The Lee Creek Enigma, <i>Mclellania aenigma</i>, a New Taxon in Fossil Cirrhipedia

Abstract

An enigmatic fossil, Mclellania aenigma Wilson, new subfamily (Balanidae: Mclellaniinae), genus, and species, found embedded in the shell of the bivalve Mercenaria, occurs in the Pliocene Croatan Formation of Lee Creek, in strata of Yorktown age in North Carolina, Virginia, and Florida, and in the Miocene Choptank Formation of Maryland. The enigmas are calcitic in contrast to the aragonitic shells of Mercenaria. The pattern of growth shows that they are produced in the living shell and are not a result of subsequent diagenetic fossilization. Because of characters in common, they are considered to be thoracican cirripeds, probably parasites. A nomenclatorial revision of the principal host-Mercenaria species resurrects Mercenaria corrugata (Lamarck, 1818).