Meeting Abstract

P3.191  Friday, Jan. 6  Sexual Dimorphism and Species Distinctions in the Genus Edotia (Crustacea: Isopoda) BOYKO, CB*; MOSCATO, DJ; Dowling College; Dowling College cboyko@amnh.org

Since 1818, 21 species of isopods have been described in the genus Edotia. Two of these have been removed to other genera and two have been relegated to synonymy. In the northwestern Atlantic three species have been described: E. triloba (Say, 1818), E. montosa (Stimpson, 1853), and E. acuta (Richardson, 1900). There has been discussion concerning the relative distinctiveness of these three species and some zoologists, starting with Wallace (1919), argued that the latter two species are not distinct enough for recognition and are synonymous with E. triloba. Others consider E. triloba and E. montosa as distinct (Kropp 1995), while yet others recognize all three species (Brandt and Bruce 2006). A preliminary study of samples from Georgia indicated that each northwestern Atlantic species of Edotia may represent different sexes and/or stages of development. We examined a large series of Edotia to address the issue of such ambiguous distinctions. Morphological proportions and sexes of over 130 specimens obtained from various collections and from throughout the range of the three species (ca. Nova Scotia to Georgia) were recorded. There is a clear sexual dimorphism between males and females based on the relative proportions of pereomere widths relative to body length. The ratio of length to width in males was found to be larger than in females. Our data suggests that there is only a single species of Edotia in the northwestern Atlantic. Based on this data and a review of the literature, there is a need to revise the genus in order to clarify the distinctions between Edotia species worldwide. Some species may be based on only a single sex but few descriptions or mentions of Edotia specimens in the literature include data on the sex of specimens.