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Hadrosaur trackways from the Lower Cretaceous of Canada

100%

Currie P. J.

Acta Palaeontologica Polonica

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1983

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tom 28

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nr 1-2

The most common ichnogenus in the Peace River Canyon is Amblydactylus, a large bipedal herbivore. The morphology of the hand and footprints suggest that the tracks and trackways were made by hadrosaurs, and the ichnites might represent the earliest record of these dinosaurs. Amblydactylus tracks were made in a wide variety of depositional environments, including the mud beneath several metres of water. Juveniles were gregarious and stayed together after hatching until they were large enough to join herds of more mature animals. Hadrosaur herds appear to have walked side by side, seldom crossing paths, although there was little structure to the herds when they were in the water and/or feeding. Calculation of the walking speeds indicate that the herbivores were generally slower than the carnivores.

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Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada

100%

Currie P. J.

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 2

Beautifully preserved, nearly complete theropod skeletons from Alberta (Canada) allow re−evaluation of the taxonomic status of North American tyrannosaurids. It is concluded that the most parsimonious interpretation of relationships leads to the separation of the two species of Albertosaurus(sensu Russell 1970) into Gorgosaurus libratusfrom the Campanian Dinosaur Park Formation and Albertosaurus sarcophagus from the upper Campanian/lower Maastrichtian Horseshoe Canyon Formation. Albertosaurus and Gorgosaurus are closely related, but can be distinguished from each other by more characters than are known to justify generic distinction within another tyrannosaurid clade that includes Daspletosaurus, Tarbosaurus and Tyrannosaurus. Daspletosaurus is known from multiple species that cover extensive geographic, ecological and temporal ranges, and it is sensible to maintain its generic distinction from Tyrannosaurus. All tyrannosaurid species have consistent ontogenetic trends. However, one needs to be cautious in assessing ontogenetic stage because many characters are size−dependent rather than age−dependent. There are relatively few osteological differences that can distinguish tyrannosaurid species at any age. For example, Nanotyrannus lancensis is probably a distinct species from Tyrannosaurus rex because there is no evidence of ontogenetic reduction of tooth counts in any other tyrannosaurid species. Some characters that are good for separating mature tyrannosaurids, such as differences in the sizes and shapes of maxillary fenestrae, are not useful for identifying the species of juveniles.

3

Oviraptorosaur tail forms and functions

51%

Persons,IV W. S., Currie P. J., Norell M. A.

Acta Palaeontologica Polonica

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2014

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tom 59

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nr 3

Oviraptorosaur caudal osteology is unique among theropods and is characterized by posteriorly persistent and exceptionally wide transverse processes, anteroposteriorly short centra, and a high degree of flexibility across the pre-pygostyle vertebral series. Three-dimensional digital muscle reconstructions reveal that, while oviraptorosaur tails were reduced in length relative to the tails of other theropods, they were muscularly robust. Despite overall caudal length reduction, the relative size of the M. caudofemoralis in most oviraptorosaurs was comparable with those of other non-avian theropods. The discovery of a second Nomingia specimen with a pygostyle confirms that the fused terminal vertebrae of the type specimen were not an abnormality. New evidence shows that pygostyles were also present in the oviraptorosaurs Citipati and Conchoraptor. Based on the observed osteological morphology and inferred muscle morphology, along with the recognition that many members of the group probably sported broad tail-feather fans, it is postulated that oviraptorosaur tails were uniquely adapted to serve as dynamic intraspecific display structures. Similarities, including a reduced vertebral series and a terminal pygostyle, between the tails of oviraptorosaurs and the tails of theropods widely accepted as basal members of the Avialae, appear to be convergences.

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Allometric growth in the frontals of the Mongolian theropod dinosaur Tarbosaurus bataar

51%

Yun C.-G., Peters G. F., Currie P. J.

Acta Palaeontologica Polonica

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2022

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tom 67

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nr 3

5

New elmisaurine specimens from North America and their relationship to the Mongolian Elmisaurus rarus

51%

Funston G. F., Currie P. J., Burns M. E.

Acta Palaeontologica Polonica

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2016

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tom 61

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nr 1

New specimens from Canada confirm the presence of elmisaurines in North America and shed light on the relationship of Leptorhynchos elegans to Mongolian forms. These specimens have hindlimb elements previously unknown from elmisaurines in the Dinosaur Park Formation, including tibiae and pedal phalanges. Metatarsal anatomy is sufficiently different to merit a generic distinction from Elmisaurus rarus, and both can be distinguished from Caenagnathus collinsi and Chirostenotes pergracilis. Differences between these taxa include body size, degree of coossification of the tarsometatarsus, and development of cruciate ridges of the metatarsal III. Histological analysis confirms that these differences are not correlated with ontogenetic age of the specimens. The results support the informal separation of caenagnathids based on metatarsal structure, and allow comments on paleobiological differences between caenagnathids and oviraptorids.

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Morphometry of the teeth of western North American tyrannosaurids and its applicability to quantitative classification

51%

Samman T., Powell G. L., Currie P. J., Hills L. V.

Acta Palaeontologica Polonica

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2005

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tom 50

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nr 4

757-776

Gross tooth morphology and serration morphology were examined to determine a quantifiable method for classifying tyrannosaurid tooth crowns from western North America. From the examination of teeth in jaws, tyrannosaurid teeth could be qualitatively assigned to one of five types based on the cross−sectional shape of the base of the tooth and characteristics of the mesial carina. A principal component analysis (PCA) revealed that much of the variance in tooth shape was a result of isometry, but some gross morphological variables exhibited strong positive allometry. Non−size associated factors were also important in determining tooth shape, particularly when data on denticle dimensions were considered in the analysis. While PCA identified important factors in variation, PCA ordination plots did not cluster the teeth into distinct, separate groupings based on taxon or bone of origin. The group classification functions determined by discriminant analysis, though not universally successful for classifying unidentified isolated teeth of all tyrannosaurids, do identify bone of origin of adult Albertosaurus, Daspletosaurus, and Gorgosaurus teeth at a statistically acceptable level.

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Variation in premaxillary tooth count and a developmental abnormality in a tyrannosaurid dinosaur

51%

Miyashita T., Tanke D. H., Currie P. J.

Acta Palaeontologica Polonica

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2010

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tom 55

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nr 4

Premaxillary tooth count tends to be stable amongst toothed dinosaurs, and most theropods have four teeth in each premaxilla. Only one case of bilaterally asymmetric variation is known in theropod premaxillary dentition, and there is no record of ontogenetic or individual variation in premaxillary tooth count. Based on these observations, a tyrannosaurid left premaxilla with three teeth (TMP 2007.20.124) is an interesting deviation and represents an unusual individual of Daspletosaurus sp. with a developmental abnormality. The lower number of teeth is coupled with relatively larger alveoli, each of which is capable of hosting a larger than normal tooth. This indicates that tooth size and dental count vary inversely, and instances of reduction in tooth count may arise from selection for increased tooth size. On the other hand, the conservative number of premaxillary teeth in most theropods implies strong developmental constraints and a functional trade−off between the dimensions of the premaxillary alveolar margin and the size of the teeth. In light of recent advances in the study of tooth morphogenesis, tooth count is a function of two parameters: dimensions of an odontogenic field for a tooth series, and dimensions of tooth positions. A probable developmental cause for the low tooth count of TMP 2007.20.124 is that the dimensions of the alveoli expanded by approximately a third during tooth morphogenesis. Numerical traits such as tooth count are difficult to treat in a phylogenetic analysis. When formulating a phylogenetic character, a potential alternative to simply counting is to rely on the morphological signature for developmental parameters that control the number of the element in question.

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New specimens of the crested theropod dinosaur Elmisaurus rarus from Mongolia

51%

Currie P. J., Funston G. F., Osmolska H.

Acta Palaeontologica Polonica

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2016

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tom 61

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nr 1

New specimens of Elmisaurus rarus from the Upper Cretaceous of Mongolia (Nemegt Formation) preserve bones not previously found in “elmisaurids” that help elucidate their relationships to Leptorhynchos elegans and other oviraptorosaurs. Elmisaurus rarus and the North American Leptorhynchos elegans are known from numerous but incomplete specimens that are closely related to, but nevertheless clearly distinguished from, Chirostenotes pergracilis and Epichirostenotes curriei. These specimens include the first known cranial bone attributed to Elmisaurus, the frontal, which clearly shows this animal had a cranial crest (most of which would have been formed by the nasal bones). The first vertebrae, scapula, femora, and tibiae from Elmisaurus are also described. The Elmisaurinae can be distinguished from the Caenagnathinae by the coossification of the tarsometatarsus and smaller size at maturity. Examination of oviraptorosaur hindlimbs reveals four distinct morphotypes, possibly attributable to paleoecological differences.

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Theropod dinosaurs from the Upper Cretaceous of the South Pyrenees Basin of Spain

51%

Torices A., Currie P. J., Canudo J. I., Pereda-Suberbiola X.

Acta Palaeontologica Polonica

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2015

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tom 60

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nr 3

The dinosaur record in the South Pyrenees Basin is diverse and rich. A total of 142 theropod teeth were studied for this paper, which constitutes one of the richest samples for these remains in Europe. Eight upper Campanian to upper Maastrichtian outcrops from the Pyrenees produced six non-avian theropod taxa (Theropoda indet., Coelurosauria indet., ?Richardoestesia, ?Dromaeosauridae indet., ?Pyroraptor olympius, ?Paronychodon). These six taxa are added to two previously described theropods (a Richardoestesia-like form and a possible ornithomimosaurid), indicating that there was considerable theropod diversity on the Iberian Peninsula during the Late Cretaceous.

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New data on anatomy of the Late Cretaceous multituberculate mammal Catopsbaatar

51%

Kielan-Jaworowska Z., Hurum J. H., Currie P. J., Barsbold R.

Acta Palaeontologica Polonica

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2002

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tom 47

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nr 3

The Gobi Desert is famous for providing one of the worlds best preserved Cretaceous terrestrial faunas, including dinosaurs and mammals. Beginning with the Central Asiatic Expeditions in the 1920s, through the Polish−Mongolian Expeditions in the 1960s–1970s, Soviet−Mongolian Expeditions in 1970s, and finally the Mongolian Academy−American Museum Expeditions in the 1990s–2000s, the number of complete skulls (see Kielan−Jaworowska et al. 2000 for review) of Cretaceous mammals often associated with postcranial skeletons, found in Mongolia increased to several hundred. In addition to these professional expeditions, there have been other types of trips to Mongolia, also aimed at collecting fossils. The Nomadic Expeditions Company in USA organizes one of these, and has made trips to Mongolia since 1996. During the 1999 Nomadic Expedition, a skull associated with parts of the postcranial skeleton of the multituberculate mammal Catopsbaatar catopsaloides was found. The specimen is more complete than others previously known of this species and brings new data on multituberculate anatomy and ontogenetic variation. In this note we discuss the new data on the structure of C. catopsaloides; the details of its anatomy will be described in subsequent papers by the two first authors.

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Skull structure and evolution in tyrannosaurid dinosaurs

51%

Currie P. J., Hurum J. H., Sabath K.

Acta Palaeontologica Polonica

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2003

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tom 48

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nr 2

Tyrannosauridae can be subdivided into two distinct subfamilies—the Albertosaurinae and the Tyrannosaurinae. Previously recognized subdivisions Aublysodontinae and Shanshanosaurinae are rejected because they are based on insufficient material and juvenile specimens. Our results are based upon a phylogenetic analysis using PAUP program (Swofford 1999) of 77 skull characters and seven genera (Albertosaurus, Alioramus, Daspletosaurus, Gorgosaurus, Nanotyrannus, Tarbosaurus, and Tyrannosaurus); with Allosaurus as outgroup. Of the 77 characters used, more than half were parsimony informative. Asingle most parsimonious tree was obtained with the Tree Length being 88. The analysis of cranial characters and comparison of postcranial features reveal that Tarbosaurus bataar is not the sister taxon of Tyrannosaurus rex (contra Holtz 2001). Their similarities are partially due to the fact that both are extremely large animals. Thus, Tarbosaurus should be considered a genus distinct from Tyrannosaurus.

12

An ankylosaurid dinosaur from Mongolia with in situ armour and keratinous scale impressions

45%

Arbour V. M., Lech-Hernes N. L., Guldberg T. E., Hurum J. H., Currie P. J.

Acta Palaeontologica Polonica

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2013

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tom 58

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nr 1

A Mongolian ankylosaurid specimen identified as Tarchia gigantea is an articulated skeleton including dorsal ribs, the sacrum, a nearly complete caudal series, and in situ osteoderms. The tail is the longest complete tail of any known ankylosaurid. Remarkably, the specimen is also the first Mongolian ankylosaurid that preserves impressions of the keratinous scales overlying the bony osteoderms. This specimen provides new information on the shape, texture, and ar− rangement of osteoderms. Large flat, keeled osteoderms are found over the pelvis, and osteoderms along the tail include large keeled osteoderms, elongate osteoderms lacking distinct apices, and medium−sized, oval osteoderms. The specimen differs in some respects from other Tarchia gigantea specimens, including the morphology of the neural spines of the tail club handle and several of the largest osteoderms.

13

Hands, feet, and behaviour in Pinacosaurus (Dinosauria: Ankylosauridae)

45%

Currie P. J., Badamgarav D., Koppelhus E. B., Sissons R., Vickaryous M. K.

Acta Palaeontologica Polonica

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2011

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tom 56

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nr 3

Structure of the manus and pes has long been a source of confusion in ankylosaurs, owing to the imperfect preservation or complete lack of these parts of the skeletons in most specimens, and the fact that many species appear to have undergone a reduction in numbers of digits and phalanges. New specimens of Pinacosaurusfrom Alag Teeg in Mongolia confirm that the phalangeal formula of the manus is 2−3−3−3−2. However, there are only three toes in the pes, which has a phalangeal formula of X−3−3/4−3/4−X. Importantly, the number of phalanges in the third and fourth pedal digits can vary between either three or four per digit, even within the same specimen. The Alag Teeg site has yielded as many as a hundred skeletons of the ankylosaur Pinacosaurus, most of which were immature when they died. Each skeleton is preserved in an upright standing position, with the bones of the lower limbs often in articulation. The remainder of the skeleton, including the upper parts of the limbs, is generally disarticulated and somewhat scattered. Based on the presence of large numbers of juvenile Pinacosaurus specimens at Alag Teeg, as well as other Djadokhta−age sites (Ukhaa Tolgod in Mongolia, Bayan Mandahu in China), it seems juvenile Pinacosaurus were probably gregarious.

14

A new oviraptorosaur [Dinosauria, Theropoda] from Mongolia: the first dinosaur with a pygostyle

45%

Barsbold R., Osmolska H., Watabe M., Currie P. J., Tsogtbaatar K.

Acta Palaeontologica Polonica

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2000

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tom 45

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nr 2

97-106

A description of Nomingia gobiensis gen. et sp. n., the first known dinosaur with a pygostyle, the structure known so far only in birds, is presented. The specimen comes from the Late Cretaceous strata at Bugin Tsav, Trans-Altai Gobi, Mongolia. N. gobiensis is assigned within the Oviraptorosauria based on the following characters: pneumatized caudal vertebrae, posteriorly concave ischium, and deep cervicodorsal hypapophyses. This specimen has been previously partially described without being formally named (Barsbold et al. 2000).

15

A new basal eusauropod from the Middle Jurassic of Yunnan, China, and faunal compositions and transitions of Asian sauropodomorph dinosaurs

39%

Xing L., Miyashita T., Currie P. J., You H., Zhang J., Dong Z.

Acta Palaeontologica Polonica

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2015

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tom 60

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nr 1

Many sauropod ghost lineages cross the Middle Jurassic, indicating a time interval that requires increased sampling. A wide taxonomic spectrum of sauropodomorphs is known from the Middle Jurassic of China, but the braincase of a new sauropod, named here Nebulasaurus taito gen. et sp. nov., is distinct. Nebulasaurus is sister taxon to Spinophorosaurus from the Middle Jurassic of Africa and represents a clade of basal eusauropods previously unknown from Asia. The revised faunal list indicates dramatic transitions in sauropodomorph faunas from the Jurassic to Cretaceous of Asia; these are consistent with geographic isolation of Asia through the Late Jurassic. Non-sauropod sauropodomorphs, non-mamenchisaurid eusauropods (including basal macronarians), and mamenchisaurids successively replaced previous grades through the Jurassic, and titanosauriforms excluded all other sauropod lineages across the Jurassic–Cretaceous boundary.

16

A New Deinonychosaurian Track from the Lower Cretaceous Hekou Group, Gansu Province, China

33%

Xing L., Li D., Harris J. D., Bell P. R., Azuma Y., Fujita M., Lee Y.-N., Currie P. J.

Acta Palaeontologica Polonica

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2013

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tom 58

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nr 4

Herein we describe deinonychosaurian (Dinosauria: Theropoda) tracks in the Lower Cretaceous Hekou Group at sites I and II of Liujiaxia Dinosaur National Geopark, Gansu Province, China. The site preserves 71 didactyl tracks, the largest concentration of deinonychosaurian tracks in Asia. The tracks pertain to a new dromaeopodid ichnospecies: Dromaeosauripus yongjingensis ichnosp. nov., which is diagnosed by: a digital pad formula of x−1−3−4−x and a mean divarication angle between digits III and IV of 19°, and having the proximal portion of digit II contacting the anterior margin of a large, rounded metatarsophalangeal pad. Six Dromaeosauripustrackways from site II comprise at least two, and possibly three, turning trackways in which the track maker(s) turned without slowing down. None of the Dromaeosauripus trackways are parallel or closely spaced, suggesting that they were made by solitary track makers. Estimates of dromaeopodid track−maker sizes are between 61–300 cm, well within the size range established by body fossils of both dromaeosaurids and troodontids.

Ograniczanie wyników

Hadrosaur trackways from the Lower Cretaceous of Canada

Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada

Oviraptorosaur tail forms and functions

Allometric growth in the frontals of the Mongolian theropod dinosaur Tarbosaurus bataar

New elmisaurine specimens from North America and their relationship to the Mongolian Elmisaurus rarus

Morphometry of the teeth of western North American tyrannosaurids and its applicability to quantitative classification

Variation in premaxillary tooth count and a developmental abnormality in a tyrannosaurid dinosaur

New specimens of the crested theropod dinosaur Elmisaurus rarus from Mongolia

Theropod dinosaurs from the Upper Cretaceous of the South Pyrenees Basin of Spain

New data on anatomy of the Late Cretaceous multituberculate mammal Catopsbaatar

Skull structure and evolution in tyrannosaurid dinosaurs

An ankylosaurid dinosaur from Mongolia with in situ armour and keratinous scale impressions

Hands, feet, and behaviour in Pinacosaurus (Dinosauria: Ankylosauridae)

A new oviraptorosaur [Dinosauria, Theropoda] from Mongolia: the first dinosaur with a pygostyle

A new basal eusauropod from the Middle Jurassic of Yunnan, China, and faunal compositions and transitions of Asian sauropodomorph dinosaurs

A New Deinonychosaurian Track from the Lower Cretaceous Hekou Group, Gansu Province, China