Leuctra enigma Kovács & Murányi, 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 enigma Kovács & Murányi sp. nov.

Figs 1 , 2 , 3 , 4 , 7 A, E

Type material.

Holotype male: Albania: • Dibër county, Bulqizë municipality, Çermenikë Mts, brooks in open forest beneath Mt. Kaptinë , 1600 m, 41°23.199'N, 20°17.338'E, 10.x.2012 (field number: loc. 25), leg. P. Juhász, T. Kovács, D. Murányi, G. Puskás ( MM: 2012-178 , PLETYP-30 ) . Paratypes: • same locality and date: 1 ♂ 1 ♀ ( BYU) • 1 ♂ 1 ♀ ( CGV) • 5 ♂ 6 ♀ ( HNHM: PLP 4184 ) • 5 ♂ 10 ♀ ( MM: 2012-178 , PLETYP-31 ) • 1 ♂ 1 ♀ ( SMNS) .

Other materials.

• Same locality, 21.vi.2012 (loc. 58), leg. Z. Fehér, T. Kovács, D. Murányi: 3 putative larvae ( HNHM: PLP 4099 ) • 2 putative larvae ( MM: 2012-1 ) • same locality, 27.v.2013 (loc. 19), leg. P. Juhász, T. Kovács, G. Magos, G. Puskás: 2 putative larvae ( MM: 2013-19 ) .

Diagnosis.

Macropterous in both sexes. Male tergite VII with huge membranous portion; tergite VIII with large, triangular posteromedial process, terminating in bi- or trilobed tip; tergite IX with large, lobed posteromedial sclerite supported by anterior sclerotised spots; tergite X posterior margin with deep and wide notch; sternite IX bears a vesicle shorter than 1 / 5 segment length; paraproct tip pointed, specillum slightly longer than paraproct, tip blunt. Female terga I – VIII with medial sclerite; subgenital plate with large lobes terminating in swollen and raised apex, central plate with anterolateral swellings and pale medial portion, posterior portion trapezoid in ventral view and nose-shaped in lateral view, well past by the lobes. Larva stout and with long setation, eyes small, clypeus lacks pointed corners.

Description.

Medium sized, robust species, both sexes macropterous. Forewing length: holotype 6.0 mm, male paratypes 5.8–6.4 mm, female paratypes 6.5–7.8 mm; body length: holotype 6.5 mm, male paratypes 6.0– 6.8 mm, female paratypes 8.0– 8.8 mm. Setation generally short and dense. General colour dark brown. Head brown with distinct M-line and occipital rugosities, compound eyes relatively small; antennae dark brown, palpi brown. Pronotum brown to dark brown, wider than long and having rounded corners, rugosities distinct. Legs brown to dark brown, tarsi slightly darker. Wings brownish but hyaline, venation brown.

Male abdomen (Figs 2 A – E , 7 A ): Tergite I membranous posteriorly and medially, with two medial spots; tergite II poorly sclerotised anteriorly. Transverse row of four pigmented spots distinct on terga II – VIII. Terga II – III with poorly developed antecosta, terga IV – VII with entire antecosta, terga III – VI full sclerotised. Tergite VII with huge medial membranous portion, a rounded or arrow-shaped sclerotised area extends between the medial pair of pigmented spots. Tergite VIII: antecosta nearly entire, gradually weakened in the medial 1 / 5, sometimes interrupted by a narrow medial notch; the posteromedial process is triangular, originated in the anterior 1 / 3 of the segment and reach the posterior 1 / 3 by its weakly bilobed or trilobed tip, medial portion with small membranous portion, medial pair of pigmented spots recognisable by the lateral sides of the process; the process is not darker than the lateral areas of the segment, wider than 1 / 3 segment width, slightly erect in side view; lateral edges of the medial membranous area obscure, while the anterior edge is sharply defined. Tergite IX mostly membranous, antecosta interrupted in the medial 1 / 3 of its length; posteromedial sclerite large, weakly bilobed anteriorly while posterior portion with long, diverging lobes, the sclerite is anteriorly supported by two sclerotised spots. Anterior margin of tergite X bilobed anteriorly but sclerotisation of lobes obscure; posterior margin with deep notch, as wide as 1 / 2 tergite width; medial portion of the notch with small protrusion at the origin of epiproct. Epiproct drop-shaped, sclerotised only at its sides, stalk gradually widening. Cercus simple, covered with long setae. Sterna II – VIII simple, sternite IX bears a very small, rounded vesicle shorter than 1 / 5 of segment length; posterolateral portions of the sternum pale coloured and weakly sclerotised. Paraproct with moderately wide base, narrowing after basal 1 / 3, apex gently curved in lateral view and tapering towards a pointed tip. Base of paraproct connected to a subrectangular lateral expansion. Specillum longer than the paraproct, gently curved in lateral view and ending in a blunt tip.

Female abdomen (Figs 2 F – G , 7 E ): Terga I – VIII with transverse row of four pigmented spots clearly visible; terga I – VIII mostly membranous but with lateral sclerites and a medial sclerite as well; medial sclerite is a longitudinal stripe, more widened on terga II and III; tergite IX mostly, tergite X fully sclerotised. Sterna I – VII simple, sterna II – VII with one subrectangular median sclerite and two small anterior sclerites that are not fused. Subgenital plate of sternite VIII large and complex, not fused with other sclerites, lacks distinct setation. It has two large and well-defined lobes, darker brown than the remainder of the plate; the lobes terminate in a swollen, rounded apex that are paler than the base of the lobes, raised in lateral view and converging in ventral view. The central plate has two anterolateral swellings, medial portion pale and lightly sclerotised; the plate terminates in a trapezoidal bulge, raised and nose-shaped in lateral view, clearly separated from the lateral lobes that extend beyond it. Sternite IX with wide but shallow anterior indentation. Paraproct, cercus, and epiproct simple. Spermathecal sclerite thin, ring-shaped, with small anterior teeth and long posterior teeth.

Putative larva (Fig. 3 ): Body stout, length of the penultimate or younger larvae 7.0– 7.5 mm. General colour pale brown, without distinctive markings, pilosity long and distinct. Head much wider than long, eye small, shorter than the widely rounded occipital region, ocelli distinct, clypeus not modified. Palpi simple, antenna longer than 1 / 2 body length. Pronotum much wider than long. Wing pads under development, posterior edge of meso- and metathorax between wing pads rounded, not like the typical prima-hippopus-inermis group shape. Legs short, tibiae not longer than femora, stretched hind leg reaches back to the seventh abdominal segment. Abdomen stout, integument matt pale brown, paraproct triangular. Cercus nearly as long as abdomen, with 25 cylindrical segments, medial segments twice longer than wide. Setation of the larva: antenna and palpi with short setae but head and clypeus with dense and erect setation, longest setae as long as the distance between hind ocelli; marginal setae continuous on pronotum, as long as the setae of the head; wing pads with similar long, erect and dense setae; femora and tibiae with hairs as long as the width of each femora, distributed on the whole surface but not forming swimming fringe; tarsi with short and scarce setation; abdominal segments evenly setose, with erect setae approximately as long as the setae of the head; cercomeres bald besides the erect apical whorl, slightly shorter than abdominal setae.

Affinities.

The new species is an isolated member of the hippopus group. The male is rather distinctive, the only Leuctra with comparable posteromedial process of tergite VIII is the Caucasian-Anatolian L. martynovi Zhiltzova, 1960 . However, L. martynovi differs by larger posteromedial sclerite of tergite IX, shallow posterior notch of tergite X, and larger vesicle of sternite IX. The subgenital plate of the female shows similarity with the narrowly defined hippopus group ( hippopus subgroup, sensu, e. g., Ravizza 2002 b), having large lobes and a pale central plate. However, the combination of bulging lobes of the subgenital plate, central plate with anterolateral swellings and trapezoid, bulging posterior portion, already distinguish it from all other Leuctra . The putative larva is distinctive by its stout body and dense, long setation. Among the Balkanian Leuctra , only L. nigra ( Olivier, 1811) and L. hirsuta Bogoesco & Tabacaru, 1960 are having similar long setation, however, their body is less stout, and their eyes are larger. The Alpine-Carpathian L. braueri Kempny, 1898 has similarly stout and hairy larva, but its clypeus is armed with prominent pointed corners.

Distribution and ecology.

The species was collected at a single high elevation site of the Çermenikë Mts, central Albania (Fig. 1 ). It was not found at any further localities, despite of intensive collecting efforts during the last twenty years conducted in central Albania. The habitat is disturbed by partial deforestation, most sections of the two confluent brooks run open or in bush of young beech (Fig. 4 A, B ). The brooks run moderately fast, 0.5–1 meter wide and not deeper than 20 centimetres (both in June and October). The substrate is stony, mixed with small sandy patches, few patches of dead wood and partly submerged plants (Fig. 4 B, C ). The specimens were swarming together with L. hirsuta in October 2012. When we visited the locality in late spring and early summer, a more diverse fauna was found: 21. vi. 2012 (leg. Z. Fehér, T. Kovács, D. Murányi): adults of Brachyptera helenica Aubert, 1956 b , Leuctra hippopoides Kaćanski & Zwick, 1970 , L. metsovonica Aubert, 1956 , Nemurella pictetii ( Klapálek, 1900) , Nemoura cinerea cinerea ( Retzius, 1783) , N. marginata Pictet, 1836 , Perla cf. pallida Guérin-Méneville, 1843 , Isoperla buresi Raušer, 1962 and Siphonoperla neglecta ( Rostock, 1881) ; 27. v. 2013 (leg. P. Juhász, T. Kovács, G. Magos, G. Puskás): adults of B. helenica , L. hippopoides , L. cf. dalmoni Vinçon & Murányi, 2007 , Nemoura cinerea cinerea , N. uncinata Despax, 1934 , N. marginata , Nemurella pictetii , Siphonoperla neglecta and S. graeca (Aubert, 1956) , and putative larvae of the new species were found. Leuctra cf. dalmoni , Nemoura uncinata , N. marginata and Isoperla buresi are new findings for Albania. Records of other aquatic insects collected at the type locality were already published: Ephemeroptera ( Kovács and Murányi 2013) : Baetis muticus , Habrophlebia lauta ; Odonata ( Murányi and Kovács 2013) : Cordulegaster bidentata ; Trichoptera ( Oláh and Kovács 2012 b, 2013): Agapetus iridipennis , Chaetopteryx bosniaca , Psychomyia pusilla , Cyrnus trimaculatus , Lepidostoma hirtum , Drusus plicatus , Mystacides azureus .

Etymology.

The name enigma (Latin; enigma or riddle) refers to the strange fact that such a distinctive new species was found only at a single locality. Used as a noun, gender neutral.

Figures

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

Figure 2. Terminalia of Leuctra enigma sp. nov. with setation omitted A male terminalia, dorsal view B same, lateral view C same, ventral view D variations of male tergite 8, dorsal view E male paraprocts and specillae, caudal view F female terminalia, ventral view G same, lateral view. Scale bar: 1 mm.

Figure 3. Putative larva of Leuctra enigma sp. nov. A head and pronotum, dorsal view B meso- and metathorax, dorsal view C hind leg, dorsal view D terminalia, dorsal view. Scale bars: 1 m.

Figure 4. Habitat of Leuctra enigma sp. nov. A type locality: partly open brook in the Çermenikë Mts. B section at forest edge C substrate of the type locality.

Figure 7. Terminalia of four Balkan members of the Leuctra hippopus group A – D male terminalia, dorsal view E – H female terminalia, ventral view. A, E L. enigma sp. nov., Çermenikë Mts, Albania B, F L. golija sp. nov., Golija Mts, Serbia C, G L. pseudohippopus Raušer, 1965, Stara Planina, Serbia D, H L. hippopoides Kaćanski & Zwick, 1970, Sutjeska, Bosnia & Herzegovina. Scale bars: 1 mm (D for A – D, H for E – H).