"Morphology, Homology, Phylogeny, and Biogeography of Early Vertebrates and Fossil Fishes"

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Complete skeletons of fossil fishes found in exceptional fossil deposits yield a wealth of information. In my lab we focus on these deposits to learn about the origins, relationships, mode of life, and anatomical features of species that lived during Silurian and Early Devonian time (400 to 430 million years ago), when early vertebrates with jaws and their jawless relatives were abundant and diverse. These exceptional fossil deposits are in the Mackenzie Mountains, NWT and elswhere in northern Canada. One locality contains at least 73 species of early vertebrates, including jawless forms and early jawed vertebrates related to sharks and bony fishes. Most are complete skeletons. Some of them allow us to examine growth of the skeleton. Others tell us about the evolution of body features such as paired fins, teeth, ears, and guts. These studies involve careful comparisons with fossils found elsewhere in the world and use modern computerized methods of reconstructing the tree of life. In the Cretaceous of Morocco we are studying marine fishes from another extraordinary fossil site. Many species of fishes have been recovered and are under study, with emphasis on their evolutionary relationships and their geographic histories. We also study growth rates of fossil fishes calculated from fossil scales and vertebrae, to see how their growth rates responded to ancient climate change. The relationships of living fishes are being clarified by modern studies of their anatomy and their DNA. The new ideas of relationships lead us to re-examine fossils of the same groups, to see whether they have been interpreted correctly in the past. This type of study will be carried out with colleagues in the USA and will focus on the freshwater fishes in the cod, dory, beardfish, troutperch, pirateperch, pike, and mudminnow families.