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Xing L.,University of Alberta | Xing L.,Chinese Academy of Sciences | Bell P.R.,Pipestone Creek Dinosaur Initiative | Harris J.D.,Dixie State University | Currie P.J.,University of Alberta
Acta Geologica Sinica | Year: 2012

Three-dimensional tracks provide unique insights into the locomotor mechanics of their track makers. An isolated, large hadrosauriform print attributable to Caririchnium lotus from the "mid"-Cretaceous Lotus track site (Jiaguan Formation) in China permits reconstruction of the footfall, weight-bearing, and kick-off phases of the step cycle. Large-scale modifications of the pes during the step cycle indicate C. lotus trackmakers were capable of locomotory modifications in response to substrate consistency beyond the "expected" shift between bipedal and quadrupedal postures. An unusual curvature to the trace of one of the outer digits indicates substantial transverse mobility. The remaining digits demonstrate lesser degrees of transverse movement accompanied by extension of the digits during footfall. The absence of overprinted scale-scratch marks and toe drags are consistent with a vertical kick-off of the pes and concomitant flexion of the digits. This track suggests that pedal mobility in C. lotus track makers was greater than previously suspected and has implications for reconstructions of hadrosauriform locomotion.

Burns M.E.,University of Alberta | Vavrek M.J.,Pipestone Creek Dinosaur Initiative
PLoS ONE | Year: 2014

A sample of six probable fragmentary ankylosaur ossicles, collected from Cenomanian deposits of the Dunvegan Formation along the Peace River, represent one of the first dinosaurian skeletal fossils reported from pre-Santonian deposits in Alberta. Specimens were identified as ankylosaur by means of a palaeohistological analysis. The primary tissue is composed of zonal interwoven structural fibre bundles with irregularly-shaped lacunae, unlike the elongate lacunae of the secondary lamellar bone. The locality represents the most northerly Cenomanian occurrence of ankylosaur skeletal remains. Further fieldwork in under-examined areas of the province carries potential for additional finds. © 2014 Burns, Vavrek.

Bell P.R.,Pipestone Creek Dinosaur Initiative | Fanti F.,University of Bologna | Acorn J.,University of Alberta
Journal of Paleontology | Year: 2013

Fossil mayfly larvae (cf. Heptageniidae) are reported for the first time in the Cretaceous of Canada. The new fossils come from the latest Campanian part of the Wapiti Formation, which crops out in west-central Alberta, near the British Columbia border. These sediments represent mixed lentic and lotic fluvial environments consistent with modern heptageniid ecology. This discovery helps fill a significant temporal gap in heptageniid evolution between the Eocene and their earliest appearance in the Turonian. © 2013 The Paleontological Society.

Bell P.R.,Pipestone Creek Dinosaur Initiative | Coria R.A.,National University of Rio Negro
PLoS ONE | Year: 2013

Paleoepidemiology (the study of disease and trauma in prehistoric populations) provides insight into the distribution of disease and can have implications for interpreting behavior in extinct organisms. A monospecific bonebed of the giant carcharodontosaurid Mapusaurus (minimum number of individuals = 9) from the Cañadón del Gato site, Neuquén Province, Argentina (Cenomanian) provides a rare opportunity to investigate disease within a single population of this important apex predator. Visual inspection of 176 skeletal elements belonging to a minimum of nine individuals yielded a small number of abnormalities on a cervical vertebra, two ribs, pedal phalanx, and an ilium. These are attributed to traumatic (two cases), infectious (two cases) and anomalous (one case) conditions in a minimum of one individual. The emerging picture for large theropod (abelisaurids, allosaurids, carcharodontosaurids, tyrannosaurids) populations suggests that 1) osseous abnormalities were relatively rare (7-19% of individuals) but consistently present, and 2) trauma was a leading factor in the frequency of pathological occurrences, evidence of an active, often perilous lifestyle. © 2013 Bell, Coria.

Bell P.R.,Pipestone Creek Dinosaur Initiative | Brink K.S.,University of Toronto
Cretaceous Research | Year: 2013

The holotype of 'Procheneosaurus' convincens, a juvenile lambeosaurine, is the most complete hadrosaurid known from Kazakhstan. North American species of Procheneosaurus are considered juveniles of Corythosaurus, Hypacrosaurus, and Lambeosaurus, rendering the generic name unusable. A replacement name, Kazaklambia convincens comb. nov., is herein proposed as this specimen is morphologically distinct from other Eurasian taxa and known juvenile lambeosaurines at a similar ontogenetic stage in having a prefrontal process of the postorbital with a dorsal thickening forming a dome lateral to the frontal dome, doming of the nasal anterodorsal to the orbit, and a frontal length/width ratio <1. The juvenile status of Kazaklambia makes phylogenetic placement difficult; however, morphometric and morphological information (particularly in relation to the hollow cranial crest and the length of the frontal) suggest a close affiliation with the basal lambeosaurines Amurosaurus and Tsintaosaurus, and support the hypothesis for an Asian origin for Lambeosaurinae. © 2013 Elsevier Ltd.

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