Rhyacophila sociata, Navas, 1916

Rhyacophila sociata

MALE

Genitalia ( Figs 11 View FIGURES 11–12 , 14 View FIGURES 13–15 ): 2nd segment of each inferior appendage ( Figs 11A View FIGURES 11–12 , 14a View FIGURES 13–15 ) with posterior edge slightly convex in dorsal and concave in ventral area respectively, ventral edge straight or slightly concave, less than 2 times longer that dorsal edge; apicodorsal vertex of 2nd segment ~ 110° and round, apicoventral angle ~ 35°, projecting as thick lobe tapered to round apex.

Parameres in ventral view curved posteromesad in distal half ( Figs 11 View FIGURES 11–12 BV, p; 14c). In lateral view ( Figs 11 View FIGURES 11–12 BL, 14d) each constricted 1/3 distance beyond base, dilated at middle, with semicircular dorsal margin, convex ventral margin; along midventral posterior margin three long, thick spines; midlateral surface with thin spicules or setae of the same size, from middle posteroventral to posterodorsal edges. Aedeagus (phallicata) in lateral view ( Fig. 11 View FIGURES 11–12 CL) with anterodorsal margin and posterior corner of dorsal concavity hooked anterad, apical edge of aedeagus mostly triangular; ventral lobe of aedeagus in ventral view triangular ( Fig. 11 View FIGURES 11–12 BV, vl), with bifid apex, in lateral view vertical edge deeply concave, with triangular projection in posteroventral edge, posteroventral angle less than 90º ( Fig. 11 View FIGURES 11–12 CL). In dorsal view posterior edges of lateroventral lobes of phallus apically straight or slightly convex, apicolateral margins straight or slightly convex ( Fig. 11 View FIGURES 11–12 CD, lvl).

Apicodorsal lobe of segment IX in dorsal view oval, slightly dilated subapicolaterally ( Figs 11 View FIGURES 11–12 DD, al; 14b), with small apicomesal excision; preanal appendages ( Fig. 11 View FIGURES 11–12 DD, pa) round, 4/5 long than apicodorsal lobe, posterior edges convex. In ventral view, apical band pentagonal shaped ( Fig. 11 View FIGURES 11–12 DV, ab), almost as long as wide, its posterior arms converging posterad and round apically, its non-sclerotized mesal area oval ( Fig. 11 View FIGURES 11–12 DV, va), anal sclerites triangular, posterior edges concave ( Fig. 11 View FIGURES 11–12 DV, as).

FEMALE

Genitalia ( Figs 12 View FIGURES 11–12 , 17 View FIGURES 16–18 ): In lateral view ( Figs 12L View FIGURES 11–12 , 17L View FIGURES 16–18 ), posterior margin of segment VIII valves on each side almost quadrangular with a dorsolateral projection, posterior and ventral margins concave. In dorsal view ( Figs 12D View FIGURES 11–12 , 17D View FIGURES 16–18 ), with indentation between segment VIII valves nearly enclosed by pair of dorsolateral rectangular projections, with rounded apical and subapical corners, delimiting heart-shape space. In ventral view ( Figs 12V View FIGURES 11–12 , 17V View FIGURES 16–18 ) segment VIII valves forming two elongate sclerites connected basally, concave edges, diverging; intersegmental membrane with pair of dark, narrow, elongate sclerites, connected laterally, rounded edges posteriorly, pointed edges anteriorly.

Diagnosis of males of Rhyacophila denticulata , R. sociata and R. fasciata

Genitalia: In R. denticulata , ( Fig. 13a View FIGURES 13–15 ) the posterior edge of the second segment of each inferior appendage is slightly concave in the middle and the ventral edge is about 2 times longer than dorsal edge. In R. sociata ( Fig. 14a View FIGURES 13–15 ) posterior edge of the second segment of each inferior appendage is slightly convex in dorsal area and concave in ventral area and the ventral edge is about 1.4 times longer than dorsal edge. In R. fasciata , the posterior edge of the second segment of each inferior appendage is slightly concave dorsally and convex ventrally and the ventral edge is less than 1.8 times longer that dorsal edge ( Fig. 15a View FIGURES 13–15 ).

In R. denticulata , the posterior edge of aedeagus is straight or slightly concave in lateral view; the ventral lobe of aedeagus is almost circular, with the apex pointed ( Fig. 13c View FIGURES 13–15 ), in lateral view rounded, almost 90º; posterior edges of lateroventral lobes of phallus are triangular; the apicolateral margins are convex and the lateral margins are diverging anteriorly. In R. sociata , the posterior edge of aedeagus is mostly triangular in lateral view; the ventral lobe of aedeagus is triangular, with the apex bifid ( Fig. 14c View FIGURES 13–15 ), in lateral view deeply concave in dorsal edge, with triangular projection in ventral edge, posteroventral angle less than 90º ( Fig. 11 View FIGURES 11–12 CL). In R. fasciata , the posterior edge of aedeagus is straight, projected posteroventrad, and rounded at posteroventral apex ( Valladolid et al. 2021, fig. 12CL); the ventral lobe of aedeagus is subtriangular and round posteriorly ( Fig. 15c View FIGURES 13–15 ); the lateroventral lobes of the phallus are straight, its posterior edges convex, apicolateral margins rounded.

In R. denticulata the apicodorsal lobe of segment IX in dorsal view is oval, with small apicomesal excision ( Figs 9 View FIGURES 9–10 DD, al; 13b); the preanal appendages are rectangular, with posterior edges triangular, apex rounded ( Figs 9 View FIGURES 9–10 DD, pa); the apical band in ventral view ( Fig. 9 View FIGURES 9–10 DV, ab) is U-shaped with its posterior arms parallel and directed posterad; the non-sclerotized mesal area ( Fig. 9 View FIGURES 9–10 DV, va) is U-shaped; the anal sclerites ( Fig. 9 View FIGURES 9–10 DV, as) are concave apically. In R. sociata the apicodorsal lobe of segment IX in dorsal view is oval, slightly dilated subapicolaterally, with small apicomesal excision ( Figs 11 View FIGURES 11–12 DD, al; 14b); the preanal appendages are round, with posterior edges convex ( Fig. 11 View FIGURES 11–12 DD, pa); the apical band in ventral view ( Fig. 11 View FIGURES 11–12 DV, ab) is pentagonal shaped with its posterior arms converging posterad; the non-sclerotized mesal area ( Fig. 11 View FIGURES 11–12 DV, va) is oval; the anal sclerites ( Fig. 11 View FIGURES 11–12 DV, as) are concave apically. In R. fasciata , the apicodorsal lobe of segment IX in dorsal view ( Fig. 15b View FIGURES 13–15 ) is dilated subapicolaterally, almost round, with a shallow apicomesal excision in some specimens; the preanal appendages ( Valladolid et al. 2021, fig. 12DD, pa) are round, convex laterally; the apical band in ventral view ( Valladolid et al. 2021, fig. 12DV, ab) is pentagonal shaped with its posterior arms widely separate and straight; the non-sclerotized mesal area ( Valladolid et al. 2021, fig. 12DV, va) is heart-shaped and with a wider posteromesal excision; the anal sclerites ( Valladolid et al. 2021, fig. 12DV, as) are truncated apically.

In R. denticulata the parameres in lateral view ( Figs 9 View FIGURES 9–10 BL, 13d) are dilated in the middle, with dorsal and ventral margins rounded and almost parallel, each has two rows of thick spines on its midventral margin; the midlateral surface has spicules or setae, decreasing in size from ventral to dorsal area. In R. sociata the parameres in lateral view ( Figs 11 View FIGURES 11–12 BL, 14d) are dilated in the middle, with semicircular dorsal margin and convex ventral margin, each has one row with three long, thick spines on its midventral posterior margin; the midlateral surface has very thin spicules or setae of the same size, from middle posteroventral to posterodorsal edge. In R. fasciata the parameres in lateral view ( Fig. 15d View FIGURES 13–15 ; Valladolid et al. 2021, fig. 12BL) are convex basally, with almost parallel dorsal and ventral margins in central area (S-shape), each has two rows of long, thick spines on the on the posterior midventral margin, each row with more than three spines pointing laterad; the midlateral surface has sparse fine setae from the middle of the anteroventral edge to the posterodorsal edge, covering most of apex, but absent in the middle anteroventral and posterodorsal edges.

Diagnosis of females of Rhyacophila denticulata , R. sociata and R. fasciata

Genitalia: In R. denticulata lateral view ( Figs 10L View FIGURES 9–10 , 16L View FIGURES 16–18 ) each of the segment VIII lateral valves has a dorsolateral and a dorsoventral projections, with posterior margin concave. In R. sociata lateral view ( Figs 12L View FIGURES 11–12 , 17L View FIGURES 16–18 ), each of the segment VIII lateral valves almost quadrangular, with a dorsolateral projection, posterior and ventral margins concave. In R. fasciata lateral view ( Fig. 18L View FIGURES 16–18 ; Valladolid et al. 2021, fig. 13L) each of the segment VIII lateral valves is quadrate with an apicodorsal projection; the upper posterior margin is nearly vertical and with an irregular edge with one or two posterior sinuosities ( Valladolid et al. 2021, figs 13La, 13Lb), the posteroventral margin is slightly concave sub-basally and straight or convex distally, in some specimens slightly indented posteriorly, the upper posterior margin and the posteroventral margin meet at a round, obtuse angle.

In R. denticulata dorsal view ( Figs 10D View FIGURES 9–10 , 16D View FIGURES 16–18 ), the indentation between the segment VIII valves is nearly enclosed by a pair of dorsolateral semicircular thick projections, with rounded apical and angled subapical corners, delimiting a circular membranous space. In R. sociata dorsal view ( Figs 12D View FIGURES 11–12 , 17D View FIGURES 16–18 ) the indentation between segment VIII valves is nearly enclosed by a pair of dorsolateral rectangular projections, with rounded apical and subapical corners, delimiting heart-shape space. In R. fasciata dorsal view ( Fig. 18D View FIGURES 16–18 ; Valladolid et al. 2021, fig. 13Da), the indentation between the segment VIII valves is nearly enclosed by a pair of thick apicodorsal projections delimiting an oval membranous space; a small projection occurs anteromesally in some specimens.

In R. denticulata ventral view ( Figs 10V View FIGURES 9–10 , 16V View FIGURES 16–18 ), the segment VIII valves form two elongate sclerites that converge basally, their mesal margins convex; the intersegmental membrane with a pair of big elongate sclerites, occupying most of the central space, dark, ovoid, pointed posteriorly and round anteriorly. In R. sociata ventral view ( Figs 12V View FIGURES 11–12 , 17V View FIGURES 16–18 ), the segment VIII valves form two elongate sclerites connected basally, the mesal margins concave; the intersegmental membrane with a pair of dark, narrow and elongate sclerites, connected laterally, rounded posteriorly and pointed anteriorly. In R. fasciata ventral view ( Fig. 18V View FIGURES 16–18 ; Valladolid et al. 2021, fig. 13V), the segment VIII valves form two elongate sclerites that are narrowly separated basally, the mesal margins are parallel in their basomesal 1/4 and straight and divergent in their apicomesal 3/4, their mesal margins convex; the intersegmental membrane with a pair of dark, ovoid or slightly elongate sclerites.

Synonyms of Rhyacophila denticulata and Rhyacophila sociata

Rhyacophila gemella Navás 1923 is a synonym of R. sociata Navás 1916 ( Valladolid et al. 2018). In our publication about R. fasciata ( Valladolid et al. 2021) View in CoL we concluded that the species Rhyacophila coppai Oláh 2020 and Rhyacophila soreda Coppa & Oláh 2020 are synonyms of R. sociata , and the species Rhyacophila kopasa Oláh & Coppa 2020 and Rhyacophila rova Oláh & Coppa 2020 are synonyms of R. denticulata . Oláh et al. (2020) described these new species, based on only a few (often only one) specimens, mainly males, using a very general morphology of specimens (colour), mostly preserved in ethanol for a long time, and some characteristics of males (shapes of parameres and presence of microtrichial bands) that are difficult to see if you observe them with only a dissecting microscope instead of with a compound microscope. The differences observed between R. coppai , R. soreda and R. sociata , and between R. kopasa , R. rova and R. denticulata are minimal, and could be included within the intraspecific variablity. Finally, the localities where the specimens were collected are included in the area of distribution of R. denticulata and R. fasciata View in CoL . We think it should be necessary to base new descriptions of species on more characters, more specimens, and DNA information. In our studies, DNA information shows that by now, there are only two species of the Complex in this area, R. denticulata and R. sociata .