Search

The highly biodiverse Lake Poso, located in Central Sulawesi, Indonesia, can be considered one of the least studied ancient lakes in the world. Here, we present a comprehensive analysis of Lake Poso's hydrology and hydrochemistry, shedding light on factors that may have contributed to the exceptional biodiversity. Riverine and lake water chemical compositions indicated a soft water lake and relative major cation and anion abundances of Ca2+ ≫ Mg2+ > Na+ > K+ and HCO 3 – ≫ SO 4 2− > Cl−, primarily a result of the high annual precipitation and chemical weathering of calcareous-siliceous metamorphic bedrock. Lake Poso's nutrient concentrations were low (average DIN/TDP mass ratio of 6.2 and 50.9 for the lake surface water and its tributaries, respectively), indicating that most of the inlets were P-limited and that the lake was likely P-limited as well. Metal pollutants indicated a minor to moderate impact of anthropogenic land use (∼32 % of the catchment area). Water isotopic compositions of the different tributaries clearly delineated rivers draining higher elevation catchments with lower δ2H and δ18O from those draining lower elevation catchments with higher δ2H and δ18O. Surface lake water isotopic compositions indicated detectable evaporation from the lake leading toward more enriched isotope compositions than the integrated source signal. Overall, the findings suggested that Lake Poso remains relatively resilient to anthropogenic land use and related nutrient and pollutant inputs. However, ongoing alterations to its hydrological balance due to significant changes in land use may drive the lake towards higher trophic levels in the future. [ABSTRACT FROM AUTHOR]

The set of ancient lakes on Sulawesi, Indonesia, represents a unique global hotspot of aquatic biodiversity. These lakes have been recognized widely because of their high number of endemic species with specialized and distinctive morphological characters, life history and ecological adaptations. An interesting case of unusual life history involving brood care exists in the planorbid limpets of the genus Protancylus , which live exclusively as epizoans on the endemic pachychilid gastropod Tylomelania. We aimed to unravel the evolutionary and phylogeographical patterns of Protancylus from the Malili lakes and Lake Poso using two mitochondrial markers in an integrated framework that includes morphological, life-history and ecological data. At least three species of Protancylus evolved allopatrically, with a newly recognized species occurring in lakes Matano and Mahalona. All species are characterized by low morphological variation, shared life-history traits including a unique reproduction strategy. Our genetic data indicates that a drift-based geographic speciation mode correlates with the present distribution pattern. The initial diversification significantly predates the ages of the respective lakes and the lineages of Protancylus are significantly older than their corresponding Tylomelania 'hosts'. The deep split between P. pileolus of Lake Poso and the populations in the Malili lakes is remarkable and hints to a very early separation in a time frame when Sulawesi reached its current composition. As colonization and onset of diversification is strikingly different in Tylomelania and the epizoic Protancylus , co-evolutionary components in this association can be excluded and both evolved largely independently. We discuss and compare our findings to other invertebrate assemblages in the ancient lakes of Sulawesi. [ABSTRACT FROM AUTHOR]

Ancient lakes are renowned as freshwater hotspots of biodiversity and endemism. However, some of these water bodies are poorly studied with the minute pill clams in the genus Pisidium (family Sphaeriidae) being particularly overlooked. The Malili lake system is located on Sulawesi, which is the largest and possibly biologically most diverse Indonesian island within the biodiversity hotspot region of Wallacea. This lake system consists of 5 interconnected lakes that harbour a unique freshwater fauna including 42 mostly endemic mollusc species described to date. The only bivalves recognized in this lake system have been in the widespread genus Corbicula. We present new insights into the sphaeriid biodiversity of the ancient Malili lakes and provide the first fossil-calibrated phylogeny for this family to discuss the biogeographical history of the Wallacean Pisidium fauna including the dating of speciation events. Both morphological and molecular data suggest that the Malili lake system is inhabited by at least three Pisidium species, two of which are potentially endemic to these lakes. This diversity is probably derived from a single colonization event from the Oriental region. The fossil-calibrated phylogeny further indicates that intra-island diversification occurred well after the island was fully formed. Our study improves understanding of the overall sphaeriid biodiversity in Indonesia as well as the endemic fauna of the ancient lakes. [ABSTRACT FROM AUTHOR]

The most species-rich genus, Caridina , of the shrimp family Atyidae is broadly distributed throughout five biogeographic realms, with the Indo-Malayan realm being the centre of its distributional range. Due to the scarcity of studies, very little is known regarding the Middle East species, which are placed on the north-western edge of the genus' distribution. Numerous museum specimens from across the entire range of Caridina in the Middle East were thus analysed using morphological characters and mitochondrial sequences (16S) in order to gain insight into the biodiversity of the genus in the region. Consequently, the present study describes three new atyid species of the genus Caridina H. Milne Edwards, 1837, Caridina enbilului sp. nov., Caridina enkii sp. nov. and Caridina shahrazadae sp. nov. from freshwater habitats of Syria, Iraq and Iran respectively. Furthermore, Caridina fossarum Heller, 1862 is redescribed, while the taxonomic status of Caridina syriaca Bouvier, 1904 and Caridina babaulti basrensis Al-Adhub & Hamzah, 1987 is discussed and the latter synonymized with Caridina fernandoi Arudpragasam & Costa, 1962. C. shahrazadae sp. nov. differs from its congener C. fossarum by the reduced branchial formula of the latter species, the absence of an appendix interna at the endopod of the male's first pleopod, and the lack of a prominent sexual dimorphism on the propodus of the third and fourth pereiopods. C. enbilului sp. nov. differs from C. fossarum in the same characters as C. shahrazadae sp. nov., while from the latter species C. enbilului sp. nov. is different in showing a distinct tooth on the pterygostomial margin of the carapace, by a well-developed arthrobranch on the first pereiopod, a well-developed podobranch on the second maxilliped and a more slender endopod of the male's first pleopod. C. enkii sp. nov. can be distinguished from C. fossarum by the more developed sexual appendages of male specimens as well as more slender pereiopods. In addition, the genetic analysis supports the existence of multiple species in the Middle East, while their phylogenetic relationships and their geographic distribution are described. [ABSTRACT FROM AUTHOR]

The article discusses a study on three new species of the microhylid genus Callulops robustus frog species from western New Guinea. It mentions evidence that Callulops is not a monophyletic group and that C. robustus is not distributed over the whole of New Guinea. The absence of a sympatric occurrence of species in the C. robustus-group is considered. Collections of C. robustus-group frogs on the islands of Yapen and Biak and in the Wondiwoi Mountains are also described.