About Achalinus niger Maki, 1931
Achalinus niger is a small snake that reaches a total length of approximately 80 cm (31 inches). Its entire body appears iridescent when viewed under light. It has a small, oval head with no clearly defined neck, a slender body, and a moderately short tail. The eyes are small and bead-like, with a black, indistinct iris. The upper surfaces of the head, body, and tail are a uniform shade of olive, grayish tan, or black. A dark longitudinal line runs along the mid-dorsal row of scales on both the body and tail. The ventral surface of the snake is either olive-yellow or dark gray. Juveniles of this species are typically black. This species is endemic to Taiwan, where it is widespread across elevations from 1,000 to 3,000 m (3,300 to 9,800 ft) above sea level. Genetic analysis has identified three distinct genetic clades: a northern clade from the Xueshan Range, a southern clade from the Alishan Range and the southern Central Mountain Range, and a third clade restricted to Meifeng, a small but highly distinct location in the middle of the Central Mountain Range. Achalinus niger inhabits forests and is sometimes found in caves. It is most often encountered in dark, moist microhabitats such as leaf litter or decaying logs. No significant threats to the species are currently known, and it is classified as a Class II protected species.
