Wednesday, 18 November 2015

Coeliccia sp. - an intriguing species from central Vietnam*

*This posting was originally on C. montana, but it is now clear, after studying of the type material, that this species has been misidentified by Asahina. It is in fact an undescribed species and will shortly be published.

The last weekend of September I was hunting for dragons along the streams of Quang Nam Province near Bhalee village. I found a handful of pretty, smallish Coeliccia that I did not see before. Superficially they are similar to the even smaller undescribed species occurring in Cuc Phuong National Park and Huu Lien Nature Reserve, especially the males. The males have a black dorsum to the thorax, with two yellow spots at the proximal end, although larger and more elongated than in the C. sp. nov. They also have a black line along the metapleural suture absent in that species. Another difference is the abdominal pattern, which has much clearer rings. And very interestingly, they have a pruinose prothorax. I know only of C. ambigua as having pruinosity, but that also covers most of the thorax. It looks rather similar to the Indian C. schmidti Asahina, 1984, but that species misses the pruinosity on the prothorax, amongst other minor differences, and has a very different female, with bright yellow prothorax and broad antehumeral stripes. The female of the present species has a very distinctive prothorax with horns on the posterior lobe, reminiscent of the Indian C. vacca Laidlawi, 1932. It is different from the C. sp. nov. also by its thorax pattern, which has a thin antehumeral stripe, broader at the proximal end. Sadly, I let it get away (good for her) so do not have a close-up of the exact configuration.

I identified the species after consultation with Philip Steinhoff and Do Manh Cuong as C. montana Fraser, 1933. Although in their redescription of 2013 they did not mention the pruinosity and although the specimen they illustrated had "paddle sticks", meaning that the yellow spots on the thorax are elongated at the distal end into a thin antehumeral line, penile organ and appendages are a close match. Philip mentioned that specimens he considered C. montana from Da Nang also missed the paddles and that a female from the same location as those males also had the distinctive horns. What is more, on photos of his preserved specimen from the redescription pruinosity is visible on the prothorax (considered dust at the time). It therefore seems reasonable to assume the northern specimens of C. montana miss the paddle sticks of their southerly brothers. Remains the original description by Fraser, which mentions pale blue rather than yellow for both the lateral sides of the thorax as for the antehumeral stripe, although facial markings are yellow. It is possible that the change in colour is due to postmortem change, or due to preservation. Fraser also describes the abdominal tip (S9-10) as blue dorsally and laterally, but black ventrally, for adult, the blue replaced by yellow in immatures. The description also does not mention the pruinosity on the prothorax. Fraser's specimen is from Laos, whereas the redescription of the species by Asahina (1969) from southern Vietnam describes the pattern on the thorax as yellow and the abdominal tip as yellow all around. Nevertheless Asahina concludes his specimen agrees "rather well" with the type specimen in the British Museum of Natural History. Given how close many species resemble others, "rather well" seems not so convincing, especially given the differences in color and patterning. If Asahina's species is not C. montana, then the species redescribed by Steinhoff & Do also is not C. montana. In identifying my specimens as C. montana I therefore mean C. montana sensu Steinhoff & Do. Philip is trying to inspect the type in the BMNH, which may help to set the record straight.

*It is now sufficiently clear that "southern" and "northern" montana in fact are two different species and neither is C. montana. Both are currently being described.

Male Coeliccia montana. Note the darkish abdomen, pruinose prothorax, yellow dorsal spots on the thorax.

The female in hand. If you look carefully, you can see the distinctive horns on the prothorax posterior lobe

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