Meeting Abstract

P1.27  Monday, Jan. 4  Embryonic development and cardiac morphometrics of the Grass shrimp Palaemonetes pugio ROMNEY, Amie L*; REIBER, Carl L; Univ. of Nevada, Las Vegas; Univ. of Nevada, Las Vegas romneya@unlv.nevada.edu

Variation in developmental strategies among the Decapoda represents their successful adaptation to diverse environmental conditions. Such variation can range from patterns of direct development, where an extensive embryonic period is followed by a shortened larval stage, to patterns of regular development where a shortened embryonic period is followed by a lengthened larval stage. Having multiple larval stages allows for transitional steps throughout development whereby an animal can compensate appropriately for varying environmental parameters. The Grass shrimp, Palaemonetes pugio, inhabits the brackish waters off the Atlantic and Gulf coasts where salinity concentrations constantly fluctuate from daily to seasonally. Larval development of the Grass shrimp has been reported by Broad (1957), yet to fully understand the physiological and morphological ontogeny of these animals, embryonic development must be described. Here, we document the embryonic development of the Grass shrimp and establish an 8 stage sequence. Under control conditions, (25°C, 30-32 ppt sea water), average time for embryonic development took approximately 12 days. Morphological changes were observed under stereomicroscope and further characterized by photo and video imaging. Features of the Grass shrimp throughout development can be used to compare embryonic and larval developmental rates with other Decapoda under various environmental conditions. Furthermore, phenotypic differences within and between similar species can be identified and related to environmental changes and developmental plasticity.