Drepanosticta quadrata

Damselflies from the family Platystictidae usually need close examination in particular the wings venation and anal appendages to identify the species confidently. Platysticids generally occurs in primary forests near small streams and the larvae have a distinctive disproportionately large head.
Within this family, the genus Drepanosticta is represented by eight species in Peninsular Malaysia. They usually fly close to streams, flitting within the forest understory. Both males and females typically have a blue spot at the abdomen base in which the shape of the spot can serve to identify some of the species from Peninsular Malaysia. Drepanosticta quadrata has a blue spot with a triangular pointed tip. This species was described from Singapore and according to references is known only from Singapore. This would thus make this damselfly a Singapore endemic. Even so, the website http://www.asia-dragonfly.net/ has this species as also occurring in China and Myanmar and has pictures of females from Johor. More work is perhaps needed to shed light on the true distribution of this damselfly as Albert Orr himself noted Drepanosticta spp. as data deficient with many species needing identity clarification.

Pictures taken at: Central Catchment Nature Reserve, August 2008

Update 2010Jan19th:

The blue marking on abdominal segments S8-9 is variable among species of this genus. D. quadrata is not endemic to S'pore. In fact, it is believed that D. quadrata and D. fontinalis could be the same species. (thanks Dr. Ian Choong)

References:

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2004. ‘Critical species of Odonata in Malaysia, Indonesia, Singapore and Brunei’, in Guardians of the Watershed. Global status of dragonflies: critical species, threat and conservation, eds, V. Clausnitzer & R. Jodicke, International Journal of Odonatology, vol 7(2), pp. 371-384.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Octopus species

This year is the International Year of the Reef and this coming National Day weekend, local marine lovers are having a series of talks and exhibitions to launch the event. This will be a great opportunity to highlight the amazing marine biodiversity Singapore has to the otherwise uninformed general public.

As part of the event, I’ll contribute an effort on this humble blog by drawing attention to the octopus, a creature which has always fascinated me with its amazing camouflaging abilities and known intelligence.

Octopuses can be found in a wide range of habitats. Many smaller species occur in rocky shores and coral rubbles where they forage in exposed pools during low tide periods. Most are excellent at camouflage and are able to match the colours of their surroundings with astounding dexterity. The video of this animal hunting says it all.

All octopuses use a strong neurotoxin at their salivary glands to immobilise prey when their long eight arms fan out into the nooks and crannies while hunting. The fast colour changes are presumably to camouflage it against predators although I remember reading somewhere that the changing colours are also a reflection of their ‘mood’.

Identification of octopuses to species level is not easy. Careful examination of their arm length; number of suckers; beak morphology etc is necessary. Nevertheless, small benthic dwelling inter-tidal species are from the family Octopodidae and this individual would be from the genus Octopus which most species belongs to. Many inter-tidal inhabitants are small. This octopus, with its arms fully extended, would be about the size of my two palms. For many people, all they see of octopuses is a blotch of black ink as the animal retreats into their hiding places at the first sign of danger. But any observer with patience and sensitivity will no doubt be rewarded with glimpses into the lives of our inter-tidal Singaporeans.

Happy National Day to ALL Singaporeans, big or small.

Pictures and videos taken at: A southern island of Singapore, July 2008


References:

Norman, M., 2003. Cephalopods. A World Guide. ConchBooks, Hackenheim, Germany.