Dictyogenus austriacum, 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 : 166-170

2.1 Dictyogenus austriacum sp. n.

urn:lsid:zoobank.org:act:FADA3CCE-E47D-4979-BE2B-B91FE1AB636D

( Figs. D.1–D .15)

Dictyogenus alpinum : Ķhtreiber 1934: 24, his figs. 12.1 and 12.4

Dictyogenus fontium : Ķhtreiber 1934:26; Pomeisl 1958:8; Rupprecht & Vinçon ca. 2003; Zwick & Zwick 2010; Graf 1999:39; Graf et al. 2017; Graf et al. 2022:98

Adults. Body length of males 15–19 mm (n = 10); females 16–25 mm (n = 33). Adult males and females are always macropterous (Figs. D.5, D.6). Head light brown with darker brown and yellow patches; M-line well-marked ( Fig. D.1 ). Interocellar area with a wide, yellow patch ( Fig. D.1 ). Pronotum dark brown, with a yellow median band extending from the anterior margin of the pronotum to its posterior margin, widened in its middle section, and narrowing distally ( Fig. D.1 ). Two yellow spots on each side of the pronotum ( Fig. D.1 ). Abdominal sterna pale brown, with dark patches, and laterally with symmetrical yellow stripes (Fig. D.6). Proximal part of tibiae with a dark band. Antennae and cerci blackish to dark brown.

Male terminalia.Tip of epiproct very short and straight ( Figs. D.2 , D. 3 ). Lateral stylets wide, with symmetrically rounded apices ( Figs. D.2 , D. 3 ). Hemitergal lobes narrow and elongated ( Fig. D.4 ).

Females. Subgenital plate short, with (Fig. D.5) or without (Fig. D.6) median notch on its distal edge.

Mature nymphs. Length 13–26 mm (n = 24). 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. D.7 , D. 10 ). Mediodorsal setae on pronotum long, but sparse and spaced, with less setae on the proximal part of the pronotum than on the distal part ( Figs. D.7–D . 10 ), and with a setation gap between both. Flexible mediodorsal setae on mesonotum and metanotum sparse and short (Figs. D.11–D.13). Abdominal tergites of male and female nymphs with intersegmental stiff setae, interspersed with longer mediodorsal flexible setae (Fig. D.14). There are 0–2 spines on the distal half of the paraprocts (in ventral view), often unevenly (2–1; 1–0) distributed between left and right (Fig. D.15) and limited to the distal half. Cerci with short mediodorsal setae, sparsely distributed. Stipe with up to five very short spines, distributed in a single, basal row.

Morphological affinities. Nymphs of D. austriacum 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 mediodorsal setae on their pronotum.

Type material. AUSTRIA. Mittlerer Langtalsee , tributary to Ĝssnitzbach, 2375 m, 46° 59’ 26.4012” N, 12° 46’ 28.8012” E, 2.8.2017, 1♁, epiproct detached, leg. C. Komposch (holotype; MZL, GBIFCH01217049 ) ; Gmünd , left tributary to Koflachbach, 1740 m, 46° 52’ 24.87” N, 13° 41’ 27.65” E, 26.6.2006, 1L♁, 1L ♀, leg. P. Zwick (paratype, MZL, GBIFCH01217045 ) ; Sankt Oswald , Sankt Oswaldbach, 1560 m, 46° 51’ 48.12” N, 13° 47’ 14.32” E, 20.7.2008, 1♁, leg. W. Graf (paratype, MZL, GBIFCH01217046 ) ; 6.8.2015, 1♁, leg. W. Graf (paratype, MZL, GBIFCH01217047 ) ; Bad Kleinkirchheim , Sankt Oswaldbach, 1530, 46° 51’ 37.95” N, 13° 47’ 08.27” E, 3.8.2021, 1♁, leg. W. Graf (paratype, MZL, GBIFCH01217048 ) ; Heiligenblut Lindhütte , Gössnitzbach, 1765 m, 47° 01’ 23.9988” N, 12° 47’ 2.4” E, 9.8.2008, 1♀, leg. C. Komposch (paratype, MZL, GBIFCH01217051 ) ; Hinterseekamp , Gössnitzbach, 2360 m, 46° 59’ 15.6012” N, 12° 46’ 4.8” E, 2.8.2017, 1♁, 1♀, leg. C. Komposch (paratype, MZL, GBIFCH01217050 ) .

Other material. AUSTRIA. Gm̧nd, left tributary to Koflachbach, 1740 m, 46° 52’ 24.87” N, 13° 41’ 27.65” E, 9.7.2006, 1♁, 2L♁, leg. R. Rupprecht (VIN) ; Sankt Oswald, Sankt Oswaldbach, 1560 m, 46° 51’ 48.12” N, 13° 47’ 14.32” E, 5.8.1995, 7♀; 12.8.2005, 1♁, 2♀; 3.8.2019, 3♀ (1♀ MZL, GBIFCH00980916 , used for molecular studies) ; 1L♁, 1L ♀; 15.8.2020, 1♀; 1.11.2021, 1♀, leg. W. Graf (GRA) ; Elberfelder Hütte, Gössnitzbach, 2320 m, 46° 58’ 24.6” N, 12° 45’ 17.3988” E, 3.8.2017, 2♀, 2L♁, leg. C. Komposch (GRA) ; Zunderwand, Rossbach, 1950 m, 46° 52’ 34.80” N, 13° 44’ 19.10” E, 2.7.2021, 1L ♀, leg. W. Graf (GRA) ; Matrei, Landeggbach, 2070 m, 47° 06’ 45.84” N, 12° 34’ 01.54” E, 8.7.2021, 1♀, 1L ♀, leg. W. Graf (GRA) ; Praxmar Lüsenstal, Moaleralmbach, 1971 m, 47° 08’ 42.25” N, 11° 07’ 30.73” E, 6.7.2021, 1L♁, leg. W. Graf (GRA) ; Bad Kleinkirchheim, Sankt Oswaldbach, 1530, 46° 51’ 37.95” N, 13° 47’ 08.27” E, 3.8.2021, 1♁, leg. W. Graf ( MZL, GBIFCH00980917 , used for molecular studies) ; Klippitztörl, Löllingbach, 1650 m, 46° 55’ 39” N, 14° 38’ 40.92” E, 15.5.2002, 1♁, 5E; 20.08.2002, 1♀, leg. W. Graf (GRA) ; Lech am Arlberg , Lechbach, 1666 m, 47° 11’ 14.1180” N, 10° 01’ 47.9568” E, 23.8.2018, 2♀, 1L♁, 4L ♀, leg. A. Hartmann (GRA) ; Hinterbichl, Dorferbach, 1600 m, 47° 03’ 36.432” N, 12° 19’ 54.264” E, 24.8.1995, 3♀, leg. A. Kofler (GRA) ; Taschelgraben, spring, 1001 m, 47° 57’ 23.70” N, 15° 20’ 41.91” E, 10.6.2004, 8♀, leg. W. Graf (GRA) ; Radenthein, Hundsfeldgraben stob02, 1725 m, 46° 52’ 0.000012” N, 13° 47’ 42.00” E, 4.9.2020, 1L ♀, leg. W. Graf (GRA) ; Radenthein, Hundsfeldgraben stob03, 1890 m, 46° 52’ 0.000012” N, 13° 48’ 19.000008” E, 4.9.2020, 1L♁, leg. W. Graf (GRA) ; Sölden, Rettenbach rettb03, 2250 m, 46° 57’ 10.206” N, 10° 57’ 15.6636” E, 12.11.2020, 1L♁, leg. W. Graf (GRA) ; Trauneralm, Traunerbach fuab01, 1565 m, 47° 07’ 11.0316” N, 12° 47’ 56.8140” E, 6.9.2020, 1L ♀, leg. W. Graf (GRA) ; Trauneralm, Traunerbach fuab02, 2060 m, 47° 06’ 54.4212” N, 12° 48’ 59.0760” E, 5.9.2020, 1L ♀, leg. W. Graf (GRA) ; Warnsdorfer Hütte, tributary to Krimmler Ache kriab03, 2120 m, 47° 5’ 29.6592” N, 12° 14’ 44.9088” E, 8.9.2020, 1L ♀, leg. W. Graf (GRA) ; Warnsdorfer Hütte, tributary to Krimmler Ache kriab02, 1950 m, 47° 05’ 36.8664” N, 12° 14’ 21.5016” E, 8.9.2020, 1L ♀, leg. W. Graf (GRA) ; Tweng, Lungau, Lantschfeldbach, 1685 m, 47° 12’ 40.4964” N, 13° 29’ 08.1312” E, 5.8.1948, 1♁, leg. H. Franz ( MZL, container CB-16655 , GBIFCH01210746 ) .

Distribution and ecology. Widely distributed in the Eastern Austrian Alps: Arlberg, Ĝssnitztal, Koflachbach, Ļsenstal, Matrei, Sankt-Oswald, Stubachtal ( Fig. J.2 ). High-altitude torrents and springs from 1500–2400 m ( Fig. D.16 ).

Adult flight period. Main emergence period from June to August, followed by a secondary period in November.

Derivatio nominis. Named after the region inhabited by the species. The adjective austriacum is to be treated as a neuter Latin adjective in the nominative case combined with Dictyogenus .

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.

FIGURES C.13–C.18: nymphs of Dictyogenus fontium (topotypical). C.13—tergites of macropterous female nymph (Val d’Anniviers); C.14—mesonotum, brachypterous male nymph (Agenetal); C.15—tergites, brachypterous male nymph (Arolla); C.16—spines on paraprocts of nymph, ventral view; C.17—cerci, mediodorsal setation; C.18—spines on stipe.

FIGURES A.16–A.18: general characteristics of nymphal Dictyogenus. A.16—exuvia of nymph (D. nadigi sp. n.); A.17— abdominal tergites of mature nymph, lateral view, showing the yellow stiff and bright flexible mediodorsal setae (D. nadigi sp. n.); A.18—abdominal tergite with stiff (s), flexible (f) and clothing (c) setae (D. nadigi sp. n.).