Friday, 17 August 2018

Two new Rhipidolestes for Vietnam

Currently 25 species of the genus Rhipidolestes are known. Many are very similar. Wilson and Xu (2007) provided a key to the known species, a great many of which occur in China. It has been a frustration for me that I had until now only been able to find Rhipidolestes owadai in northern Vietnam, where it is quite widespread and sometimes locally very common. How could there be no other species around, with directly across the border so many others? But frustrating as it might be, during 4 years in Vietnam I never found anything else.
It was with this knowledge that this spring I accompanied Phil Benstead and a fine group of people to the north of Vietnam on a two-week tour. Of course we encountered R. owadai. And I explained again and again that this is strangely enough the only species of the genus in Vietnam. Until on June 12 we spent a morning in the pouring rain at the Love Waterfall in Sa Pa at approximately 2000m altitude. I found a completely drenched somewhat smallish Rhipidolestes, virtually dead, in the mist and rain. The altitude was way higher than any R. owadai I had ever seen, so I paid close attention. It was a new species for Vietnam! Checking the details, it is close to identical to the detailed description of R. jucundus Lieftinck, 1948, a high altitude species from Fujian Province in China. That is far away from Sa Pa, but at least the altitude is similar. Possibly the cone on S9 is larger than in the type, but Lieftinck did not draw it and although the specimen is kept at Naturalis, the collection is currently closed. Also, Lieftinck described only one row of cells between CuA (his Cu2) and the wing margin in all wings. In my specimen there are two rows in the hindwing. However, otherwise everything fits exactly. I am confident this is indeed R. jucundus.
But things turned stranger after returning home and checking a R. owadai, or so I thought, I had collected in comparison. I did not properly note the location, but I probably took it in Cao Bang, at Pia Oac. looking at it again, it was immediately obvious it had a blue face, quite unlike R. owadai. Further study pointed to R. cyanoflavus Wilson, 2000. This species at least was described from nearby Guangdong Province in China. I am quite embarrassed not having recognized it in the field, but anyway, a third Rhipidolestes found to occur in Vietnam!

Many thanks to Keith Wilson and Martin Schorr, who provided some of the papers I needed.

Rhipidolestes jucundus in the rain at Love Waterfall
Its bright orange face
The rather distinctive appendages in dorsal view, although similar to those of R. malaisei from Myanmar. Apologies for the faeces visible.
The appendages in lateral view, with the upward pointed tooth of the inferiors clearly visible.
Not even a proper picture. Rhipidolestes cyanoflavus, from northern Vietnam, probably Pia Oac.
I have to admit, it is not clear how I missed noticing the face is blue.

The superior appendages, clearly different from R. owadai.