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Detecting a signature of adaptive radiation: diversification in Lake Tanganyika catfishes

Peart, CR; (2015) Detecting a signature of adaptive radiation: diversification in Lake Tanganyika catfishes. Doctoral thesis , UCL (University College London). Green open access

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Abstract

This thesis compares two independent radiations of catfish in Lake Tanganyika, Claroteine and Synodontis catfishes, to investigate generalities in patterns and processes of diversification between radiations in an ancient “island-like” environment. The introductory chapter places this work in a theoretical context and explores previous research on taxa from Lake Tanganyika. Chapter two provides the first molecular phylogeny of species in the sub-family Claroteinae from Lake Tanganyika, including additional putative species of the genus Phyllonemus. This phylogeny is fossil calibrated to assess when diversification occurred and molecular species delimitation is also performed. Chapter three investigates geographic structure in one species from each radiation, Lophiobagrus cyclurus (from the Claroteine radiation) and Synodontis multipunctatus. Each species was sampled from multiple localities along the length of Lake Tanganyika and their DNA sequenced using restriction site associated (RAD) sequencing to produce large genomic datasets. These datasets allow the comparison of geographic patterns between taxa and, in the Lophiobagrus dataset (which also includes the closely related species L. aquilus), an investigation into the extent of introgression. Chapter four investigates niche partitioning and morphological diversification in both the claroteine and Synodontis radiations. These analyses are conducted using a single dated molecular phylogeny containing both of the radiations allowing explicit comparisons. Eco-morphological divergence is assessed using both morphological measurements thought to be ecologically relevant (e.g., size of the eye) and stable isotope ratios of both nitrogen and carbon as a proxy for niche space. While the first three chapters investigate generalities in the patterns and drivers of diversification by comparing two independent radiations in the same “island-like” environment, Chapter fives takes a different approach by placing one of the Lake Tanganyika radiations, Synodontis, in its broader phylogenetic context. In this chapter morphological diversification is investigated in the largely riverine continental radiation of Synodontis found throughout sub-Saharan Africa.

Type: Thesis (Doctoral)
Title: Detecting a signature of adaptive radiation: diversification in Lake Tanganyika catfishes
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Third party copyright material has been removed from ethesis.
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences
URI: https://discovery.ucl.ac.uk/id/eprint/1461240
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