Centrosaurus apertus, a large bodied ceratopsid from the Late Cretaceous of North America, is one... more Centrosaurus apertus, a large bodied ceratopsid from the Late Cretaceous of North America, is one of the most common fossils recovered from the Belly River Group. This fossil record shows a wide diversity in morphology and size, with specimens ranging from putative juveniles to fully-grown individuals. The goal of this study was to reconstruct the ontogenetic changes that occur in the craniofacial skeleton of C. apertus through a quantitative cladistic analysis. Forty-seven cranial specimens were independently coded in separate data matrices for 80 hypothetical multistate growth characters and 130 hypothetical binary growth characters. Both analyses yielded the max-limit of 100,000 most parsimonious saved trees and the strict consensus collapsed into large polytomies. In order to reduce conflict resulting from missing data, fragmentary individuals were removed and the analyses were rerun. Among both the complete and the reduced data sets the multistate analyses recovered a shorter t...
Growth series of femora, tibiotarsi, and humeri of the Canada goose Branta canadensis were examin... more Growth series of femora, tibiotarsi, and humeri of the Canada goose Branta canadensis were examined to evaluate whether bone surface textures are reliable indicators of relative age and skeletal maturity in this taxon. The relationship between surface texture and ...
Recent biomechanical evidence has fuelled debate surrounding the winter habits of the hadrosauria... more Recent biomechanical evidence has fuelled debate surrounding the winter habits of the hadrosaurian dinosaur Edmontosaurus (ca. 70 Ma). Using histological characteristics recorded in bone, we show that polar Edmontosaurus endured the long winter night. In contrast, the bone microstructure of temperate Edmontosaurus is inconsistent with a perennially harsh environment. Differences in the bone microstructure of polar and temperate Edmontosaurus consequently dispute the hypothesis that polar populations were migratory. The overwintering signal preserved in the microstructure of polar Edmontosaurus bone offers significant insight into the life history of dinosaurs within the Late Cretaceous Arctic.
Centrosaurus apertus, a large bodied ceratopsid from the Late Cretaceous of North America, is one... more Centrosaurus apertus, a large bodied ceratopsid from the Late Cretaceous of North America, is one of the most common fossils recovered from the Belly River Group. This fossil record shows a wide diversity in morphology and size, with specimens ranging from putative juveniles to fully-grown individuals. The goal of this study was to reconstruct the ontogenetic changes that occur in the craniofacial skeleton of C. apertus through a quantitative cladistic analysis. Forty-seven cranial specimens were independently coded in separate data matrices for 80 hypothetical multistate growth characters and 130 hypothetical binary growth characters. Both analyses yielded the max-limit of 100,000 most parsimonious saved trees and the strict consensus collapsed into large polytomies. In order to reduce conflict resulting from missing data, fragmentary individuals were removed and the analyses were rerun. Among both the complete and the reduced data sets the multistate analyses recovered a shorter t...
Growth series of femora, tibiotarsi, and humeri of the Canada goose Branta canadensis were examin... more Growth series of femora, tibiotarsi, and humeri of the Canada goose Branta canadensis were examined to evaluate whether bone surface textures are reliable indicators of relative age and skeletal maturity in this taxon. The relationship between surface texture and ...
Recent biomechanical evidence has fuelled debate surrounding the winter habits of the hadrosauria... more Recent biomechanical evidence has fuelled debate surrounding the winter habits of the hadrosaurian dinosaur Edmontosaurus (ca. 70 Ma). Using histological characteristics recorded in bone, we show that polar Edmontosaurus endured the long winter night. In contrast, the bone microstructure of temperate Edmontosaurus is inconsistent with a perennially harsh environment. Differences in the bone microstructure of polar and temperate Edmontosaurus consequently dispute the hypothesis that polar populations were migratory. The overwintering signal preserved in the microstructure of polar Edmontosaurus bone offers significant insight into the life history of dinosaurs within the Late Cretaceous Arctic.
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Papers by Allison Tumarkin-deratzian