Electrogena brulini Wagner, 2017
Wagner, Andre, Vuataz, Laurent & Sartori, Michel, 2017, Electrogena brulini sp. nov. and E. vipavensis Zurwerra & Tomka, 1986 syn. nov. revealed by integrative taxonomy of E. gridellii (Grandi, 1953) (Ephemeroptera: Heptageniidae), Zootaxa 4362 (3), pp. 359-384 : 364-366
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|Electrogena brulini Wagner|
Electrogena brulini Wagner , sp. nov.
Electrogena gridellii sensu Belfiore (1996) pro parte, nec Belfiore (1982)
Nymph description: Length: Male: body 7–10 mm, cerci 8–12 mm. Female: body 8–11 mm, cerci 10–15 mm. Colouration of cuticle generally greyish, epidermal pigmentation reddish, well contrasted.
Head: surface with distinctive light and dark markings ( Figs 6, 8, 10, 12 View FIGURES 2–21 ), specific to this species; noteworthy the presence of spots (b), between (a) and (c) ( Fig. 6 View FIGURES 2–21 ); a pattern formed by a triangle (f) and a line (d) delimiting a white marking (e) ( Fig. 10 View FIGURES 2–21 ) disappearing almost entirely in last instar; a light line along the inner margin of compound eyes, a dark colouration behind the ocelli ( Figs 8, 12 View FIGURES 2–21 ). Labrum, rather slender, R_LBR = 4.3–5.4; anterior margin with one row of bristles, stout and short in the middle and elongated outwardly ( Figs 40, 44 View FIGURES40–51 ). Mandible with a prostheca bearing 5–8 bristles (N_PRO), all bristles evenly thick, at the most the basal one a little thinner ( Fig. 42 View FIGURES40–51 ). Addition of right and left N_PRO: 10–15 bristles. Maxillae with a row of 16–23 comb-shaped setae on anterior margin (N_ CBS), the 5th (starting from inner side) bearing 8–13 teeth (N_ TCB), outer margin of galea-lacinia with 4–20 setae (N_ OUT), inner margin and ventral face of the first segment of palpus bearing 5–29 thin setae (N_ PLP). Hypopharynx with laterally expanded superlinguae, densely covered with long thin setae, apex of lobes with long setae (as E. gridellii in Fig. 49 View FIGURES40–51 ), sometimes missing when worn or very difficult to see because obscured by dirt as in Fig. 48 View FIGURES40–51 . Labium, ventral face, only inner third of the paraglossae with bristles (rarely reaching half of the width) ( Fig. 46 View FIGURES40–51 ), R_ GLA = 2.8–3.7, R_GLB = 2.7–3.2.
Thorax: Pronotum with a well contrasted pattern but no reddish-brown spot (h), the lateral margins regularly rounded with a dark line (g) ( Fig. 16 View FIGURES 2–21 ). Mesonotum with several light brown markings, and a brown semilunar vertical one (arrow in Figs 18, 20 View FIGURES 2–21 ). Coxa bicoloured: proximal half white, distal half dark grey ( Figs 28, 30 View FIGURES 22–31 ). Thoracic sterna: sclerites light, imaginal colouration becoming brown during nymph development. Legs: well contrasted pattern rather similar between fore-, mid and hind legs ( Figs 28 View FIGURES 22–31 , 33 View FIGURES 32–39 ). Femora dorsal face with four markings (distal ones can be joined) forming a white cross always reaching the anterior and the posterior margins, strong contrast visible at all instars ( Figs 4 View FIGURES 2–21 , 32, 33 View FIGURES 32–39 ); ventral face of femora with a large spot, generally double, a dark cuticular spot ( Fig. 27 View FIGURES 22–31 , k) covering a reddish epidermal one ( Fig. 27 View FIGURES 22–31 , j) already visible in young nymphs ( Fig. 32 View FIGURES 32–39 ); medium sized blunt pointed bristles on the dorsal face of forefemora ( Fig. 36 View FIGURES 32–39 ), more peaked in mid and hind femora ( Fig. 37 View FIGURES 32–39 ); only one (sometimes none) strong spine in the middle of the ventral face of all femora, near the outer margin (N_BVF). Tibia contrasted, distal quarter and proximal third light, middle darker ( Figs 28 View FIGURES 22–31 , 33 View FIGURES 32–39 ); pectinate setae scarce on foretibia, numerous on mid and hind tibia ( Fig. 35 View FIGURES 32–39 , inset). Tarsi with proximal and distal part darkened (mainly on dorsal face), exceptionally forming a distinct ring on distal part; claws with 2 teeth, rarely 3 (N_CLW).
Abdomen: Terga with contrasted markings: terga IV–V (sometimes also VI) generally with a large dark triangle on the anterior margin ( Fig. 2 View FIGURES 2–21 ), in dark nymphs, only light spots subsisting; terga posterior margin light, rarely with grey line on terga I–VIII, absent on tergum IX; terga II–VII with anterolaterally a very tiny, light, reddish-brown spot, generally covered by the previous tergum, smaller than the posterolateral one ( Fig. 22 View FIGURES 22–31 ); terga II–IX posterolaterally with a reddish-brown spot, faint in terga VIII-IX ( Fig. 22 View FIGURES 22–31 ); no contrast between terga VII and VIII–X ( Fig. 2 View FIGURES 2–21 ); tergum X dark with a light marking on each side ( Fig. 14 View FIGURES 2–21 ); posterior margin of each tergum with thin and elongated spines with microdenticulations at their bases. Sterna II–VIII with a dark, arch-shaped cuticular pattern, epidermis always entirely light ( Fig. 24 View FIGURES 22–31 ), except some nymphs with only a very faint pattern becoming brown as E. gridellii in Fig. 25 View FIGURES 22–31 ; ganglionic chain brownish, only last ganglion and the thoracic ones larger and darker violet ( Fig. 24 View FIGURES 22–31 ). In the male last instar nymphs, styliger processes and titillator visible through sternum IX, but titillators too poorly formed to be diagnostic. Gill I tongue-shaped, gills II–VI broad and asymmetrical, gill VII elongated, narrow at apex and slightly pointed ( Fig. 50 View FIGURES40–51 ). Paracercus and cerci light, becoming darker only in the last instars, colouration fading apically.
Male imago: Length: body 7.5–9 mm, forewing 8.5–10 mm, cerci 20–25 mm.
Head: Eyes clearly separated, sclerite joining the compound eyes weakly rounded forming a wide V ( Fig. 84 View FIGURES68–85 ).
Thorax: dark brown ( Figs 52, 54 View FIGURES52–55 ). Wings veins yellowish-brown; costa, subcosta and radius anterior brighter yellow; distal half of costal and subcostal fields sometimes milky ( Fig. 64 View FIGURES 56–67 ). Distal part or entire forefemora darkened ( Figs 60–61 View FIGURES 56–67 ); mid and hind femora dorsally with a brown spot at the distal third and a second spot, variably visible at the proximal third ( Fig. 60 View FIGURES 56–67 ); ventral face of mid and hind femora with a brown spot at the distal third ( Fig. 61 View FIGURES 56–67 ).
Abdomen: Terga dorsally all uniform medium brown with a pair of lighter comma-shaped markings ( Fig. 56 View FIGURES 56–67 ); posterolaterally a darker marking and laterally a light area ( Fig. 54 View FIGURES52–55 ), anterolaterally sometimes very slightly brownish ( Fig. 54 View FIGURES52–55 ). Sterna pale with a large subtriangular light orange-brown marking covering more or less the entire face, ganglia violet ( Fig. 58 View FIGURES 56–67 ). Cerci brown, colouration fading to the apex. Penis lobes regularly rounded, can be slightly bent outwards, distance between lobes ranging from zero up to a ninth of a penis lobe width ( Fig. 68 View FIGURES68–85 ), numerous small dorsal spines basolaterally on penis lobes ( Fig. 72 View FIGURES68–85 ). Titillator massive, with generally two teeth, shape variable ( Figs 75–78 View FIGURES68–85 ). Styliger almost straight with lateral humps ( Fig. 66 View FIGURES 56–67 ).
Female imago: Length: body 7.5–10 mm, forewing 10–12 mm, cerci 16–20 mm. Same general colouration as in male, but lighter; no colour difference between abdomen and thorax ( Figs 86, 88 View FIGURES 86–99 ). Wings with same colouration as in male ( Fig. 90 View FIGURES 86–99 ). Rusty colouration behind ocelli (n), area between the pair of ocelli and the compound eyes not darkened (l), sclerite joining the compound eyes with only laterally a distinct thin brown line on the margin ( Fig. 98 View FIGURES 86–99 , m). Subgenital plate covering about half of sternum VIII surface, subanal plate tapering to apex, in apical view narrow and lateral margins rolled up towards the inside ( Figs 94, 95 View FIGURES 86–99 ).
Male and female subimago: Same colouration as imago, but paler. Wings without pattern, entirely grey.
Egg: Dimensions: 150/110µm; micropyle: 10/6.5µm. Chorion entirely and regularly covered with relatively dense microgranules, KCT’s evenly distributed over the surface, but more concentrated and somewhat larger on one pole (about the third of the egg) ( Fig. 100 View FIGURES 100–103 ). Micropyle bordered with the same microgranules as surface ( Fig. 101 View FIGURES 100–103 ).
Etymology. From Michel Brulin ( France), the initiator and driving force of the inventory of mayflies in France. A man who, despite his vast knowledge, remains humble and amazed by the life of these insects.
Diagnosis. Nymph: general colouration contrasted, all femora with a large spot on the ventral face; two teeth on claws; 1 bristle (can miss) on ventral face of femora, near the outer margin; bristles of femora bluntly pointed; prostheca consisting in 5–7 bristles ( Fig. 42 View FIGURES40–51 ).
The nymph of Electrogena ozrensis (Tanasijevic, 1975) has not yet been described. Nevertheless, samples and rearing were performed in April 2017 close to the type-locality in Tuzla ( Bosnia). On the basis of the original description, it was possible to link the reared imagines with E. ozrensis , and then with the nymphs. This work being not a revision of the genus Electrogena , we add only some elements allowing to separate Electrogena brulini sp. nov. from the other cited species; essentially based on the present work and on the complete work of Belfiore (1997):
- the double large reddish and grey spot on the ventral face of femora has never been mentioned in European Electrogena species. Nevertheless, this character should not be confused with other colourations that are common: E. affinis usually with a single well- marked spot; E. lateralis sometimes with a faint spot; E. quadrilineata and E. ozrensis with a similar double coloured spot, but the cuticular one more extended, reaching nearly the inner and the outer margins; E. ujhelyii only with a variable cuticular colouration, a transverse distal band (can reach the apex), a longitudinal band on the inner margin, up to almost the whole face grey in dark populations.
- the middle sized blunted bristles on the dorsal face of femora discriminates E. brulini from the long, narrow and pointed bristles as in E. gridellii , from the rounded distal bristles as in E. grandiae and E. hyblaea , from the truncate parallel bristles as in E. ozrensis and E. quadrilineata .
- the sterna colouration in E. brulini ( Fig. 24 View FIGURES 22–31 ) is less extensive, lateral spots not reaching the posterior margin as in E. ujhelyii ( Fig. 26 View FIGURES 22–31 ). This precision may be important, since both species are sympatric in Friuli-Venetia.
- the regular and more or less symmetrical form of the expansions of the pronotum discriminates it from Electrogena braaschi (Sowa, 1984) which has a unique form of expansions, extending forwards.
Imago: dorsal face of mid and hind femora with a distinct and an indistinct dark band ( Fig. 60 View FIGURES 56–67 ); ventral face of mid and hind femora with a distinct dark spot ( Fig. 61 View FIGURES 56–67 ); venation of wings pale brownish; terga pale reddish-brown, posterolaterally a brown spot and anterolaterally a very slightly brownish little marking ( Figs 54 View FIGURES52–55 , 56 View FIGURES 56–67 , 88 View FIGURES 86–99 ); titillators with 2 apico-lateral teeth ( Figs 75–78 View FIGURES68–85 ).
In nymph stage, E. brulini can currently be discriminated from all other species except E. calabra . As we had no fresh specimens and as the meristic and ratio characters are of no help to discriminate E. brulini from E. calabra in the nymph stage, the adults have to be compared to exclude a possible synonymy. In imagines, the very inconspicuous spots of the terga discriminate E. brulini from E. calabra which has, according to Bauernfeind & Soldan (2012) “Basolaterally a rounded dark reddish spot near the anterior border and a smaller dot near the posterior border of segments II–VIII”. In E. brulini , the comparison of Figs 2 View FIGURES 2–21 /52 and 3/53 shows that the cuticular colouration is little conservative, but the comparison of Figs 22 View FIGURES 22–31 /54 and 23/55 shows that the epidermal lateral spots are more conservative. As we observed such characteristics in our rearing of different Electrogena species, we can assume that it is true in E. calabra too. In females, the comparison with the original description seems to indicate that the subgenital plate covers about ¾ of sternum VIII surface in E. calabra (only about the half in E. brulini ) and that the subanal plate does not taper to the apex in E. calabra . This imaginal colouration, represented in Belfiore (1995) and the characteristics of the subgenital and subanal plates, exclude a synonymy. Nevertheless, a thorough study is needed to better separate the two species in both adult and nymph stages.
Material examined: HOLOTYPE: 1 male nymph (preserved in ethanol), CH / TI, Meride, Gaggiolo, 45.8973°N 8.9382°E 715 m, 3.V.2014, A. Wagner leg (GBIFCH00341000) [ MZL] GoogleMaps . PARATYPES: 16 males, 15 females, 36 nymphs, 4 male subimagines, 2 female subimagines: same sampling data as the holotype; 35 nymphs: same locality as holotype, 18.IV.2014 GoogleMaps ; 1 nymph: CH / TI, Stabio, Gaggiolo, 45.8388°N 8.9129°E 379 m, 18.IV.2014 GoogleMaps ; 1 nymph: CH / TI, Arzo, Gaggiolo, Arzo, 45.8753°N 8.9448°E 492 m, 18.IV.2014 GoogleMaps ; 3 nymphs: CH / TI, Arzo, Gaggiolo, upstream of Arzo, 45.8787°N 8.9494°E 507 m, 18.IV.2014 GoogleMaps ; 18 nymphs: IT / LO, Valle Santa Croce, Torrente Molgoretta, 45.7176°N 9.3448°E 304 m, 4.IV.2015; 1 nymph: IT / FV, Buja, Fiume Ledra, 46.2282°N 13.1086°E 175 m, 6.IV.2015; 11 nymphs: IT / FV, Povoletto, Via Reclusane, 46.2658°N 13.3126°E 158 m, 6.IV.2015; 7 nymphs: IT / FV, Savogna, Torrente Rieca, 46.1845°N 13.5821°E 541 m, 6.IV.2015; 24 nymphs: IT / FV, Stregna, Torrente Erbezzo, 46.1287°N 13.5699°E 232 m, 6.IV.2015; 16 nymphs: IT / FV, Prepotto, Fiume Judrio, 46.0826°N 13.5434°E 145 m, 6.IV.2015; 18 nymphs: SL / LC, Kocevje, Reka, 45.5695°N 14.8051°E 512 m, 8.IV.2015 GoogleMaps ; 4 nymphs: SL / LC, Kocevje, Gornja Briga, 45.5327°N 14.7935°E 625 m, 8.IV.2015 GoogleMaps ; 3 nymphs: SL / LC, Kostel, Kolpa tributary, 45.4646°N 14.8425°E 242 m, 8.IV.2015 GoogleMaps ; 2 nymphs: SL / LC, Ribnica, Ribnica tributary, 45.7359°N 14.7103°E 488 m, 8.IV.2015 GoogleMaps ; 6 nymphs: SL / LC, Sodrazica, Bistrica, Jelovec, 45.7691°N 14.6222°E 547 m, 8.IV.2015 GoogleMaps ; 12 nymphs: SL / LC, Sodrazica, Bistrica, Zimarice, 45.7763°N 14.6111°E 552 m, 8.IV.2015 GoogleMaps ; 4 nymphs: SL / LC, Sodrazica, Podklanec, 45.7655°N 14.5811°E 581 m, 8.IV.2015 GoogleMaps ; 1 nymph: SL / IC, Bloke, Bloscica , 45.7879°N 14.4761°E 727 m, 8.IV.2015 [all MZL]; 3 male imagines GoogleMaps , 3 female imagines, 3 nymphs: CH / TI, Meride, Gaggiolo, Spinorolo, 45.8973°N 8.9382°E 616 m, 3.V.2014 [ NHMW] GoogleMaps ; 12 nymphs: IT / FV, Grimaco, Rio Godriana , 46.1574°N 13.5941°E 292 m, 6.IV.2015 [ NHMW] GoogleMaps ; 12 nymphs: SL / LC, Kocevje, Kocevska Reka, 45.5695°N 14.8051°E 512 m, 8.IV.2015 [ NHMW] GoogleMaps .
Other material examined: 1 nymph: CH / TI, Chiasso, Breggia, 45.8407°N 9.0218°E 230 m, 6.III.1948, J. Aubert leg GoogleMaps ; 1 nymph: CH / TI, Stabio, Laveggio, 45.8463°N 8.9399°E 340 m, 15.III.1990, B. Jann leg GoogleMaps ; 3 nymphs: CH / TI, Meride, Gaggiolo, Spinorolo, 45.8973°N 8.9382°E 616 m, 3.IV.2012, B. Jann leg GoogleMaps ; 1 nymph: IT / FV, Buja, Fiume Ledra, Andreuzza, 46.2068°N 13.0947°E 171 m, 6.IV.2015; 4 nymphs: IT / FV, Attimis, Torrente Racchiusano, 46.1733°N 13.3330°E 230 m, 6.IV.2015; 2 nymphs: IT / FV, Savogna, Torrente Rieca, 46.1845°N 13.5821°E 541 m, 6.IV.2015; 3 nymphs: IT / FV, Grimaco, Rio Godriana , 46.1574°N 13.5941°E 292 m, 6.IV.2015; 30 nymphs: IT / FV, San leonardo, Torrente Cosizza, 46.1492°N 13.5638°E 218 m, 6.IV.2015; 1 nymph: IT / FV, Prepotto, Fiume Judrio tributary, 46.0827°N 13.5427°E 147 m, 6.IV.2015; 1 nymph: SL / LC GoogleMaps , Kostel, Kolpa tributary, 45.4646°N 14.8425°E 242 m, 8.IV.2015; 14 nymphs: SL / IC GoogleMaps , Bloke, Bloscica , 45.7879°N 14.4761°E 727 m, 8.IV.2015, A. Wagner leg [ MZL]. GoogleMaps
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