Eristicophis

Common names: McMahon's viper, Asian sand viper, leaf-nosed viper.^[2]

Eristicophis is a monotypic genus created for a venomous viper species, E. macmahonii. It is found only in the desert region of Balochistan near the borders of Iran, Pakistan and Afghanistan.^[1] No subspecies are currently recognized.^[3]

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Description

This is a relatively small species growing to less 1 m long. Males are 22-40 cm in length, the females 28-72 cm.^[2]

The head is large, broad, flat and wedge-shaped. It is also distinct from the neck. The snout is broad and short. The eyes are of a moderate size. The crown of the head is covered with small scales. The nostrils are a pair of small slits. It has a characteristic rostral scale, that is wider than it is high, strongly concave and bordered above and to the sides by four much enlarged nasorostral scales arranged in a butterfly shape. There are 14-16 supralabials, which are separated from the suboculars by 3-4 rows of small scales. There are 16-19 sublabials. The circumorbital ring consists of 16-25 scales.^[2]

The body is dorsoventrally slightly depressed and appears moderately to markedly stout. The tail is short, and prehensile, tapering abruptly behind the vent. The skin feels soft and loose. The dorsal scales are short and keeled, in 23-29 midbody rows that are arranged in a straight and regular pattern. The ventral scales have lateral keels, numbering 140-144 in males and 142-148 in females. The subcaudals are without keels: males have 33-36, females 29-31.^[2]

The color pattern consists of a reddish to yellowish brown ground color, overlaid dorsolatterally with a regular series of 20-25 dark spots, bordered partly or entirely with white scales. Posteriorly, these spots become more distinct. The white border areas often extend over the back as bands. The head has a white stripe that runs from the back of the eye to the angle of the mouth. The top of the head may have scattered dark flecks. The labials and throat are white, as is the belly. The tip of the tail is yellow with distinct crossbands.^[2]

Geographic range

In the desert region of Balochistan near the Iran-Afghanistan-Pakistan border. They type-locality given is "Amirchah [Amir Cháh on map], 30th March, 3300 feet, Zeh, 1st April, 2500 feet, Drana Koh, 2nd April, Robat I., May, 4300 feet." Listed as "W. Baluchistan" in the catalogue of the Bombay Natural History Museum, Bombay India. Smith (1943:497) listed it as the "desert south of Helmand [River], in Baluchistan."^[1]

According to Mallow et al. (2003), this species is reported from Pakistan, Afghanistan, eastern and northwestern Baluchistan, southern Iran and India in the Rajasthan Desert. It is limited to the Dast-i Margo Desert and nearby dune areas, from Seistan in the extreme east of Iran into Afghanistan south of the Helmand River. It also occurs in Baluchistan, between the Chagai Hills and Siahan Range, east to Nushki.^[2]

Habitat

Associated with (shifting) dune habitats of fine, loose sand. Not found above an altitude of 1300 m.^[2]

Behavior

Employ rectilinear and serpentine motion to move around, but will sidewind when moving over loose sand or when alarmed. Occasionally, it climbs into bushes using its prehensile tail. This species is mainly nocturnal, but may also be crepuscular. It is also said to be bad-tempered, hissing very loudly and deeply. It will raise the front part of its body off the ground in a loop and strike aggressively.^[2]

Eristicophis can appear to sink down into the sand using a rocking or peristaltic motion. Following this, it will usually shake and rotate its head along the longitudinal axis to cover its head, leaving only its snout and eyes free of sand. It is thought that the enlarged nasorostral scales keep sand from entering the nostrils.^[2]

Feeding

Feeds on small lizards, small rodents and sometimes birds. Mice are held in the mouth until dead, or nearly so.^[2]

Reproduction

This species is oviparous, laying up to a dozen eggs. These hatch after 6-8 weeks, with the hatchlings being about 6 inches (15 cm) long.^[4]

Venom

Relatively little data is available, but it is regarded as a potentially dangerous species by the U.S. Navy (1991) with venom similar to that of Echis.^[5]

See also

• List of viperine species and subspecies
• Viperinae by common name
• Viperinae by taxonomic synonyms
• Snakebite

References