A snake can change its finery: a new cryptic species of the Trimeresurus kanburiensis complex (Reptilia: Serpentes: Viperidae) from central Thailand with an unusual ontogenetic color change

We describe a new species of green pitviper from the northern part of Central Thailand based on morphological and molecular (2406 bp from cyt b, ND4, and 16S rRNA mitochondrial DNA genes fragments) lines of evidence. Trimeresurus cryptographicus sp. nov. is distinguished from its congeners by the combination of the following morphological characters: small size, maximum known SVL of 523 mm; dorsal scales in 23(22)-21-15 rows, moderately keeled except the outermost rows; ventral scales 171178; subcaudal scales 5773, all paired; iris golden yellow in both sexes; body uniformly bright grass-green with indistinct serrated dark transverse markings in adults (499523 mm SVL) but neonates and juveniles (231245 mm SVL) have prominent irregular, serrated dark grey crossbands on a light green dorsum; suborbital stripe bluish-white and thin in male, absent in females; ventrolateral stripe, white, distinct, present on the first two dorsal scale rows in both sexes; throat, chin, and lower labials pale blue; ventral surfaces greenish-yellow; tail light brick-red mottled with dark spots, ventral side of the tail with white markings. While the new species differs from the morphologically similar species Trimeresurus macrops by a notable divergence in mitochondrial DNA sequences, it is more closely related to T. kuiburi (p = 1.7% for cytochrome b, p = 1.6% for 16S rRNA, and p = 1.8% for ND4 gene fragments). The new species is currently known only from low elevation in tropical limestone forest of Phitsanulok Province, in the northern part of central Thailand (ca. 100 m a.s.l.). This discovery further underlines the importance of limestone massifs of Indochina as local centres of herpetofaunal diversity and endemism.