Leuctra khachapuri Žiak et Martynov, 2019

Martynov, Alexander V. & Žiak, Matej, 2019, A new micropterous species of Leuctra (Plecoptera: Leuctridae) from the Lesser Caucasus (Georgia), Zootaxa 4671 (4), pp. 581-588 : 582-586

Leuctra khachapuri Žiak et Martynov , sp. nov.

( Figs. 1–15 )

Description. Adult habitus: Small sized species, micropterous in both sexes, wings reduced to inconspicuous brown plates shorter than corresponding scutum. Body length: male 4.7˗5.2 mm, female 6.4 mm. Setation generally short, but distinct and dense mainly on abdomen ( Figs. 5 , 14 ). General color dark brown, body completely sclero- tized ( Figs. 1 , 11 ). Head and flagellum brown, scapus, pedicelus and maxillary palp somewhat lighter ( Figs. 2, 3 ). Pronotum brown, as long as wide with sharp corners, rough surface distinct. Legs same brown.

Male: Tergum I–VI simple and heavily sclerotized. Posterior margin on tergum VII with semicircular parame- dian membranous area ( Fig. 6 ). Tergum VIII concave anteriorly, bears a pair of posteromedial heavily sclerotized and widely spaced horn-shaped processes, extended to posterior margin of tergum VIII, which is membranous ( Fig. 6 ); between horn-shaped processes there is an additional pair of small narrow spaced, rounded processes ( Figs. 7, 8 ). Tergum IX mostly membranous, with distinct antecosta, divided medially for of segment width ( Fig. 8 ). Tergum X deeply notched and bilobed. Between the lobes large, simple and posteriorly ⅕ rounded epiproct with irregular shape ( Fig. 8 ). Paraprocts strong ( Figs. 4, 5 ), styles 1.4x shorter than specilla. Styles base wide with triangular rounded lateral edges ( Figs. 4 , 6 ), and ending in tapered apices, gently bent inward. Specilla long, gently narrowed to the apex, apex pointed and directed upward in lateral view; in dorsal view apex spear-shaped. Cercus simple, cylindrical, gently narrowed and blunted to the tip, covered with long setae. Sterna II–VIII simple, sternum IX with U-shaped unsclerotized area, no ventral vesicle ( Fig. 1 ).

Female: Abdominal segments I–VII divided to tergum and sternum. Terga I–X simple, entirely sclerotized, se- tation long and dense, but gentle and light. Sterna II–VII simple, with short setae. Sternum VIII well sclerotized with long and dense setae ( Figs. 13, 15 ). Subgenital plate large ( Fig. 14 ), trapezoidal, reaches of the length of sternum IX, with sharp corners at the base, tapered to posterior margin, and gently crimped laterally ⅓; posterior margin threelobed with a pair of very shallow notches medially, weakly sclerotized; a pair of thin and prolonged sclerites arm the subgenital plate laterally. A pale patch, resembling a cross, extending mesally from anterior to posterior margin and shifted to posterior margin ( Fig. 14 ). Plate covered by long gentle setae in distal half. Sternum IX also well sclerotized, with long and dense setae ( Fig. 14 ).

Etymology. This species is named after the popular traditional Georgian food dish – khachapuri .

Material examined. Holotype: male, Georgia, Adjara, Kobulety District, Kintrishi State Nature Reserve, flank of Narusala and Khino Mts. , Bzhudzha River , source, near snowfields, 41°46’00”N 42°06’59”E, altitude about 2260 m a.s.l., 10.vi.2013, leg. A.V. Martynov ( NMNH NASU, IN Grg12Pleco/6) . Paratypes: 2 males, same place and data as holotype ( SNM and NMNH NASU, IN Grg12Pleco/1) ; 1 female, Georgia, Adjara, Kobulety district, Kintrishi State Nature Reserve, between Narusala and Sarbiela Mts., limnocrene and left spring in the Cherulisghele River Basin , 41°45’40”N 42°06’29”E, altitude 2305 m a.s.l., 10.vi.2013, leg. A.V. Martynov ( NMNH NASU, IN Grg10Pleco/1) .

Diagnosis. Micropterous in both sexes. The male of L. khachapuri is distinguished from other congeners by the pair of posteromedial well sclerotized horn-shaped processes between which there is an additional pair of small rounded processes on tergum VIII in combination of tergum IX with antecosta divided medially for of segment’s width. The male is also distinguished by a large rounded epiproct. The paraprocts are well developed ⅕, each has a small medial conical protuberance. The specilla is long, narrowed and pointed at the apex, styles 1.4X shorter than specilla. Cercus cylindrical narrowed and blunted to the tip. The female subgenital plate is large, trapezoidal, threelobed, laterally sclerites thin and prolonged; bearings a pale patch, resembling a cross.

Affinities. Based on the shape of the processes and the placement of the male tergal projections, structure of the male epiproct and paraprocts, the new species is included in the hippopus species-group ( Ravizza & Vinçon 1998, Ravizza 2002). Morphologically, as well as geographically, the most similar species to L. khachapuri is L. abkhaziae . The male of L. abkhaziae has similar horn-shaped and widely spaced processes on tergum VIII, but processes are more elongated laterally, an additional pair of small rounded processes are absent. The tergal processes of L. khachapuri are thinner. The length of specilla is shorter, about half of that of L. khachapuri . The females of both species can be easily separated. The female of L. khachapuri has a large, trapezoidal subgenital plate, whereas the subgenital plate of L. abkhaziae is triangular; the convergent sides of the plate bear a pair of elongate-oval sclerites together forming a V-shape (Teslenko & Palatov 2019).

Three Balkanian species ( L. istenicae Sivec, 1982 ; L. ligurica Aubert, 1962 ; and L. olympia Aubert, 1956 ) are also morphologically similar to L. khachapuri . Males of these Balkanian species have a similar paired horn-shaped and widely spaced processes on tergum VIII. The horn-shape processes of L. istenicae are longer than L. khachapuri extending to the middle of tergum IX ( Sivec 1982). The male of L. ligurica has narrow horn-shaped processes, closely spaced extending slightly beyond tergum IX ( Aubert 1962). The processes on tergum VIII of L. olympia are short, curved laterally, directed perpendicular to the body axis, and rounded bulbous protrusion is present between the tergal processes ( Aubert 1956). In contrast, L. istenicae , L. ligurica , and L. olympia lack an additional pair of small rounded protuberances between the processes, present in L. khachapuri ( Figs. 6–8 ).

Distribution and ecology. All apterous and micropterous species of hippopus species-group are associated with crenal zones of streams. Leuctra khachapuri also occurs in similar habitats. All specimens of the new species were collected from the Adjaro-Imeretian (Meskhetian) Mountain Range (Adjara, Georgia) of Lesser Caucasus, a territory of Kintrishi State Nature Reserve, in streams at an altitude of 2260–2305 m a.s.l. between the Khino, Na- rusala and Sarbiela mountains. The type locality is the source of Bzhudzha River, the crenal zone of the stream near snowfields ( Fig. 16 ). The stream has a width of 0.3–1.5 m, with a substrate of stones and sand, and a current velocity of 0.1–0.7 m /s. Adults of L. khachapuri were collected from a limnocrene that flows out to form a tributary of the Cherulisghele River Basin. The area of the limnocrene is about 0.5 m 2, depth 01– 0.15 m forming the left tributary of the Cherulisghele River with current velocity 0.1–0.5 m /s, width 0.2–0.6 m, substrate of stones, sand, and soil ( Fig. 17 ). Additional photographs of the two streams are also available in Godunko et al. (2015, figs. 44–46, 48) and Martynov et al. (2016, figs. 5, 6). Adults of the new species were collected on banks near the streams.

It should be noted that aquatic insects of the alpine zone of Adjaro-Imeretian Mountain Range are poorly studied. Other stoneflies collected with L. khachapuri were Protonemura eumontana Zhiltzova, 1957 , Nemoura sp., Isoperla sp.; and also three mayfly species, which were recently described, Nigrobaetis (Takobia) katerynae Martynov & Godunko, 2017 , Baetis (Rhodobaetis) vadimi Godunko et al., 2015 and Electrogena sp. (description in prep.) ( Godunko et al. 2015, Martynov et al. 2016, Martynov & Godunko 2017). Additionally, in these streams and nearby waterbodies, unassociated larvae of Leuctra sp. were collected.

Figures

FIGURES 1–5. Leuctra khachapuri Žiak et Martynov, sp. nov., male: 1.—total view; 2.—head and thorax, dorsal view; 3.— same, ventral view; 4.—terminalia, dorsal view: 5.—same, lateral view.

FIGURES 6–10. Leuctra khachapuri Žiak et Martynov, sp. nov., male: 6.—abdominal tip, dorsal view; 7.—processes of ter- gum VIII, dorsal view; 8.—abdominal tip, dorsal view; 9.—same, ventral view; 10.—epiproct, cerci and styles, dorsal view.

FIGURES 11–15. Leuctra khachapuri Žiak et Martynov, sp. nov., female: 11.—total view; 12.—head and thorax, dorsal view; 13.—abdomen, ventral view; 14.—apical part of abdomen, ventral view; 15.—same, lateral view.

FIGURES 16–17. Collecting sites of Leuctra khachapuri Žiak et Martynov, sp. nov.: 16.—type locality, stream near snowfields, source of Bzhudzha River, crenal zone; 17.—spring, left tributary of Cherulisghele River. Photos by A.V. Martynov (June 2013).