Age estimates for an adaptive lake fish radiation, its mitochondrial introgression, and an unexpected sister group: Sailfin silversides of the Malili Lakes system in Sulawesi

摘要: The Malili Lakes system in central Sulawesi (Indonesia) is a hotspot of freshwater biodiversity the Wallacea, characterized by endemic species flocks like sailfin silversides (Teleostei: Atherinomorpha: Telmatherinidae) radiation. Phylogenetic reconstructions these fishes have previously revealed two Lake Matano Telmatherina lineages (sharpfins and roundfins) forming an ancient monophyletic group, which however masked introgressive hybridization sharpfins with riverine populations. present study uses mitochondrial data, newly included taxa, different external calibration points, to estimate age speciation processes, test for phylogeographic relationships between Kalyptatherina from islands off New Guinea, Marosatherina SW Sulawesi, flock. Contrary previous expectations, closest relative Telmatherinidae, sister this clade. Palaeogeographic suggest that closer relationship radiation might be explained 'terrane-rafting’ scenario, while proto-Marosatherina colonized marine dispersal. most plausible analysis conducted here implies c. 1.9 My onset divergence major clades Matano. Diversification within both apparently considerably more recent (c. 1.0 My); stream haplotypes are even origin 0.4 My). Sulawesi’s Telmatherinidae likely originated Sahul Shelf area, possibly reached island both, dispersal island/terrane-rafting, rivers. Estimates split epibenthic predominantly pelagic benthopelagic roundfins widely coincide geological estimates rift lake. clearly predates events For Matano, results support scenario initial benthic-pelagic after colonization lake populations, followed rapid last 1 My. Secondary populations occurred recently, has thus not contributed benthic