Dictyogenus padanum, 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 : 181-185

2.5 Dictyogenus padanum sp. n.

urn:lsid:zoobank.org:act:A6A3E933-6F99-4555-BE7B-EBA0A11D2F0E ( Figs. H.1–H .15)

Dictyogenus fontium Consiglio 1967:44; 1980:14; Ravizza & Ravizza Dematteis 1990:330; Aubert et al. 1996:15; Fochetti & Tierno de Figueroa 2008:62; Lubini et al. 2012:212; Fochetti 2020:382; Roesti 2021:138

Adults. Body length of males 15–22 mm (n = 66); females 16–29 mm (n = 43). Adult males and females of D. padanum sp. n. have both macropterous and brachypterous populations, often occurring syntopically. Head mostly yellow ( Fig. H.1 ); M-line not well-marked ( Fig. H.1 ). Interocellar yellow patch wide, continuous with the median yellow band on the pronotum ( Fig. H.1 ). Yellow median band on pronotum widening in its posterior margin ( Fig. H.1 ). Side of the pronotum with sculpted rugosities ( Fig. H.1 ). Abdominal sterna pale brown, laterally with symmetrical, dark patches ( Fig. H.7 ). Proximal part of tibiae with a dark band. Antennae and cerci blackish to dark brown.

Male terminalia. Tip of epiproct straight, slightly bent down ( Figs. H.2–H .5). Lateral stylets cudgel-shaped, symmetrically widening at apex ( Figs. H.2–H .5; Fochetti & Tierno de Figueroa 2008: 62, 64, sub nom. D. fontium ). Hemitergal lobes long and slender (Fig. H.6).

Morphological affinities. Specimens of D. padanum sp. n. differ from topotypical D. fontium and from D. nadigi sp. n. by the lateral stylets of their adult males, which bulge out symmetrically at their apex ( Figs. H.2–H .5), whereas they are convex ( Figs. C.2–C . 4 ) or straight ( Figs. G.2 , G. 3 ) on their distal side in the two other species.

Females. Subgenital plate short, with ( Fig. H.7 ) or without median notch on its distal edge.

Mature nymphs. Length 13–28 mm (n = 36). Mature male and female nymphs with prefigured macropterism or brachypterism. No dimorphic setation is seen between macropterous male and macropterous female nymphs, and also no dimorphic setation between brachypterous male and brachypterous female nymphs. No tuft of flexible mediodorsal occipital setae; only stiff mediodorsal occipital setae (Fig. H.8). No setae on pro-, meso- and metanotum of macropterous and brachypterous male or female nymphs (Figs. H.8–H.11; Fochetti & Tierno de Figueroa 2008, sub nom. D. fontium ). Abdominal tergites of macropterous male and female nymphs without mediodorsal flexible setae (Figs. H.12, H.13). Intersegmental stiff setae on abdominal tergites are very short and sparse on the first segments, and with only 4–6 on segments VII–X (Figs. H.12, H.13). Paraprocts, in ventral view, with 0–3 spines, unevenly distributed between left and right (Figs. H.14, H.15), and limited to the distal half. Mediodorsal setae on base of cerci very short and sparse. Stipe with numerous spines distributed in a single row.

Morphological affinities. Nymphs of D. padanum sp. n., females and males, macropterous and brachypterous, lack setae on the pro-, meso- and metanotum. This separates them from the topotypical specimens of D. fontium and D. nadigi sp. n., whose brachypterous male and female specimens have setae on their meso- and metanotum, as well as mediodorsal flexible setae on abdominal tergites.

Type material. SWITZERLAND. Canton of Valais. Gabi-Gstein, lower Chrummbach ( Diveria ), 1250 m, 46° 11’ 07.89” N, 8° 04’ 17.23” E, 19.6.2018, 1♁, leg. G. Vinçon (holotype, MZL, GBIFCH01217065 ) ; 4♁b, 2♀ b, leg. G. Vinçon (paratypes, MZL, GBIFCH01217067 ) . ITALY. Ingria, Soana tributary, 1200 m, 45° 27’ 29.82” N, 7° 33’ 31.89” E, 24.6.2018, 1♁, 2♁b, 1♀ b, leg. G. Vinçon (paratypes, MZL, GBIFCH01217066 ) ; Oropa Valley, Sanctuario, Orsuccio tributary, 1800 m, 45° 40’ 21.2448” N, 7° 56’ 26.2068” E, 4.7.2020, 2♁, 3♀, leg. G. Vinçon (paratypes, MZL, GBIFCH01217064 ) ; Oropa valley, Fenereccio, Furia , 1300 m, 45° 37’ 03.0144” N, 7° 58’ 36.9876” E, 5.6.1978, 1♁ (epiproct in separate vial), leg C. Ravizza (paratypes, MZL, GBIFCH01217071 , in: CB-18640 , GBIFCH00899349 ).

Other material. ITALY. Alpe piane, Cervarolo, 1220m, 45° 51’ 59.058” N, 8° 15’ 40.7988” E, 1.6.1991, 2♀, 3E, leg. G. Vinçon ( RED) ; Champdepraz , Gran Lago tributary, 2528 m, 45° 38’ 39.1128” N, 7° 33’ 14.562” E, 12.7.2003, 3♀, leg. G. Vinçon ( RED) ; Campello Monti , Gravellona, 1750 m, 45° 56’ 18.56” N, 8° 14’ 11.28” E, 11.7.2003, 1♀ ; 19.6.2018, 2♁, 4♁b, 1L ♀, leg. G. Vinçon ( VIN) ; Ingria , Soana tributary, 1300 m, 45° 27’ 43.24” N, 7° 33’ 14.09” E, 30.6.2016, 3♁b, leg. G. Vinçon ( VIN) ; Fondo , Burdeiver, 1300 m, 45° 31’ 52.35” N, 7° 41’ 05.03” E, 7.6.2013, 1L♀, 4L♀b ; 21.6.2014, 2♁, 1♁b, 1♀, 1L ♀ b; 31.7.2015, 3♀ b, 1L ♀ b, leg. W. Graf ( GRA) ; Traversella , Burdeiver tributary, 2160 m, 45° 31’ 05.52” N, 7° 38’ 41.28” E, 12.7.2012, 3♁b, 1♀ b, leg. G. Vinçon ( VIN) ; Vallone di Nana , torrente di Nana, 2500 m, 45° 51’ 34.596” N, 7° 41’ 36.384” E, 19.7.2003, 2♁, leg. G. Vinçon ( VIN) ; Colla del Colombardo , Borgialetto, spring, 1448 m, 45° 12’ 05.8068” N, 7° 18’ 53.2548” E, 20.6.2019, 6♁b, 2♀, leg. G. Vinçon ( VIN) ; Valprato Soana , Piamprato, 1580 m, 45° 33’ 28.01” N, 7° 34’ 10.92” E, 11.7.2008, 1♁, 2♀, leg G. Delmastro (VIN); Alpette , spring, 1250 m, 45° 23’ 59.4636” N, 7° 34’ 24.3912” E, 7.8.2019, 4♁b, 3♀ b, leg. G. Vinçon ( VIN) ; Oropa valley, Fenereccio, Furia , 1300 m, 45° 37’ 03.0144” N, 7° 58’ 36.9876” E, 13.7.1987, 10L, leg C. Ravizza ( MZL, CB-18640 , GBIFCH00899363 ) ; 5.6.1978, 10♁, 10♀, leg C. Ravizza ( MZL, CB-18640 , GBIFCH00899349 ) ; Civiasco, Pascone , 1200 m, 45° 49’ 07.3956” N, 8° 17’ 25.6236” E, 2.6.1991, 2♁, leg. G. Vinçon ( VIN) ; Locana, Piantonetto , 1710 m, 45° 28’ 36.5484” N, 7° 22’ 21.2016” E, 9.9.2008, 3♀, leg. G. Vinçon ( VIN) ; Frudiere , spring, 2050 m, 45° 43’ 54.174” N, 7° 49’ 0.0732” E, 13.7.2003, 1♁b, 2♀ b, leg. G. Vinçon ( VIN) ; Valpelline, Bionaz , 1650 m, 45° 54’ 27.2484” N, 7° 30’ 5.6124” E, 8.8.1977, 1♁b, 6L, leg. C. Ravizza ( MZL, CB-18641 , GBIFCH00899360 ) . SWITZERLAND. Gabi-Gstein, lower Chrummbach ( Diveria ), 1250 m, 46° 11’ 07.89” N, 8° 04’ 17.23” E, 19.6.2018, 5♁b, 2♀ b, 2L ♀ b, 1E, leg. G. Vinçon ( VIN) ; Gabi-Gstein, upper Chrummbach ( Diveria ), 2200 m, 46° 11’ 13.488” N, 8° 02’ 39.822” E, 13.6.2018, 1♁, 1♀, leg. G. Vinçon ( VIN) ; Innri Alpa, Alpjerbach , 2140 m, 46° 13’ 13.674” N, 8° 05’ 42.4356” E, 23.8.2019, 2♁b, 2♀, 1♀ b, leg. G. Vinçon ( VIN) ; Rotelsee, Chrummbach ( Diveria ), 2025 m, 46° 14’ 44.6172” N, 8° 01’ 56.2548” E, 16.7.2004, 1♁, 1L♁, leg. P. Stucki ( MZL, CB-13265 ) . Canton of Ticino. Giona 24 ( Aubert et al. 1996), brooklet near Alpe di Neggia , 1281 m, 46° 06’ 27.2016” N, 8° 50’ 35.664” E, 21.5.1988, 1L♁b, 1L ♀ b, leg. J. Aubert ( MZL, CB-13264 ) ; 18.7.1988, 2♁, leg. J. Aubert ( MZL, CB-13265 ) ; 22.4.2005, 1L ♀, 1L ♀ b, leg. H. Vicentini ( MZL, CB-13264 ) ; Alla Ca , Ticino tributary, 2300 m, 46° 28’ 41.749” N, 8° 24’ 13.8735” E, 20.7.2007, 2♀, leg. W. Graf ( GRA) ; San Bernardino, Moesa tributary, 1610 m, 46° 27’ 27.3096” N, 9° 11’ 43.3032” E, 22.5.1988, 1L ♀, leg. J. Aubert ( MZL, CB-13264 ) ; unnamed brook, Rii , 1200 m, 46° 06’ 18.3024” N, 8° 50’ 21.9336” E, 16.9.1985, 1L♁b, leg. J. Aubert ( MZL, CB-13264 ) ; Colla, Corticella , 980 m, 46° 05’ 51.0684” N, 9° 02’ 54.8592” E, 11.4.1986, 1L ♀ b, leg. J. Aubert ( MZL, CB-13264 ) ; San Carlo, Lake Ritom tributary, 1860 m, 46° 32’ 47.886” N, 8° 42’ 7.3872” E, 11.4.1986, 3L ♀ b, leg. V. Lubini ( MZL, CB-16956 , GBIFCH01210790 )

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Distribution and ecology. Widely distributed in the Italian and the southern Swiss Alps: Ticino ( Aubert et al.

1996), Piedmont, Aosta Valley, and Oropa Valley ( Ravizza & Ravizza Dematteis 1990), and Simplon ( Figs. J.2 , J. 3 ).

The species occurs in high-altitude brooks and springs, from 1200 m to 2500 m.

Adult flight period. June to September.

Derivatio nominis. Named after the Po drainage basin, whose spring brooks are inhabited by the species. The adjective padanum 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 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 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 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 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 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.