Multilocus phylogeography of the brown-spotted pitviper Protobothrops mucrosquamatus (Reptilia: Serpentes: Viperidae) sheds a new light on the diversification pattern in Asia

Abstract

Understanding the influence of geographical events and climate changes on genetic diversity is essential in explaining current patterns of genetic structure and geographic distribution of organisms. We inferred phylogenetic relationships, investigated historical demography, explored the evolutionary history, and clarified intraspecific taxonomy of Protobothrops mucrosquamatus, which is one of the commonest and most wide-ranging of Asian pitvipers. A total of 184 samples from 54 localities were sequenced and analyzed for two mitochondrial gene fragments and two nuclear genes. Phylogenetic reconstruction based on mtDNA sequences revealed the existence of a minimum of five geographically structured and wellsupported lineages within P. mucrosquamatus.. Based on the mtDNA gene tree, and the geographic relationship between populations allied by matrilineal lineages, a complex longitudinal and latitudinal diversification pattern was uncovered in P. mucrosquamatus. The estimated date of the origin of the species (about 5.3 Ma) and divergence of the intraspecific lineages match the rapid uplifting of Qinghai-Xizang Plateau, and is also consistent with those of some other co-distributed Asian pitvipers. Formation of the two island lineages (Taiwan and Hainan) was generally congruent with the first isolation of the islands, but the two lineages showed different relationships with the continental Asian populations in comparison with some other pitvipers. Population historical demographic analyses, based on three methods, showed that all lineages have experienced slight population expansion in and around the Dali Glacial. Tests of intraspecific taxonomy indicated that no cryptic taxon is present within this widely distributed snake.

Genetic diversity and sex‐biased dispersal in the brown spotted pitviper (Protobothrops mucrosquamatus): Evidence from microsatellite markers

“…Based on genetic structure analysis, we detected two clusters in P . mucrosquamatus , different from previous mtDNA‐based findings (Guo et al, 2019 ) to some extent. This difference may be due to different genetic and evolutionary patterns between mtDNA and microsatellite markers.…”

“…mucrosquamatus , with multiple alleles ( N a = 22.75), high H o (0.480–0.899), and high H e (0.713–0.951) (Table 3 ). These results are consistent with previous findings based on mtDNA (Guo et al, 2019 ), but are higher than that detected using microsatellite markers in smooth snakes ( Coronella austriaca ) ( H o = 0.357–0.507, H e = 0.418–0.601) (Pernetta et al, 2011 ) and olive sea snakes ( Aipysurus laevis ) ( H o = 0.222–0.847, H e = 0.263–0.881) (Lukoschek et al, 2008 ) and comparable to that reported in slatey‐grey snakes ( Stegonotus cucullatus ) ( H o = 0.62–0.84, H e = 0.55–0.83) (Dubey et al, 2008 ). In addition, the mean PIC (0.879) of P .…”

“…At K = 2, most of the genetic information of 4 populations (HN, VM, SCV, and TW) in southern China and Myanmar Vietnam came from the same ancestral population (blue), while 1 population in southwestern China (SWC), the genetic information is mainly from another ancestral group (red). The two clusters displayed different population membership to that reported previously based on mtDNA (Guo et al, 2019 ), but were consistent with geographical origin. From the bar plot of various K values ( K = 2–6), the majority of individuals revealed low probabilities of being assigned to any particular clusters (Appendix S4 ).…”

One species hides many: Molecular and morphological evidence for cryptic speciation in a thread snake (Leptotyphlopidae: Leptotyphlops sylvicolus Broadley & Wallach, 1997)

“…Recent publications on the more modern Caenophidians also use a rate of 0.65% per million years (e.g. Guo et al, 2019), but others employed a rate of 1.34% per million years (e.g. Myers, Hickerson, & Burbrink, 2017).…”

Climate warming will increase chances of hybridization and introgression between two Takydromus lizards (Lacertidae)

“…Across the range where the two Takydromus species live in sympatry, there are several physical barriers such as Luoxiao Mountains and the Ganjiang River presumed to limit animal migration (Figure 4; Cai et al, 2012). However, the role of these barriers in limiting the migration of terrestrial reptiles including T. septentrionalis is small or negligible (Cai et al, 2012;Guo et al, 2019;Huang et al, 2007;Lin et al, 2012), thus allowing an inference that introgression and hybridization between T. septentrionalis and T. sexlineatus are less likely to be geospatially nonrandom across the range where they are sympatric. Climate warming will not only drive the northward drift of sympatric areas but also increase the size [by up to 58% under the SSP585 (high greenhouse gas emission) scenario] of these areas if nothing is done to limit the emission of greenhouse gases in the future (Figure 5, Table 2).…”