Arcynopteryx sajanensis Zapekina-Dulkeit, 1960

Teslenko, Valentina A., 2012, A taxonomic revision of the genus Arcynopteryx Klapálek, 1904 (Plecoptera, Perlodidae), Zootaxa 3329, pp. 1-18 : 11-13

Arcynopteryx sajanensis Zapekina-Dulkeit, 1960

( Figs 30–38 )

Zapekina-Dulkeit 1960: 666, 667, figs 1−5; Illies 1966:354; Teslenko & Zhiltzova 2009: 26, figs 122−125.

Diagnosis. Arcynopteryx sajanensis is distinguished from other species by the shape of the hemitergal lobe, which is short, bears a small rectangular projection on the inner mesal edge, and short, rounded knob directed medially and upward ( Figs 31 & 32 ). The cowl is larger than other Arcynopteryx species, paragenital plates are darkly sclerotized with rough outer edges. The arrow-like sclerites of the internal basal anchor are longer, than other Arcynopteryx species, theirs apex extended to the level of the rectangular projections on the inner mesal edges of the hemitergal lobes. Two lateral sclerotized bands are long, petal-shaped with thin base and wide rounded top ( Fig. 33 ). The aedeagus ( Fig. 34 ) is large, membranous, narrowed to the apex; with a pair of large rounded lobes at dorsolateral margins. The apex of aedeagus is thin with two small swellings laterally, and bears fine, erect, clear spinules of different sizes.

The posterior margin of the female subgenital plate smooth medially, with two small triangular, well sclerotized lobes laterally ( Fig. 35 ), the top of each lobe directed to the middle. Egg is large, sides of collar with sharp longitudinal carinae; shoulder with smooth margin and small, short and sharp tubercles situated close to collar sides ( Figs. 36-38 ). Chorion is covered with hexagonal FCI’s; flat floor often contain 7-10 punctations.

Adult habitus. The head ( Fig. 30 ) is wider than pronotum, with pale M-line; the clypeus is slightly darkened, the tentorial pits are brown. A thin dark stripe connects the lateral ocelli with median one. A wide U-shaped dark brown band below the median ocellus is diverged laterally and connected with a pair of brownish bands which are spread the M-line posteriorly. The tentorial pits are pale in front of the lateral ocelli; interocellar area exhibits a triangular pale spot, merging with a large hemispherical pale spot in the middle of the occiput. A brown band extends from each compound eye along the postfrontal suture to the coronal stem. A posterolateral spot with dark brown callosities presents behind each compound eye ( Fig. 30 ). M-shaped pattern on the head is not always clearly expressed both in males and females (especially in light specimens). The submental gills are very small and short. The antennae and palpi are brownish; the basal antennal segments are brown. The pronotum is slightly longer in width than in length, the angles, anterior and posterior margins are rounded, the lateral margins are straight; a median pale band is slightly expanded anteriorly. The pronotal rugosities are brown, X-shaped, and reach the lateral fields in the first and the last thirds of the pronotal length ( Fig. 30 ). The mesanotum is brown with pale patches on the prescutum, scutum, and scutellum (usually in males). The metanotum is entirely brown. The abdominal segments are light brown, covered by short colorless hairs, pronounced on terga posterolaterally. The legs are pale, the femur is brown anteriorly. The cerci are longer than abdomen, pale, with light brown hairs; each cercal segment is darkened distally. The forewing is pale; veins are brownish, and then grades into colorless to the margins, C vein is pale yellow. The venation includes an irregular net near the apex, occasionally consisting of two rows of cells. The hind wing anal area is large, and A1 and A5 are forked. Brachypterous and long-winged specimens co-occurred at the same sampling site.

Male. Body length 12.0−18.0 mm, forewing of full-winged male 12.0− 14.5 mm, wingspan 27.0− 30.5 mm; the length of shortened wings 3.5–5.0 mm. Abdominal tergum 9 is light brown with dark brown band anterolaterally, the posterior margin exhibits a medial elevated notch which runs half of the length of tergum 9, and two submedial, rounded swellings. These swellings are dark brown and densely covered by small stout setae and fine colorless hairs posteriorly ( Fig. 31 ). Sternum 9 is scoop-shaped, extended backward and curved upward, the posterior margin rounded and pale medially. Tergum 10 is divided into two hemiterga ( Fig. 31 ). Each hemitergal lobe is short, bears a small rectangular projection on the inner mesal edge and a rounded knob directed medially and upward ( Figs 31 & 32 ). In dorsal view, a knob is slightly membranous at the top, heavy sclerotized from below, and covered by small, stout setae ( Fig. 32 ). The knobs are very short, do not touch each other. In dorsal view, the cowl is larger than other Arcynopteryx species, and is supported by flat and darkly sclerotized paragenital plates with rough outer edges. The sclerites of the internal basal anchor are arrow-like, longer than other Arcynopteryx species, and fragile, and black ( Fig. 33 ), they extended posteriorly to the level of the rectangular projections on the hemitergal lobes. In lateral view, the lever arm of the epiproct is stout, hemispherical, hollowed, and is divided into two thin well sclerotized stripes ventrally ( Fig. 33 ). Two lateral sclerotized bands are fastened to the lever arm ventrally and support the cowl ventrolaterally; each lateral sclerotized band is long, petal-shaped with a thin base and wide rounded top ( Fig. 33 ). The stylet of the epiproct resembles a long, fine bristle directed upward and backward. Inside the cowl the stylet is curved in a loop, the basal plate of the loop is triangular, well sclerotized and attached to the lateral bands at the bottom of the cowl ( Fig. 33 ). In dorsal view, the everted aedeagus ( Fig. 34 ) is large, membranous, narrowed to the apex; with a pair of large rounded lobes at dorsolateral margins. The lobes may not be fully everted; the apex of aedeagus is thin with two small swellings laterally, and bears fine, erect, clear spinules of different sizes. In Fig. 34 , the apex of aedeagus is not fully everted.

Female. Body length 15.0−21.0 mm, forewing of full-winged female 16.5−19.0 mm, wingspan 37.0− 39.5 mm. Length of shortened wings 5.0–6.0 mm. Sternum 8 is without spots. The subgenital plate is large, relatively short, extends laterally from sides of sternum 8, and does not exceed half of sternum 9 ( Fig. 35 ). The posterior margin is smooth medially, with two small triangular lobes laterally ( Fig. 35 ). The top of each lobe is directed to the middle. Lobes are more sclerotized than the rest surface of subgenital plate, and covered with conspicuous colorless setae. Sternum 9 is pale medially, with two brown circular spots mesolaterally ( Fig. 35 ).

Egg is large, ovular, and circular in cross-section, 567.0 x 413.5 µm ( Fig. 36 ). The collar is stalked, its rim flanged and irregularly incised. The sides of collar bear several sharp longitudinal carinae; the margin of shoulder is smooth; short sharp tubercles are situated close to the collar sides ( Fig. 37 ). The chorion is covered with hexagonal FCI’s ( Figs 36−38 ); FCI walls are raised with thin, shallow furrows; flat floors often contain 7-10 punctations ( Fig. 38 ). Row of micropyles is subequatorial; theirs orifices are small with distinct lips surrounded by pentagon rosettes ( Fig. 38 ).

Material examined. Lectotype, male. Russia. Sayan Mountain, Bolshoi Arzybai River, tributary of Malka River, Yenisei River Basin, 24.08.1953, coll. G. Dulkeit. Paralectotypes: 1 male, 2 females, the same place; 4 males, 2 females, Dezo River, left tributary of the Mana River, 7.07.1955, coll. G. Dulkeit. Trans-Baikal Region: 10 males, 6 females, Khamar-Daban Mountains, car Osinovyi, 1400-1600 m, alpika, Osinovaya River, upstream, 1250 m, 20.07 − 4.08.20009, coll. Yu. Sundukov.

Distribution. A. sajanensis is restricted in Russia by the Altai, Sayan and the Khamar-Daban Mountains ( Teslenko et al. 2010).

Figures

FIGURES 30 – 35. Arcynopteryx sajanensis: 30. Head and pronotum of female. 31. Male abdominal tip, dorsal. 32. Male right hemitergal lobe, dorsal. 33. Cowl: sclerites of the internal basal anchor, lever arm, paragenital plate, stylet and loop of the epiproct, and two lateral sclerotized bands, lateral. 34. Aedeagus, dorsal. 35. Female abdominal tip, ventral. Scale (mm): 32 – 34 = 1.0.

FIGURES 36 – 38. Arcynopteryx sajanensis, egg: 36. Habitus lateral. 37. Collar, lateral. 38. Chorion structure, micropylar orifice, mound, lip and pentagon rosettes, dorsal view.