Fowlea asperrima

Fowlea asperrima is endemic to Sri Lanka. It is non-venomous and belongs to Colubridae family.

Merrem's hump-nosed viper (Hypnale hypnale)

English: Merrem's hump-nosed viper
Sinhala: කුණකටුවා / පොලොන් තෙලිස්සා [Kunakatuwua/Polon thelissa]
Binomial name: Hypnale hypnale

Hypnale hypnale (Merrem's hump-nosed viper) is a venomous pit viper species found in Sri Lanka and India. Based on the taxonomic revisions done so far, have stated that there are four species that belong to the genus Hypnale which live in Sri Lanka (Including possibly new species Hypnale sp. ‘amal’). Among them, population of H. hypnale in Sri Lanka has been observed mainly in anthropogenic habitats and no observations have been made in undisturbed forests (Maduwage et al. 2009). At a glance, morphologically all these four species look similar. But with a closer look, H. hypnale can be easily distinguished from its congeners using scalation and with the help of non raised snout tip. This species is more active at night and in the day time they live under the logs, rocks and in the leaf litter. Venom of this genus mainly causes local envenoming, coagulopathy, acute renal failure and death. A research done by Dr. Anjana Silva and others (Silva et al. 2012) to compare the in-vivo toxicity of venoms of this genus reveals that the venom of H. hypnale has the highest toxicity compared to the venom of H. zara and H. nepa, with the LD50 value of 1.6 μg protein/g. Since there are known human bite reports with serious complications, this snake has been placed in the category of ‘Medically important’. 

Ref: Silva, Anjana, Panduka Gunawardena, Danister Weilgama, Kalana Maduwage, and Indika Gawarammana 2012 Comparative in-Vivo Toxicity of Venoms from South Asian Hump-Nosed Pit Vipers (Viperidae: Crotalinae: Hypnale). BMC Research Notes 5(1): 471. 

Maduwage, Kalana, Anjana Silva, Kelum Manamendra-Arachchi, and Rohan Pethiyagoda 2009 A Taxonomic Revision of the South Asian Hump-Nosed Pit Vipers (Squamata: Viperidae: Hypnale). Zootaxa 2232: 1–28. 

Maduwage K, Kularatne K, Wazil A, Gawarammana I: Coagulopthy, acute kidney injury and death following Hypnale zara envenoming – The first case report from Sri Lanka. Toxicon 2011, 58:641–643

Sri Lankan krait (Bungarus ceylonicus)

English: Sri Lankan krait
Sinhala:මුදු කරවලා[Mudu Karawala]
Binomial: Bungarus ceylonicus

Bungarus ceylonicus(Sri Lankan krait ,මුදු කරවලා), is a relatively rare, deadly venomous and endemic elapid snake found mainly in wet and intermediate zones of the island. They live in undisturbed forests, but sometimes in anthropogenic habitats. It has a black, shiny skin crossed with thick white transverse bands that get disappeared with the age. There is a set of other non-venomous snakes in Sri Lanka which belong to the genus Lycodon that mimics the color pattern of Bungarus ceylonicus. But B. ceylonicus can be distinguished by enlarged hexagonal vertebral scales, relatively shiny body scales and undivided subcaudal scales. Also head and the neck are not much distinguishable in kraits when it is compared with the members of genus Licodon. 

The Sri Lankan krait is oviparous and feeds on other reptiles, small mammals like rats and skinks. Even thought the snake is highly venomous, it showed a very timid and non-aggressive behavior in the day time and reluctant to bite. It was also observed that it always tried to escape and hide in covered safe places when threatened or sometimes tried to protect itself by hiding its head under the body loops. But during the night they are said to be become very active and could provide fatal bites for a considerable provocation. Being a relatively rare to find and shy reptile, fatal human bites are rare. But deaths have been reported due to envenomation. 

Venom of B. ceylonicus is mainly powerful neurotoxins that act on nerve endings near the synaptic clefts of neurons. Also, members of the genus Bungarus produce a mix of presynaptic and postsynaptic neurotoxins that need immediate hospitalization and treatments in case of an envenomation. 

A specific anti venom has not been developed so far that work effectively for the bites of B. ceylonicus. Even the B. ceylonicus bites are rare; some clinical studies have been done to study the effect of venom on human. The first fatal case report dates back to 1993 for B. ceylonicus(De Silva et al. 1993) which describes a death of a patient within 90 hours after the bite, followed by a cardio-respiratory arrest even with provided treatments such as anti-venom and mechanical ventilation. 

Also one such recent case study ( Rathnayaka N. et al, 2017) describes a dry bite occurred at day time which was ended without any envenamation symptoms. According to the report, other incident has been taken place at night while the victim was at sleep with signs and symptoms of moderate envenoming such as tightness in the chest and dyspnoea followed by neuromuscular paralysis. Anotether study (Dalugama C. et al, 2017) describes an envenomation by the same snake which caused bilateral partial ptosis, ophthalmoplegia, facial muscle weakness and dysphagia. According to the authors, that patient had been administered polyvalent Indian anti-venom which showed a poor response for the envenomation of B. ceylonicus. Even the snakes are dangerous; they provide an immense support to maintain a proper balance in an eco system. Habitat destruction an unwanted killing have become the main threat for this relatively rare species.

References:

• A Naturalist's Guide to the Reptiles of Sri Lanka by Anslem de Silva and Kanishka Ukuwela
• Neurotoxic envenoming by the Sri Lankan krait (Bungarus ceylonicus) complicated by traditional treatment and a reaction to antivenom. Trans. R. Soc. Trop. Med. Hyg. 87, 682e684.De Silva, A., Mendis, S., Warrell, D.A., 1993.
• Confirmed Ceylon krait (Bungarus ceylonicus) envenoming in Sri Lanka resulting in neuromuscular paralysis: a case report C Dalugama, IB Gawarammana - Journal of medical case reports, 2017
• Two rare case reports of confirmed Ceylon krait (Bungarus ceylonicus) envenoming in Sri Lanka. Toxicon, 127, 44–48. Namal Rathnayaka, R. M. M. K., Kularatne, S. A. M., Kumarasinghe, K. D. M., Jeganadan, K., & Ranathunga, P. E. A. N. (2017).

Lowland Hump-nosed Pit Viper (Hypnale zara)

English: lowland Hump-nosed Pit Viper
Binomial: Hypnale zara
Sinhala: පහතරට මූකලන් තෙලිස්සා

Hypnale zara is a venomous pitviper species endemic to Sri Lanka. Based on the taxonomic revisions done so far, have stated that there are four species that belong to the genus Hypnale which live in Sri Lanka (Including possibly new species Hypnale sp. ‘amal’). Among them, population of H. zara has been restricted to the forests of lowlands and the foothills of the central highlands and no observations have been recorded in anthropogenic habitats (Maduwage et al. 2009). At a glance, morphologically all these four species look similar. But with a closer look, H. zara can be easily distinguished from its congeners using attributes like mentioned in the above named photographs. This species is more active at night and in the day time they live under the logs, rocks and in the leaf litter. 

Venom of this genus mainly causes local envenoming, coagulopathy, acute renal failure and death. A research done by Dr. Anjana Silva and others (Silva et al. 2012) to compare the in-vivo toxicity of venoms of this genus reveals that the venom of H. zara is less toxic compared to the venom of H. hypnale and has a higher LD50 value compared to H. nepa with the LD50 value of 6 μg protein/g. A report authored by Dr. Kalana Maduwage(Maduwage et al. 2011) describes a fatal case of a 47 years old male due to coagulopthy and acute kidney failure followed by envenoming of H. zara. 

Even it is common to seen in lowland forests, deforestations might be the main threat for the species and protecting the remaining fragments of lowland forests will guarantee the future existence of the species.

References: 

• Silva, Anjana, Panduka Gunawardena, Danister Weilgama, Kalana Maduwage, and Indika Gawarammana 2012 Comparative in-Vivo Toxicity of Venoms from South Asian Hump-Nosed Pit Vipers (Viperidae: Crotalinae: Hypnale). BMC Research Notes 5(1): 471.
• Maduwage, Kalana, Anjana Silva, Kelum Manamendra-Arachchi, and Rohan Pethiyagoda 2009 A Taxonomic Revision of the South Asian Hump-Nosed Pit Vipers (Squamata: Viperidae: Hypnale). Zootaxa 2232: 1–28.
• Maduwage K, Kularatne K, Wazil A, Gawarammana I: Coagulopthy, acute kidney injury and death following Hypnale zara envenoming – The first case report from Sri Lanka. Toxicon 2011, 58:641–643.

Highland Hump-nosed Pit Viper (Hypnale nepa)

English: Highland Hump-nosed Pit Viper
Binomial: Hypnale nepa 
Sinhala: කදුකර මූකලන් තෙලිස්සා

Hypnale nepa is a venomous pitviper species endemic to Sri Lanka. Based on the taxonomic revisions done so far, have stated that there are four species that belong to the genus Hypnale which live in Sri Lanka (Including possibly new species Hypnale sp. ‘amal’). Among them, population of H. nepa has been restricted to the highlands. At a glance, morphologically all these four species look similar. But with a closer look, H. nepa can be easily distinguished from its congeners using attributes like mentioned in the above named photograph.

This species is more active at night and they mostly live under the logs, rocks and in the leaf litter. Also they have been observed both in disturbed and undisturbed forests. It has been found that this species feeds on other snakes(Aspidura sp.), skinks, soft-shelled eggs and frogs (Maduwage et al. 2009).

Venom of this genus mainly causes local envenoming, coagulopathy and acute renal failure. H. nepa has the least toxicity among the studied three species of Hypnale with the LD50 value of 9.5 μg protein/g. Currently it is in the category of ‘Mildly venomous’ and so far no deaths have been reported due to envenomation (Silva et al. 2012).

Above photographed specimen was found at Dothalugala area in the Knuckles region. Observed place was an undisturbed montane forest. Elevation above the sea level of that location was about 1282m and that falls in the same elevation range (1250-1850m) of H. nepa’ s distribution mentioned in the research paper published by Dr. Kalana Maduwage and others (Maduwage et al. 2009). In the IUCN Red List it is in the category of ‘Least concern’. But necessary actions have to taken to make sure the future existence of the species.

References:

• Silva, Anjana, Panduka Gunawardena, Danister Weilgama, Kalana Maduwage, and Indika Gawarammana 2012 Comparative in-Vivo Toxicity of Venoms from South Asian Hump-Nosed Pit Vipers (Viperidae: Crotalinae: Hypnale). BMC Research Notes 5(1): 471.
• Maduwage, Kalana, Anjana Silva, Kelum Manamendra-Arachchi, and Rohan Pethiyagoda 2009 A Taxonomic Revision of the South Asian Hump-Nosed Pit Vipers (Squamata: Viperidae: Hypnale). Zootaxa 2232: 1–28.
• The IUCN Red List of Threatened Species(tm) 2015-4 - http://www.iucnredlist.org

Sri Lanka wolf snake (Lycodon carinatus)

Scales are identical in size and keeled.

English: Sri Lanka wolf snake
Binomial: Lycodon carinatus
Sinhala: දාර රදනකයා[Dara Radanakaya]

Sri Lanka wolf snake is an endemic and nocturnal species of snakes found in Sri Lanka. They mainly live in lowland wet and submontane zones and prefer damp forest areas. Above photographed one also found while it was in a wet place of the forest ground. This species is non-venomous. But it greatly mimics deadly venomous Sri Lankan krait in morphology and coloration. This snake has identically sized rough scales on the back and those have been keeled. But Kraits have large hexagonal line of scales running down the spine and the body of the Krait is shiny compared to the Sri Lankan wolf snake.

Referaces: 

•  L. J Mendis Wickramasinghe: Recognizing Deadly Venomous Snakes form Harmless Snakes of Sri Lanka – Dilmah conservation
•  Richira Somaweera : Snakes of Sri Lanka[in Sinhala]

Beddome's cat snake (Boiga beddomei)

English: Beddome's cat snake
Binomial: Boiga beddomei
Sinhala: කහ මාපිලා[Kaha mapila]

Beddome's cat snake is a nocturnal and mostly arboreal colubrine snake found in Sri Lanka and India. It is considered to be mildly venomous. Above photographed one was found in a wet zone forest  of Sri Lanka in December, 2015.

Sri Lankan Pipe Snake (Cylindrophis maculatus)

English: Sri Lankan Pipe Snake
Binomial: Cylindrophis maculatus
Sinhala: දෙපත් නයා/වටඋල්ලා[Depath naya/Wata ulla]

An endemic species of snake found in lowlands and the highlands of Sri Lanka. They are nocturnal and non venomous. If threatened, it curls the posterior half of the body by showing white colored underside to repel the enemy. This behavior might show that it has two heads which gives its Sinhala name, 'Depath naya' which has the mining of ’The cobra who has two heads'.

Shaw’s Wolf Snake (Lycodon striatus sinhaleyus)

English: Shaw’s Wolf Snake
Binomial Name: Lycodon striatus sinhaleyus
Sinhala: ඉරි කරවලා/කබර රදනකයා[Iri karawala/Kabara radanakaya]

Shaw’s Wolf Snake is a non venomous colubrid snake found in Sri Lanka. Sub species sinhaleyus is endemic. Other sub species of this snake has been distributed in other Asian countries. More common in wet-zone compared to dry zone. Feed on geckos. Most of the time it is misunderstood with venomous Kraits.

Sri Lanka cat snake (Boiga ceylonensis)

English : Sri Lanka cat snake

Binomial Name : Boiga ceylonensis

Sinhala : නිදි මාපිලා[Nidi mapila]

Boiga ceylonensis is a mildly venomous species of snake lives in Sri Lanka and India.

This snake is nocturnal and lives in evergreen forests. They mainly feed on lizards and geckos. In Sri Lanka there is a belief that this snake is highly venomous and bites people at night while sleeping to die in the sleep.

Trinket snake (Coelognathus helena)

Eggs

English : Trinket snake

Binomial Name :Coelognathus helena

Sinhala : කටකලුවා / හබරලියා [Katakaluwa / Habaraliya]

C. helena is a nonvenomous snake of Sri Lanka. This snake can be found in wet zone and dry zone with the elevation above the sea level is lesser than 1000 meters. It has a black color tongue and a mouth. Mouth is opened to show black color when threatened.

Merrem's Hump-nosed pit viper (Hypnale hypnale)

English : Merrem's hump-nosed pit viper / Hump nosed pit viper
Binomial Name : Hypnale hypnale
Sinhala : කුණකටුවා / පොළොන් තෙලිස්සා [kunakatuwa / Polon thelissa]

H. hypnale is a moderately venomous snake lives in Sri Lanka and India. Lives in wet, intermediate and dry zone. Give birth to live young instead of laying eggs. Responsible for the higherst snake bites of Sri Lanka

Common Rough-sided snake (Aspidura trachyprocta)

English : Rough-sided snake
Binomial Name : Aspidura trachyprocta
Sinhala : දලව මැඩිල්ලා [Dalawa Madilla]

Aspidura trachyprocta is a non venomous endemic snake living in highlands of Sri Lanka. It is nocturnal and the most common snake of Horton plains national park. They come in various colors ranging from blackish brown to light reddish brown. Its diet consists of earth worms and ants.

Green vine snake (Ahaetulla nasuta)

English : Green vine snake
Binomial name : Ahaetulla nasuta
Sinhala : ඇහැටුල්ලා / ඇස්ගුල්ලා

Green vine snake is a mildly venomous reptile living in all environmental regions of Sri Lanka except montane zones elevation above the sea level is greater than 1000 meters. Most of the time this snake can be seen on trees or shrubs. They have a green color body as an adaptation for arboreal life. Their female snakes give birth to young instead of laying eggs. There is a folk story among Sri Lankan people that this snake pull out human eyes using its pointed head when threatened, which is not true. A.nasuta feed on lizards and frogs.

Sri Lankan Green Pit Viper (Trimeresurus trigonocephalus)

Engish:     Sri Lankan Green Pit Viper

Scientific: Trimeresurus trigonocephalus

Sinhala:    පලා පොළඟා [Pala Polanga]

T. trigonocephalus is an endemic snake of Sri Lanka. It is moderately venomous and venom mostly consists of hemotoxins that can affect on the bloodstream of it’s pray or enemy. This nocturnal viper has a pair of pit organs on either side of their head that can detect infrared light / heat rays emitted by its pray or enemy. There for Sri Lankan Green Pit Vipers are considered to have a night vision similar to a modern military equipment. Even though they are distributed across most parts of Sri Lanka, Most commonly seen in wet zone rain forest such as Sinharaja and Kanneliya.