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Insular biogeographic origins and high phylogenetic distinctiveness for a recently depleted lizard fauna from Christmas Island, Australia

Biology Letters

By:
, , , ORCID iD , ORCID iD , and
https://doi.org/10.1098/rsbl.2017.0696

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Abstract

Striking faunal turnover across Asia and Australasia, most famously along the eastern edge of the Sunda Shelf or ‘Wallace's Line’, has been a focus of biogeographic research for over 150 years. Here, we investigate the origins of a highly threatened endemic lizard fauna (four species) on Christmas Island. Despite occurring less 350 km south of the Sunda Shelf, this fauna mostly comprises species from clades centred on the more distant regions of Wallacea, the Pacific and Australia (more than 1000 km east). The three most divergent lineages show Miocene (approx. 23–5 Ma) divergences from sampled relatives; and have recently become extinct or extinct in the wild, likely owing to the recent introduction of a southeast Asian snake (Lycodon capucinus). Insular distributions, deep phylogenetic divergence and recent decline suggest that rather than dispersal ability or recent origins, environmental and biotic barriers have impeded these lineages from diversifying on the continental Sunda Shelf, and thereby, reinforced faunal differentiation across Wallace's Line. Our new phylogenetically informed perspective further highlights the rapid loss of ancient lineages that has occurred on Christmas Island, and underlines how the evolutionary divergence and vulnerability of many island-associated lineages may continue to be underestimated.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Insular biogeographic origins and high phylogenetic distinctiveness for a recently depleted lizard fauna from Christmas Island, Australia
Series title:
Biology Letters
DOI:
10.1098/rsbl.2017.0696
Volume:
14
Issue:
6
Year Published:
2018
Language:
English
Publisher:
The Royal Society
Contributing office(s):
Western Ecological Research Center
Description:
Article 20170696; 5 p.
First page:
1
Last page:
5
Country:
Australia
Other Geospatial:
Christmas Island