ORCID Profile
0000-0002-7610-0118
Current Organisation
Ohio University Heritage College of Osteopathic Medicine
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Publisher: Public Library of Science (PLoS)
Date: 26-06-2013
Publisher: Wiley
Date: 14-05-2021
DOI: 10.1111/PALA.12542
Abstract: Morphological convergence can be assessed using a variety of statistical methods. None of the methods proposed to date enable the visualization of convergence. All are based on the assumption that the phenotypes either converge, or do not. However, between species, morphologically similar regions of a larger structure may behave differently. Previous approaches do not identify these regions within the larger structures or quantify the degree to which they may contribute to overall convergence. Here, we introduce a new method to chart patterns of convergence on three‐dimensional models using the R function conv.map . The convergence between pairs of models is mapped onto them to visualize and quantify the morphological convergence. We applied conv.map to a well‐known case study, the sabre‐tooth morphotype, which has evolved independently among distinct mammalian clades from placentals to metatherians. Although previous authors have concluded that sabre‐tooths kill using a stabbing ‘bite’ to the neck, others have presented different interpretations for specific taxa, including the iconic Smilodon and Thylacosmilus . Our objective was to identify any shared morphological features among the sabre‐tooths that may underpin similar killing behaviours. From a s le of 49 placental and metatherian carnivores, we found stronger convergence among sabre‐tooths than for any other taxa. The morphological convergence is most apparent in the rostral and posterior parts of the cranium. The extent of this convergence suggests similarity in function among these phylogenetically distant species. In our view, this function is most likely to be the killing of relatively large prey using a stabbing bite.
Publisher: Wiley
Date: 06-09-2020
DOI: 10.1111/JOA.13285
Publisher: The Royal Society
Date: 12-04-2017
Abstract: Over the past two decades, the development of methods for visualizing and analysing specimens digitally, in three and even four dimensions, has transformed the study of living and fossil organisms. However, the initial promise that the widespread application of such methods would facilitate access to the underlying digital data has not been fully achieved. The underlying datasets for many published studies are not readily or freely available, introducing a barrier to verification and reproducibility, and the reuse of data. There is no current agreement or policy on the amount and type of data that should be made available alongside studies that use, and in some cases are wholly reliant on, digital morphology. Here, we propose a set of recommendations for minimum standards and additional best practice for three-dimensional digital data publication, and review the issues around data storage, management and accessibility.
Publisher: PeerJ
Date: 08-12-2015
DOI: 10.7717/PEERJ.1475
Abstract: Minmi is the only known genus of ankylosaurian dinosaur from Australia. Seven specimens are known, all from the Lower Cretaceous of Queensland. Only two of these have been described in any detail: the holotype specimen Minmi paravertebra from the Bungil Formation near Roma, and a near complete skeleton from the Allaru Mudstone on Marathon Station near Richmond, preliminarily referred to a possible new species of Minmi . The Marathon specimen represents one of the world’s most complete ankylosaurian skeletons and the best-preserved dinosaurian fossil from eastern Gondwana. Moreover, among ankylosaurians, its skull is one of only a few in which the majority of sutures have not been obliterated by dermal ossifications or surface remodelling. Recent preparation of the Marathon specimen has revealed new details of the palate and narial regions, permitting a comprehensive description and thus providing new insights cranial osteology of a basal ankylosaurian. The skull has also undergone computed tomography, digital segmentation and 3D computer visualisation enabling the reconstruction of its nasal cavity and endocranium. The airways of the Marathon specimen are more complicated than non-ankylosaurian dinosaurs but less so than derived ankylosaurians. The cranial (brain) endocast is superficially similar to those of other ankylosaurians but is strongly ergent in many important respects. The inner ear is extremely large and unlike that of any dinosaur yet known. Based on a high number of diagnostic differences between the skull of the Marathon specimen and other ankylosaurians, we consider it prudent to assign this specimen to a new genus and species of ankylosaurian. Kunbarrasaurus ieversi gen. et sp. nov. represents the second genus of ankylosaurian from Australia and is characterised by an unusual melange of both primitive and derived characters, shedding new light on the evolution of the ankylosaurian skull.
Publisher: Public Library of Science (PLoS)
Date: 18-08-2010
Location: United States of America
Location: United States of America
No related grants have been discovered for Lawrence Witmer.