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Title: Systematics and evolution of New Caledonian Araucaria
Author: Kranitz, Mai-lan
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2005
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13 of the world’s 19 Araucaria species are endemic to New Caledonia. This thesis has investigated the evolution and systematics of this group. A molecular phylogenetic study based on sequence data from two chloroplast regions resolved all 13 New Caledonian species as a monophyletic group, sister to the Norfolk Island Pine (A. heterophylla). The relationships between the New Caledonian species was not fully resolved as little sequence variability was detected, however, three main groups were defined. The species with bigger leaves occupied a basal polytomy, whereas the vast majority of species with smaller leaves were grouped together in a clade. Within this ‘small leaved’ clade, the three New Caledonian species with a coastal distribution formed another monophyletic group. The timing of the radiation of all these species was tested via a molecular clock approach using different calibration tools (fossil data, geological events, substitution rates). The precise dating of the New Caledonian radiation remains uncertain because different calibration methods give different dates. However, it seems likely to have occurred between 10 and 43 mya. A combination of molecular and morphological approaches was used to assess species limits and population identities. This resulted in re-determination of the identity of several populations and the distributions of some species. The current state of knowledge of the taxonomy of the New Caledonian species was summarised. Finally, the distribution of chloroplast haplotypes among 468 individuals from 49 populations representing all New Caledonian Araucaria revealed strong taxonomic signal, and high genetic diversity among the species with bigger leaves, and low diversity in the coastal species. The distribution of genetic variation is discussed in the context of the evolution and conservation of the New Caledonian Araucaria spp.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available