EBC

Native of Montréal, Canada, Catherine received both her BSc and her MSc from McGill University. In 2004, she completed a Master's degree in Paleontology under the supervision of Dr. Robert L. Carroll. The title of her thesis is "Vertebral development and its evolution in modern salamanders" and her work focused on the integration of new developmental characters within the phylogenetic context of the evolution and interrelationships of modern amphibians. Before her master's degree, Catherine completed a Bachelor of sciences, majoring in biology with a minor in prehistoric archaeology. During this period, she carried out two research projects, one of them related to her Master's work and the other one, under the supervision of Dr. David Green, on the morphological basis for the classification of three sub-species of Thamnophis sirtalis (Garter snake).

Research interests:

Catherine's current PhD work involves both paleontology and developmental biology as well as some genetics. Once upon in the Devonian, around 360 million years ago, the first vertebrates invaded land. The morphological changes needed to accomplish this transition were great, which is why pretty much everybody in this group is working on it. Catherine works on the evolutionary changes that occurred in the pelvic girdle across this transition. In all sarcopterygian (lobe-finned) fishes, the pelvic girdle is a simple unipartite structure which is not linked to the vertebral column but serves for the attachment of the fin skeleton and musculature. In tetrapods, the pelvis is a complex, tripartite (ishium, ilium and pubis) structure connected to the vertebral column through a sacral rib. The evolution of this robust pelvic morphology was essential to allow the first amphibians to crawl on land, but surprisingly few people have investigated how this important transition occurred. Catherine's project approaches this problem from several angles. On the one hand, she studies the pelvic morphology of fossil sarcopteryians and early tetrapods, as well as the morphology and myology of some modern tetrapods and fish. This diversity of pelvic morphology will be set within a phylogenetic context. She will also be examining the development of the pelvis and associated musculature in the axolotl (Ambystoma mexicanum) and the Australian lungfish (Neoceratodus forsteri). Neoceratodus is one of the very few living sarcopterygians and serve as a proxy for the morphology and development observed in fish closely related to the first tetrapods. Urodeles like Ambystoma have the most primitive pelvic morphology among living tetrapods, allowing us to use their morphology and development as a proxy for primitive tetrapods. In order to examine the early development of the pelvic girdle and associated musculature in those two amphibians, Catherine will be using traditional techniques like immunostaining and clearing and staining as well as developping versions of immunostaining more specific to salamanders, the lungfish and expression of genes of interest. The information gathered from all the sources mentionned above will then be integrated to understand how the specialised tetrapod pelvic anatomy came into being. In a self-contained component of the project, to be carried out in collaboration with Prof Joss and Dr Zerina Johanson (Australian Museum, Sydney), Catherine will investigate the expression of the genes Pitx-1, Pitx-2, Tbx4 and Tbx5 in the pelvic fin of Neoceratodus. These genes contribute to the determination of appendage identity in both fishes and tetrapods, but Tbx4 and 5 have recently been found to have a distinctive and anomalous expression pattern in salamanders. The data from Neoceratodus will help to determine whether the salamander pattern is autapomorphous or represents the primitive tetrapod condition. Finally, if time allows, Catherine will undertake a survey of genes known to be associated with pelvic (and in particular sacral) malformation in standard lab tetrapods (principally mouse), and will attempt to investigate the expression patterns of some of these genes in Neoceratodus and/or axolotl. She may also use gene knockdown techniques such as morpholinos or RNAi to investigate the role of specific genes in patterning the sacrum of Ambystoma.

Publications:

Boisvert, C. A. 2005. The pelvic fin and girdle of Panderichthys and the origin of tetrapod locomotion. Nature vol 438, p 1145-1147
Boisvert, C. A. 2005. A lobe-finned fish sheds new light on the origin of the tetrapod pelvic girdle. Journal of Vertebrate Paleontology vol 25 supplement 3, p 38a
Boisvert, C. A. 2005. Pelvic girdle transformations from lobe-finned fish to tetrapods. PaleoBios 25:20.
Boisvert, C. A. 2005. Pelvic morphology in sarcopterygians and tetrapods: novelties at the fish-tetrapod boundary. GFF 127:45.
Clément, G., and C. A. Boisvert. In press. Lohest's true and false "Devonian amphibians": evidence for a rhynchodipterid lungfish in the Late Famennian of Belgium. Journal of Vertebrate Paleontology.
Carroll, R. L., C. Boisvert, J. Bolt, D. M. Green, N. Philips, C. Rolian, R. Schoch, and A. Tarenko. 2004. Changing patterns of ontogeny from osteolepiform fish through Permian tetrapods as a guide to the early evolution of land vertebrates.; pp. 321-342 in G. Arratia, R. Cloutier, and M. V. H. Wilson (eds.), Recent advances in the origin and early radiation of vertebrates. Verlag Dr. Friedrich Pfeil, München.

Unpublished thesis

Boisvert, C. A. 2004. Vertebral development and its evolution in modern salamanders. Department of Biology, McGill University, Montréal, 78 pp., 7 colour plates, 103 appendices

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