Lamelligomphus sp. - a new species after all?*

*This entry slightly adjusted now that the Lamelligomphus sp. has been described by Karube (2015) as L. vietnamensis.

Last year in October I caught a Lamelligomphus (see the entry) that until now I have not been able to identify. Sebastien also had photos of similar specimens, but only recently did we see it again. In August Sebastien informed me he had seen several in northern Vietnam and this weekend when visiting northern Bac Kan Province I too caught up with it again. I had a single male hovering over a clear stream that I could catch. Superficially it is like L. hainanensis. It has similar penile head shape, similar anterior hamule shape, no humps on S8, small teeth on the interior of the superior appendages. Indeed, I had thought previously this was L. hainanensis, until I found it earlier this year. But what I call L. hainanensis has a continuous green-yellow stripe over the top of the frons, even if it is slightly incised. The Lamelligomphus sp. (now Lamelligomphus vietnamensis) has the stripe clean cut into two parts. Also, L. hainanensis has all black or only slightly marked labrum, whereas the present Lamelligomphus has two clear yellow spots on the labrum. The inferior appendages are more blunt and do not project at all beyond the superiors. In dorsal and ventral view there are also small differences. And where L. hainanensis is a smaller species, with abdomen 41-42 mm, in the present species it is 47-48 mm. It is clearly a common species, has undoubtedly been overlooked (like L. formosanus), but I cannot fit it onto any known Chinese species. It is close enough in structure to L. hainanensis, but there cannot be two species with the same name, obviously.

Lamelligomphus vietnamensis. Typical as the genus goes.

Compare this photo of an earlier L. hainanensis. Very similar in overall patterning, but longer overlap of inferiors, which also clearly protrude.

Dorsal view of Lamelligomphus vietnamensis.

This is the face of  Lamelligomphus vietnamensis. Note the broken line over the frons and the large oval spots on the labrum. The yellow over the anteclypeus is, I think, normally continuous.

I already published this photo of face of L. hainanensis with continuous stripe over frons and all black labrum. Sometimes there are small yellow spots  near the sides (actually also in this specimen). 

Dorsal view of appendages

Ventral view

And lateral view. The short inferiors that do not protrude at all typical

Penile organ by the looks of it similar to L. hainanensis