Lithostege viidaleppi, Rajaei & Kostjuk, 2024

Lithostege viidaleppi sp. n. ( Figs 9–10 & 16, 19, 21)

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Type material. Holotype ♂, Tajikistan, 6 km from Nikolajevsky pass [ Nikolaev mountain pass], eastern slopes of Khozratisho Range [Khazratishoh, Khazrati-Shokh], above Chertovyj bridge, h = 2200 [m], 31.v.[19]58. meadows slope, Yu. Stshetkin, gen. prep. 1022/2010; in ZFMK ; Paratypes (in total 4 ♂, 9 ♀): 2 ♂, 2 ♀, same as holotype; gen. preps ♂ 1611/2011, 1612/2011 and ♀ 1023/2010, 1613/2011 H. R.; all in ZFMK . 1 ♂, 2 ♀, SW Tajikistan, 60, 5 km NW Shuroabad village on the road to the Pass , on wheat crops (nearby Artemisia ), in the grass, 2050 m, 30.v.58, [leg.] Yu.L. Stshetkin; deposited in ZSM . 1 ♀, Tajikistan, 6 km from Nikolajevsky pass [Nikolaev mountain pass], eastern slopes of Khozratisho Range [Khazratishoh, Khazrati-Shokh], above Chertovyj bridge, h = 2200 [m], 31.v.[19]58. meadows slope, Yu. Stshetkin ]; 2 ♀, Tajikistan, Chasratishhoch- Geb. , Shuroabad, 2000 m, 3.vi.58, Stshetkin ; 1 ♀, Taj. [ Tajikistan] SSR, in about 800 m from Shuroabad vicinity, near Khozratisho Range, 2000 m, 31.v.58, [handwriting of Yu. L. Stshetkin], g. prep. 2763/2024 H. Rajaei; all in ZSM ; 1 ♂, Tadzh. [ Tajikistan], 04.vii.1989, Peter I Mts., K [ishlak] Odilovot, 2000 m, U. Jürivete leg. ; 1 ♀, [ Tajikistan], Peter I [Mts.], Surhob [river], Odilovot, 2500 m, 04.vii.07.1989, U. Jürivete leg.; all in IZBE .

Additional material (tentatively identified as L. viidaleppi sp. n., but needs confirmation). 1 ♀, Afghanistan, Prov. Panjshir, Astanah N. Shava vic., 2600–2700 mNN, lux 28.vii.–9.viii.2007, leg. Einheimische Sammler via Shafiq Assad, SMNK, E-Lep. 250; gen. prep. 990/ 2023 I. Kostjuk .

Etymology. This new species is named after Dr. Jaan Viidalepp, senior taxonomist and scientific member of the Estonian Institute of Zoology and Botany, as well as the Estonian University of Life Sciences. He is a senior author of numerous monographs published on the family Geometridae , including “Check List of the Geometridae of the former U.S. S.R.” and the third volume of “Geometrid Moths of Europe”.

Diagnosis. Lithostege viidaleppi sp. n. belongs to the amoenata species-group (for the characteristics of this species-group, see the description under L. amoenata ). Externally, this species ( Figs 9–10) can be confused with L. amoenata and L. hausmanni sp. n. ( Figs 5–7), but L. viidaleppi sp. n. is restricted southern Tajikistan and northeastern Afghanistan ( L. amoenata is confined to southwestern Turkmenistan and northern and northeastern Iran; L. hausmanni sp. n. is known only in central and southeastern Afghanistan and northern Iran). Additionally, the male and female genitalia of this species are characteristic. In male genitalia, L. viidaleppi sp. n. features an apical process on the valva that is approximately twice as long as the stout costal process; the juxta is elongated, narrower at the base than the apex; aedeagus is long, subapically curved ( L. amoenata has both apical and costal process of roughly the same size; the juxta is elongated, and narrower at the apex than the base; the aedeagus is short and not curved; L. hausmanni sp. n. has a very long apical process, a costal process reduced to a series of small teeth; the juxta is elongated and narrower at the base than the apex; the aedeagus is short, subapically curved). Female genitalia of L. viidaleppi sp. n. presents a bowl-shaped antrum with its ventral margin featuring a U-shaped incision; the ductus bursae is tubular and short; the corpus bursae is spherical, only one-third of its dorsal part covered with loose spicules (conversely, L. amoenata has a very short antrum with a lip-shaped incision on its ventral margin; a tubular and thick ductus bursae; a spherical corpus bursae that is fully covered with dense spicules; L. hausmanni sp. n. has a short and triangular antrum with a short V-shaped incision on its ventral margin; the ductus bursae is curved and narrow; the corpus bursae is spherical, and half of it is covered with small spicules).

Description. Wingspan 26–29 mm (measured based on the whole type series). Wing ground colour creamy to light brown. Forewing with light to dark brown transverse lines; basal and antemedial lines projected towards termen on common stalk of Rs and M, angled at 80° and then connected to forewing costa; postmedial line brown, externally highlighted with one thick and one or two very thin creamy lines, strongly curved towards termen on M1 and M3 and towards basis on M2; subterminal line lightcreamy, continuous and evenly curved on upper side, zigzagged on underside. There are several additional transverse lines, including a weaker basal line, a broad grey and a narrow wavy line at median area, showing intraspecific variation. Fringes chequered creamy and brown. Hindwing elongate-oval, light-brown to grey-ochrous. Underside light creamy to light brown with reminiscent of pattern similar to upper side; only the subterminal line zigzagged on underside as opposed to evenly curved on upperside.

Male genitalia ( Fig. 16). valva broad at base, tapering towards apex; apex projected and pointed; a tooth-like process present on subapical part of costa; apical process roughly twice longer than costal process; saccular part of valva medially curved. Uncus basally triangular, distally tapered, apically finger-shaped; lateral arms of gnathos present, but medially not connected; socii at the base of uncus as a tiny setose projection.

Saccus very short, broad, rounded. Juxta elongate, its apical part bowl-shaped and wider than basal part. Aedeagus long, subapically curved; large vesica apically covered with very short teeth. Juxta elongate, its apical part bowl shape and wider than basal part. Aedeagus long, subapically curved; vesica largely inflated with very short and broad sack-like diverticulum submedially and extensive field of sparse short teeth distally surrounding narrow tubular vesica ejaculatorius.

Female genitalia ( Fig. 19). ovipositor as thick as ductus bursae; posterior apophysis two times longer than anterior apophysis; antrum bowl-shaped, its ventral margin with U-shaped incision; ductus bursae short, tubular; corpus bursae spherical, only one third of its dorsal part covered with loose spicules.

Bionomics. The specimens of this new species were collected between the end of May to early July, at an altitude of 2000–2700 m.

Distribution. Lithostege viidaleppi sp. n. is restricted to southern Tajikistan and possibly northeastern Afghanistan (the latter locality needs further confirmation) ( Fig. 21).