In Peninsula Malaysia there are about half-a-dozen or so pit viper species present, some more northerly towards the border with Thailand others scattered throughout. Altitude as well as distribution can help identify some species too. The only two 'green' species found within the areas we visited are Trimeresurus nebularis (Cameron Highland Pit Viper) and Trimeresurus fucatus (Siamese Peninsula Pit Viper). T. nebularis was only confirmed as a separate species in 2004 (VOGEL, DAVID & PAUWELS), named after the small highland area that it was thought to be confined to (it's Latin name 'nebularis' means 'from the clouds' in reference the cloud forests it inhabits). T. fucatus (Popeia) has a wider distribution being found in Malaysia, Thailand and parts of Myanmar and was confirmed from a Holotype in 1990 from Thailand. Prior to that it was thought to be a subspecies of Trimeresurus popeia (Pope's Pit Viper). To complicate things T. nebularis was recently confirmed at Fraser's Hill to the south of its known limit.
There's still a lot to learn about the Trimeresurus genus complex.
I recently managed to see several specimens of Trimeresurus fucatus on a field trip to Peninsula Malaysia, some straightforward but one that raised a question or two for me.
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| Trimeresurus fucatus, immature female Bukit Fraser, Pehang, Malaysia I initially thought this was T. nebularis based on field marks I was aware of but subtle differences in eye colour as well as a more matt appearance to the scales point towards T. fucatus |
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| Trimeresurus fucatus, immature female Bukit Fraser, Pehang, Malaysia |
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| Trimeresurus fucatus, immature female Bukit Fraser, Pehang, Malaysia |
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| Trimeresurus fucatus, immature female Bukit Fraser, Pehang, Malaysia |
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| Me with T. fucatus Bukit Fraser, Pehang, Malaysia |
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| Sheer delight! How I spotted this among the greenery, I'll never know. Pure luck. |
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| Trimeresurus fucatus, male, Bukit Fraser |
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| Trimeresurus fucatus, male, Bukit Fraser |
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| Trimeresurus fucatus, male, Bukit Fraser Males can be very handsome and well marked like this individual. |
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| Trimeresurus fucatus, female, Bukit Fraser |
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| Trimeresurus fucatus, female, Bukit Fraser |
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| Trimeresurus fucatus, female, Bukit Fraser Portrait showing head scalation. |
Venom is basically an evolutionary modified saliva packed with enzymes - peptides, polypeptides, metalloproteinases to name but a few, all designed to have a targeted effect on the snake's preferred prey. Some venoms attack the nervous system (neurotoxins), live cells (cytotoxins), muscles (myotoxins), blood (haemotoxins), kidneys (nephrotoxins) or the coronary system (cardiotoxins and sarafotoxins) - depending on the species/family of snake. They are complicated and incredible secretions and many venoms have more than one effect on its intended victim (eg. shock, haemorrhaging, paralysis and pre-digestion). These complex components can be collected, separated and used to try and find cures in modern medicine.
In the case of most Asian green pitvipers the venom is primarily haemotoxic or blood (platelet) destroying and also causes painful blistering, bleeding and necrosis at and around the bite site. Not necessarily lethal in its own right but secondary infection is the real problem and digits or limbs can be lost if medical help is not sought and antivenom administered to halt further damage.
Thankfully none of the vipers seen on our trip were particularly aggressive, although the female pictured above did look particularly grumpy and I certainly wouldn't have liked to have been bitten by her.
EDIT: Following another recent taxonomic change this has now been re-classified as Trimeresurus sabahi fucatus.
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