Oligodon russelius

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Scientific Classification
Conservation status
Least Concern (IUCN 2019)Dutta et al. 2016, Bhandarkar and Paliwal 2021
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Oligodon
Species:	O. russelius
Binomial name
Oligodon russelius Oligodon russelius (Daudin 1803)

Oligodon russelius, commonly known as Russell's Kukri snake, is a species of nonvenomous snake in the family Colubridae found in South Asia.

This snake is known as Russell's Kukri attributed to Dr. Patrick Russell. Adults reach maximum SVL 25.6 inches.

It is observed active during daylight hours. When threatened, it flattens its posterior head to intimidate its predator (Wall 1921).

Description

Scalation detail

Head elongate, slightly flattened, indistinct from neck. Snout elongate, moderate, flat in dorsal view, rounded in lateral profile, rather depressed. Rostral shield large, flat, distinctly visible from above, pointed posteriorly; internasal subtriangular; nostrils rather large, nasals large and elongated, divided by the nostril, in anterior contact with rostral, internasal and prefrontal dorsally, first and second supralabial ventrally, loreal posteriorly; loreal single, elongate horizontally; prefrontal rather large, broader than long, and sub-hexagonal; frontal large, pentagonal, elongate, shortened posteriorly and longer than wide; supraocular narrow, short, sub-rectangular, posteriorly wider; parietals large, short, butterfly-wing-like in shape, bordered by supraocular, frontal, upper postocular anteriorly, anterior and upper posterior temporals. One preocular, vertically elongated, pentagonal, in contact with prefrontal and loreal. Anteriorly, supraocular dorsally, and third supralabial ventrally, eye moderate round, nearly half of the size of snout length, pupil rounded; two postoculars, subequal or sometimes upper one larger, rounded or sub quadrangular, upper postocular in broad contact with supraocular and parietal, lower postocular in contact with anterior temporal and fourth and fifth supralabials; temporals 1 þ 2, elongated, subrectangular; anterior temporal almost the same size as lower posterior temporal, in contact with parietal and both postoculars dorsally, and fifth and sixth supralabial ventrally; lower posterior temporal in contact with sixth and seventh supralabials ventrally. Supralabials seven (on both sides), 5th–7th largest in size; first supralabial in contact with rostral anteriorly, anterior and posterior nasals dorsally, second with posterior nasal and loreal dorsally, third with loreal, preocular and orbit dorsally, fourth with orbit and the lower postocular dorsally, fifth with lower postocular and anterior temporal dorsally, and sixth with anterior and lower posterior temporals dorsally, seventh with lower posterior temporal dorsally and scales of the neck posteriorly.

Mental of smaller size, triangular; first infralabial pair larger than mental plate and in broad contact with each other, in contact with anterior chin shields posteriorly; seven infralabials, 1st–3rd in contact with anterior chin shields, fourth infralabial largest in size in contact with both anterior and posterior chin shields; 4th–7th infralabials in contact with gular scales; two larger anterior chin shields, and two smaller posterior chin shields; anterior chin shields in broad contact between them; posterior chin shields bordered posteriorly by six gular scales.

Body robust, elongate and subcylindrical; dorsal scales in 17-17-15 rows, all smooth and pointed posteriorly. Ventral scales 169–180 in males, 183–207 in females, cloacal plate divided.

Tail comparatively long 17.0–18.9% of total length in males, robust and thick; subcaudals 46–54, divided.

Coloration

Dorsum dark olive brown, lateral surface paler and yellowish; 30–45 black cross stripes along the body and 6–10 on the tail; the markings on the tail are rudimentary; two inverted V-shaped black markings on the head, (1) the first one on the interorbital region, starting from the anterior edge of supraoculars, pointing forward to prefrontal–internasal region; in some individuals the V-shaped marking is not complete; (2) the second one on the parietal–frontal region, starting from the gape of the mouth, pointing forward to the frontal region, and completing the V shape at the interorbital position; another inverted Y-shaped black marking on the nape, starting from the lateral side of the neck, pointing forward to the level of the interparietal region; dark markings below the eye, usually on the posterior border of fourth and fifth supralabials; all the dark markings are in a range of brown, from chestnut to chocolate brown; venter uniform yellow or cream.

Skull and Dentition

premaxilla single, blunt anteriorly, with a broad ascending process, a prominent nasal crest, and a relatively short transverse process; nasals elongate, triangular, lateral processes tapering anteriorly to form a pointed process at the point of articulation with the ascending process; parietals rough, anterior process flat behind frontals; maxilla with 8–10 functional teeth, gradually increasing in size posteriorly; palatine with 4 or 5 teeth; pterygoid with 16 or 17 teeth; and mandible with 15 or 16 teeth.

Distribution

Oligodon russelius is found in Sri Lanka, Bhutan, Nepal, Bangladesh, India and Pakistan.

Habitat

Oligodon russelius is known from low, deciduous, and scrub jungle terrains, including areas close to human settlements. This kukri snake species is also active in twilight and slightly beyond, but during monsoon (August–October) and the colder months (October–March).

Reproduction

This species is sexually dimorphic where adult females are larger than adult males (Wall 1921). It is oviparous. The clutch contains four or five remarkably elongate eggs with measured dimensions 36 × 10 mm and the SVLs of the hatchlings are around 181.0–193.0 mm (Wall 1921). Usually, hatchlings are brighter in colors with faded and less prominent cross stripes, but with distinct white margins. The juveniles have been mostly observed in April to July and during the winter. A scavenging behavior of this species was observed by Pandirkar et al. (2015), where the snake fed on a dead garden lizard (Calotes versicolor).

References

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