Xenochrophis piscator (Schneider, 1799)

Checkered Keelback, Xenochrophis piscator , snake, water snake

Xenochrophis

Xenochrophis is a genus of snakes belonging to family colubridae which are endemic to Asia. They are often referred as painted keelback. The current genus was acknowledged by Günther in 1964. Etymologically, Xenochrophis derived from Greek words viz., Xenos - strange; chroma - colour; ophis - snake; which denotes a strange - coloured snake. It is represented by thirteen species worldwide viz., Xenochrophis asperrimus (Boulenger, 1891); Xenochrophis bellula (Stoliczka, 1871); Xenochrophis cerasogaster (Cantor, 1839); Xenochrophis flavipunctatus (Hallowell, 1860); Xenochrophis maculatus (Edeling, 1864); Xenochrophis melanozostus (Gravenhorst, 1807); Xenochrophis piscator (Schneider, 1799); Xenochrophis punctulatus (Günther, 1858); Xenochrophis sanctijohannis (Boulenger, 1890); Xenochrophis schnurrenbergeri (Kramer, 1977); Xenochrophis trianguligerus (Boie, 1827); Xenochrophis tytleri (Blyth, 1863) & Xenochrophis vittatus (Linnaeus, 1758). 

Checkered Keelback | Xenochrophis piscator (Schneider, 1799)

Checkered Keelback (Xenochrophis piscator) is a common species of non-venomous snake found within Asia under family colubridae (Natricidae).

This is the widely distributed species of snakes under the genus Xenochrophis. Morphologically, it is capricious snake in color and pattern. It can be easily identified by examining blackish dots over the dorsal surface on greenish brown color. The average length of the species is recorded 90 cm & maximum 175 cm.

Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Xenochrophis
Species:	piscator
Binomial name
Xenochrophis piscator (Schneider, 1799)

Head of these snakes is triangular with smooth and shiny scales; clearly distinct from neck. There are two black streaks that originate from the eyes and ends after reaching the posterior part of lip & the color of area b/w the streaks is usually brighter than rest of head. Two yellowish-black dots are can be seen on the internal side of the parietal scales which may be lacking in adults. 

The eyes in this species are somewhat smaller & shorter than its distance from the nostril (in adults) & having rounded pupil. The dorsal body is covered with keeled scales while smoother on lateral rows. The scales in the individuals of this species can have 2-4 different colors within a single specimen, however generally the specimens found are having dark olive green colour with blackish- brown, reddish & yellowish blotches are observed. Juveniles of the species can be seen having clear olive green color with black blotches over the body and two yellow linings dorsally. On the ventral portion the belly is usually had yellowish-white color or white mixed with red or green rarely whereas the sub-caudal scales are paired in a zigzag manner. 

Tails of these snakes are also shielded with highly keeled scales. The size of the tail is of usual length which is pointed towards tip. Color is almost as rest of the dorsal body but without any markings. Temporal scales in the individuals are 2+2 or 2+3. There are 9 upper labials, with the 4-5 touches the eyes while 5 lower labials which are in contact with the anterior chin-shields. Dorsal scales are arranged in 19:19:17 and are strongly keeled having outer rows remains smooth. Ventral scales are 120–158, anal mostly divided, with sub-caudal scales of 64–90. 

Checkered Keelback is a species which shows its activity at any time of the day. However can be found during early morning & evening mostly.Behavior is excessively alert, aggressive and very quick to respond. To show its alertness and aggression this species expands much of its fore body to show false hood. While when threatened they always try to escape at first by creeping or by jumping manner but if cornered it tries to bites in very aggressive manner. The species is oviparous and mating occurs in winters till summer after which females of the species lays around clutch of 90 eggs. New born's can be observed from May to whole monsoon periods.

Characters of species observed in Bhopal, MP
Characteristics	Range
Full body length	720 mm-855 mm
Snout-vent length	522 mm-650 mm
Tail length	190 mm-220 mm
**Dorsal  scales (A:M:P)	13:17:15
Supra-labial scales	8/8
Infra-labial scales	9/9
Ventral scales	135-157
Anal scale	Divided
Sub-caudal scales	89-98
**Note: A- Anterior; M-Midbody; P-Posterior

These snakes can subsist at any type of water body viz., lakes, river, pond, sewer line, logged water or in agricultural lands, wells or in surroundings without any water resource. Diet includes fishes, rodents, frogs & toads; their tadpole even on the household material viz., rejected meat. They also show scavenger feeding. The snakes of this species widely distributed in southeast Asia & found in countries like Srilanka, India, Myanmar, Nepal, Thailand, Bangladesh, Pakistan, Afghanistan, Cambodia, Laos, Vietnam, West Malaysia, China, Taiwan, and Indonesia. 

Prime threat of these snakes is that has been observed is the killing by way of vehicular movements near the forest trail or even in residential places (as its settlement near human habitation). 

Literature Cited: 

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