15 January 2011

Singapore Welcomes the Malay Dartlet

Singapore Welcomes the Malay Dartlet
Species #297 of the Singapore Checklist

It started with an innocuous request for an ID of a skipper that NParks Senior Biodiversity Officer Serene Chng of the National Biodiversity Centre (NBC) of NParks emailed to me. Her colleague, Jun-Yan's shot of a rather pristine specimen of this skipper, did not match the any pictures of the extant butterfly species in the Field Guide to the Butterflies of Singapore.

The dark brown underside, coupled with a sharply defined orange-yellow discal band on the underside of the hindwing indicates that this is a Malay Dartlet (Oriens paragola). Upon looking at various reference books, it was concluded beyond doubt that this species is indeed the Malay Dartlet, which was not recorded in the Singapore Checklist by the early authors.

Although described as a species that frequents lowland forest in Malaysia, it was either missed out by the early authors or the species may have migrated over to Singapore over the years. ButterflyCircle member, Sunny Chir, made a trip to check out the area where this skipper was photographed, and was rewarded with a sighting and a shot of another specimen of the Malay Dartlet in the same vicinity where the first one was shot. Subsequent checks at the location where the species was first photographed indicated that there was already a small colony of the species there, and more individuals were observed amongst the grassy patches, together with other Hesperiidae.

A comparison of Jun-Yan's shot with a typical Common Dartlet shot

With Jun-Yan's latest shot of a pristine specimen in a nature reserve, Species #297, the Malay Dartlet, which is new to Singapore, is added to the Checklist. The genus Oriens is now represented by two species in Singapore's butterfly fauna.

The Malay Dartlet differs from the more often encountered Singapore species, the Common Dartlet (Oriens gola pseudolus) in having undersides that are dark brown, with a distinct orange-yellow discal patch on the hindwing and other markings reflecting the upperside markings. The contrasting orange-yellow markings are distinctive and a diagnostic feature that distinguishes this species from other similar lookalike species. The orange markings are also not edged with black spots, unlike the two other related species in the genus.

ButterflyCircle credits the discovery of the Malay Dartlet in Singapore to Sek Jun-Yan, Senior Biodiversity Officer of the National Parks Board, whose fortunate encounter with this species confirms a new addition to the Singapore butterfly fauna.

Text by Khew SK : Photos by Sek Jun-Yan, Sunny Chir and Khew SK