Sabah pit viper, Trimeresurus sabahi Regenass & Kramer, 1981 – of Sarawak / Borneo – around 1300m ASL

Trimeresurus sabahi (Sabah pit viper) is a montane pit viper endemic to northern Borneo (Malaysia: Sabah, Sarawak), typically occurring in submontane to montane forest between ~1,000–1,600 m a.s.l. It is a medium-sized arboreal species (~62 cm SVL) characterized by a uniform green dorsum, a narrow bicolored ventrolateral stripe (whitish above, reddish-brown below), reddish-orange iris, and the absence of a postocular light stripe.
Compared to other members of the Trimeresurus (subgenus Popeia), T. sabahi is distinguished by this unique color pattern, the lack of dark dorsal crossbands, and specific scalation (21–23 midbody rows). Taxonomic revisions have restricted T. sabahi sensu stricto to Borneo, whereas closely related forms formerly treated as subspecies (barati, buniana, fucatus, toba) are now recognized as separate species. This makes T. sabahi morphologically and geographically distinct within the T. sabahi species complex.