Meeting Abstract

P1.89  Sunday, Jan. 4  Molecular markers for studying the distributions of the intertidal ghost shrimp Neotrypaea californiensis and N. gigas DECONINCK, A.; PERNET, B.**; California State University, Long Beach; California State University, Long Beach bpernet@csulb.edu

The vigorous burrowing activities of thalassinidean shrimp have such dramatic effects on their soft sediment habitats that these animals have sometimes been considered both ecosystem engineers and keystone species. Because they are such strong interactors, basic information about their life histories and population dynamics is needed to effectively manage the habitats in which they live. These data, however, can only be obtained if the shrimp can be accurately identified. On the west coast of the United States, two species of burrowing intertidal shrimp in the genus Neotrypaea, N. californiensis and N. gigas, are currently recognized (a third species, N. biffari, does not burrow in soft sediments). The two burrowing species are not easily differentiated morphologically except as adult males that bear a master claw (which is often lost in collection), which has led to uncertainty about their distributions. Here we describe and validate (using mtDNA data) allozyme markers that can be scored rapidly and inexpensively for the identification of these species. Surveys using these markers reveal that both species coexist at most sites surveyed in southern California, with some sites dominated by one or the other, but that N. californiensis is heavily dominant to the north of Pt. Conception. We also report on morphological analyses aimed at identifying characters useful for differentiating male, female and juvenile ghost shrimp on the west coast of the US.