Telosticta bidayuh (Platystictidae) is part of a genus described in 2012, comprising 17 species endemic to Borneo and Palawan. There are 14 of them in Sarawak, but only six (fortunately for identification by amateurs!) in the western part that we surveyed.
Unlike the other three species we encountered (T. dupophila, T. santubong, and T. serapi), it is one of the Telosticta that feature fairly long (though not complete) antehumeral stripes.
The first photo shows the dorsal view of the thorax of Telosticta bidayuh, the fourth that of T. feronia, whose antehumeral stripe is very similar.
Telosticta Dow & Orr, 2012 (1)
In the same publication, Dow & Orr (1) show the distribution of the blue coloration on the last segments. And fortunately, Telosticta bidayuh and T. feronia are very different;
While Telosticta bidayuh shows only two adjoining colored spots on the eighth segment, T. feronia presents a complete, rectangular spot on segments eight and nine.
The coloration on S8 of T. bidayuh is not necessarily bilobed but can form a single spot, as shown in some of my photos; this variation is noted in the previously cited work.
We encountered the species twice. The first time, on March 26th, very briefly, and the second, on March 30th, for longer; however, during this second contact, I was only able to take mediocre photos with a backup camera and especially a backup lens, having fallen into the water the day before…
The authors previously cited tell us that its abdomen measures 33.5 mm without the anal appendages. It therefore measures around 41 mm in total.
During our second encounter, at Ranchan Recreational Park, the individuals we contacted were in the forest, in dark areas, some distance from a major waterfall, above the trickles of water escaping laterally from the main stream. It was also encountered on small, steep trickles of water, always in the forest.
At this site, we found it in the company of Coeliccia nigrohamata. However, the authors encountered it accompanied by T. serapi.
It is endemic to Sarawak and is currently known only from a very limited area in the extreme west of Sarawak, around Kuching. It is very rare, and the photos we took are the first ones on iNaturalist.
IUCN Red List.
Note on this specimen the dark green spot at the end of the dorsal surface of the thorax, which is merely a plant particle.
Etymology of Telosticta bidayuh (1)
Telosticta is a feminine noun, composed of the Greek telos (τλος), meaning "toll," from the name of Jan van Tol, whose surname comes from the Dutch word of the same meaning, in tribute to his contributions to our knowledge of Platystictidae, and the suffix -sticta, a common generic ending in the family [Platystictidae]. Sticta comes from the Greek stiktos, which means spotted or tattooed, and refers to the South Asian genus Platysticta, whose wingtips bear a dark spot.
Bidayuh: Bidayuh is the collective name for several indigenous peoples of Borneo, and the species' currently known distribution range corresponds to the heartland of these peoples' territory.
Telosticta bidayuh male, Sarawak, Bung Ngiraja, 26/03/2025
1- Dow & Orr, 2012 – Telosticta, a new damselfly genus from Borneo and Palawan (Odonata: Zygoptera: Platystictidae) – The Raffles Bulletin of Zoology 60 (2) : 365-401.