Investigating the drivers of diversification in a non-Antarctic notothenioid radiation

Funding Bodies: Yale University

Affiliations: Yale University, SAERI

PhD Project Overview

Notothenioid fishes, which dominate the species diversity, abundance, and biomass of the Antarctic continental shelf ichthyofauna, are an iconic example of adaptive radiation in an extreme marine environment. Interestingly, however, one of the most species-rich notothenioid subclades occurs almost entirely outside of Antarctic waters. Patagonotothen comprises ~15 species distributed in marine habitats around southern South America and the Falkland Islands. Only one species, Patagonotothen guntheri, has a distribution that extends south of the Antarctic Polar Front. Given their high species richness and recent evolutionary origin (3-6 Ma), Patagonotothen is considered a rapid evolutionary radiation nested within the larger notothenioid adaptive radiation, but the drivers of diversification in this clade remain unclear. Persistent uncertainty in species boundaries and phylogenetic relationships has prevented development of a robust evolutionary framework in which to investigate patterns of diversification. The broader objective of this project is to describe existing patterns of lineage, morphological, and ecological diversity of Patagonotothen fishes and to understand how this diversity evolved.

Project Objectives

  • To use molecular and morphological data to delimit species boundaries and to infer evolutionary relationships among delimited species of Patagonotothen
  • To integrate data on phylogeny, phenotype, and ecology in order to characterize evolutionary dynamics of trait disparity within the radiation

Highlights 2020- 2021

  • 1 month placement at SAERI in the Falkland Islands, which provided opportunity for collection of whole fish specimens needed for quantification of phenotypic and ecological traits and tissue samples needed for DNA sequence data collection
  • Extracted whole genomic DNA from tissue samples representing eight species of Patagonotothen; DNA will be sequenced for use in downstream species delimitation and phylogenetic analyses
  • Collected data on body shape variation from whole specimens representing eight Patagonotothen species

Elyse Parker

Dates: Jan 2020 - ongoing
Elyse is currently a PhD candidate at Yale University and has returned to studying Antarctic and sub-Antarctic notothenioids. Her dissertation is focused on investigating patterns of phenotypic, ecological and genetic diversity of notothenioids and understanding how this diversity evolved. To this end, she is working with Dr. Paul Brickle (SAERI) to investigate the evolutionary history of the notothenioid subclade Patagonotothen, which is distributed around the Falkland Islands and southern South America.
Sampling site at Camilla Creek, Falkland Islands.
PO Box 609, Stanley Cottage North
Ross Road, Falkland Islands
Stanley, FIQQ 1ZZ
Falkland Islands: +500 27374
UK Office: +44 (0)203 745 1731
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