Bornean keeled pit viper (Tropidolaemus subannulatus)
Formerly part of the Wagler's pit viper species complex, the Bornean keeled pit viper was elevated to species status in 2007 (Vogel et al, 2007).
This species occurs in similar habitats to Wagler's pit viper including lowland primary or mature secondary forest, as well as riverine and coastal forest.
As with other pit vipers, this is a venomous snake, with heat-sensing pits on the sides of the head.
It is exclusively arboreal, and may be found at heights ranging from low vegetation to mid-canopy levels of around 20 metres or so. Its diet comprises birds and arboreal rodents.
Juveniles and adult males have a vibrant green upperside and yellowish green belly, patterned with numerous thin, pale bicoloured bars : the leading edge of these bars are generally white, and the trailing edge blue or red or a combination of both colours. There is a bicoloured red and white stripe behind the eye.
Adult females tend to have a complex pattern comprising a ground colour of cream, with broken bluish, greenish or turquoise bands, and a thick stripe of the same colour on the sides of the head.
As of 2020, this species is listed as occurring in Borneo, Sulawesi and many islands of the southern Philippines.