Protosticta beaumonti - interesting addition to the Vietnamese list

June 7 we visited Mau Son Mountain, close the border with China. Sebastien had visited the area the previous weekend and was plagued by mist. We had mostly cloudy conditions. Nevertheless we also ran into most of the species he saw and a few others. One species that grabbed my attention was the Protosticta there, that looked different from what I am used to see from P. satoi, a species that occurs in a light and a dark color phase and moreover is apparently rather variable in body length. It has caused me before to be convinced for a while (in Ba Be National Park) that two species were involved, so extreme is the individual size variation. And although the Protosticta of Mau Son was long-bodied, it was about the same length as my largest P. satoi from Ba Be. Nevertheless, it had quite a different and consistent thorax pattern, with a clear elongated spot on the metepisternum. Under the microscope the appendages, at a first glance very similar to P. satoi, do in fact display some differences, with several more pronounced lobes and processes. Additionally the dorsum of S9 of the female is dark, not white as in P. satoi. This combination convinced me enough to make me search the literature.

Jan van Tol (2008) erected P. satoi as a different species, but postulated that it might be conspecific with P. beaumonti (Wilson, 1997) from southern China. Do Manh Cuong (2011) discusses the whole issue. It is clear though that the Protosticta from Mau Son is structurally different in detail and consistent with the description by Wilson, including the patterning of the female abdomen. Apparently, the species had been overlooked in Vietnam. I apologize for the bad close-ups. These little critters are, well, little.

Protosticta beaumonti, male, in full glory

The thorax pattern, different male

The female. Apart from the similar spot on the flanks, note the dark dorsum of S9.

In close-up for the skeptics

The complete and long bodied male

Appendages of P. beaumonti in lateral view

Those of male Protosticta satoi, indeed, one could think they were similar 

But look close in ventral view, look at the processes of the superior appendages of P. beaumonti

Compare with the smooth appearance of P. satoi

And it is not just the angle, here dorsal view of P. satoi, likewise, much smoother