the first feathers with complex branching structures and a plainer form evolved for the purpose of sexual display. The evolution of these complex display feathers was essential to the...

Several published censuses have noted the presence of two tyrannosaurids, Daspletosaurus sp. and Albertosaurus sarcophagus, within the Upper Cretaceous Horseshoe Canyon Formation of Alberta. Although A. sarcophagus is known from more than a dozen major discoveries in these strata, Daspletosaurus sp. is known from just a single problematic skeleton...

Preserved labile tissues (e.g. skin, muscle) in the fossil record of terrestrial vertebrates are increasingly becoming recognized as an important source of biological and taphonomic information. Here, we combine a variety of synchrotron radiation techniques with scanning electron and optical microscopes to elucidate the structure of 72 million-year...

Preserved labile tissues (e.g. skin, muscle) in the fossil record of terrestrial vertebrates are increasingly becoming recognized as an important source of biological and taphonomic information. Here, we combine a variety of synchrotron radiation techniques with scanning electron and optical microscopes to elucidate the structure of 72 million-year...

Here we describe an extremely large and relatively complete (roughly 65%) skeleton of Tyrannosaurus rex (RSM P2523.8). Multiple measurements (including those of the skull, hip, and limbs) show that RSM P2523.8 was a robust individual with an estimated body mass exceeding all other known T. rex specimens and representatives of all other gigantic ter...

The femoral fourth trochanter is the attachment site of the caudofemoralis musculature, which is the primary hindlimb retractor in most non‐avian dinosaurs. Early ornithischian dinosaurs are uniquely characterized by a fourth trochanter with a prominent pendant process. Throughout the evolution of ornithischians, the fourth trochanter repeatedly co...

Synopsis Tyrannosaurid dinosaurs had large preserved leg muscle attachments and low rotational inertia relative to their body mass, indicating that they could turn more quickly than other large theropods. Methods To compare turning capability in theropods, we regressed agility estimates against body mass, incorporating superellipse-based modeled m...