The taxonomic status of the kukri snake Oligodon arenarius Vassilieva, 2015 with a redescription of Oligodon macrurus (Angel, 1927) (Squamata, Serpentes, Colubridae)

Abstract

We investigated the taxonomic status of the recently described kukri snakeOligodon arenariusVassilieva, 2015 and the morphologically similarOligodon macrurus(Angel, 1927), two species endemic to the southern coast of Vietnam. Based on phylogenetic analyses using three mitochondrial genes (12S–16S rRNA, cytochromeb), we recoveredO. arenariusandO. macrurusin a clade within theO. cyclurus-taeniatusspecies group, agreeing with previous intrageneric classifications. Genetic distances betweenO. arenariusandO. macrurusare extremely low (less than 0.5% based on 12S–16S) and renderO. arenariusparaphyletic. All preserved specimens ofO. arenariusandO. macrurusconvey little to no differences in color pattern, hemipenial morphology and osteological features; the latter of which is based on three dimensional micro computer tomography (µCT) scans of one specimen per species. Contrasting these results, univariate and multivariate analyses revealed significant differences in relative tail length, and the number of ventral and subcaudal scales between both species. Although the molecular and morphological datasets present conflicting results, integrating the evidence leads us to synonymizeO. arenariuswithO. macrurus. We provide a formal redescription ofO. macrurus, designate a neotype specimen to avoid future taxonomic confusion, and provide the first detailed osteological description of this species.Oligodon macrurussensu stricto is endemic to coastal dunefields and adjacent forest habitats in southern Vietnam, where ongoing human development, tourism and road mortality pose significant threats to its conservation. Consequently, we suggest thatO. macrurusshould be listed as “Vulnerable” based on the assessment criteria of the International Union for Conservation of Nature (IUCN).