Paleo-Drainage Basin Connectivity Predicts Evolutionary Relationships across Three Southeast Asian Biodiversity Hotspots

Abstract

Understanding factors driving diversity across biodiversity hotspots is critical for formulating conservation priorities in the face of ongoing and escalating environmental deterioration. While biodiversity hotspots encompass a small fraction of Earth's land surface, more than half the world's plants and two-thirds of terrestrial vertebrate species are endemic to these hotspots. Tropical Southeast (SE) Asia displays extraordinary species richness, encompassing four biodiversity hotspots, though disentangling multiple potential drivers of species richness is confounded by the region's dynamic geological and climatic history. Here, we use multilocus molecular genetic data from dense multispecies sampling of freshwater fishes across three biodiversity hotspots, to test the effect of Quaternary climate change and resulting drainage rearrangements on aquatic faunal diversification. While Cenozoic geological processes have clearly shaped evolutionary history in SE Asian halfbeak fishes, we show that paleo-drainage re-arrangements resulting from Quaternary climate change played a significant role in the spatiotemporal evolution of lowland aquatic taxa, and provide priorities for conservation efforts.

Genetic identification and structure of Clarias batrachus (Linnaeus, 1758) from Southeast Asia using a mitochondrial DNA marker

“…The latter may be caused by the close proximity of the North and East Sunda paleo-drainages (Rainboth, 1991). The results for lack of genetic differentiation between Java and Laos pair was consistent with a "radiation by paleo-drainage" model of diversification observed for halfbeaks across Southeast Asia (De Bruyn et al 2013).…”

A revision of the spirit loaches, genus Lepidocephalus (Cypriniformes, Cobitidae)

“…Previous reports of the distribution that included peninsular Malaysia and western Borneo (e.g., Roberts, 1989) were based on the holotypes of L. pahangensis, and L. pallens, respectively. The occurrence of L. macrochir in the Barito River basin in southern Borneo and the Pepeh River in central Java supports the hypothesis of de Bruyn et al (2013) of a paleo East Sunda River basin connecting these land masses.…”

DNA Barcoding Indonesian freshwater fishes: challenges and prospects

“…In Tor douronensis, in particular, they observed four mitochondrial lineages with allopatric distributions across Peninsular Malaysia, Borneo and Sumatra. Along the same line, De Bruyn and colleagues [34] evidenced that species boundaries in the genus Dermogenys, Nomorhamphus and Hemirhamphodon derived from mitochondrial sequences were matching palaeodrainage boundaries during periods of low sea levels but poorly matched current islands boundaries. The authors also detected cryptic diversity for widespread species with insular endemic mitochondrial lineages.…”

“…De Bruyn and colleagues [35], for instance, have demonstrated that Borneo's diversity (including Kalimantan in Indonesia and Sabah and Sarawak provinces in Malaysia) resulted not only from the accumulation of immigrants but also from in situ diversification that further enabled the dispersal of species to other islands in Sundaland including Java and Sumatra. Dispersal among Sundaland islands has been made possible by eustatic changes during glacial times through the Pleistocene that created connections between the islands of Sundaland but also with the continent [9,10,34,46]. range from free-spawning tactics without parental care to substrate spawning, submerged plant nest building, bubble nesting, and mouth-brooding with parental care.…”

“…The main reasons for this exceptional diversity are the important fragmentation of the rivers across the numerous islands of the archipelago, together with the occurrence of several major biogeographical boundaries in the country including the Wallace and Lydekker lines ( Fig. 1) and complex palaeoecological and geological histories [33][34][35][36][37].…”