Calliophis bivirgatus

Calliophis bivirgatus is a species of snake in the family Elapidae known commonly as the blue coral snake or blue Malayan coral snake. It is native to Southeast Asia.

Geographic range and distribution
This terrestrial snake occurs in Brunei, Indonesia, Malaysia, Singapore, Thailand, and Burma. It lives at 100 to 1100 m in elevation.

There are three subspecies:
 * C. b. bivirgatus – Indonesia
 * C. b. flaviceps – Indonesia, Malaysia, Thailand, Singapore, Burma
 * C. b. tetrataenia – Indonesia, Malaysia, Brunei

Description
This species was assigned to the new world coral snake genus Maticora until phylogenetic studies revealed this species to be nested within the tropical coral snake species clade Calliophis and sister species to Calliophis intestinalis, the banded Malaysian coral snake.

This is a medium-sized coral snake with a slender body. The adult can reach 1.8 m long. It has a red head, tail and belly. The back is dark blue to black in color, and it usually has a large blue or white stripe on each flank.

The snake, especially when juvenile, is often confused with the pink-headed reed snake (Calamaria schlegeli) as they share similar habitat and appearance. But the latter is much smaller, reaching a maximum length of 50 cm. The reed snake is nonvenomous, while the coral snake is potentially lethal. They also are very similar to another venomous snake, the red-headed krait (Bungarus flaviceps).

Biology
This uncommon snake is considered semi-fossorial and is found in the leaf litter of primary and secondary forests. It preys on other snakes. When threatened it usually flees, but it may remain in place with its red tail erect as a defensive message.

Venom
Blue coral snake venom has only occasionally caused human deaths. This species has unusually long venom glands, extending to 25% of the length of the body. The venom contains a neurotoxin, Calliotoxin, that causes near instantaneous paralysis by delaying inactivation of the prey's sodium channels. This effect has not been observed in humans. The venom also contains phosphodiesterases, which promote the release of adenosine, causing in turn hypotension, inflammation, and neurotransmitter blockade in prey items and other bite victims. This ability is especially important as their prey consists mostly of other venomous snakes.

In humans, local effects of a bite self-resolve without complication and systemic effects are rare.

There is hope that the venom may eventually prove useful in the management of chronic pain in humans.