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

在特殊的化石沉积物中发现的完整的鱼类化石骨骼产生了丰富的信息。在我的实验室里，我们把重点放在这些沉积物上，以了解生活在志留纪和泥盆纪早期(4亿至4.3亿年前)的物种的起源、关系、生活方式和解剖特征，当时早期有颌骨的脊椎动物和它们的无颌近亲丰富多样。这些特殊的化石矿藏位于加拿大北部的麦肯齐山脉、西北部等地。 一个地方至少有73种早期脊椎动物，包括无颌型和与鲨鱼和硬骨鱼有关的早期有颌形脊椎动物。大多数都是完整的骨架。其中一些可以让我们检查骨骼的生长情况。其他人告诉我们身体特征的进化，如成对的鳍、牙齿、耳朵和肠道。这些研究包括与世界其他地方发现的化石进行仔细的比较，并使用现代计算机方法重建生命树。 在摩洛哥的白垩纪，我们正在研究另一个非同寻常的化石遗址中的海洋鱼类。许多鱼类已被发现，并正在进行研究，重点是它们的进化关系和地理历史。我们还研究了根据化石鳞片和脊椎骨计算出的化石鱼类的生长率，以了解它们的生长率对古代气候变化的反应。 通过对鱼类解剖学和DNA的现代研究，活着的鱼类的关系正在得到澄清。新的关系观念引导我们重新审视同一组的化石，看看它们在过去是否被正确解释。这一类型的研究将与美国的同事一起进行，重点是鳕鱼、多利鱼、熊鱼、鲑鱼、海盗、梭鱼和泥鱼家族中的淡水鱼。

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.