Trimeresurus

It is a genus of venomous pit vipers that are distributed in Asia and found from the Indian subcontinent through Southeast Asia, the Pacific Islands, Japan, The Malay archipelago to Timor and China. Trimeresurus genus includes relatively small and primarily arboreal species having thin body with prehensile tail. Though species such as Trimeresurus flavoviridis reported to attain of 242 cm, and is known as the longest pit viper in East Asia. Most of species under Trimeresurus genus are normally having green colored body; however some other species may also have orange, yellow, red, black, or gold motifs. The diet of theses serpent includes birds, amphibians, lizards, small rodents and mammals. Currently there are around 32 species documented under the genus so far.

Trimeresurus malabaricus  (Image Source:  commons.wikimedia.org)

Alike most other viper species, almost all species in the genus are ovoviviparous, except some species like T. flavoviridis, T. kaulbacki, and T. macrolepis which are oviparous. Te species fall under the genus are T. albolabris Gray, 1842 (White-lipped pit viper); T. andalasensis David, Vogel, Vijaykumar & Vidal, 2006 (Sumatran palm pit viper); T. andersonii Theobald, 1868 (Anderson’s pit viper, Andaman pit viper); T. borneensis W. Peters, 1872 (Bornean pit viper); T. arunachalensis Captain, Deepak, Pandit, Bhatt, and Athreya, 2019 (Arunachal pit viper); T. cantori (Blyth, 1846) (Cantor's pit viper); T. brongersmai Hoge, 1969 (Brongersma's pit viper); T. erythrurus Cantor, 1839 (Red-tailed bamboo pit viper); T. cardamomensis Malhotra, Thorpe, Mrinalini, & Stuart, 2011 (Cardamom Mountains green pit viper); T. gracilis Ōshima, 1920 (Kikushi habu); T. fasciatus Boulenger, 1896 (Banded pit viper); T. flavomaculatus Gray, 1842 (Philippine pit viper); T. gramineus Shaw, 1802 (Bamboo pit viper); T. gumprechti David, Vogel, Pauwels & Vidal, 2002  (Gumprecht's green pit viper); T. gunaleni  Vogel, David, & Sidik, 2014 (Gunalen's pit viper); T. hageni Lidth de Jeude, 1886 (Hagen's pit viper); T. honsonensis Grismer, Ngo, & Grismer, 2008 (Hon Son pit viper); T. insularis Kramer, 1977 (Sunda Island pit viper orWhite-lipped island pit viper); T. kanburiensis Smith, 1943 (Kanburi pit viper); T. labialis Steindachner, 1867 (Nicobar bamboo pit viper); T. macrolepis Beddome, 1862 (Large-scaled pit viper); T. macrops Kramer, 1977 (Large-eyed pit viper); T. malabaricus Jerdon, 1854 (Malabar rock pit viper); T. malcolmi Loveridge, 1938 (Malcolm's pit viper); T. mcgregori Taylor, 1919 (McGregor's pit viper or McGregor's tree viper or Philippine pit viper); T. medoensis Zhao, 1977 (Motuo bamboo pit viper); T. mutabilis Stoliczka, 1870 (Central Nicobar pit viper or Central Nicobar bamboo pit viper); T. nebularis Vogel, David, & Pauwels, 2004 (Cameron Highlands pit viper or Clouded pit viper); T. phuketensis Sumontha, Kunya, S.G. Pauwels, Nitikul & Punnadee, 2011 (Phuket pit viper); T. popeiorum Smith, 1937 (Popes' pit viper); T. puniceus Kuhl, 1824 (Flat-nosed pit viper); T. purpureomaculatus Gray, 1832  (Mangrove pit viper); T. rubeus Malhotra, 2011 (Ruby-eyed green pit viper); T. sabahi Regenass & Kramer, 1981 (Sabah bamboo pit viper or Sabah pit viper); T. Salazar Mirza, Bhosale, Phansalkar, Sawant, Gowande, & Patel 2020 (Salazar’s pit viper); T. schultzei Griffin, 1909 (Schultze's pit viper); T. septentrionalis Kramer, 1977 (Nepal pit viper or Himalayan white-lipped pit viper); T. sichuanensis Guo & Wang, 2011 (Sichuan pit viper); T. stejnegeri Schmidt, 1925 (Stejneger's pit viper); T. strigatus Gray, 1842 (Horseshoe pit viper); T. sumatranus Raffles, 1822 (Sumatran pit viper); T. tibetanus Huang, 1982 (Tibetan bamboo pit viper); T. trigonocephalus Donndorff, 1798 (Sri Lankan pit viper); T. truongsonensis Orlov, Ryabov, Thanh, & Cuc, 2004 (Quang Binh pit viper); T. venustus Vogel, 1991 (Beautiful pit viper or Brown-spotted pit viper); T. vogeli David, Vidal & Pauwels, 2001 (Vogel's pit viper); T. wiroti Trutnau, 1981 (Wirot's pit viper) and T. yingjiangensis Chen, Zhang, Shi, et al., 2019 (T. yunnanensis Schmidt, 1925 (Yunnan bamboo pit viper).

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 Malabar pit viper | Trimeresurus malabaricus, (Jerdon, 1854)

 Malabar pit viper (Trimeresurus malabaricus) is a venomous snake species of pit viper which is endemic to the Western Ghats of India.  It is also known as rock viper. Different morph of this Serpent has been recorded viz., yellow, brown, and green.  Currently no subspecies have reported.

Trimeresurus malabaricus
(Image Source: L. Shyamal -  commons.wikimedia.org)

Trimeresurus malabaricus is nocturnal species but can be sighted basking on rocks and trees nearby streams. The species is most active during the monsoon months. It is usually a slow moving serpent but have the capacity of strike fast when needed. Malabar pit viper is moderate venomous species whose bite is not recorded as lethal to humans; bite of the serpent causes moderate pain and swelling which generally subsides within a day or two.

The species is endemic to the hills of Western Ghats dispersed along the southern and western parts of India occurring at an altitude ranging from 600–2,000 m.asl. The prime diet of the serpent includes frogs, birds, lizards, and rodents.  In its range the serpent has been recorded from different localities viz., Amboli hills, Travancore hills, Nilgiris, Periyar Tiger Reserve, Meghamalai, Palni hills, Anaimalai, Goa and Karnataka.

Trimeresurus malabaricus is viviparous species which give birth to 4-5 live juveniles They may attain maximum snout to vent length of 41 inches, whereas males of the species are always smaller than their female counterparts like most of the serpents.

Males of the species seem to have grayer and blotchier morphs which prefer ground level. However on the other hand females choose high canopy forests and show more intense morphs. Thus it also makes them more susceptible to habitat loss. This species in its range inhabits the riparian forests and prefers hilly streams and inundations sited inside dense rainforests mostly, but may claim deciduous and evergreen forests sometimes also, where it can be sighted on ground debris, on rocks near streams.

Scalation observed in this species is as: Supralabials 9-10/9-10, first separating the nasal completely; there is a row of scales present between the upper labials and subocular scale; 7-9 between the eyes, dorsal scales are in 21/23:19?21:15/17 rows and low keeled; ventral 143-158 in males and 136-159 in females; Anal single; Subcaudal are 50-63 (paired) in males and 44-54 (paired) in females. Hemipenis is observed at 12^th caudal plate.

There is no serious threat to the species except habit loss due to deforestation in its range. It is  also categorized as least concern (LC) by IUCN.

Literature Cited:

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Bhupathy, S. and Sathishkumar, N. (2013). Status of reptiles in Meghamalai and its environs, Western Ghats, Tamil Nadu, India. Journal of Threatened Taxa, 5 (15): 4953-4961 - get paper here

Boulenger, G.A. (1890). The Fauna of British India, Including Ceylon and Burma. Reptilia and Batrachia. Taylor & Francis, London- get paper here

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Castoe, T.A. and Parkinson, C.L. (2006). "Bayesian mixed models and the phylogeny of pitvipers (Viperidae: Serpentes)". Molecular Phylogenetics and Evolution, 39: 91-110.

Chandramouli, S.R., Ganesh, S.R. (2010). Herpetofauna of Southern Western Ghats, India − reinvestigated after decades. Taprobanica, 2 (2), 72-85

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Das, I. (2002). A Photographic Guide to Snakes and Other Reptiles of India. Ralph Curtis Books. Sanibel Island, Florida. ISBN 0-88359-056-5.

David P., Vogel G. and Dubois A. (2011). On the need to follow rigorously the Rules of the Code for the subsequent designation of a nucleospecies (type species) for a nominal genus which lacked one: the case of the nominal genus Trimeresurus Lacépède, 1804 (Reptilia: Squamata: Viperidae). Zootaxa, 2992: 1–51

Ganesh, S.R., Chadramouli, S.R., Sreekar, R. and Shankar, P.G. (2013). Reptiles of the Central Western Ghats, India- A reappraisal and revised checklist, with emphasis on the Agumbe Plateau. Russian Journal of Herpetology. 20 (2), pp. 134- 142

Guo, P., Qin, L., Guanghui, Z., Fei, Z., Fang, Y., Ting, T., Rong, X., Min, F., Ping, W. and Xin, F. (2015). Cryptic diversity of green pitvipers in Yunnan, South-west China (Squamata, Viperidae). Amphibia-Reptilia 36 (3): 265 - 276 - get paper here

Inger, R.F., Shaffer, H.B., Koshy, M. and Bakde, R. (1984). A report on a collection of amphibians and reptiles from the Ponmudi, Kerala, South India. J. Bombay Nat. Hist. Soc. 81 (3): 551-570 - get paper here

Jerdon,T.C. (1854). Catalogue of the Reptiles inhabiting the Peninsula of India. Part, 2, J. Asiat. Soc. Bengal, xxii: 522-534 [1853] - get paper here

Kanagavel, A., Rajkumar, S., Nikhil, W. and Rajeev, R. (2012). A Malabar Pit Viper, Trimeresurus malabaricus (Jerdon, 1854) morph from the southern Western Ghats. Reptile Rap (14): 27–28 - get paper here

Malhotra, A. and Thorpe, R.S. (2004). "A phylogeny of four mitochondrial gene regions suggests a revised taxonomy for Asian pitvipers (Trimeresurus and Ovophis)". Molecular Phylogenetics and Evolution, 32: 83-100.

Mirza, Z.A., Bhosale, H.S., Phansalkar, P.U., Sawant, M., Gowande, G.G. and Patel, H. (2020). "A New Species of Green Pit Vipers of the Genus Trimeresurus Lacépède, 1804 (Reptilia, Serpentes, Viperidae) from western Arunachal Pradesh, India". Zoosystematics and Evolution, 96 (1): 123–138.

Palot, M..J. (2015). A checklist of reptiles of Kerala, India. Journal of Threatened Taxa, 7 (13): 8010–8022 - get paper here

Sagar, U. (2016). Some observations on the Malabar Pit Viper Trimeresurus malabaricus in central Western Ghats, India. Reptile Rap, (18): 36–39 - get paper here

Smith, M.A. (1943). The fauna of British India, Ceylon and Burma including the whole of The Indo-Chinese Sub-region, Reptilia and Amphibia. Vol. 3 “Serpentes”. Taylor & Francis, London.

Srinivasulu, C., Srinivasulu, B., Shankar, G., Thakur, S., Kulkarni, N.U. and Jose, J. (2013). "T malabaricus". IUCN Red List. 2013: e.T172708A1372028. doi:IUCN.UK.2013. Retrieved on 12 May, 2020

Sumontha, M., Kunya, K., Pauwels, O.S.G., Nitikul, A. and Punnadee, S. (2011). "Trimeresurus (Popeia) phuketensis, a New Pitviper (Squamata: Viperidae) from Phuket Island, Southwestern Thailand". Russian Journal of Herpetology,18 (3): 11-17.

Trimeresurus at en.wikipedia.org retrieved on 12 many 2020

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