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Ancient mitochondrial genomes unveil the origins and evolutionary history of New Zealand’s enigmatic takahe and moho

Verry, Alexander1

Published Nov 24, 2023 on Dryad. https://doi.org/10.5061/dryad.j0zpc86mz

Data files

Nov 24, 2023 version files 6.55 GB

Abstract

Many avian species endemic to Aotearoa New Zealand were driven to extinction or reduced to relict populations following successive waves of human arrival, due to hunting, habitat destruction, and the introduction of mammalian predators. Among the affected species were the large flightless South Island takahe (Porphyrio hochstetteri) and the moho (North Island takahe; P. mantelli), with the latter rendered extinct and the former reduced to a single relictual population. Little is known about the evolutionary history of these species prior to their decline and/or extinction. Here we sequenced mitochondrial genomes from takahe and moho subfossils (12 takahe and four moho) and retrieved comparable sequence data from takahemuseum skins (n = 5) and contemporary individuals (n = 17) to examine the phylogeny and recent evolutionary history of these species. Our analyses suggest that prehistoric takahepopulations lacked deep phylogeographic structure, in contrast to moho, which exhibited significant spatial genetic structure, albeit based on limited sample sizes (n = 4). Temporal genetic comparisons show that takahe have lost much of their mitochondrial genetic diversity, likely due to a sudden demographic decline soon after human arrival (~750 years ago). Time-calibrated phylogenetic analyses strongly support a sister-species relationship between takahe and moho, suggesting these flightless taxa diverged around 1.5 million years ago, following a single colonisation of New Zealand by a flighted Porphyrio ancestor approximately four million year ago. This study highlights the utility of palaeogenetic approaches for informing the conservation and systematic understanding of endangered species whose ranges have been severely restricted by anthropogenic impacts.