Diversity of the snail‐eating snakes Pareas (Serpentes, Pareatidae) from Taiwan

Abstract

Diversity of the snail-eating snakes Pareas (Serpentes, Pareatidae) from Taiwan. -Zoologica Scripta, 00, 000-000. Pareatidae are a group of mollusc-eating snakes widely distributed in South-eastern Asia. Due to their dietary specialization, the asymmetric dentition of pareatids has recently become an interesting issue in evolutionary biology. However, phylogenetic relationships and species diversity of pareatids are still poorly studied. A total of three Pareas species, P. formosanus (Van Denburgh 1909), P. compressus (Oshima 1910) and P. komaii (Maki 1931), have been reported for Taiwan. However, only P. formosanus is currently regarded as a valid species. Using mitochondrial sequence phylogeny, nuclear c-mos haplotype network, as well as multivariate morphometrics, we re-evaluated the taxonomic status of Pareas from Taiwan, the Ryukyus and adjacent regions. These lines of evidence showed congruent results for the coexistence of three Pareas species in Taiwan, with prominent genetic and morphological differentiation and differing level of dentition asymmetry. The currently used name P. formosanus should be applied only to the snakes with red iris, comparatively short lower jaw and totally smooth dorsal scales. An examination of the type material indicated that the name P. compressus should be regarded as a junior synonym of P. formosensis sensu stricto. Pareas komaii (Oshima 1910) is confirmed as a valid taxon with yellow iris, elongated lower jaw and strongly keeled dorsals. The third clade is characterized by a yellow iris, elongated lower jaw and weakly keeled dorsals. Despite their sympatric occurrence, every examined individual showed consistent grouping from mitochondrial, nuclear and morphological markers, indicating there is no gene flow among these three clades. Here, we describe the third clade as a new specie, Pareas atayal sp. nov.

Geographic variation in advertisement calls of a Microhylid frog – testing the role of drift and ecology

“…In recent years, several cryptic herptile species have been reported in Taiwan (Lue and Lin ; You et al. ), and two tree frogs have been shown to exhibit extremely high within‐island divergence ( Buergeria robusta , Lin et al. ; B. japonica , Tominaga et al.…”

“…; You et al. ). Taiwan is a relatively small island in the subtropical region, with latitudes and longitudes spanning less than 3 degrees (22°–25°N, 120°–122°E).…”

“…The topography of Taiwan is extremely steep with many rivers flowing from high mountains to the coast, creating a highly fragmented landscape, which likely contributed to the high levels of differentiation in many terrestrial species (Lin et al 2012;Tseng et al 2015;You et al 2015). Taiwan is a relatively small island in the subtropical region, with latitudes and longitudes spanning less than 3 degrees (22°-25°N, 120°-122°E).…”

“…Herptile taxa, with their limited dispersal ability, might be particularly sensitive to such landscapes. In recent years, several cryptic herptile species have been reported in Taiwan (Lue and Lin 2008;You et al 2015), and two tree frogs have been shown to exhibit extremely high within-island divergence (Buergeria robusta, Lin et al 2012;B. japonica, Tominaga et al 2015).…”

Asymmetry of mandibular dentition is associated with dietary specialization in snail-eating snakes

“…These congeneric species have been recently assigned into phylogenetically distinct, non-sibling species (You, Poyarkov & Lin, 2015). The morphology of museum-preserved specimens collected at the same locality were compared.…”