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  • 1. Barrett, Paul M.
    et al.
    Evans, David C.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Evolution of dinosaur epidermal structures2015Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, nr 6, artikel-id 20150229Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Spectacularly preserved non-avian dinosaurs with integumentary filaments/feathers have revolutionized dinosaur studies and fostered the suggestion that the dinosaur common ancestor possessed complex integumentary structures homologous to feathers. This hypothesis has major implications for interpreting dinosaur biology, but has not been tested rigorously. Using a comprehensive database of dinosaur skin traces, we apply maximum-likelihood methods to reconstruct the phylogenetic distribution of epidermal structures and interpret their evolutionary history. Most of these analyses find no compelling evidence for the appearance of protofeathers in the dinosaur common ancestor and scales are usually recovered as the plesiomorphic state, but results are sensitive to the outgroup condition in pterosaurs. Rare occurrences of ornithischian filamentous integument might represent independent acquisitions of novel epidermal structures that are not homologous with theropod feathers.

  • 2.
    Bazzi, Mohamad
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Kear, Benjamin P.
    Uppsala universitet, Enheten för musik och museer, Evolutionsmuseet.
    Blom, Henning
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Ahlberg, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Univ New England, Sch Environm & Rural Sci, Palaeosci Res Ctr, Armidale, NSW 2351, Australia.
    Static Dental Disparity and Morphological Turnover in Sharks across the End-Cretaceous Mass Extinction2018Ingår i: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 28, nr 16, s. 2607-2615Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Cretaceous-Palaeogene (K-Pg) mass extinction profoundly altered vertebrate ecosystems and prompted the radiation of many extant clades [1, 2]. Sharks (Selachimorpha) were one of the few larger-bodied marine predators that survived the K-Pg event and are represented by an almost-continuous dental fossil record. However, the precise dynamics of their transition through this interval remain uncertain [3]. Here, we apply 2D geometric morphometrics to reconstruct global and regional dental morphospace variation among Lamniformes (Mackerel sharks) and Carch-arhiniformes (Ground sharks). These clades are prevalent predators in today's oceans, and were geographically widespread during the late Cretaceous-early Palaeogene. Our results reveal a decoupling of morphological disparity and taxonomic richness. Indeed, shark disparity was nearly static across the K-Pg extinction, in contrast to abrupt declines among other higher-trophic-level marine predators [4, 5]. Nevertheless, specific patterns indicate that an asymmetric extinction occurred among lamniforms possessing lowcrowned/triangular teeth and that a subsequent proliferation of carcharhiniforms with similar tooth morphologies took place during the early Paleocene. This compositional shift in post-Mesozoic shark lineages hints at a profound and persistent K-Pg signature evident in the heterogeneity of modern shark communities. Moreover, such wholesale lineage turnover coincided with the loss of many cephalopod [6] and pelagic amniote [5] groups, as well as the explosive radiation of middle trophic-level teleost fishes [1]. We hypothesize that a combination of prey availability and post-extinction trophic cascades favored extant shark antecedents and laid the foundation for their extensive diversification later in the Cenozoic [7-10].

  • 3. Bell, Phil R.
    et al.
    Campione, Nicolàs E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi.
    Taphonomy of the Danek Bonebed: a monodominant Edmontosaurus (Hadrosauridae) bonebed from the Horseshoe Canyon Formation, Alberta2014Ingår i: Canadian journal of earth sciences (Print), ISSN 0008-4077, E-ISSN 1480-3313, Vol. 51, nr 11Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Danek Bonebed (Horsethief Member, Horseshoe Canyon Formation, Late Campanian) is dominated by the remains of at least 12 Edmontosaurus regalis. Skeletal remains of a tyrannosaurid and ceratopsid are also known. The predominantly disarticulated remains were interred on a periodically inundated floodplain and, although the cause of death is unknown, a sudden, catastrophic death explains the demographic spread, faunal diversity, rare greenstick fractures, and homogeneous weathering/abrasion categories of the assemblage. The Danek Bonebed shares a similar taphonomic signature to the Liscomb Bonebed (Prince Creek Formation, Alaska), but it is unique among all other described hadrosaurid bonebeds in the unusually high proportion of bite-marked bones (similar to 30%), suggesting scavenging played a major role in the reworking of the assemblage. The highest frequency of bite marks is found on small, often unidentifiable (and commonly ignored) bone fragments, underscoring the role that such fragments can play in taphonomic interpretation. Finally, the recognition of E. regalis from central Alberta is an important datum linking contemporaneous occurrences in southern Alberta with slightly older records of this species from the Wapiti Formation in northwestern Alberta.

  • 4. Benson, Roger B. J.
    et al.
    Campione, Nicolàs E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi.
    Carrano, Matthew T.
    Mannion, Philip D.
    Sullivan, Corwin
    Upchurch, Paul
    Evans, David C.
    Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage2014Ingår i: PLoS biology, ISSN 1544-9173, E-ISSN 1545-7885, Vol. 12, nr 5, s. e1001853-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Large-scale adaptive radiations might explain the runaway success of a minority of extant vertebrate clades. This hypothesis predicts, among other things, rapid rates of morphological evolution during the early history of major groups, as lineages invade disparate ecological niches. However, few studies of adaptive radiation have included deep time data, so the links between extant diversity and major extinct radiations are unclear. The intensively studied Mesozoic dinosaur record provides a model system for such investigation, representing an ecologically diverse group that dominated terrestrial ecosystems for 170 million years. Furthermore, with 10,000 species, extant dinosaurs (birds) are the most speciose living tetrapod clade. We assembled composite trees of 614-622 Mesozoic dinosaurs/birds, and a comprehensive body mass dataset using the scaling relationship of limb bone robustness. Maximum-likelihood modelling and the node height test reveal rapid evolutionary rates and a predominance of rapid shifts among size classes in early (Triassic) dinosaurs. This indicates an early burst niche-filling pattern and contrasts with previous studies that favoured gradualistic rates. Subsequently, rates declined in most lineages, which rarely exploited new ecological niches. However, feathered maniraptoran dinosaurs (including Mesozoic birds) sustained rapid evolution from at least the Middle Jurassic, suggesting that these taxa evaded the effects of niche saturation. This indicates that a long evolutionary history of continuing ecological innovation paved the way for a second great radiation of dinosaurs, in birds. We therefore demonstrate links between the predominantly extinct deep time adaptive radiation of non-avian dinosaurs and the phenomenal diversification of birds, via continuing rapid rates of evolution along the phylogenetic stem lineage. This raises the possibility that the uneven distribution of biodiversity results not just from large-scale extrapolation of the process of adaptive radiation in a few extant clades, but also from the maintenance of evolvability on vast time scales across the history of life, in key lineages.

  • 5.
    Benson, Roger B. J.
    et al.
    Univ Oxford, Dept Earth Sci, S Parks Rd, Oxford OX2 3AN, England..
    Hunt, Gene
    Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, POB 37012,MRC 121, Washington, DC 20560 USA..
    Carrano, Matthew T.
    Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, POB 37012,MRC 121, Washington, DC 20560 USA..
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Cope's rule and the adaptive landscape of dinosaur body size evolution2018Ingår i: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 61, nr 1, s. 13-48Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The largest known dinosaurs weighed at least 20million times as much as the smallest, indicating exceptional phenotypic divergence. Previous studies have focused on extreme giant sizes, tests of Cope's rule, and miniaturization on the line leading to birds. We use non-uniform macroevolutionary models based on Ornstein-Uhlenbeck and trend processes to unify these observations, asking: what patterns of evolutionary rates, directionality and constraint explain the diversification of dinosaur body mass? We find that dinosaur evolution is constrained by attraction to discrete body size optima that undergo rare, but abrupt, evolutionary shifts. This model explains both the rarity of multi-lineage directional trends, and the occurrence of abrupt directional excursions during the origins of groups such as tiny pygostylian birds and giant sauropods. Most expansion of trait space results from rare, constraint-breaking innovations in just a small number of lineages. These lineages shifted rapidly into novel regions of trait space, occasionally to small sizes, but most often to large or giant sizes. As with Cenozoic mammals, intermediate body sizes were typically attained only transiently by lineages on a trajectory from small to large size. This demonstrates that bimodality in the macroevolutionary adaptive landscape for land vertebrates has existed for more than 200million years.

  • 6.
    Brink, Kirstin S.
    et al.
    University of Toronto.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Hawthorn, Jessica R.
    University of Toronto.
    Amniote faunal revision of the Pictou Group (Permo-Carboniferous), Prince Edward Island, Canada2013Ingår i: Comptes rendus. Palevol, ISSN 1631-0683, E-ISSN 1777-571X, Vol. 12, nr 7–8, s. 473-485Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The amniote faunal assemblages from the Pictou Group (Prince Edward Island, Canada) are re-evaluated for the first time in 50 years. Fossils recovered from formations within this group (Orby Head, Hillsborough River, and Kildare Capes) indicate the presence of a parareptile, representing the first occurrence of a non-synapsid amniote from the PEI redbeds. The amniote taxa from PEI are re-described within the context of current research, providing the basis for an updated faunal list for the vertebrate-bearing formations within the Pictou Group. The presence of a parareptile, diadectid, and possibly two synapsids (caseid and/or varanopid), together with the absence of edaphosaurids and definitive ophiacodontids, suggests similarities with the upland Bromacker and Richards Spur localities of Germany and Oklahoma, respectively. However, more research and new fossil discoveries are needed to confidently resolve the systematics and palaeoecology of amniotes from the Lower Permian of Atlantic Canada.

  • 7.
    Brown, Caleb M.
    et al.
    Tyrrell Museum of Paleontology.
    Campione, Nicolas E.
    Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.
    Giacomini, Henrique C.
    University of Toronto.
    O'Brien, Lorna J.
    University of Toronto.
    Vavrek, Matthew J.
    Philip J. Currie Dinosaur Museum.
    Evans, David C.
    Royal Ontario Museum.
    Ecological modelling, size distributions and taphonomic size bias in dinosaur faunas: a comment on Codron et al. (2012)2013Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, nr 1, s. 20120582-Artikel i tidskrift (Refereegranskat)
  • 8.
    Brown, Caleb M.
    et al.
    Tyrrell Museum of Paleontology.
    Evans, David C.
    Royal Museum of Nature.
    Campione, Nicolas E.
    Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.
    O'Brien, Lorna J.
    University of Toronto.
    Eberth, David A.
    Tyrrell Museum of Paleontology.
    Evidence for taphonomic size bias in the Dinosaur Park Formation (Campanian, Alberta), a model Mesozoic terrestrial alluvial‐paralic system2013Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 372, nr SI, s. 108-122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A study of the distribution of dinosaurian body masses in the Dinosaur Park Formation (DPF; Campanian; southern Alberta), reveals a prominent negative skew; a pattern distinct from those of modern terrestrial faunas. We find a direct and robust correlation between taxon size (estimated live body mass) and known completeness. There is a clear dichotomy between large and small-bodied taxa at around 60 kg, in which taxa less than 60 kg are significantly less complete (mean completeness = 7.6%) than those with an estimated mass of 60 kg or greater (mean = 78.2%). Along with completeness, there is also a strong association of body size and taphonomic mode, with small taxa known largely from isolated and occasionally associated remains, and large taxa known from articulated skeletons. In addition, there is a significant correlation between taxon body mass and both date of discovery and of description, with taxa < 60 kg taking an average of 65.9 and 75.6 years to discover and describe, respectively, compared to 33.6 and 34.1 years for taxa > 60 kg. The rates of both cumulative discovery and description for large taxa are best described by a logarithmic curve nearing an asymptote, whereas small taxa show either a linear or power increase through time. This suggests that our current knowledge of the large-bodied dinosaur assemblage is reasonably representative of the true biological fauna with few discoveries likely to be made in the future. However, small taxa are greatly underestimated in both their diversity and abundance, with many more potential discoveries to be made. Given that (1) the sedimentary deposits and fossil assemblages in the DPF together represent one of the best studied examples of a Mesozoic alluvial‐paralic (terrestrial) ‘palaeoecosystem,’ and (2) similar patterns have been suggested (but not documented) for other Mesozoic terrestrial ecosystems in the Western Interior of North America, we suggest that this pattern of size bias may typify vertebrate fossil assemblages in terrestrial Mesozoic systems. If so, such biases must be considered before patterns of diversity in dinosaur communities through time can be considered accurate, or used to compare and interpret Mesozoic palaeoecosystems.

  • 9. Brown, Caleb Marshall
    et al.
    VanBuren, Collin S.
    Larson, Derek W.
    Brink, Kirstin S.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Vavrek, Matthew J.
    Evans, David C.
    Tooth counts through growth in diapsid reptiles: implications for interpreting individual and size-related variation in the fossil record2015Ingår i: Journal of Anatomy, ISSN 0021-8782, E-ISSN 1469-7580, Vol. 226, nr 4, s. 322-333Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Tooth counts are commonly recorded in fossil diapsid reptiles and have been used for taxonomic and phylogenetic purposes under the assumption that differences in the number of teeth are largely explained by interspecific variation. Although phylogeny is almost certainly one of the greatest factors influencing tooth count, the relative role of intraspecific variation is difficult, and often impossible, to test in the fossil record given the sample sizes available to palaeontologists and, as such, is best investigated using extant models. Intraspecific variation (largely manifested as size-related or ontogenetic variation) in tooth counts has been examined in extant squamates (lizards and snakes) but is poorly understood in archosaurs (crocodylians and dinosaurs). Here, we document tooth count variation in two species of extant crocodylians (Alligator mississippiensis and Crocodylus porosus) as well as a large varanid lizard (Varanus komodoensis). We test the hypothesis that variation in tooth count is driven primarily by growth and thus predict significant correlations between tooth count and size, as well as differences in the frequency of deviation from the modal tooth count in the premaxilla, maxilla, and dentary. In addition to tooth counts, we also document tooth allometry in each species and compare these results with tooth count change through growth. Results reveal no correlation of tooth count with size in any element of any species examined here, with the exception of the premaxilla of C.porosus, which shows the loss of one tooth position. Based on the taxa examined here, we reject the hypothesis, as it is evident that variation in tooth count is not always significantly correlated with growth. However, growth trajectories of smaller reptilian taxa show increases in tooth counts and, although current samples are small, suggest potential correlates between tooth count trajectories and adult size. Nevertheless, interspecific variation in growth patterns underscores the importance of considering and understanding growth when constructing taxonomic and phylogenetic characters, in particular for fossil taxa where ontogenetic patterns are difficult to reconstruct.

  • 10.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Postcranial Anatomy of Edmontosaurus regalis (Hadrosauridae) from the Horseshoe Canyon Formation, Alberta, Canada2014Ingår i: Hadrosaurs: Proceedings of the International Hadrosaur Symposium / [ed] David A. Ebert, David C. Evans, Indiana University Press, 2014, s. 208-244Kapitel i bok, del av antologi (Refereegranskat)
  • 11.
    Campione, Nicolas E.
    et al.
    Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
    Brink, Kirstin S.
    University of Toronto.
    Freedman, Elizabeth A.
    Montana State University.
    McGarrity, Christopher T.
    University of Toronto.
    Evans, David C,
    Royal Ontario Museum.
    Glishades ericksoni’, an indeterminate juvenile hadrosaurid from the Two Medicine Formation of Montana: implications for hadrosauroid diversity in the latest Cretaceous (Campanian-Maastrichtian) of western North America2013Ingår i: Palaeobiodiversity and Palaeoenvironments, ISSN 1867-1594, Vol. 93, nr 1, s. 65-75Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Glishades ericksoni was named on the basis of partial paired premaxillae collected from the Late Campanian Two Medicine Formation of Montana, and was described as a non-hadrosaurid hadrosauroid. This interpretation of G. ericksoni has significant implications for hadrosauroid diversity and distribution because it represents the first occurrence of a non-hadrosaurid hadrosauroid in the Late Campanian of North America, and therefore implies either a prolonged period of sympatry between these forms and hadrosaurids or a biotic interchange with Asia. Given its small size, and therefore potential juvenile status, the taxonomic identity of G. ericksoni is re-evaluated here. Comparison with similarly-sized, taxonomically determinate, and coeval hadrosaurid specimens from the Two Medicine Formation (ProsaurolophusGryposaurus, andMaiasaura) suggest that the combination of characters used to distinguish G. ericksoni as a non-hadrosaurid hadrosauroid are more widely distributed or individually variable in hadrosaurids, or can be explained as the result of ontogenetic variation. In particular, the unique combination of characters used to diagnose G. ericksoni is also found in juvenile individuals of Prosaurolophus,Gryposaurus, and Maiasaura. Inclusion of juveniles of these taxa, scored on the basis of comparable anatomy, in the original phylogenetic analysis recovers the juvenile hadrosaurid specimens outside Hadrosauridae. Consequently, G. ericksoni cannot be confidently differentiated from a juvenile saurolophine, which are common in the upper and middle sections of the Two Medicine Formation, and is thus considered a nomen dubium. Given their absence in well-sampled Late Campanian and Maastrichtian deposits, non-hadrosaurid hadrosauroids appear to have been completely replaced by hadrosaurids in western North America by the Late Campanian.

  • 12. Campione, Nicolas E.
    et al.
    Evans, David C.
    Royal Ontario Museum.
    A universal scaling relationship between body mass and proximal limb bone dimensions in quadrupedal terrestrial tetrapods2012Ingår i: BMC Biology, ISSN 1741-7007, E-ISSN 1741-7007, Vol. 10, s. 60-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background

    Body size is intimately related to the physiology and ecology of an organism. Therefore, accurate and consistent body mass estimates are essential for inferring numerous aspects of paleobiology in extinct taxa, and investigating large-scale evolutionary and ecological patterns in the history of life. Scaling relationships between skeletal measurements and body mass in birds and mammals are commonly used to predict body mass in extinct members of these crown clades, but the applicability of these models for predicting mass in more distantly related stem taxa, such as non-avian dinosaurs and non-mammalian synapsids, has been criticized on biomechanical grounds. Here we test the major criticisms of scaling methods for estimating body mass using an extensive dataset of mammalian and non-avian reptilian species derived from individual skeletons with live weights.

    Results

    Significant differences in the limb scaling of mammals and reptiles are noted in comparisons of limb proportions and limb length to body mass. Remarkably, however, the relationship between proximal (stylopodial) limb bone circumference and body mass is highly conserved in extant terrestrial mammals and reptiles, in spite of their disparate limb postures, gaits, and phylogenetic histories. As a result, we are able to conclusively reject the main criticisms of scaling methods that question the applicability of a universal scaling equation for estimating body mass in distantly related taxa.

    Conclusions

    The conserved nature of the relationship between stylopodial circumference and body mass suggests that the minimum diaphyseal circumference of the major weight-bearing bones is only weakly influenced by the varied forces exerted on the limbs (that is, compression or torsion) and most strongly related to the mass of the animal. Our results, therefore, provide a much-needed, robust, phylogenetically corrected framework for accurate and consistent estimation of body mass in extinct terrestrial quadrupeds, which is important for a wide range of paleobiological studies (including growth rates, metabolism, and energetics) and meta-analyses of body size evolution.

  • 13.
    Campione, Nicolas E.
    et al.
    Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
    Evans, David C.
    Royal Ontario Museum.
    Cranial Growth and Variation in Edmontosaurs (Dinosauria: Hadrosauridae): Implications for Latest Cretaceous Megaherbivore Diversity in North America2011Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, nr 9, s. e25186-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The well-sampled Late Cretaceous fossil record of North America remains the only high-resolution dataset for evaluating patterns of dinosaur diversity leading up to the terminal Cretaceous extinction event. Hadrosaurine hadrosaurids (Dinosauria: Ornithopoda) closely related to Edmontosaurus are among the most common megaherbivores in latest Campanian and Maastrichtian deposits of western North America. However, interpretations of edmontosaur species richness and biostratigraphy have been in constant flux for almost three decades, although the clade is generally thought to have undergone a radiation in the late Maastrichtian. We address the issue of edmontosaur diversity for the first time using rigorous morphometric analyses of virtually all known complete edmontosaur skulls. Results suggest only two valid species, Edmontosaurus regalis from the late Campanian, and E. annectens from the late Maastrichtian, with previously named taxa, including the controversial Anatotitan copei, erected on hypothesized transitional morphologies associated with ontogenetic size increase and allometric growth. A revision of North American hadrosaurid taxa suggests a decrease in both hadrosaurid diversity and disparity from the early to late Maastrichtian, a pattern likely also present in ceratopsid dinosaurs. A decline in the disparity of dominant megaherbivores in the latest Maastrichtian interval supports the hypothesis that dinosaur diversity decreased immediately preceding the end Cretaceous extinction event.

  • 14.
    Campione, Nicolas E.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi.
    Evans, David C.
    Brown, Caleb M.
    Carrano, Matthew T.
    Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions2014Ingår i: Methods in Ecology and Evolution, ISSN 2041-210X, E-ISSN 2041-210X, Vol. 5, nr 9, s. 913-923Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Body mass is strongly related to both physiological and ecological properties of living organisms. As a result, generating robust, broadly applicable models for estimating body mass in the fossil record provides the opportunity to reconstruct palaeobiology and investigate evolutionary ecology on a large temporal scale. A recent study provided strong evidence that the minimum circumference of stylopodial elements (humerus and femur) is conservatively associated with body mass in living quadrupeds. Unfortunately, this model is not directly applicable to extinct bipeds, such as non-avian dinosaurs. This study presents a new equation that mathematically corrects the quadruped equation for use in bipeds. It is derived from the systemic difference in the circumference-to-area scaling relationship of two circles (hypothetical quadruped) and one circle (hypothetical biped), which represent the cross-section of the main weight-bearing limb bones. When applied to a newly constructed data set of femoral circumferences and body masses in living birds, the new equation reveals errors that are significantly lower than other published equations, but significantly higher than the error inherent in the avian data set. Such errors, however, are expected given the unique overall femoral circumference-body mass scaling relationship found in birds. Body mass estimates for a sample of bipedal dinosaurs using the new model are consistent with recent estimates based on volumetric life reconstructions, but, in contrast, this equation is simpler to use, with the concomitant potential to provide a wider set of body mass estimates for extinct bipeds. Although it is evident that no one estimation model is flawless, the combined use of the corrected quadrupedal equations and the previously published quadrupedal equation offer a consistent approach with which to estimate body masses in both quadrupeds and bipeds. These models have implications for conducting large-scale macroevolutionary analyses of body size throughout the evolutionary history of terrestrial vertebrates, and, in particular, across major changes in body plan, such as the evolution of bipedality in archosaurs and quadrupedality in dinosaurs.

  • 15.
    Campione, Nicolas E.
    et al.
    Carleton University , Ottawa , Canada.
    Holmes, Robert
    University of Alberta.
    The anatomy and homologies of the ceratopsid syncervical2006Ingår i: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809, Vol. 26, nr 4, s. 1014-1017Artikel i tidskrift (Refereegranskat)
  • 16.
    Campione, Nicolas E.
    et al.
    University of Toronto, Department of Ecology and Evolutionary Biology, Toronto, Canada.
    Reisz, Robert R.
    University of Toronto Mississauga.
    Morphology and evolutionary significance of the atlas-axis complex in varanopid synapsids2011Ingår i: Acta Palaeontologica Polonica, ISSN 0567-7920, E-ISSN 1732-2421, Vol. 56, nr 4, s. 739-748Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The atlas−axis complex has been described in few Palaeozoic taxa, with little effort being placed on examining variation of this structure within a small clade. Most varanopids, members of a clade of gracile synapsid predators, have well preserved atlas−axes permitting detailed descriptions and examination of morphological variation. This study indicates that the size of the transverse processes on the axis and the shape of the axial neural spine vary among members of this clade. In particular, the small mycterosaurine varanopids possess small transverse processes that point posteroventrally, and the axial spine is dorsoventrally short, with a flattened dorsal margin in lateral view. The larger varanodontine varanopids have large transverse processes with a broad base, and a much taller axial spine with a rounded dorsal margin in lateral view. Based on outgroup comparisons, the morphology exhibited by the transverse processes is interpreted as derived in varanodontines, whereas the morphology of the axial spine is derived in mycterosaurines. The axial spine anatomy of Middle Permian South African varanopids is reviewed and our interpretation is consistent with the hypothesis that at least two varanopid taxa are present in South Africa, a region overwhelmingly dominated by therapsid synapsids and parareptiles.

  • 17.
    Campione, Nicolas E.
    et al.
    University of Toronto at Mississauga, Mississauga, Ontario, Canada.
    Reisz, Robert R.
    University of Toronto Mississauga.
    Varanops brevirostris (Eupelycosauria: Varanopidae) from the Lower Permian of Texas, with discussion of varanopid morphology and interrelationships2010Ingår i: Journal of Vertebrate Paleontology, ISSN 0272-4634, E-ISSN 1937-2809, Vol. 30, nr 3, s. 724-746Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A comprehensive revision of Varanops brevirostris on the basis of a large, well-preserved specimen from a new Lower Permian locality in Texas provides valuable new anatomical information and additional autapomorphies for this varanopid synapsid taxon. These include the loss of the postorbital boss, the presence of a smooth transition between the dorsal and lateral surfaces of the postorbital, hypertrophied basipterygoid processes, the presence of deep, elongate lateral neural spine excavations, posterior dorsal vertebrae with dorsally tapered neural spines, and a deep groove proximal to the femoral fourth trochanter. Furthermore, this specimen is the first fully developed adult specimen of Varanops, and it preserves the most complete lower jaw of the taxon. A revised phylogenetic analysis places V. brevirostris as the sister taxon to the Varanodon-Watongia clade. A stratocladistic analysis assessing varanopid relationships by incorporating a stratigraphic character into the analysis recovers the same topology among varanodontines, but an alternate topology between mycterosaurines and Elliotsmithia longiceps.

  • 18.
    Cuthbertson, Robin S.
    et al.
    University of Calgary.
    Mallon, Jordan C.
    Canadian Museum of Nature.
    Campione, Nicolas E.
    Carleton Univ, Dept Earth Sci, Ottawa, Canada.
    Holmes, Robert B.
    University of Alberta.
    A new species of mosasaur (Squamata: Mosasauridae) from the Pierre Shale (lower Campanian) of Manitoba2007Ingår i: Canadian journal of earth sciences (Print), ISSN 0008-4077, E-ISSN 1480-3313, Vol. 44, nr 5, s. 593-606Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Plioplatecarpus nichollsae, sp. nov., from the lower Campanian (Pembina Member, Pierre Shale Formation) is diagnosed by the following: a thickened ventral rim of the external naris, a short supratemporal fenestra, a frontal shield with well-developed posterolateral lappets that overlap the parietal dorsally, proximal rib shafts with an approximately circular (but not inflated) cross section, a scapula shaped as in other Plioplatecarpus species but approximately the same size (not larger) than the coracoid, and a moderately large parietal foramen that reaches the frontoparietal suture but does not invade the frontal. The last two characters require that the diagnosis of the genus Plioplatecarpus be emended. With other Plioplatecarpus species, P. nichollsae shares a robust humerus with a distal expansion at least as great as the total length of the bone, a rectangular preorbital frontal shield, a "peg and socket" postorbitofrontal-jugal articulation, a transversely directed ectopterygoid process of the pterygoid, a large, robust quadrate with a distinct eminence on the posterior surface of its shaft, an unossified gap in the ventral wall of the basioccipital, and at least 11 pygal vertebrae. P. nichollsae also shares primitive features with Platecarpus, as well as features apparently intermediate betweenPlatecarpus and Plioplatecarpus. Revision of the genus Platecarpus, currently hypothesized to be both paraphyletic and polyphyletic, as well as a better understanding of the early Campanian mosasaur fauna from the Morden area, are necessary before the phylogenetic significance of some of these characters, and therefore the relationships of Plioplatecarpus nichollsae, can be fully resolved.

  • 19.
    Den Boer, Wendy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Uppsala universitet, Enheten för musik och museer, Evolutionsmuseet.
    Kear, Benjamin P.
    Uppsala universitet, Enheten för musik och museer, Evolutionsmuseet.
    Autopodial Anatomy Elucidate Climbing Ability in Miocene Balbarid 'kangaroos' (Marsupialia, Macropodifromes)Manuskript (preprint) (Övrigt vetenskapligt)
  • 20.
    Den Boer, Wendy
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Swedish Nat Hist Museum, Dept Palaeobiol, S-10405 Stockholm, Sweden.
    Campione, Nicolás E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för organismbiologi, Evolution och utvecklingsbiologi. Univ New England, Palaeosci Res Ctr, Sch Environm & Rural Sci, Armidale, NSW 2531, Australia.
    Kear, Benjamin P.
    Uppsala universitet, Enheten för musik och museer, Evolutionsmuseet.
    Climbing adaptations, locomotory disparity and ecological convergence in ancient stem 'kangaroos'2019Ingår i: Royal Society Open Science, E-ISSN 2054-5703, Vol. 6, nr 2, artikel-id 181617Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Living kangaroos, wallabies and rat-kangaroos (Macropodoidea) constitute the most ecologically diverse radiation of Australasian marsupials. Indeed, even their hallmark bipedal hopping gait has been variously modified for bounding, walking and climbing. However, the origins of this locomotory adaptability are uncertain because skeletons of the most ancient macropodoids are exceptionally rare. Some of the stratigraphically oldest fossils have been attributed to Balbaridae-a clade of potentially quadrupedal stem macropodoids that became extinct during the late Miocene. Here we undertake the first assessment of balbarid locomotion using two-dimensional geometric morphometrics and a correlative multivariate analysis of linear measurements. We selected the astragalus and pedal digit IV ungual as proxies for primary gait because these elements are preserved in the only articulated balbarid skeleton, as well as some unusual early Miocene balbarid-like remains that resemble the bones of modern tree-kangaroos. Our results show that these fossils manifest character states indicative of contrasting locomotory capabilities. Furthermore, predictive modelling reveals similarities with extant macropodoids that employ either bipedal saltation and/or climbing. We interpret this as evidence for archetypal gait versatility, which probably integrated higher-speed hopping with slower-speed quadrupedal progression and varying degrees of scansoriality as independent specializations for life in forest and woodland settings.

  • 21.
    Evans, David C.
    et al.
    Royal Ontario Museum.
    Bavington, Rebecca
    University of Toronto MIssissauga.
    Campione, Nicolas E.
    Royal Ontario Museum, Toronto, Canada.
    An unusual hadrosaurid braincase from the Dinosaur Park Formation and the biostratigraphy of Parasaurolophus(Ornithischia: Lambeosaurinae) from southern Alberta2009Ingår i: Canadian journal of earth sciences (Print), ISSN 0008-4077, E-ISSN 1480-3313, Vol. 46, nr 11, s. 791-800Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The lambeosaurine hadrosaurid Parasaurolophus is known from rare occurrences in Campanian deposits of western North America. A previously undescribed large hadrosaurid braincase from the Dinosaur Park Formation (Alberta, Canada) is assigned to the genusParasaurolophus on the basis of several derived characters associated with the frontal–nasal articulation at the base of the crest. This identification is supported by two separate phylogenetic analyses, in which the specimen clusters with other more completely known Parasaurolophusexemplars. If correctly identified, the specimen represents the third and largest cranial specimen of the genus from the Late Cretaceous of Alberta. The specimen occurs in the same deposits as the holotype specimen of Parasaurolophus walkeri and may represent a late ontogenetic stage of this taxon. As opposed to a small frontal dome in the holotype of P. walkeri, the external contribution of the frontal to the skull roof is obliterated in the new specimen. If these hypothesized ontogenetic changes in the skull roof correlate with the size and posterodorsal development of the crest, as in other lambeosaurines, it suggests that the crest had not reached its full expression in the holotype. When placed into a detailed biostratigraphic context for the first time, the limited Parasaurolophus material from the Belly River Group is distributed in the lower half of the Dinosaur Park Formation at Dinosaur Provincial Park. This suggests thatParasaurolophus may be associated with the lower Centrosaurus–Corythosaurus assemblage zone and may have preferred more inland environments than other hadrosaurids, such asLambeosaurus and Prosaurolophus.

  • 22.
    Larson, Derek W.
    et al.
    University of Toronto.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Brown, Caleb M.
    Tyrrell Museum of Paleontology.
    Evans, David C.
    Royal Ontario Museum.
    Ryan, Michael J.
    Cleveland Museum of Natural History.
    Hadrosauroid material from the Santonian Milk River Formation of Alberta, Canada2014Ingår i: Hadrosaurs: Proceedings of the International Hadrosaur Symposium / [ed] David A. Eberth, David C. Evans, Indiana University Press, 2014, s. 136-152Kapitel i bok, del av antologi (Refereegranskat)
  • 23.
    Modesto, Sean P.
    et al.
    Cape Breton University.
    Smith, Roger M. H.
    Iziko Museums of South Africa.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Reisz, Robert R.
    University of Toronto Missisauga.
    The last “pelycosaur”: a varanopid synapsid from the PristerognathusAssemblage Zone, Middle Permian of South Africa2011Ingår i: Die Naturwissenschaften, ISSN 0028-1042, E-ISSN 1432-1904, Vol. 98, nr 12, s. 1027-1034Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on a partial varanopid skull and mandible from the Pristerognathus Assemblage Zone of the Beaufort Group, in the South African Karoo Basin, which is probably latest Middle Permian (Capitanian) in age. This mycterosaurine is not only the youngest known varanopid from the Southern Hemisphere, but it is also the youngest known “pelycosaur” (i.e., non-therapsid synapsid). Like all other members of this clade of hypercarnivores, the teeth are strongly flattened, recurved, and have finely serrated cutting edges. The anterior dentary teeth form a caniniform region, and the splenial features a foramen intermandibularis oralis, the first ever to be described in a “pelycosaur.” The last varanopids were the smallest carnivores of latest Middle Permian continental faunas. Occupation of the small carnivore guild appears to have allowed varanopids to achieve a nearly cosmopolitan distribution throughout the Middle Permian, between the great Early Permian radiation of basal synapsids and the spectacular diversification of therapsid synapsids in the Late Permian and Early Triassic.

  • 24. VanBuren, Collin S.
    et al.
    Campione, Nicolas E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Paleobiologi.
    Evans, David C.
    Head size, weaponry, and cervical adaptation: Testing craniocervical evolutionary hypotheses in Ceratopsia2015Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 69, nr 7, s. 1728-1744Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The anterior cervical vertebrae form the skeletal connection between the cranial and postcranial skeletons in higher tetrapods. As a result, the morphology of the atlas-axis complex is likely to be shaped by selection pressures acting on either the head or neck. The neoceratopsian (Reptilia:Dinosauria) syncervical represents one of the most highly modified atlas-axis regions in vertebrates, being formed by the complete coalescence of the three most anterior cervical vertebrae. In ceratopsids, the syncervical has been hypothesized to be an adaptation to support a massive skull, or to act as a buttress during intraspecific head-to-head combat. Here, we test these functional/adaptive hypotheses within a phylogenetic framework and critically examine the previously proposed methods for quantifying relative head size in the fossil record for the first time. Results indicate that neither the evolution of cranial weaponry nor large head size correlates with the origin of cervical fusion in ceratopsians, and we, therefore, reject both adaptive hypotheses for the origin of the syncervical. Anterior cervical fusion has evolved independently in a number of amniote clades, and further research on extant groups with this peculiar anatomy is needed to understand the evolutionary basis for cervical fusion in Neoceratopsia.

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