Publication Date

Fall 2012

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Advisor

Leslee Parr

Keywords

cryptic species, genetics, ghost shrimp, Neotrypaea californiensis, Neotrypaea gigas, phylogeography

Subject Areas

Genetics; Ecology; Biology

Abstract

Many marine species produce larvae that disperse and develop into post-larvae in the open ocean over a period of weeks to months. However, the patterns and potential of larvae to disperse across long geographic distances are poorly understood. Here genetic variation found at the mitochondrial locus, cytochrome C oxidase subunit I, in adult ghost shrimp, Neotrypaea californiensis, was used as a proxy to infer dispersal potential of ghost shrimp larvae found in estuaries along the west coast of the United States. Multiple haplotypes were shared among 346 adult ghost shrimp specimens collected from estuaries in Washington, Oregon, and California indicated that larvae of this species are transported across great distances during the pelagic dispersal phase of development. Interestingly, extreme population structure (FST ranged from 0.062 to 0.98) was observed among sampling sites located in close proximity to one another. Phylogenetic analyses and analysis of molecular variance revealed that the cause of population structure was in part attributed to the presence of three putative cryptic species that were deeply divergent from N. californiensis. Qualitative and quantitative morphological measurements commonly employed for shrimp species identification were inconsistent among putative cryptic species groups but did show that the newly identified cryptic species were not undiagnosed individuals of the closest relative of N. californiensis, N. gigas.

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