Microvertebrate assemblages from the Lower Devonian (pesavis/sulcatus zones) of central New South Wales, Australia

Determination of microvertebrates in samples collected from 20 sites of the Lower Devonian (pesavis/sulcatus conodont zones) Trundle Beds, Jerula Formation and Gleninga Formation of central New South Wales reveals significant associations which are of use for biostratigraphy. There are two different faunal groupings in the Trundle Beds (pesavis/sulcatus zone). Group A features scales of a climatiid acanthodian Nostolepoides platymarginata nov. gen. et sp., an ischnacanthid? acanthodian Gomphonchus? bogongensis sp. nov., acanthodian Machaeracanthus sp., chondrichthyan Ohiolepis? sp., palaeoniscoid Ligulalepis toombsi Schultze, thelodont Turinia cf T. australiensis Gross and a variety of placoderms; Group B contains scales of ischnacanthid acanthodians Trundlelepis cervicostulata gen. et sp. nov. and Gomphonchus? guangxiensis (Wang), Machaeracanthus sp., acanthodian teeth, jaw and spine fragments, and diverse placoderms and sarcopterygians. The Gleninga Formation (pesavis/lower sulcatus zone) fauna features a high proportion of the scales of Turinia cf T. australiensis, Nostolepoides platymarginata nov. gen. et sp., Gomphonchus? bogongensis nov. sp., Machaeracanthus sp., Ligulalepis toombsi Schultze and a diverse collection of placoderm scales, sarcopterygian fragments and onychodont teeth. The Jerula Formation (sulcatus zone) samples are characterized by an abundance of scales of the thelodont Turinia cf T. australiensis and two placoderms plus onychodont teeth and other sarcopterygian fragments. In the Jerula and Gleninga Formations thelodont scales are more abundant than acanthodian scales, reflecting a possible littoral origin. In the Trundle Beds, acanthodian scales are more abundant than thelodont, indicating a depositional environment further offshore. This hypothesis is consistent with the condition of preservation of the scales, and the associated conodont assemblages.