Diversification of bent-toed geckos (Cyrtodactylus) on Sumatra and west Java

Area of Science:

• Evolutionary Biology
• Island Biogeography
• Geology

Background:

• Island ecosystems are shaped by geological events and connectivity.
• Sumatra and Java have undergone significant geological transformations, including marine incursions and land bridge formation.
• Understanding colonization patterns is key to explaining island biodiversity.

Purpose of the Study:

• To investigate the colonization history and diversification of bent-toed geckos (Cyrtodactylus) on Sumatra and west Java.
• To determine the influence of geological history on island invasions.
• To reconstruct the evolutionary relationships and ancestral ranges of these geckos.

Main Methods:

• Mitochondrial and nuclear DNA sequence data were analyzed.
• Phylogenetic relationships and divergence times were estimated.
• Ancestral range evolution was reconstructed to infer dispersal routes.

Main Results:

• Sumatran and Javan Cyrtodactylus are closely related to Thai-Malay Peninsula species, not Bornean species.
• Cyrtodactylus colonized Sumatra three times during the late Oligocene and early Miocene.
• West Java was colonized once from Sumatra in the early Miocene.

Conclusions:

• Geological history, including land bridge formation, facilitated Cyrtodactylus dispersal between Sundaland and the islands.
• Despite Miocene marine isolation, geckos dispersed via land bridges.
• Multiple instances of in situ diversification occurred on Sumatra.