Calliophis Bibroni

Calliophis bibroni, commonly known as Bibron’s coral snake, is a species of venomous snake belonging to the family Elapidae. It is a small, secretive coral snake endemic to the Western Ghats of India, a global biodiversity hotspot. The species is of particular scientific interest due to its restricted distribution, specialised diet, distinctive morphology, and its role in studies of mimicry among Asian coral snakes.

Taxonomy and etymology

The species was first described in 1858 and was originally placed in the genus Elaps before later taxonomic revisions assigned it to the genus Calliophis. The genus Calliophis comprises Asian coral snakes characterised by slender bodies, reduced eyes, and potent venom adapted primarily for subduing other reptiles.
The specific epithet bibroni honours Gabriel Bibron (1806–1848), a French zoologist and herpetologist who made significant contributions to nineteenth-century reptile systematics. The use of eponymous naming reflects common zoological practice of the period.

Distribution and habitat

Calliophis bibroni is endemic to the Western Ghats mountain range of southern India. Its confirmed distribution includes:

• Southern Karnataka
• Kerala
• Northwestern Tamil Nadu

The species inhabits wet evergreen and semi-evergreen forests, typically at mid to higher elevations within the Ghats. It is associated with forest floor microhabitats, leaf litter, and loose soil, where it remains largely concealed. A documented roadkill specimen was recorded in August 2013 along a highway passing through Mudumalai National Park, highlighting the species’ vulnerability to habitat fragmentation and road mortality.

Morphological description

Bibron’s coral snake is a small, slender-bodied elapid with several distinctive scalation and cranial features adapted to a fossorial or semi-fossorial lifestyle.
The eyes are minute, with the eye diameter approximately half the distance from the mouth, indicating a reliance on non-visual sensory cues. The frontal scale is nearly as long as its distance from the snout but is significantly shorter than the parietal scales. True ocular scales are absent, causing the prefrontal scale to contact the third upper labial. There is a single, very small postocular scale, and the temporal scales are arranged in a 1+1 pattern.
The species has seven upper labial scales, with the third and fourth contacting the eye. The first lower labial is markedly elongated and forms a long suture with its counterpart on the opposite side. There are two pairs of chin shields, with the anterior pair being smaller and in contact with the third and fourth lower labials.
Dorsal scales are smooth, lacking apical pits, and are arranged in 13 rows at midbody. Ventral scales number 222–226, the anal scale is entire, and the subcaudal scales are divided, numbering 27–34 pairs.

Colouration and size

The dorsal colouration ranges from cherry red to dark purplish brown, while the ventral surface is red. The body is marked with black crossbands, which may be discontinuous or, in some individuals, extend across the belly. The anterior portion of the head is distinctly black on the dorsal surface, providing a sharp contrast with the body colour.
Adults may reach a total length of approximately 64 centimetres, of which the tail accounts for around 5 centimetres. Sexual dimorphism in size has not been clearly documented.

Behaviour and ecology

Calliophis bibroni is a secretive and rarely encountered species, spending much of its time concealed beneath leaf litter, soil, or debris. It is primarily terrestrial and is thought to be most active during periods of high humidity, such as the monsoon season.
Like other coral snakes, it relies on venom primarily for prey immobilisation rather than defence. Encounters with humans are rare, and bites are extremely uncommon due to its reclusive habits.

Diet and feeding specialisation

The species exhibits ophiophagy, meaning it specialises in feeding on other snakes. Its known prey consists predominantly of members of the family Uropeltidae, a group of small, fossorial shield-tailed snakes endemic to the Western Ghats.
This highly specialised diet is reflected in its venom composition, which is adapted for rapid immobilisation of elongate reptilian prey rather than mammals. Such dietary specialisation limits ecological flexibility but reduces competition with sympatric snake species.

Reproduction

Calliophis bibroni is oviparous, reproducing by laying eggs. Detailed information on clutch size, incubation period, and reproductive seasonality remains limited, reflecting the species’ elusive nature. As with other elapids, reproduction is likely seasonal and linked to climatic conditions, particularly rainfall.

Venom and medical significance

As a member of the family Elapidae, C. bibroni possesses neurotoxic venom delivered through fixed front fangs. However, due to its small size, secretive habits, and rarity, it is not considered medically significant in terms of snakebite risk to humans. There are no well-documented cases of envenomation attributable to this species.

Conservation status and threats

While not among the most commonly assessed Indian snakes, Calliophis bibroni is potentially vulnerable due to its restricted range, habitat specificity, and low encounter rates. Major threats include:

• Habitat loss and fragmentation in the Western Ghats
• Road mortality
• Forest degradation and land-use change