Isoperla pesici, Murányi, 2011

Murányi, Dávid, 2011, Balkanian species of the genus Isoperla Banks, 1906 (Plecoptera: Perlodidae), Zootaxa 3049, pp. 1-46 : 33-35

Isoperla pesici sp. n.

( Figs. 99–108, 126)

Type material: Holotype male: MONTENEGRO: Nikšić municipality: Vidrovan, outlet of the Vukovo Vrelo Spring, N 42°51.47’ E 18°56.59’, 675 m a.s.l., 21.06.2008, leg. V. Pešić ( HNHM: PLP2868 ; used for drawings Figs. 99–102) . Paratypes: same locality and date: 1f ( HNHM: PLP3350 ; used for drawing Fig. 103), 8m 7f ( HNHM: PLP3351 ; used for drawing Fig. 104, three penial armatures prepared on slides, eggs prepared for SEM), 2m 1f ( CGV) , 2m 1f ( CPZ) ; Vidrovan Stream (upper reach of the Zeta River) in the village, N 42°51’06.9” E 18°56’26.3”, 03.06.2009, leg. W. Graf: 6m 3f ( CWG; eggs prepared for SEM) ; Danilovgrad municipality: Spuž, tributary of the Zeta River, N 42°32’03.1” E 19°11’23.6”, 28.05.2009, leg. W. Graf: 1m ( CWG) ; Kolašin municipality: Redice, small spring and its outlet above the village, N 42°54’02.3” E 19°16’11.4”, 1270 m, 01.06.2009, leg. W. Graf: 1m 1f ( CWG) .

Diagnosis: This large, macropterous species is characterized by a combination of coloured and divided upper and lower medial penial armatures, by the upper armature being further divided into small, round left and right parts, and by the lower armature also being subdivided. Scales of these armatures are all spike-like. Lateral penial armatures are lacking in this species.

Description: Large-sized species, macropterous ( Fig. 107). Body length: holotype 12.0 mm, male paratypes 11.5–13.0 mm (n=20), female paratypes 11.5–14.0 mm (n=14); forewing length: holotype 12.0 mm, male paratypes 11.5–12.5 mm (n=20), female paratypes 12.5–14.5 mm (n=14). General colour yellowish but the meso- and metanotum brown, and the abdomen mostly brownish; pilosity of the body and legs short and dense. Head yellow with a longitudinal brown stripe medially, connecting posterior ocelli and the labrum, but with a yellow spot between the ocelli ( Figs. 99, 107). Tentorial callosities more or less distinct, M-line distinct, occiput brown laterally and with a few rugosities. Eyes as large as the area delimited by the three ocelli. Scape dark brown, pedicel and the following three or four antennomeres are brown but distal parts darker; palpi light brown. Pronotum brown with a yellow medial line and yellow sides, rectangular, edges angled; rugosities set in brown background, large and brown coloured but indistinct. Mesonotum dark brown but yellow anteriorly and medially, metanotum dark brown. Wings yellowish, venation pale in the anterior fourth, remainder veins brown. Ventral surface of thorax mostly pale, meso- and metabasisternum bear two brown (not dark brown) stripes laterally, furcasternites pale, furcal pits black ( Fig. 102). Femora pale but the dorsal surface and the ventral edges brown. Tibiae pale ventrally, brown dorsally; tarsi dark.

Male abdomen: First tergite light brown but yellowish anteriorly and medially. Tergites II–VIII light brown to brown, with some darker marks anteriorly and medially. Tergite IX similar but paler, and with paired posterior dark marks; tergite X yellowish with two brown, triangular patches medially, and with weak posterolateral brown edges ( Fig. 101). Transverse row of four pigmented spots seen on tergites I–VIII, tergite IX have two spots, tergite X lacks spots. Ventral surface of abdomen yellow, sternites II–VII have a weak, interrupted light brown transversal anterior line; sternites II–VII have a medial transverse row of four spots, sternite VIII with two spots. Vesicle of sternite VIII brown, 1.5X longer than wide, its posterior margin rounded; as long as half the segment ( Fig. 100). Sternite IX uniformly yellow, the medial penial armature visible through the integument in the posterior fourth. Paraprocts brown, sharp, thin and recurved; cerci yellow, distal segments light brown to brown.

Penis: Lobes and the distribution of non coloured scales, hairs and sensilla cannot be studied in details because the specimens were collected without complete evertion of the penis. The medial penial armature is divided into an upper and a lower part, both are coloured; in all probability, upper armature located on the medial lobe adjacent to the ventral lobe, lower armature located on the central part of the ventral lobe ( Fig. 104). Lateral penial armatures lacking. The upper medial penial armature is further divided into a left and a right part which are small and round. Length of the parts are 75–100 µm, width 70–80 µm. The lower medial penial armature is subdivided into a left and a right part which are diverging towards the basal section, usually forming an upturned V. Length 220–260 µm, width 100–125 µm. The scales are spike-like and straight, those on the lower part are usually longer and thinner. Their length is 30–60 µm, width 5–10 µm. Origin of the narrow stripe of hydra-like scales, characteristic for the species group, can be seen above the upper medial armatures. Small branched hair-like scales occur above the lower medial armature, these are grading into bigger ones towards the armature; triangular scales forming a wide stripe beneath the armature.

Female abdomen: First tergite brown but yellowish anteriorly and medially. Tergites II–VII entirely brown, pale markings become more extensive on tergites VII–IX, but a medial dark brown mark always present; tergite X yellow or with some brownish patches medially. Transverse row of four pigmented spots seen on all but tergite X. Sternites II–VII yellow with a weak transversal posterior line, medial transverse row of four spots poorly developed. Subgenital plate covers most of sternite VIII and the anterior part of sternite IX. Plate mostly yellow, but the posterior margin usually brown, and the anteromedial part is light brown; posterior margin roundly triangular ( Fig. 103). Sternite IX yellow, bearing two pale brown lateral patches on the posterior half. Sternite X and the paraprocts yellowish; cerci yellow, distal segments light brown to brown.

Egg: Chorion light brown, 0.33–0.36 mm long and 0.26–0.28 mm wide (n=30). Shape oval, one side of all the examined eggs are depressed ( Fig. 105), though this shape is possibly an artifact (see Tierno de Figueroa et al. 2000). Hatching line inconspicuous. Micropyles placed in a transverse row on the opercular fourth, not raised ( Fig. 106). Chorion with shallow punctation, FCIs not visible. Collar and anchor missing.

Larva: unknown.

Affinities: See I. tripartita tripartita above.

Ecology and distribution: The species was collected at spring outlets in June, between 200 and 1270 m in the Zeta and the upper Morača valleys ( Fig. 126). The Vukovo Vrelo spring system consists of many springs of variable size that have stony substrate and permanently cold water ( Fig. 108). Their water is entrapped in a small artificial lake, then flows in a big stream. The shore vegetation of the springs is ruderal, with Juncus stocks and some low bush. The species was found in common with Leuctra quadrimaculata Kis, 1963a , Amphinemura triangularis , Protonemura intricata intricata , Nemoura cinerea cinerea , Nemurella pictetii ( Klapálek, 1900) and Dinocras megacephala ( Klapálek, 1907) . When visited in October, the following species were collected: L. hirsuta Bogoescu & Tabacaru, 1960 , L. major Brinck, 1949 , P. autumnalis Raušer, 1956 , P. montana Kimmins, 1941 and N. pictetii . The species was found in further two tributaries of the Zeta River with similar cold water. The small spring at Redice is in the source area of the Morača River, and its outlet flows on a steep slope. Here the species was found in common with P. intricata intricata , N. pictetii , Perlodes intricatus ( Pictet, 1841) and Siphonoperla graeca ( Aubert, 1956) (pers. com. W. Graf).

Etymology: The species is dedicated to Dr. Vladimir Pešić, Podgorica, Montenegro, noted Acarologist and the collector of the type series. The name is used as the genitive of a noun of male gender.