Rediscovery and revalidation of Calamaria annamensis Bourret, 1937 (Squamata: Calamariidae), a rare reed snake restricted to the Truong Son Range of central Vietnam

Abstract

The reed snakes of the genus Calamaria H. Boie in F. Boie are among the least-studied Southeast Asian snakes, with several taxa known only from their original description. Calamaria pavimentata annamensis Bourret, 1937, described from “Dong Tam Ve (province de Quang-tri), Annam ”, now Bac Huong Hoa Nature Reserve, Quang Tri Province, Vietnam, based solely on a single specimen. This taxon was subsequently treated as a junior synonym of C. pavimentata Duméril, Bibron & Duméril, for example by Smith (1943) and Inger & Marx (1965), without any comprehensive reassessment to date.

Here, we report the rediscovery of this taxon based on three newly collected specimens from the type locality and revalidate it as Calamaria annamensis stat. nov., based on integrative morphological and mitochondrial DNA analyses. We established detailed morphological comparisons to specimens of C. pavimentata alleged to originate from Java Island, Indonesia (type locality), and from Guangxi Province, China (as defined by Yeung et al. 2022), and other congeners from mainland Southeast Asia.

Mitochondrial DNA (cytochrome b) analysis supports the distinctiveness of Calamaria annamensis stat. nov., revealing an uncorrected p -distance of 19.4% from C. pavimentata and ranging from 16.7% (C. nebulosa Lee) to 21.5% (C. lumbricoidea Boie) when compared with other congeners. This revalidation increases the number of Calamaria species to 71, of which twelve are currently recorded from Vietnam. Our findings also underscore the urgent need for comprehensive taxonomic and molecular studies on the widely distributed Calamaria pavimentata and C. septentrionalis Boulenger species complexes in Vietnam to resolve their true diversity and distribution.