Description of a new species of Southeast Asian reed snake from northern Laos (Squamata: Colubridae: Genus <i>Calamaria</i> F. Boie, 1827) with a revised diagnosis of <i>Calamaria yunnanensis</i> Chernov, 1962

I describe a new <i>Calamaria</i> from northern Laos that was previously misidentified as <i>Calamaria yunnanensis</i> Chernov, 1962. This new species is quite similar to <i>C. yunnanensis</i>, but is distinguished by having a considerable pairwise genetic distance in the mitochondrial gene CytB (~20.2%) and the following morphological characters: nine modified maxillary teeth; length of rostral scale visible from above half the length of the prefrontal suture; eye diameter less than eye–mouth distance; preocular scale absent; single postocular scale present, less than eye diameter; 179 ventral scales in female; 21 subcaudal scales in female; subcaudals 10.9% of total body scales on the ventral surface; dorsal scales reducing to six rows above 12^th subcaudal anterior to the tail tip, reducing to four rows above the last subcaudal; dorsal ground colour in preservative bluish-grey with five indistinct dark brown longitudinal stripes throughout body; and entire ventral region immaculate yellow in preservative. To clarify the taxonomic status of <i>C. yunnanensis</i>, I provide a revised diagnosis of this species and thoroughly describe a referred specimen sampled for mitochondrial DNA sequence data in past studies. Additional material from south-western China, northern Laos, Thailand and Myanmar is needed to resolve issues in the taxonomy of <i>Calamaria</i> in this region. http://www.zoobank.org/urn:lsid:zoobank.org:pub:AD8D2EAF-E76E-4D49-9DA8-4C5A656B4F9A