Leuctra visitor, Murányi & Kovács, 2024

Murányi, Dávid & Kovács, Tibor, 2024, Four new species of Leuctra Stephens, 1836 from the Balkans (Plecoptera, Leuctridae), ZooKeys 1218, pp. 49-79 : 49-79

Leuctra visitor sp. nov.

Figs 1 , 10 , 11 , 12 B, F

Type material.

Holotype male: Montenegro: • Plav municipality, Visitor Mts, forest springs and their outlet along the Katun road , 1730 m, 42.6308°N, 19.8358°E, 5.v.2023 (field number: loc. 13), leg. T. Kovács, D. Murányi ( MM: 2023-49 , PLETYP-37 ) . Paratypes: • same locality and date: 1 ♂ 1 ♀ ( BYU) • 1 ♂ 1 ♀ ( CGV) • 11 ♂ 8 ♀ (3 pairs in copula) ( EKCU: PLP 5706 ) • 1 ♂ 2 ♀ ( MM: 2023-49 , PLETYP-38 ) • 1 ♂ 1 ♀ ( SMNS) • Plav municipality, Visitor Mts, partly open brook and spring along the Katun road , 1845 m, 42.6185°N, 19.8378°E, 11.vi.2022 (loc. 24), leg. A. Hunyadi, T. Kovács, D. Murányi, P. Olajos: 5 ♂ 3 ♀ ( EKCU: PLP 5584 ) • 8 ♂ 9 ♀ (1 pair in copula) ( MM: 2022-90 , PLETYP-39 ) • Plav municipality, Visitor Mts, forest streams and brooks along the Katun road , 1515 m, 42.6294°N, 19.8442°E, 11.vi.2022 (loc. 22), leg. A. Hunyadi, T. Kovács, D. Murányi, P. Olajos: 1 ♀ ( EKCU: PLP 5572 ) • same locality, 5.v.2023 (loc. 12), leg. L. P. Kolcsár, T. Kovács, D. Murányi: 8 ♂ 7 ♀ (2 pairs in copula) ( EKCU: PLP 5701 ) • 6 ♂ 8 ♀ (1 pair in copula) ( MM: 2023-48 , PLETYP-40 ) .

Diagnosis.

Brachypterous in both sexes. Male tergite VII with small membranous portion; tergite VIII with strong posteromedial process that is not erect in side view and bear angular teeth, membranous area longer than 1 / 2 segment length with a crossband, the posterior margin indented in a rounded membranous field between the posteromedial process and segment sides; tergite IX with short but wide posteromedial sclerite; tergite X posterior margin with a wide V-shaped notch; sternite IX bears a vesicle much shorter than 1 / 2 segment length; specillum slightly longer than paraproct, tip blunt behind subterminal constriction. Female subgenital plate large, trapezoid, with an incision between the long lobes slightly widening towards the median bulge but not forming a triangular field; median bulge is wide in ventral view and distinctly raised in lateral view, with distinct, erect setation; spermathecal sclerite ring-shaped, with large and converging posterior teeth.

Description.

Medium sized, robust species, both sexes brachypterous (Fig. 11 A – C ). Forewing length: holotype 3.2 mm, male paratypes 3.0– 3.8 mm, female paratypes 4.2–5.2 mm; body length: holotype 6.2 mm, male paratypes 5.4–7.0 mm, female paratypes 6.8–9.0 mm. Setation generally short and dense. General colour dark brown to blackish. Head, antennae, and palpi dark brown. Pronotum dark brown, as wide as long and having rounded corners, rugosities distinct. Legs brown to dark brown. Wings brownish but hyaline, venation brown.

Male abdomen (Figs 10 A – D , 12 B ): Tergite I membranous in its whole medial portion, tergite II membranous anteromedially behind antecosta. Transverse row of four pigmented spots distinct on terga I – VII. Terga II and III with medially divided antecosta, terga IV – VII with entire antecosta and full sclerotised, tergite VII with small posterior membranous portion. Tergite VIII: antecosta interrupted by a wide membranous area, each part ends in a small triangular plate, and the membranous area between them is bridged by a weakly sclerotised crossband; width of the membranous area is less than 1 / 2 the segment width, and reaches below 1 / 2 the segment length above the posteromedial process, posterior margin of the membranous portion nearly straight; the surrounding sclerotisation of the membranous area paler than remainder of the segment; posteromedial process paler than the lateral areas of the segment, not erect in side view and slightly overhangs the segment posterior edge, as wide as the membranous area above, bilobed with angular teeth slightly pointed laterad, the space between the teeth is deeply indented and concave; posterior margin between the posteromedial process and segment sides indented in a shallow, rounded membranous field but not lobed. Tergite IX mostly membranous, antecosta interrupted in the medial 1 / 2 of its length; posteromedial sclerite short but wide, medial areas usually slightly darker, the medial portion usually not narrowed. Anterior margin of tergite X bilobed anteriorly, posterior margin with deep, V-shaped notch, 1 / 2 as wide as tergite width. Epiproct large, posteriorly rounded, sclerotised only at its sides, stalk relatively long. Cercus short, covered with long setae. Sterna II – VIII simple, sternite IX bears a vesicle much shorter than 1 / 2 segment length, its width more than 1 / 2 its length; the area surrounding the vesicle is pale, posterior edge with two pale and weakly sclerotised areas. Paraproct with moderately wide base, abruptly narrowed after basal 1 / 3, apex gently curved in lateral view and tapering towards a sharp tip. Base of paraproct connected to a subrectangular lateral expansion with an apical, short, blunt triangular process. Specillum slightly longer than the paraproct, gently curved in lateral view and ending in a subterminally constricted, blunt tip.

Female abdomen (Figs 10 E, F , 12 F ): Terga I – VIII with transverse row of four pigmented spots clearly visible; terga I – VIII mostly membranous but with lateral sclerites, terga II, III, and VI – VIII, sometimes also tergite V, bear a patch-like medial sclerite, largest on tergite VIII; tergite IX membranous only anterolaterally, tergite X fully sclerotised. Sterna I – VII simple, sterna II – VII with one subrectangular median sclerite and two small anterior sclerites that are fused with the median sclerite on sternite VII. Subgenital plate of sternite VIII large and trapezoid, not fused with other sclerites. It has two large wide lobes, slightly darker brown than remainder of the plate; posterior margin convex, incision between the lobes is a membranous strip, slightly widened towards the median bulge near the centre of the plate but not forming a triangular field; median bulge is wide in ventral view, distinctly raised, nose-shaped in lateral view, with distinct erect setation. Sternite IX with wide but shallow anterior indentation. Paraproct, cercus, and epiproct simple. Spermathecal sclerite ring-shaped, with small anterior teeth and large, converging posterior teeth.

Affinities.

The males are morphologically closest to L. dalmoni (compare with Fig. 12 C, D ) while the female is closest to L. prima (compare with Fig. 12 J ). Males can be distinguished from L. dalmoni on the basis of the following characters: a weak crossband on the membranous area of tergite VIII lacking in L. dalmoni , angular teeth of the posteromedial process of tergite VIII stronger than those of L. dalmoni ; the posterior indentation of tergite X is V-shaped, while it is rounded in L. dalmoni ; the ventral vesicle of sternite IX is shorter than 1 / 2 the segment length, while clearly longer than 1 / 2 the segment length in L. dalmoni . The males of the new species can be easily distinguished from L. prima and L. pseudosignifera : L. pseudosignifera is characterised by a pair of rounded sclerotised expansions, located between the posteromedial process and segment sides of tergite VIII (Fig. 12 K ); the posteromedial process of tergite VIII is erect in lateral view in L. prima ; furthermore, this species has a divided posteromedial sclerite on tergite IX (Fig. 12 I ). Females can be distinguished from L. prima on the basis of the distinct, erect hairs of the subgenital plate as seen in lateral view, and the nose-shape of the bulge of the subgenital plate; the bulge is rounded in L. prima and the subgenital plate lacks distinct setation. The wide bulge of the subgenital plate (in ventral view), and the erect hairs (in lateral view) distinguish the new species from L. dalmoni and L. pseudosignifera ; furthermore, L. pseudosignifera is characterised by a triangular membranous field at the end of the incision between the lobes of the subgenital plate (Fig. 12 L ). Distinction of both sexes from L. puskasi was described in detail above.

Distribution and ecology.

The species was collected at three high-elevation brooks and spring outlets in the Visitor Mts of eastern Montenegro (Fig. 1 ). The Visitor is a mostly volcanic range of small area, with its highest peak reaching more than 2200 meters, surrounded by the notably higher limestone chains of the Prokletije Mts. The Visitor receives high precipitation and is covered with dense forest, resulting in a rich pattern of different waterflows. The streams where the new species was found are running in mixed forest or partly open meadows, the lentic parts usually with dense Caltha growth (Fig. 11 D, E ). The brooks have variable flow rates but are permanent streams, the substrate is stony mixed with mud and plenty of dead wood. The specimens were emerging together with L. dalmoni (Fig. 12 C, G ) and both species were present with many mating pairs in May, but we found no interbreeding couples (Fig. 11 C ). We visited the area three times: the new species was more numerous than L. dalmoni in early May 2023, both scarce in early June 2022, and both absent by late June 2023. In May, the upper site (1845 m) was not available, and even the lowest site (1515 m) was partly covered by snow, but all were snow-free by late June. We found a rich accompanying stonefly fauna at the lowest site: Brachyptera helenica (adults and matured larvae, early June), B. graeca Berthélemy, 1971 (adults, late June), B. seticornis (adults, early June), Capnia s. l. vidua rilensis (adults, May and early June), Leuctra nigra (adults, May and June), L. dalmoni (adults, May and early June), L. metsovonica Aubert, 1956 b (adults, early June), Protonemura cf. auberti Illies, 1954 b (adults and matured larvae, early June), Nemurella pictetii (adults, May and June), Nemoura cinerea cinerea (adults, early June), Nemoura marginata (adults, May and early June), a yet unnamed Nemoura of the marginata group (adults, May and early June), N. uncinata Despax, 1934 (adults, May and early June), Arcynopteryx dichroa ( McLachlan, 1872) (adults and matured larvae, June), a yet unnamed Isoperla related to I. breviptera Ikonomov, 1980 (adults and matured larvae, June), I. cf. tripartita Illies, 1954 a (larvae, June), and unidentified larvae of Siphonoperla and Chloroperla (early June). Some of these were probably not developing in the same stream section since the site is placed at a junction of three different brooks. The type locality (sampled only in May) was inhabited by the new species, L. nigra (adults), L. dalmoni (adults), the unnamed Nemoura (adults and putative larvae), an unidentified Protonemura (larvae), and the unnamed Isoperla (larvae). At the highest site (sampled only in June), the new species was found together with Leuctra nigra (adults), L. dalmoni (adults), the unnamed Nemoura (adults), Nemurella pictetii (adults), Arcynopteryx dichroa (larvae), and the unnamed Isoperla (adults). Capnia s. l. vidua rilensis, Leuctra dalmoni , and L. metsovonica are new records for Montenegro.

Etymology.

The name visitor is derived from the Visitor Mountains of Montenegro, where the new species was found and probably restricted to the high elevations of the range. Used as a noun, gender neutral.

Figures

Figure 1. Collection sites of the four new Leuctra species.

Figure 10. Terminalia of Leuctra visitor sp. nov. A male terminalia, dorsal view B same, lateral view C same, ventral view D male paraprocts and specillae, caudal view E female terminalia, ventral view F same, lateral view. Setation omitted with the exception of subgenital plate on F. Scale bar: 1 mm.

Figure 11. Habitus and habitat of Leuctra visitor sp. nov. A male habitus B female habitus C copula D partly open brook at 1845 m in the Visitor Mts. E type locality: forest springs and their outlet at 1730 m in the Visitor Mts.

Figure 12. Terminalia of five Balkan members of the Leuctra prima group A – D, I, K male terminalia, dorsal view E – H, J, L female terminalia, ventral view A, E L. puskasi sp. nov., Kozara Mts, Bosnia & Herzegovina B, F L. visitor sp. nov., Visitor Mts, Montenegro C, G L. dalmoni Vinçon & Murányi, 2007, Visitor Mts, Montenegro D, H L. dalmoni, Golija Mts, Serbia I – J L. prima Kempny, 1899, Börzsöny Mts, Hungary K – L L. pseudosignifera Aubert, 1954, Poljana Mts, Slovakia. Scale bars: 1 mm (D for A – D, I, K; E for E – H, J, L).