*WINNER* Examining Snapping Shrimp Morphology Using Geometric Morphometrics in a Phylogenetic Framework

Abstract

The snapping shrimp genus Alpheus (ca. 331 spp.) comprises an ecologically diverse, species-rich genus that displays a tremendous amount of variation in key morphological characters. However, despite this dramatic variation in morphology, Alpheus is well-known for harboring numerous cryptic species complexes, many of which have been revealed only by molecular tools or subtle phenotypic differences. This necessitates a closer examination of snapping shrimp morphology to identify characteristics of additional diagnostic importance. Our study uses geometric morphometrics in a phylogenetic framework to quantify the shapes of characters that have historically been used in species diagnoses and identification. We digitized the major chelae and rostrums across three species from the Alpheus gracilipes species complex to test the reliability of geometric morphometrics in species diagnosis and will compare our results against those of Nomura & Anker's 2005 study. Additionally, we designed primers specific to Alpheus shrimp to amplify the 12S gene region, and analyzed partial sequences from the COI, 16S, and 12S mitochondrial genes for all shrimps (n = 7) in the Alpheus gracilipes species complex. Results from this study will be used to generate an updated list of diagnostically informative characters and provide a baseline for other species complexes.