The Himalayan uplift and evolution of aquatic biodiversity across Asia: Snowtrout (Cyprininae: Schizothorax) as a test case

QTP elevated more than 3,000m in late-Miocene [11]. The uplift also drove strong selection for high-elevation specialists that could subsist under more severe conditions [12]. However, data remain sparse for high elevation Himalayan fishes, an aspect inherently magnified by the lack of large-scale monitoring programs [13]. Such data-deficiencies, tightly linked with the geomorphic and climatic history of the region, underscore the strong potential for cryptic spe- cies yet to be identified and formally described. Schizothorax and its outgroups Snowtrout (Fig 1B) offers a unique opportunity to deciphering the geologic processes that drove fish diversification and distribution in the Himalaya. The genus belongs to the largest and most diverse freshwater fish family (Cyprinidae: 1,700+ valid species, with 11 recognized subfamilies) [14], and comprises 28 recognized species across lakes and rivers of the QTP, the endorheic Tarim River basin, as well as the snow-fed tributaries of the Himalaya/ sub-Hima- laya (Fig 1A) [15–17]. Several hypotheses have been offered to explain its origin and dispersal. Researchers first suggested the Schizothoracinae initially dispersed into the QTP from southeastern Asia [18], and subsequently became isolated by orogeny and climate change. Others proposed that a Fig 1. (A) Simplified drainage map of Asia, showing major basins from which Schizothorax were obtained. Area in yellow indicates the Tibetan Plateau, referred to as Qinghai-Tibetan Plateau (QTP) in China. The Tarim River, an

endorheic basin north of the QTP in Central Asia, is not depicted. Three major rivers, the Irrawaddy, Salween, and Mekong, drain the QTP into Southeastern Asia (SEA), whereas the Yangtze River flows east into the China Sea (Republished from Fig 1 [100] under a CC BY license, with permission of the Council on Foreign Relations, original copyright 2016). (B) Schizothorax sp. cf richardsonii (i.e., potentially S. richardsonii) captured 02 December 2016 at confluence of Bibigang Chhu and Mangde Chuu, Bhutan (Total length = 540 mm). https://doi.org/10.1371/journal.pone.0289736.g001 PLOS ONE Himalayan uplift and aquatic evolution PLOS ONE | https://doi.org/10.1371/journal.pone.0289736 October 24, 2023 3 / 27