BIOTIC INTERACTIONS BETWEEN CONULARIIDS AND EPIBIONTS FROM THE SILURIAN WAUKESHA BIOTA

Abstract: Here we describe an epibiont association between conulariids and holdfast producers, with attachment scars resembling those of the tubular epibiont, Sphenothallus, from the Silurian (late Telychian Series) Brandon Bridge Formation, Wisconsin. The conulariid population represents the most abundant sessile organisms in the Waukesha Biota and consists of two species, Conularia niagarensis Hall, 1852 and Metaconularia cf. manni (Roy, 1935). Attachment scars present on the conulariid test offer a unique glimpse into the paleoecology of this Silurian benthic assemblage. However, body fossils of the attached epibiont are scarce and have not been observed attached or near conulariid specimens. This study evaluates the identity and paleoecological relationship between the conulariids and their enigmatic epibionts. Statistical analyses of attachment trace size, frequency, and distribution on the conulariid test gives insight to the nature of their symbiotic relationship. Our results did not find any significant support for a parasitic relationship. However, commensalism cannot be ruled out and serves as an alternative explanation for the relationship between these two organisms.