Biotic Diversity and Vertebrate Evolution in Late Devonian Non-Marine Ecosystems (Catskill Formation: Eastern North America)

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9628163 Shubin The Late Devonian was an important interval in the history of non-marine ecosystems because it contains the evolutionary diversification of most major groups of jawed fish, the development of ecologically modern floral assemblages, and the invasion of land by vertebrates. Most of the higher taxa that first appear at this time are to dominate the composition of the world's biotas for over 350 million years. Recent discoveries in the Late Devonian of Pennsylvania reveal well-preserved, highly diverse vertebrate assemblages that occur in close stratigraphic proximity to macrofossil plants, palynomorphs, arthropods, and bivalves. The biotic diversity provides the basis for global syntheses on the phylogeny and biogeographic distribution of basal vertebrates as well as an understanding of the ecosystems in which they evolved. This proposal seeks funds to both document and interpret the biotic diversity of the non-marine facies of the upper portion of the Catskill Delta (Late Devonian-Early Mississippian, eastern North America). The first major goal is to investigate the phylogenetic affinities and stratigraphic position of known fossil assemblages; these combined data allow both intraformation and global comparisons of biotic diversity. Assessment of intraformational stratigraphic relationships enables an understanding of the biotic diversity in different portions of the Catskill Delta system. Strontium isotope geochemistry and sedimentological analysis are used to infer life habits of Devonian vertebrates. The goal of these approaches is to reconstruct the environments in which the earliest tetrapods lived and assess the barriers that affected the dispersal of Devonian vertebrates. These data, when integrated with both phylogenetic and geographic data of Devonian vertebrates. These data, when integrated with both phylogenetic and geographic data of non-marine organisms, will provide new insights on the biotic composition of Devonian continents as well as the evolutionar y diversification of early tetrapods and fish. This analysis will inform: 1) higher level phylogenetic hypotheses of gnathostome vertebrates, 2) biogeographic analysis of the distribution of the tetrapods and jawed fish, and 3) paleobiological analysis of the elaboration of terrestrial and freshwater ecosytems.