 |
| Shells of the endemic Parreysiinae taxa from the Sittaung River basin, Myanmar. (a) Leoparreysia canefrii Vikhrev, Bolotov et Kondakov gen. et sp. nov., Sittaung River near Taungoo, (b) Radiatula mouhoti Vikhrev, Bolotov et Konopleva sp. nov., Sittaung River near Taungoo, (c) Lamellidens brandti Bolotov, Konopleva et Vikhrev sp. nov., Pathi River, (d) Trapezidens obesa feae Kondakov, Konopleva et Vikhrev gen. et ssp. nov., Myit Kyi Pauk Stream, Scale bar = 2 cm. in Bolotov, Vikhrev, Kondakov, Konopleva, Gofarov, Aksenova et Tumpeesuwan, 2017. (Photos: Ekaterina S. Konopleva). |
Abstract
Southeast Asia harbors a unique and diverse freshwater fauna of Mesozoic origin, which is under severe threat of extinction because of rapid economic development and urbanization. The largest freshwater basins of the region are certainly the primary evolutionary hotspots and they attract the most attention as key biodiversity areas for conservation. In contrast, medium-sized rivers are considered low-importance areas with secondary biodiversity, whose faunas originated via founder events from larger basins during the Pleistocene, although such a scenario has never been tested by using a phylogenetic approach. In this investigation, we used freshwater mussels (Unionidae) as a model to estimate the levels of endemism within the Sittaung, a little-known remote basin in Myanmar, compared with the surrounding larger rivers (Irrawaddy, Salween and Mekong). We discovered that the Sittaung represents an exceptional evolutionary hotspot with numerous endemic taxa of freshwater mussels. On the basis of our extensive dataset, we describe two new tribes, two genera, seven species and a subspecies of Unionidae. Our results highlight that medium-sized basins may represent separate evolutionary hotspots that harbor a number of endemic lineages. These basins should therefore be a focus of special conservation efforts alongside the largest Southeast Asian rivers.
Leoparreysiini Vikhrev, Bolotov et Kondakov tribe nov.
Pilsbryoconchini Bolotov, Vikhrev et Tumpeesuwan tribe nov.
 |
| Shells of the endemic Parreysiinae taxa from the Sittaung River basin. (a) Leoparreysia canefrii Vikhrev, Bolotov et Kondakov gen. et sp. nov., Sittaung River near Taungoo, Myanmar (holotype RMBH biv254_4). (b) Radiatula mouhoti Vikhrev, Bolotov et Konopleva sp. nov., Sittaung River near Taungoo, Myanmar (holotype RMBH biv256). (c) Lamellidens brandti Bolotov, Konopleva et Vikhrev sp. nov., Pathi River, Myanmar (holotype RMBH biv243_14). (d) Trapezidens obesa feae Kondakov, Konopleva et Vikhrev gen. et ssp. nov., Myit Kyi Pauk Stream, Myanmar (holotype RMBH biv250_4). Scale bar = 2 cm. (Photos: Ekaterina S. Konopleva). |
 |
| Shells of the endemic Pseudodontinae and Rectidentinae taxa from the Sittaung River basin. Pseudodontinae (a,b), including (a) Pseudodon bogani Bolotov, Kondakov et Konopleva sp. nov., Kanni River, Myanmar (holotype RMBH biv241_5), and (b) P. manueli Konopleva, Kondakov et Vikhrev sp. nov., Pyowne Stream, Myanmar (holotype RMBH biv246_3). Rectidentinae (c,d), including (c) Trapezoideus nesemanni Konopleva, Vikhrev et Bolotov sp. nov., Tauk Ue Kupt River, Myanmar (holotype RMBH biv255_2), and (d) T. panhai Konopleva, Bolotov et Kondakov sp. nov., Kyan Hone River (holotype RMBH biv138_4). Scale bar = 2 cm. (Photos: Ekaterina S. Konopleva). |
 |
| Haplotype-level phylogeny and distribution of Indo-Chinese Unionidae. (a) Multi-locus fossil-calibrated phylogeny based on the BEAST 1.8.4 model and obtained for the complete data set of mitochondrial and nuclear sequences (five partitions: three codons of ... (b) Map of distribution areas. Red circles indicate our collecting localities ... |
Ivan N. Bolotov, Ilya V. Vikhrev, Alexander V. Kondakov, Ekaterina S. Konopleva, Mikhail Yu. Gofarov, Olga V. Aksenova and Sakboworn Tumpeesuwan. 2017. New Taxa of Freshwater Mussels (Unionidae) from A Species-rich but overlooked Evolutionary Hotspot in Southeast Asia
Scientific Reports. 7, Article number: 11573. DOI: 10.1038/s41598-017-11957-9
