Isoperla vevcianensis Ikonomov, 1980

Murányi, Dávid, 2011, Balkanian species of the genus Isoperla Banks, 1906 (Plecoptera: Perlodidae), Zootaxa 3049, pp. 1-46 : 21-22

Isoperla vevcianensis Ikonomov, 1980

( Figs. 62–66, 127)

Isoperla vevcianensis Ikonomov, 1980 — Ikonomov 1980: 26 (original description of male, female and larva).

Material examined: ALBANIA: Librazhd district : Qarishtë , Mts Jablanica, brook E of the village, N 41.24569° E 20.51238°, 1900 m, 04.07.2008, leg. Z. Barina, D. Pifkó, A. Vojtkó: 1m ( HNHM; used for drawings, penial armatures prepared on slide); Steblevë, Mts Jablanica, brook SE of the village, N 41.27905° E 20.50103°, 1865 m, 03.07.2008, leg. Z. Barina, D. Pifkó, A. Vojtkó: 1m ( HNHM; penial armatures prepared on slide), 1m ( CGV; penial armatures prepared on slide) .

Diagnosis: This broadheaded species is characterized by the presence of a medial penial armature that is covered in spike-like scale and divided into a trapezoidal upper and a rounded lower part, by the absences of lateral penial armatures, and by the presence of an enlarged vesicle of sternite VIII.

Description: Large-sized species, macropterous. Body length: males 12–13 mm (n=3); forewing length: males 13–13.5 mm (n=3). General colour yellowish but the meso- and metanotum and the abdomen mostly brown; pilosity of the body and legs short and dense. Head broad and rounded, yellow with a brown patch between the three ocelli; tentorial callosities and M-line more or less distinct, a few wrinkles present between the M-line and the lateral margins; the occiput lacks rugosities but is brown laterally ( Fig. 62). Eyes smaller than the area delimited by the three ocelli. Scape dark brown, pedicel and the following three or four antennomeres are brown but distal part of the antenna is dark brown; palpi brown. Pronotum yellow, rectangular, edges angled; rugosities are numerous and brown coloured, anterior and posterior lines brown under and above the rugosities. Mesonotum dark brown but yellow anteriorly, sometimes medially also; metanotum dark brown but yellow anteriorly. Wings yellowish, venation pale in the anterior two thirds, brownish in the posterior third. Ventral surface of thorax mostly pale, meso- and metabasisternum mostly dark brown; furcasternites light brown, furcal pits black ( Fig. 65). Femora pale but the dorsal surface and the ventral edges brown. Tibiae brown, tarsi dark brown.

Male abdomen: First tergite dark brown but yellowish medially. Tergites II–VI entirely dark brown, tergite VII entirely dark brown or dark brown with two pale patches posteriorly. Pale markings become more extensive on tergites VIII–IX, but a transverse anterior dark brown stripe and a medial dark brown arrow-like mark always present; tergite X yellowish with two brown patches medially ( Fig. 63). Transverse row of four pigmented spots seen on all but tergite X. Sternites II–VI brown with a medial transverse row of four spots; posterior part of sternite VII with a more or less extensive pale pattern. Sternite VIII paler and with a dark pattern, but only two big spots. Vesicle of sternite VIII brown, as wide as long, its posterior margin is weakly rounded; as long as half the segment’s length ( Fig. 64). Sternite IX yellowish brown but darker posteriorly, the medial penial armatures barely visible in the posterior half. Paraprocts dark brown, blunt, strong and slightly recurved; cerci dark brown in the basal segments, distal part of the cerci are usually paler.

Penis: Lobes and the distribution of non coloured scales, hairs and sensilla cannot be studied because the specimens were collected without evertion of the penis. The medial penial armature is divided into an upper and a lower part and probably located on the ventral lobe ( Fig. 66), lateral penial armatures lacking. The upper medial penial armature is trapezoidal, tapered towards the basal section; length 500 µm, width 450 µm. The lower medial penial armature is rounded, slightly elongated; length 200 µm, width 120 µm. The scales are spike-like, those on the upper part are longer but of the same width. The length of the longer ones of the upper part is 150 µm, of the shortest ones in the lower part is 30 µm; width 15 µm. The penis is bald between the upper and lower parts, but bears quite large triangular scales laterally to the lower part; these are grading into smaller ones, shown on Fig. 66, to the right side of the lower medial penial armature. Hydra-like scales occur above a bald line apically to the upper medial penial armature.

Female and larva not studied herein, egg unknown.

Affinities: The species was originally not assigned to a species group sensu Consiglio 1967 ( Ikonomov 1980); herein it is assigned to the silesica group. It differs from I. breviptera , I. silesica and I. zwicki by the shape of the upper medial penial armature which is trapezoidal contrary to the triangular armature of I. breviptera and the rounded armature of I. silesica and I. zwicki ; furthermore, I. breviptera is micropterous. The broad head and the large vesicle of sternite VIII is diagnostic of I. vevcianensis .

Ecology and distribution: The species was originally described from the Macedonian side of the Jablanica Mountains ( Ikonomov 1980), only a few kilometers from the present Albanian localities ( Fig. 127). Hitherto, it was known only from the type locality ( Ikonomov 1986); consequently, the species is new for Albania. It seems to be an endemic of the Jablanica Mountains as it was not found in adjacent Macedonian or Albanian mountain systems. In Albania, it was collected from alpine grassland brooks above 1850 m during early July. Associates include I. tripartita tripartita at the Qarishtë brook and I. tripartita tripartita , Leuctra cf. metsovonica Aubert, 1956 , Nemoura caligula Zwick, 1978 and a deformed Protonemura female at the Steblevë brook. Isoperla tripartita tripartita was more numerous than I. vevcianensis at either site. At the type locality it occurred between 1100 and 1450 m in June and July.