Assessing the effectiveness of geometric morphometric analysis in the identification of sphaeriidae (Bivalvia: Veneroida).

Abstract

Sphaeriidae, freshwater bivalves common throughout North America, are difficult to identify and, thus, are rarely used in biological and ecological studies. However, geometric morphometric analysis (GMA), which measures morphological shapes using anatomical landmarks, shows promise in improving sphaeriid identification. My goal was to determine whether GMA could accurately identify two similar species of sphaeriids compared to traditional and genomic identification. I used 279 specimens from 45 locations across the Great Lakes, 138 of which were identified using genomics. Each specimen was aged (adults vs. juveniles) and photographed using a microscope camera. Anatomical landmarks were placed on each shell’s photograph to capture shell shape. GMA illustrated the shape differences between the species with thin-plate spline analyses. GMA identifications of adults had high agreement with traditional and genomic methods (87%). However, GMA identification accuracy of juveniles was lower (60% vs. traditional and 50% vs genomic).