Phylogeography and ecology of New Zealand freshwater Amphipoda (Paracalliope, Paraleptamphopus, and Phreatogammarus)
type: CreativeWork
description: This thesis examines phylogenetic patterns in three New Zealand amphipod taxa in relation to current geographic distributions and historical climatic (e.g. glaciation, marine inundation) and geological (e.g. mountain building) events using DNA sequencing and distributional data. It also examines how recognition behaviour can be used to delineate potential species boundaries and to assess the role of sexual selection. The endemic genus Phreatogammarus has been found in only a limited number of sites and is not very abundant. An analysis of the genetic variation of two species within the genus using allozyme electrophoresis revealed high levels of genetic differentiation among populations but low levels within populations. This suggested that limited dispersal occurred among habitats with one population possibly representing a cryptic species. The endemic freshwater genus Paraleptamphopus is thought to contain a large number of undescribed species with a number of these existing in small waterbodies such as seepages. Examination of the phylogeographic patterns using both mtDNA (CO1) and nuclear DNA (28S) showed that a number of distinct genetic lineages exist, with CO1 revealing 21 haplotypes with genetic distance of over 20%. Using a molecular clock rate of 2.4%, most haplotypes diverged approximately 8-12 million years ago during the Miocene era, possibly as a result of greater land availability increasing habitat diversity or by allopatric speciation. Morphological and genetic differences were not congruent, with morphologically similar taxa appearing among highly genetically distinct lineages, and some morphologically distinct forms appearing within single lineages. The distribution and habitat variables of 419 sites were analysed to determine what was affecting the presence or absence of Paraleptamphopus. The presence of native vegetation in catchments had a positive affect on Paraleptamphopus distribution suggesting that large anthropogenic changes in catchment …
abstract: This thesis examines phylogenetic patterns in three New Zealand amphipod taxa in relation to current geographic distributions and historical climatic (e.g. glaciation, marine inundation) and geological (e.g. mountain building) events using DNA sequencing and distributional data. It also examines how recognition behaviour can be used to delineate potential species boundaries and to assess the role of sexual selection. The endemic genus Phreatogammarus has been found in only a limited number of sites and is not very abundant. An analysis of the genetic variation of two species within the genus using allozyme electrophoresis revealed high levels of genetic differentiation among populations but low levels within populations. This suggested that limited dispersal occurred among habitats with one population possibly representing a cryptic species. The endemic freshwater genus Paraleptamphopus is thought to contain a large number of undescribed species with a number of these existing in small waterbodies such as seepages. Examination of the phylogeographic patterns using both mtDNA (CO1) and nuclear DNA (28S) showed that a number of distinct genetic lineages exist, with CO1 revealing 21 haplotypes with genetic distance of over 20%. Using a molecular clock rate of 2.4%, most haplotypes diverged approximately 8-12 million years ago during the Miocene era, possibly as a result of greater land availability increasing habitat diversity or by allopatric speciation. Morphological and genetic differences were not congruent, with morphologically similar taxa appearing among highly genetically distinct lineages, and some morphologically distinct forms appearing within single lineages. The distribution and habitat variables of 419 sites were analysed to determine what was affecting the presence or absence of Paraleptamphopus. The presence of native vegetation in catchments had a positive affect on Paraleptamphopus distribution suggesting that large anthropogenic changes in catchment …
author: Sutherland, Darin Lee
keywords: genetics, evolution, Crustacea, species diversity, species recognition
date published: 2006
date modified: 2026-07-24T05:57:52Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Waikato