A DIMINUTIVE LATE DEVONIAN RECOVERY FAUNA FROM THE CLEVELAND SHALE

The Hangenberg Event was one of several extinction pulses at the end of the Devonian period marked by significant diversity loss and ecological turnover. Although the long term consequences of this event are quite well documented, the immediate aftermath is less well constrained. This study presents a fossilized fauna immediately after the Hangenberg Event that is preserved in the uppermost Cleveland Formation in Northern Ohio and compares it to the well established fauna from the overlying Bedford Formation. Four localities from which the Hangenberg Event has been previously constrained reveal that a diminutive, pyritized recovery fauna, while locally abundant, was geographically limited. The fauna is dominated by brachiopods, with less common bivalves and gastropods. They are rarely greater than 1 cm along the greatest axis and they range from fragmented to butterflied in preservation. This fauna contrasts in size and dominant taxa from the abundant and diverse Bedford fauna found at these localities just several meters above the recovery fauna interval. We interpret the Hangenberg recovery fauna to represent opportunists making an initial colonization during ongoing stressful conditions associated with the extinction event.