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Keywords:

  • Acanthodii;
  • Gondwana;
  • Teresina Formation;
  • Middle-Late Permian;
  • scales;
  • fin spines

Abstract

Acanthodian fishes have been recorded from Silurian through to Permian rocks. Bone beds in the Teresina Formation of the Passa Dois Group (Paraná Basin) in São Gabriel, State of Rio Grande do Sul (southern Brazil) have yielded acanthodian scales and fin spine fragments and are preserved in association with shark and lower actinopterygian fish scales and teeth and possible shark fin spines. All fish remains are disarticulated and preservation is often fragmentary. However, there is no geological or palaeontological evidence that the materials in these bone beds, of Middle-Late Permian age, could have been re-worked from older strata. We therefore interpret these bone beds and the acanthodian remains as the youngest known record of acanthodians worldwide. The presence of acanthodians in the Passa Dois Group enhances the significance of the Middle-Upper Permian rocks of the Paraná Basin in South America in interregional correlation, and may contribute to the discussion of the allegedly global mass extinction event at the end of the Palaeozoic era. Copyright © 2007 John Wiley & Sons, Ltd.