Reptiles and Amphibians of Thailand

Thailand's Snakes, Lizards, Turtles, and Frogs

Angel's Stream Snake

Paratapinophis praemaxillaris

This species is found in Thailand, but not within Bangkok itself
Angel's brown Stream Snake Angel's Mountain Keelback Paratapinophis praemaxillaris Opisthotrophis งูลายสอลาวเหนือ thailand
Angel’s Stream Snake found in Nan Province (© Michael Cota)

English name: Angel’s Stream Snake (aka: “Angel’s Mountain Keelback”, “Brown Stream Snake”)
Scientific name: Paratapinophis praemaxillaris (formerly Opisthotrophis praemaxillaris)
Thai name: งูลายสอลาวเหนือ (Ngu Lai Sor Lao Neua)

Description: To at least 1m in length. A large robust snake with a distinct head. Nasal openings are somewhat laterally positioned. Body is brownish-grey with indistinct inverted yellow “V’s” which connect to give a sense of reticulation. Females have indistinct bands that continue across the back from the yellow markings, while males are relatively patternless on top.

Relevant scale counts: 19 midbody scale rows. Males have scales with a unique middle row of tubercles on the back half of the body. There are two pairs of chin shields.

Similar Species: Boomsong’s Stream Snake is brownish rather than grey, lands markings, and has heavily keeled dorsal scales.
Yunnan Water Snake has distinct black X-marks filled in with beige on the sides and keeled dorsal scales.

Range: Southern China, northern Laos, and northern Thailand.

Habitat: Lives in rocky mountain streams at 450-1400m elevation.

Place in the ecosystem: Feeds on fish, frogs, freshwater shrimp and earthworms. 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: It has a wide distribution and has been found within several protected areas, but the extremely low number of snakes found mean its true status is still unknown. Continued loss of forest cover may be a serious threat to the species.

Interesting facts: Angel’s Stream Snake is known from fewer than ten specimens spread across four sites in three countries. It is one of several southeast Asian stream snake species that has only been encountered on rare occasions.

The Rediscovery of Angel’s Stream Snake, Paratapinophis praemaxillaris
IUCN Red List: Angel’s Mountain Keelback
Reptile Database: Paratapinophis praemaxillaris
Thai National Parks: Angel’s Mountain Keelback
A Field Guide to the Reptiles of Southeast Asia

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