Rhopalopyx elongata

This species was first recorded in the UK in East Sussex in 2013 and subsequently found in London in 2014. It is very similar to Rhopalopyx vitripennis which is found in Ireland. Separation from vitripennis is difficult but there are differences in the male genitalia.

I keyed this using the Hackston keys and got as far as the trio of closely-related species, Paluda flaveola, Rhopalopyx elongata and Rhopalopyx vitripennis. I then turned to the old RES key to narrow it down further and the shape of the vertex elimated Paluda flaveola. The RES key doesn't include elongata at all, but the description of habitat for vitripennis made that seem rather unlikely. The German photographic atlas didn't really help, other than confirming that both species do look like my specimen. Bidermann & Niedringhaus revealed that I really needed a male to be sure.

I think, given that elongata is known to be present in England and, as far as I know, vitripennis is not, it's a safe bet to call it elongata. Tristan B agrees that it will be elongata and advises that it seems to have spread quickly, though I don't know it's been recorded in Norfolk before or not.

The keying to tribe was slightly complicated by the two forewings having different venation - one having a small (submarginal?) cell that was missing on the other. Just in case I had misinterpreted this I ran it through the Macrostelini key too, but this didn't lead anywhere.

female Rhopalopyx elongata showing vertex from above and side, frons dimensions, forewings, hindwing, cavity behind antenna and sternites, Wendling Beck Environment Project (Norfolk, UK), 21st August 2023

When surveying the same location the following month I had the following leafhopper come to light. Sadly it made a bid for freedom as I placed the lid on the pot - fortunately it failed, but unfortunately it timed its attempt just as I was pushing the lid down and it became flattened in the process. Keying it was impossible as most of the leafhopper was destroyed and I only got it to Rhopalopyx by examining the genitalia and flicking through the German key until I found some similar diagrams. One wing was intact, shown here, and the venation doesn't seem to be quite like either of the wings of the one above, so this made me doubt whether it really was a Rhopalopyx. Happlily, although the abdomen was squashed, the critical bits were preserved.

At first glance the pygofer was a good match for elongata when compared to the drawings in Bidermann & Niedringhaus - the macrosetae stopped well short of the apex which bore a stepped tip just as shown (and although the other lobe was damaged, it was similar in this respect). Both Bidermann & Niedringhaus and the Dutch paper by den Bieman, de Haas & Soethof show a difference in the shape of the lobe before the stepped tip, being evenly curved on elongata and more sinuous, with the broadest bit being nearer the tip, on vitripennis - mine resembled vitripennis in this respect. However the text doesn't allude to this being important to identification and in fact, den Bieman, de Haas & Soethof mention variation in the shape of the pygopher lobes.

The aedeagus in lateral view approximately resembles both vitripennis and elongata, which at least helps to confirm that I was in the right ballpark, however the differences between the two species seem to be rather subtle. I was not entirely convinced that mine was any better a match for elongata than it was for vitirpennis. For some reason Bidermann & Niedringhaus only show the rear view for vitripennis, not elongata. The fact that it isn't shown for elongata might be taken to indicate that it is the same from this view, however mine does not really resemble that shown for vitripennis (or indeed other Rhapolopyx species, or anything else I can see). The stem is narrow and parallel-sided for a much longer distance, and also there are tiny triangular projections on each side at the apex. Reassuringly den Bieman, de Haas & Soethof do show elongata aedeagus in dorsal view and it is a very good match for my specimen, albeit without showing the tiny projections at the apex.

Assuming the current understanding of the species group taxonomy and identification is correct then I think this must be elongata. The Dutch paper alludes to the possibility of future development in the group's taxonomy, stating that the group "is in need of a proper taxonomic evaluation using different kinds of characters, including molecular analysis."

male Rhopalopyx elongata showing forewings (lit from above and behind) and pygofer lobe and aedeagus (multiple views), Wendling Beck Environment Project (Norfolk, UK), 15th September 2023