This species is not found in Thailand
English name: Hung-Ta Chang’s Mountain Stream Snake (aka: “Hung-Ta Chang’s Mountain Keelback”)
Scientific name: Opisthotropis hungtai (formerly Opisthotropis maculosa)
Description: 39-51cm long. Has a small head indistinct from the neck and small eyes. Glossy black body with a yellow spot on every scale. Top of head is black with yellow speckling at the edges. Belly is yellow with brownish-black mottling on the chin shields.
Relevant scale counts: 15 midbody scale rows. Scales are smooth. 7 supralabials with 4th and 5th in contact with eye, prefrontal not in contact with supraocular, frontal in contact with preocular, 1st pair of chin shields longer than or equal to 2nd pair, 170–189 ventrals and 76-98 subcaudals in males and 168–175 ventrals and 69-84 subcaudals in females.
Similar Species: Yellow-spotted Mountain Stream Snake has yellow chin shields without mottling, 7 supralabials with 4th supralabial in contact with the eye, prefrontal is in contact with supraocular, frontal is not in contact with preocular, 2nd pair of chin shields longer than 1st pair, 182 ventral scales and 67 subcaudals in the single known specimen (male), and is only known from Thailand.
Hai Ha Mountain Stream Snake has 8-9 supralabials with the 4th and 5th in contact with the eye, 164-169 ventrals and 75-79 subcaudals in females. It is only known from Vietnam and China.
Range: Guangdong and Guangxi in southern China.
Habitat: Found in rocky streams in dense forest at 300-1150m elevation.
Place in the ecosystem: Diet is unknown but it likely feeds of fish, frogs, earthworms, and/or crustaceans as other members of its genus are known to do. Would be eaten by larger snakes and monitors.
Danger to humans: Is a rear-fanged snake but its venom properties and potential danger are unknown.
Conservation status and threats: Has been found in a number of sites in China, but due to its recent discovery its conservation status is unknown. The loss of forest cover and the pet trade could both threaten the species in the near future.
Interesting facts: After the Yellow-spotted Mountain Stream Snake was discovered in Thailand in 2007, similar snakes which appeared to be the same species were discovered in Vietnam and southern China. However, in 2017 genetic studies proved that the Vietnam specimen was actually a separate species, which was named the Hai Ha Mountain Stream Snake. Then in 2020 genetic studies proved that the Chinese specimens were split, with the southernmost one turning out to also be the Hai Ha Mountain Stream Snake while the rest were yet another new species, Hung-Ta Chang’s Mountain Stream Snake. In appearance they can only be distinguished by scale counts and different coloration on the bottom of the head.
A new species of Opisthotropis from northern Vietnam previously misidentified as the Yellow-spotted Mountain Stream Keelback
Re-examination of the Chinese record of Opisthotropis maculosa, resulting in the first national record of O. haihaensis and description of a new species