Trapped on the Roof of the World: taxonomic diversity and evolutionary patterns of Tibetan Plateau endemic freshwater snails (Gastropoda: Lymnaeidae: Tibetoradix)

Abstract

The high-elevation Tibetan Plateau (western China) is inhabited by a unique, though not particularly speciesrich, community of organisms. We explored the species content and evolutionary history of the Tibetan Plateau endemic freshwater snail genus Tibetoradix. Phylogenetic relationships within the genus were reconstructed based on available sequence data. We used a single-rate Poisson Tree Processes approach for species delimitation and compared putative species-level clades with already described taxa. We found that the genus consists of at least 6 species, of which we described 4 as new to science. Shell and soft body morphology was examined and the radula in Tibetoradix was described for the first time. Based on our findings, the diversification of the genus did not result in a prominent morphological differentiation and a number of species can be regarded as morphologically cryptic. Single species found in different drainage areas indicate relatively good passive dispersal abilities of the snails. The allopatric distribution of the species could result from competitive exclusion between them. The absence of Tibetoradix spp. outside the Tibetan Plateau could be explained by a scenario of an "evolutionary trap", where adaptations to high elevation conditions prevented the taxa from a successful colonization of lower elevations.

Geographical and climate‐dependent patterns in spatial distributions of snail (Mollusca: Gastropoda) assemblages in freshwater wetlands across Northeast China

“…Lower temperatures and shorter growing seasons at high altitudes would result in slower growth rates, and slower evolutionary rates than those at lower altitudes (Wissinger et al, 2016). Moreover, the range of altitude around the Changbai Mountains might act as dispersal impediments for wetland snails (see Vinarski et al, 2021).…”

Comparative transcriptomics of high-altitude Vulpes and their low-altitude relatives

“…The harsh environmental conditions have led to various adaptive responses in a variety of species (Li et al, 2018). Current studies on plateau adaptation of native species have included many species, such as the Tibetan loach (Yang et al, 2019), Himalayan marmot (Bai et al, 2019), the Tibetan locust (Ding et al, 2018), snub-nosed monkey (Yu et al, 2016), yak (Qiu et al, 2012;Lan et al, 2021), freshwater snails (Vinarski et al, 2021), viperine snakes (Souchet et al, 2020), and ectothermic snakes (Li et al, 2018). The mechanisms of adaptation to high-altitude might have undergone convergent evolution in some species.…”