14 July 2009As remarkable fossils are unveiled and novel interpretations of existing data are proposed, palaeontologists face new challenging issues, such as establishing the speed and mode of character evolution, the timing of key events in vertebrate history, and the impact of extinct species on hypotheses of relationships.
An international team of 14 specialists (from Australia, England, France, Germany, India, Italy, Japan, Morocco, and Slovak Republic) have now joined efforts to contribute state-of-the-art research on various groups of Palaeozoic and Mesozoic limbed vertebrates.
The volume discusses topics as diverse as comparative morphology, reconstruction of evolutionary relationships, biogeographic distribution, study of growth series, and analytical methods for quantifying morphological variation, using exemplar vertebrate groups as case studies. From gigantic alligator-like amphibians to small armoured reptiles, the volume offers tantalizing glimpses of the past diversity of limbed vertebrates.
“Many of these creatures are neither amphibians nor reptiles proper, at least not as we know them today”, says Marcello Ruta, senior editor and one of the contributors to the volume. “These animals are representatives of those ancient lineages from which extant amphibians, reptiles, birds, and mammals arose.
“When you look at the diversity of extant limbed vertebrates, you immediately identify two broad groups: the amphibians (frogs, salamanders and their allies) on the one hand, and amniotes (reptiles, birds, and mammals) on the other. The ancestry of both groups is deeply rooted into the Palaeozoic bestiary; some of our greatest challenges today imply sorting out the evolutionary affinities of those Palaeozoic animals relative to their living counterparts. This is not a mere question of ‘badging’, because the reconstruction of a solid evolutionary framework has far-reaching implications for understanding the dynamics of Life on Earth, patterns of origination and extinction, and global changes in biodiversity”.
The results appear in the latest issue of the Special Papers in Palaeontology series, co-edited by Dr Marcello Ruta (Department of Earth Sciences, University of Bristol), Professor Jennifer Clack (University Museum of Zoology, University of Cambridge), and Dr Angela Milner (Department of Palaeontology, The Natural History Museum, London).
Flicking through the pages of the Special Papers in Palaeontology volume, you will encounter the bizarre chroniosuchians similar to miniature crocodiles covered in bony scutes, the incredibly long-tailed and salamander-like nectrideans, and the temnospondyls, one of the most speciose and most widely distributed of all extinct amphibian groups. The volume draws from the fascinating world of Palaeozoic limbed vertebrates and amalgamates sophisticated methods of macroevolutionary analysis with traditional – and more exciting than ever – monographic treatments of fossils.
Long before dinosaurs rose to dominance, the forests, rivers, lakes, swamps and seas of our planet hosted a truly astounding variety of vertebrates, unlike anything living today. There, among countless hordes of crawlers and creepers, the great-great-grandmothers of frogs, lizards and humans first hatched.
The Special Papers in Palaeontology is a publication of the Palaeontological Association.
Many of these creatures are neither amphibians nor reptiles proper, at least not as we know them today