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8
Australian region after YOUNG
(1996) who discusses why the Australian Devonian scheme utilises as zones EDDIGE( ensensis , norrisi) certain of the subzones in the standard scheme (see, e.g., W 1996). OUNG
Thelodont assemblages (fig. 4, column C) were first proposed by Y (1995) and augmented by T URNER(1997b); the scales are found mostly in shallow water facies and tend to dominate in numbers when thus found. Acanthodians are proving more prevalent in a range of deeper water facies types and in time might prove more ALIUKEVICIUS 's standard scheme are now being found in southuseful for international correlation; taxa from V China for instance (see B URROWet al., this volume). In reference to fig. 4 the following assemblages are URROWproposed as biostratigraphically significant:
a) Silurian assemblage (mid-Ludlow to Pridoli): three taxa are named which might be united under a Gomphonchus turnerae assemblage. The presence of Sinacanthus type spines is still doubtful and there are undetermined ischnacanthid and other remains still to assess (B & T URNER , this volume). Thisassemblage has potential correlation value to Irian Jaya and S. China. ALIUKEVICIUS
b) lower Lochkovian assemblage (Early Devonian): Nostolepis striata ? and Poracanthodes sp. cf. P. porosus if verified, provide correlation with the northern hemisphere (fig. 2; V & K RUCHEKthis INTERvolume, fig. 1).
c) late Lochkovian-early Pragian assemblage (Early Devonian): taxa combined here under Turinia australiensis -Trundlelepis -Terenolepisinclude the palaeoniscoid Terenolepis turnerae, the lophosteiform Lophosteus incrementus , a series of probable endemic placoderms, onychodonts, porolepiforms. The late delta or pesavis s.s. transgression event is typified by this assemblage in eastern and possibly western Australia.
d) pirenae-dehiscens CZ assemblage (Early Devonian): a Turinia sp. cf. T. australiensis - Kadunglelepis - Ligulalepis toombsi assemblage comprising a possible new species of Turinia, Jerulalepis picketti, Kadunglelepis serrata (now thought to be a cladodont shark), Ohiolepis sp., and acanthodian Nostolepoides platymarginata . Gomphonchus ? bogongensisoccurs but might appear earlier in the sulcatus CZ.
e) A later Emsian assemblage includes Buchanosteus , Weejasperaspis , Goodradigbeeon and Murrindalaspis placoderm scales, with acanthodian Cheiracanthoides wangi .
Later assemblages cannot yet be defined except for thelodonts and the presence of key phoebodont taxa, which give correlations to the standard phoebodont scale of G & I VANOV(fig. 3 here; G INTER& I VANOVthis volume, fig. 2). Other taxa which have been noted elsewhere are stipulated.
Conclusions
International Geological Correlation Project 328: Palaeozoic Microvertebrate Biochronology and Global
Marine/Non-Marine Correlation extended from 1991 to 1996 with the major objective of coordinating research on Palaeozoic microvertebrates, by integrating new data from developed and developing countries to establish an effective global database of Palaeozoic taxa. During the lifespan of the project the taxonomy of important lower vertebrates and closely related groups has been clarified by publications and workshops. We even eventually have tried to recognise "mini" tetrapod bits to see if we can pinpoint or extend the origin of the four-legged animals back in time. By using fish microremains and the individual databases set up, this knowledge has been