Fossils in the mountains: Understanding the relationship between biodiversity and geography during the Early Palaeozoic

Fossils in the mountains: Understanding the relationship between biodiversity and geography during the Early Palaeozoic

 

The eminent Alpine geologist, Rudolf Trümpy once stated, ‘One bad fossil is worth a good working hypothesis’. Although characterized by poor preservation, fossils have for many decades provided age and geographic constraints on the evolution of the World’s mountain belts. Palaeontological data helped expose horizontal and lateral crustal movements and signalled the importance of continental drift as a planetary-scale process. In Europe and North America the bioregionality of many fossil groups has provided key data for the definition of continents, microcontinents and volcanic arcs and their movements during the Early Palaeozoic. Moreover, identification of species pumps and refugia in the island terranes of the Iapetus and related oceans, now exposed along the length of the Caledonian-Appalachian orogenic belt, has enhanced our knowledge of the Great Ordovician Biodiversification Event and the Late Ordovician Mass Extinction. Mechanisms for the diversification and extinction of taxa can be hypothesized and many terranes hold key evidence on the early evolution and phylogeny of marine animal groups. The movement of most crustal units towards lower latitudes and their carbonate environments during the later Ordovician is correlated with the highest species richness of the period terminated by the intense, short-lived Hirnantian ice age.