Dictyogenus julium, 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 : 173-176

2.3 Dictyogenus julium sp. n.

urn:lsid:zoobank.org:act:7D24FB22-4BE7-4B24-91E1-B67C1A7BB755

( Figs. F.1–F .15)

Dictyogenus fontium : Nicolai 1983:159; Desio & Dorigo 2012:33

Dictyogenus sp. : Mori & Brancelj 2006:75

Adults. Body length of males 15–24 mm (n = 25); females 18–27 mm (n = 40). Adult males and females are always macropterous. Head light brown and yellow; M-line well-marked ( Fig. F.1 ). Interocellar area with a wide, yellow patch ( Fig. F.1 ). Pronotum dark brown, with a yellow median band extending from the anterior margin of the pronotum to its posterior margin, widened in its distal section ( Fig. F.1 ). Two yellow, elongated spots on each side of the pronotum ( Fig. F.1 ). Abdominal sterna pale brown, laterally with dark patches (Figs. F.5, F.6). Proximal part of tibiae with a dark band. Antennae and cerci blackish to dark brown.

Male terminalia. Tip of epiproct very short and slightly curved down ( Figs. F.2 , F. 3 ). Lateral stylets narrow with nearly parallel sides and blunt tip ( Figs. F.2 , F. 3 ). Hemitergal lobes short and wide ( Fig. F.4 ).

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

Mature nymphs. Length 13–26 mm (n = 26). 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. F.7 , F.8). Mediodorsal setae on pronotum present, procumbent, arranged as several, loosely demarcated rows on both sides of the central suture ( Figs. F.7 , F.8). Mediodorsal row of setae long and continuous on mesonotum and metanotum (Figs. F.9, F.10). Abdominal tergites with few longer mediodorsal flexible setae and shorter intersegmental stiff setae (Figs. F.11, F.12). Paraprocts, in ventral view, with few spines, unevenly distributed between left and right ( Fig. F.13 ) and limited to the distal half. Mediodorsal setae on base of cerci continuous, but uncompressed, longer than the width of the cercal segment (Fig. F.14). Spines on stipe numerous, arranged in a single row (Fig. F.15).

Morphological affinities. By their slightly downcurved epiproct tip ( Figs. F.2 , F. 3 ), adult males of D. julium sp. n. are close to those of D. alpinum ( Fig. B.1 ). By the short subgenital plate (Figs. F.5, F.6) of their adult females, and the absence of flexible mediodorsal occipital setae of their nymphs ( Figs. F.7 , F.8), however, the differences with D. alpinum become evident.

Type material. ITALY. Sella Chiampon , karst spring , 760 m, 46° 22’ 23.6064” N, 12° 52’ 11.3448” E, 14.5.2010, 1♁, leg. G. Vinçon (holotype, MZL, GBIFCH01217052 ) ; 26.9.2021, 1♁, 1♀ (paratypes, MZL, GBIFCH01217054 ) ; 24.5.2022, 4♁, 2♀, 1L ♀, 3E (paratypes, MZL, GBIFCH01217053 ) .

Other material. AUSTRIA. Bodental, Meerauge, 1120 m, 46° 28’ 34.23” N, 14° 13’ 03.83” E , 24.6.2002, 4♀, leg. W. Graf ( GRA); Ferlach, Loiblbach tributary, 1250 m, 46° 26’ 48” N, 14° 13’ 47” E , 16.6.2000, 1♀; 16.6.2015, 2♀, leg. W. Graf ( GRA); Mitterbach unterhalb Weinebene , 1460 m, 46° 50’ 50.2728” N, 14° 59’ 31.6176” E , 15.4.2021, 1L, leg. M. Konar. ITALY. Sella Chiampon, karst spring, 760 m, 46° 22’ 23.6064” N, 12° 52’ 11.3448” E , 14.5.2010, 3♁, 1♀, 5E; 22.6.2018, 1♁, 1♀, 2E, leg. G. Vinçon ( VIN); Valpicetto, Rio Molini , 860 m, 46° 32’ 05.8308” N, 12° 50’ 53.4012” E , 24.5.2022, 3♁, 2E, leg. G. Vinçon ( VIN); Sella Ciampigotto , spring, 1750 m, 46° 29’ 14.964” N, 12° 35’ 21.4872” E , 22.6.2018, 1E, leg. G. Vinçon ( VIN); Sella Nevea , karst spring, 1100 m, 46° 23’ 43.90” N, 13° 29’ 47.70” E , 23.06.2018, 3E; 26.09.2021, 1♀, leg. G. Vinçon ( VIN); Passo della Mauria, Tagliamento , 1208 m, 46° 26’ 59.78” N, 12° 31’ 19.84” E , 1.8.1974, 8♀, leg. C. Consiglio ( MZL) . SLOVENIA. Vršic Pass, Soca tributary, 1553 m, 46° 25’ 50.52” N, 13° 44’ 31.78” E , 23.6.2018, 1♀, 1E, leg. G. Vinçon ( VIN); Vršic Pass, Mlinarica tributary, 1400 m, 46° 24’ 52.76” N, 13° 44’ 40.80” E , 23.6.2018, 1♁, 1♀; 27.9.2021, 3♀, leg. G. Vinçon ( VIN); Dolina Korosice, Kamniška Bistrica , 1000 m, 46° 17’ 52.8” N, 14° 33’ 37.44” E , 21.6.1978, 1♁, 1♀, leg. I. Sivec ( SIV) ; 24.7.2022, 1♀, leg. W. Graf ( GRA); Ukanc, Savica , 760 m, 46° 17’ 36.3228” N, 13° 47’ 45.6612” E , 23.5.2022, 1♁, 3E, leg. G. Vinçon ( VIN); Bohinjska Bistrica, Sava Bohinjka , 480 m, 46° 17’ 24.27” N, 14° 02’ 06.11” E , 18.5.1993, 6♁, 6♀, leg. I. Sivec ( SIV); Livek, Idrsko , spring, 600 m, 46° 12’ 46.46” N, 13° 35’ 40.11” E , 21.5.2022, 3♀, 1E, leg. G. Vinçon ( VIN); Bistra , spring, 1039 m, 46° 26’ 21.84” N, 14° 46’ 27.48” E , 31.5.1990, 1L ♀, leg. I. Sivec ( SIV); Zgornje Jezersko, Jezernica spring, 932 m, 46° 23’ 53.52” N, 14° 31’ 31.8” E , 28.6.2000, 1♁, 2L♁, 2L ♀, leg. G. Urbanic ( SIV); Mojstrana Vrata, Bistrica tributary, 722 m, 46° 26’ 37.18” N, 13° 54’ 30.14” E , 10.6.1988, 2♁, 1♀, leg. I. Sivec ( SIV); Matkov Kot , karst spring, 900 m, 46° 24’ 29.844” N, 14° 36’ 48.852” E , 6.8.1979, 3♀, leg. I. Sivec ( SIV) .

Distribution and ecology. The species occurs in the Julian Alps, the Lavanttal Alps, and the Karawanks, in Slovenia, Italy and Austria ( Fig. J.2 ), and is a typical inhabitant of karst springs (480–1200 m).

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

Derivatio nominis. The species is named after the region where it was collected, namely the Julian Alps, named after Gaius Julius Caesar, member of the Roman gens Julia. The adjective julium 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 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.