Geological history and within-island diversity: a debris avalanche and the Tenerife lizard Gallotia galloti

R.P. Brown, P. Hoskisson, J. Welton, M. Baez

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Several processes have been described that could explain geographical variation and speciation within small islands, including fragmentation of populations through volcanic eruptions. Massive landslides, or debris avalanches, could cause similar effects. Here we analyse the potential impact of the 0.8 million-year-ago (Ma) Güimar valley debris avalanche on the phylogeography of the lizard Gallotia galloti on the Canary Island of Tenerife. Distributions of mitochondrial DNA lineages (based on cytochrome b sequences) were analysed on a 60-km southeastern coast transect centred on this area. Three main clades were detected, which can be divided into northern (one clade) and southern (two clades) groups that introgress across the valley. Maximum-likelihood estimates of migration rates (scaled for mutation rate) revealed highly asymmetric patterns, indicating that long-term gene flow into this region from both the northern and the southern populations greatly exceeded that in the opposite directions, consistent with recolonization of the area. The ancestral Tenerife node on the G. galloti tree is estimated at 0.80 Ma, matching closely with the geological estimate for the debris avalanche. Morphological variation (body dimensions and scalation) was also analysed and indicated a stepped cline in female scalation across the valley, although the patterns for male scalation and male and female body dimensions were not as clear. Together these findings provide support for the hypothesis that the debris avalanche has shaped the phylogeography of G. galloti and may even have been a primary cause of the within-island cladogenesis through population fragmentation and isolation. Current estimates of timing of island unification mean that the original hypothesis that within-island diversity is explained by the secondary contact of populations from the two ancient precursor islands of Teno and Anaga is less plausible for this and some other Tenerife species. Large-scale landslides have occurred on many volcanic islands, and so may have been instrumental in shaping within-island diversities.
LanguageEnglish
Pages3631-3640
Number of pages9
JournalMolecular Ecology
Volume15
Issue number12
DOIs
Publication statusPublished - 14 Aug 2006

Fingerprint

Avalanches
mass movement
debris avalanche
Lizards
Islands
lizard
lizards
History
history
Landslides
Phylogeography
valleys
landslides
phylogeography
valley
Population
landslide
fragmentation
Genetic Speciation
Volcanic Eruptions

Keywords

  • Geological history
  • diversity
  • debris avalanche
  • lizard
  • Gallotia galloti
  • geographical variation

Cite this

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Geological history and within-island diversity: a debris avalanche and the Tenerife lizard Gallotia galloti. / Brown, R.P.; Hoskisson, P.; Welton, J.; Baez, M.

In: Molecular Ecology, Vol. 15, No. 12, 14.08.2006, p. 3631-3640.

Research output: Contribution to journalArticle

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