ECOLOGICAL INTERACTIONS BETWEEN RHIPIDOMELLA (ORTHIDES, BRACHIOPODA) AND ITS ENDOSKELETOBIONTS AND PREDATORS FROM THE MIDDLE DEVONIAN DUNDEE FORMATION OF OHIO, UNITED STATES

Abstract

Abstract Only the small (2.0 ± 0.1 cm) orthide brachiopod Rhipidomella in the Middle Devonian Dundee Formation exposed at Whitehouse Quarry, Ohio, preserves evidence of interactions with endoskeletobionts and predators (39.6%, n  =  48), as opposed to the slightly larger atrypides, spiriferides, and stropheodonts (n  =  245). All traces of predation and boring by other organisms are lacking on such larger brachiopods as strophomenides and spiriferides, which are more often encrusted in Devonian localities of North America—the Silica Shale of Ohio, Hamilton Group of New York, and Cedar Valley Limestone of Iowa. Punctate shells of Rhipidomella preserve interactions with endoskeletobionts and predators, phenomena less common for punctate brachiopods. All traces on Rhipidomella were preserved as endoskeletobionts; if calcified encrusters were present, they likely were lost postmortem. Several Rhipidomella individuals bear partially repaired grooves from parasitic interactions with sinuous, boring organisms, a...