Hydropsyche pluvialis Oláh & Johanson 2008

Hydropsyche pluvialis species group

Fig. 151–153

This species group was established and defined by Mey (1996a) for species characterized by having (1) endophallus attached to the dorsum of the phallotheca; (2) sclerous endothecal process (usually narrow and digitiform) present and located laterally of phallotremal sclerites; (3) and phallotremal sclerites elongated behind the secondary gonopore, located at the apical opening of the endophallus, being falciform in lateral view and pincer-shaped in ventral and dorsal view; sometimes trough-like with fused ventrum and being rimmed laterally; opening, closing and channelling the discharged sperm content of the endophallus. Since the establishment of the species group, more species have been described that belong to it. We have detected internal species clusters within the group based on genitalic characteristics. These species clusters do not necessarily represent monophyletic groups, but rather comprise species sharing similarities, which may also be based on plesiomorphic characters.

The phallic apparatus in the H. pluvialis group is generally conservative, with a stable structure. However, a peculiar anterior shift of the apicodorsal setose processes is present in almost all species. The apicodorsal setose processes moved dorsobasad on segment X, to near the apical end of the median keel on segment IX. The intersegmental depression is harboured by the median keel and the apicodorsal process itself, as visible in lateral view. The extent of anterior movement of the apicodorsal lobes, and the width and dept of the inetersegmental depression are characters used as basis for species cluster grouping. There are different levels of this development, but the species in the species group are easily separated into 3 species clusters (Fig. 151– 153). The species in the Hydropsyche pluvialis species cluster all have wide and shallow intersegmental depression (Fig. 151); the species in the Hydropsyche rhomboana species cluster all have wide and deep intersegmental depression (Fig. 152); and the species in the Hydropsyche pallipenne species cluster are characterized by their narrow and deep intersegmental depression (Fig. 153).