Genetic and morphological data supporting the hypothesis of adaptive radiation in the endemic fish of Lake Matano

Abstract

Adaptive radiation resulting from differential selection acting on functional features is believed to be an important source of biodiversity. In this study, morphometric measures and mitochondrial DNA are used to test for adaptive radiation within four fish genera (Glossogobius, Oryzias, Dermogenys and Telmatherina) endemic to an ancient island lake (Lake Matano, Sulawesi, Indonesia), using the framework proposed by Schluter (The Ecology of Adaptive Radiation, Oxford University Press, 2000). We demonstrate common ancestry and rapid divergence in one genus (Telmatherina) based on 560 bp of 16S sequence data. We found higher levels of variation in feeding‐related traits (N = 8) for Telmatherina relative to the other genera, while no differences were found for sexual display traits (N = 8) or neutral morphological traits (N = 8). Telmatherina also had the highest number of distinct colouration patterns among the four genera. These data, combined with the very low productivity of the lake, are indicative of selection driving adaptive radiation. The morphometric divergence in the Telmatherina likely results from selection acting on feeding traits in this low productivity lake, leading to trophic specialization among closely related morphotypes. These results provide indirect but compelling data supporting the adaptive radiation of Telmatherina in this system.

DNA Barcoding Indonesian freshwater fishes: challenges and prospects

“…74,75]. Mitochondrial sequencing was performed as one of the initial steps for estimating sailfin silverside species diversity [41,76]. In agreement with morphology and nuclear data, mitochondrial markers resolved major lineages of the radiation [41], and provided valuable insights into the phylogenetic history, the origin, and time estimates of its divergence [77].…”

“…For instance, introgressive hybridization between stream-and lake-dwelling sailfin silversides [78] has lead to severe confusion in previous studies relying solely on mitochondrial markers for species delineation [e.g. 73,76,79]. The absence of species-level resolution in mitochondrial markers is not unexpected in evolving radiations, particularly when ecological speciation takes place in the absence of geographical barriers, as observed in the endemic lacustrine species of Lake Matano [80,81].…”

The biogeochemistry of tropical lakes: A case study from Lake Matano, Indonesia

“…The region around Lake Matano receives an average rainfall of 2,737 mm per year and has an average temperature of 24uC with a range of 22-31uC (Hope 2001). The Malili Lakes are the principal freshwater resource in the region and also host a unique and diverse aquatic ecosystem (Von Rintelen and Glaubrecht 2003;Roy et al 2004;Herder et al 2006). Ancient lakes, such as Lake Matano, have relatively stable physical characteristics and are therefore conducive to the development of high degrees of species endemism.…”

Adaptive radiation and hybridization in Wallace's Dreamponds: evidence from sailfin silversides in the Malili Lakes of Sulawesi

“…However, to understand the mechanisms shaping whole radiations, model systems should be larger than a single species pair but small enough to be covered almost completely. Recent molecular phylogenetic evidence based on freshwater gastropods (von Rintelen et al 2004) and fishes (Roy et al 2004) suggest strongly that the organismic diversity of the Malili Lakes of Central Sulawesi (Indonesia) may represent such a system. This ancient lake system (Brooks 1950) consists of the three main lakes, Matano, Towuti and Mahalona, and two smaller lakes, Lontoa and Masapi (figure 1).…”