A Bilaterally Partitioned Colour Variant of an Appalachian Brook Crayfish (Cambarus bartonii bartonii) from eastern Pennsylvania

Abstract

This observation of a bilaterally partitioned colour phenotype of an Appalachian Brook Crayfish (Cambarus bartonii bartonii) from Fishing Creek, Columbia County, Pennsylvania, USA, appears to be the first report of such an aberrant phenotype for this species. The pattern is similar to that reported previously in Papershell Crayfish (Orconectes immunis) and Ameri can Lobster (Homarus americanus). Although the cause of the colour pattern in the specimen of C. b. bartonii could not be determined, hypotheses related to previous cases in aquatic crustaceans include bilateral partition of primary and secondary sexual characteristics (bicoloured gynandromorphy) and mutation during embryogenesis.