Dictyogenus weigandi, Reding, 2024

Reding, Jean-Paul G., 2024, Notes on the genus Dictyogenus Klapálek, 1904 (Plecoptera, Perlodidae) in the Austrian, Italian, Slovenian and Swiss Alps, with the description of six new species, Zootaxa 5397 (2), pp. 151-194 : 170-173

2.2 Dictyogenus weigandi sp. n.

urn:lsid:zoobank.org:act:B834CF02-6689-4742-8FCB-F1524BE55847

( Figs. E.1–E .12)

Dictyogenus fontium : Weigand et al. 1998:53

Dictyogenus fontium : Weigand 2012:80

Adults. Body length of males 16–21 mm (n = 22); females 19–28 mm (n = 50). Adult males and females are always macropterous (Fig. E.6). Head mostly yellow, with two brown, triangle shaped patches on both sides of the interocellar area ( Fig. E.1 ). M-line well marked. Light brown area on each side of the pronotum, with dark, sculpted rugosities ( Fig. E.1 ). Proximal part of tibiae with a dark band. Antennae and cerci blackish to dark brown.

Male terminalia. Tip of epiproct long and slightly curved down ( Figs. E.2 , E. 3 ). Lateral stylets about as wide as their stem, regularly rounded and not tapering out at apex ( Fig. E.3 ). Hemitergal lobes long and slender ( Fig. E.4 ).

Morphological affinities. The epiproct tip of D. weigandi sp. n. ( Figs. E.2 , E. 3 ) is close in shape to the one of D. alpinum ( Fig. B.1 ). The lateral stylets of D. weigandi sp. n. ( Fig. E.3 ), however, are wider than those of D. alpinum ( Figs. B.1 , B. 2 ), and do not taper apically.

Females. Subgenital plate very short, covering not more than the third of sternite IX, with (Fig. E.5) or without (Fig. E.6) median notch on its distal edge.

Mature nymphs. Length 13–26 mm (n = 13). Mature male and female nymphs with prefigured macropterism. No sexually dimorphic setation is seen on male and female nymphs. No tuft of flexible mediodorsal occipital setae; only stiff mediodorsal occipital setae ( Figs. E.7 , E.8). Pronotum without medio-dorsal setae ( Figs. E.7 , E.8). Mesoand metanotum with long, but uncompressed setae (Fig. E.9). Abdominal tergites of male and female nymphs with dense intersegmental stiff setae, interspersed with long mediodorsal flexible setae ( Figs. E.10 , E.11). Paraprocts, in ventral view, with 1–5 spines, unevenly distributed between left and right, and limited to the distal half. Cerci with long, medium dense, mediodorsal setae (Fig. E.12). Stipe with very few spines, distributed in a single, short row.

Morphological affinities. Nymphs of D. weigandi sp. n. differ from those of D. alpinum by the absence of flexible mediodorsal occipital setae, and from those of D. fontium by the presence of long and dense mediodorsal flexible setae on their abdominal tergites.

Type material. AUSTRIA. Reichraminger Hintergebirge , spring E2, 1180 m, 47° 43’ 58.548” N, 14° 26’ 49.488” E, 27.10.2001, 1♁, leg. W. Graf (holotype, MZL, GBIFCH01217057 ) ; 27.10.2001, 1♁, leg. W. Graf (paratype, MZL, GBIFCH01217056 ) ; 20.10.2020, 1♁, leg. W. Graf (paratype, MZL, GBIFCH01217058 ) ; Reichraming , Sulzbach, 860 m, 47° 52’ 43.932” N, 14° 25’ 36.66” E, 21.10.2004, 3♁, 1♀, leg. W. Graf (paratypes, MZL, GBIFCH01217055 ) .

Other material. AUSTRIA. Nationalpark Kalkalpen, Rettenbachquelle , 679 m, 47° 45’ 28.02” N, 14° 18’ 59.50” E, 20.6.2008, 2♀; 18.10.2020, 1♀ ; 24.6.2021, 2♀, 2E, 4L♁, 2L ♀, leg. W. Graf ( GRA); Reichraminger Hintergebirge, spring E2 , 1180 m, 47° 43’ 58.548” N, 14° 26’ 49.488” E, 27.10.2001, 14♁, 11♀, 1L♁; 20.10.2020, 1♁, 4♀, 1L♁, 3L ♀; 21.6.2021, 1♀, leg. W. Graf ( GRA) .

Distribution and ecology. Endemic to the region of the Austrian Nationalpark Kalkalpen, Upper Austria ( Fig. J.2 ). The species is a typical inhabitant of karst springs (680–1180 m).

Adult flight period. Main emergence period in June, followed by a secondary period in October.

Derivatio nominis: Dedicated to the Austrian entomologist Dr. Erich Weigand (Molln, Upper Austria), for his merits in preserving the unique entomofauna of the Nationalpark Kalkalpen.

Figures

FIGURES A.1–A.3: general characteristics of adult Dictyogenus. A.1—head and pronotum of adult male (D. alpinum); A.2—vesicle on sternite VII of adult male; A.3—venation of forewing of Dictyogenus (annotations by Dr. Olivier Béthoux). Photo Bertrand Launay.

FIGURES I.2–I.7: Dictyogenus vinconi sp. n. I.2—adult female, head and pronotum; I.3—epiproct and lateral stylet of adult male; I.4—ventral lobe on sternite VII of adult male; I.5—hemitergal lobes of adult male; I.6—subgenital plate of adult female; I.7—subgenital plate of adult female.

FIGURES J.3: distribution maps of Dictyogenus. J.3—distribution map of Dictyogenus (topotypical D. fontium, D. nadigi sp. n., and D. padanum sp. n.) in alpine drainage basins.

FIGURES A.4–A.9: general characteristics nymphal Dictyogenus. A.4—separation of abdominal tergites I and II; A.5— lacinia with shoulder-like angle; A.6—prefigured ventral vesicle on sternite VII in mature male nymph, ventral view; A.7— nymph, row of stiff spines on occiput (dorsal view); A.8—female nymph, sternite VIII, ventral view; A.9—female nymph, sternite VIII, ventral view.

FIGURES B.7–B.12: nymphs of Dictyogenus alpinum. B.7—mediodorsal setation of nymph (head and pronotum); B.8— spines on paraprocts of nymph, in ventral view; B.9—mediodorsal setae on cerci; B.10—spines on stipe of nymph; B.11— mature female nymph, sternite 8, ventral view; B.12—mediodorsal setation on tergites of nymph.

FIGURES A.10–A.15: general characteristics of nymphal Dictyogenus. A.10—male nymph, sternite VIII, ventral view; A.11—stiff spines and rows of flexible mediodorsal setae on metanotum; A.12—stiff spines on metanotum (D. fontium); A.13— immature nymph, tergites, dorsal view; A.14—abdominal tergites of mature female nymph, dorsal view; (ts = tergal setae; tsp = tergal spines); A.15—meso- and metanotum of brachypterous nymph.