Devonian Vertebrates in Biostratigraphy D. L. DINELEY (Communicated by A. RITCHIE) DiNELEY, D. L. Devonian vertebrates in biostratigraphy. Proc. Linn. Soc. N.S. W. 107 (3), (1983)1984: 185-196. Standards of" precision in biostratigraphic dating and correlation of marine formations within the Devonian System now call for similar advances in the stratigraphy of non-marine formations. Vertebrates are amongst the fossils most commonly found in non-marine units but are very rare in the marine facies. Use of palynomorphs, macroplants and invertebrates and intensive study of interbedded marine and non-marine facies in all parts of the world are now urgent in clarification of Devonian world stratigraphy. The efforts of vertebrate palaeontologists are vital in this connection. D. L. Dineley, Department of Geology, University of Bristol, Bristol BS8 ITR, United Kingdom A paper read at the Symposium on the Evolution and Biogeography of Early Vertebrates, Sydney and Canberra, February 1983; accepted for publication 18 April 1984, after critical review and revision. Introduction In several parts of the stratigraphic column vertebrates have become recognized as valuable biostratigraphic indices. Vertebrate evolution is comparatively rapid but the disadvantages of vertebrates in biostratigraphy are manifestly well known. Devonian vertebrate biostratigraphy is still in a relatively primitive state, being broadly confined to the continental facies. A notable 'pioneer' Devonian paper was by Gross in 1950 and from the most recent general statement (Westoll, 1979) a summary diagram has been prepared. Between these two mentioned dates Devonian invertebrate biostratigraphy has advanced significantly (House, Scrutton, Bassett, 1979). The International Commission on Stratigraphy, through its Subcommission on the Devonian System, is moving towards the adoption of international formal biostratigraphic definition of the (marine) Series and Stages within the System. So far it has agreed that a) the base of the Middle Devonian is the base of the P. partitus conodont zone. This is approximately the base of the Eifelian stage (Heisdorf-Lauch boundary) in the Rhineland where the stratotype is at Wetteldorf b) the base of the Upper Devonian is the base of the Lower Pa. asymmetricus zone which coincides with the base of the Assize de Frasnes in Belgium c) while the existing stages of the Middle and Upper Devonian will not be discarded, the choice between the Lower Devonian stages of the Ardennes-Rhineland and those of Bohemia as the international standard has yet to be made. Pelagic fossils (especially microfossils) have been useful in this work but correlation of the marine with the non-marine facies lags behind. There is much evidence to suggest that spores and macroplant fossils will ultimately be of greatest value in this work, though there are dangers in the unquestioning use of spores alone. In general, the broad recognition of Lower Devonian, Middle Devonian and Upper Devonian vertebrate faunas can be made, and faunas from the two higher Series are found in all continents except South America. Smaller biostratigraphic units based on vertebrates, however, are exceptional, and in the Lower Devonian the faunas tend to differ between four or five palaeobiogeographical provinces (Young, 1981). As the examination of extensive and critical sections around the Lower/Middle and Middle/Upper Series boundaries has proceeded, it has become obvious that ac-curate correlation of marine horizons with non-marine is particularly wanting and that Proc. Linn. Soc. N.S.W., 107 (3), (1983) 1984
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