Diamesa achipseensis Makarchenko, Semenchenko et Palatov, 2024

Makarchenko, Eugenyi A., Semenchenko, Alexander A. & Palatov, Dmitry M., 2024, Morphological description and DNA barcoding of Diamesa achipseensis sp. nov. (Diptera: Chironomidae: Diamesinae) from Southwestern Caucasus, Zootaxa 5481 (4), pp. 477-482 : 478-480

Diamesa achipseensis Makarchenko, Semenchenko et Palatov , sp. nov.

http://zoobank.org/NomenclaturalActs/ 6EE16603-172D-4F5A-BABD-49380AC31B55

( Figs. 1–11 )

Type material. Holotype, adult male, RUSSIA: Caucasus, Krasnodar Region, Adler District, Sochi urban district, Sochi National Park , Achipse River , 3 km North of the Estosadok Village , altitude 600 m above sea level, 12.IV.2024, 43°42'25.9"N 40°15'46.18"E, leg. D. Palatov.

Derivatio nominis. The species is named as achipseensis after the type locality in the Achipse River of the Southwestern Caucasus.

Description

Adult male (n = 1). Total length 3.2 mm. Total length/wing length 0.83.

Coloration. Dark brown. Head, thorax and abdomen with hypopygium dark brown, antenna grey. Legs brown. Wings greyish.

Head. Eyes reniform, bare. Temporal setae including 6–7 preoculars, 6 inner verticals, 8 outer verticals and 8–10 postorbitals. Clypeus with 10 setae. Antenna with 13 flagellomeres and slightly reduced plume of setae; maximal length of these setae on flagellomeres 770 μm; terminal flagellomere with 1 subapical seta, 40 μm long; pedicel with 3 setae, 60–70 μm long; AR 0.70–0.74. Palpomere length (μm): 48, 100, 160, 176, 252. Palpomere 3 in distal part with sensilla capitata with diameter 12 μm. Head width/palpal length 1.02.

Thorax. Antepronotum with 6–7 ventrolateral setae. Dorsocentrals 14–15, 116–148 μm long; prealars 11–12, 120–152 μm long. Scutellum with 34 setae, 160–180 μm long.

Wing. Length 3.84 mm, width 1.12 mm. Costal extension 82 μm long. Anal lobe outline rounded. Squama with 34 setae. R and R 1 with 28 setae, R 4+5 with 3 setae in subapical part. RM/MCu 2.2.

Legs. Spur of front tibia 84 µm long. Spurs of mid tibia 60 µm and 64 µm long. Spurs of hind tibia 84 µm and 56 µm long. Hind tibial comb with 18 setae. Length (μm) and proportions of leg segments are as in Table 1 .

Hypopygium ( Figs. 1–10 ). Tergite IX narrow, with 16–18 setae from one side, 48–60 μm long and with anal point, 40 µm long, which bends under tergite IX, dark brown in basal 2/3 and light grey in distal 1/3, with rounded apex ( Figs. 1–3 ). Laterosternite IX with 8–11 setae. Transverse sternopodeme (TSA) wide rectangular with rounded outer angles ( Fig. 8 ), 56 µm high, 156 µm wide; TSA height/TSA width 0.36. Aedeagal lobe knife-shaped, 180 μm long and 48 μm wide, weakly chitinized; phallapodeme sclerotized, 120–128 μm long. Gonocoxite 476 µm long, without inferior volsellae, basally with superior volsellae consisted of ventral and dorsal parts ( Figs. 6, 9–10 ); ventral part located on stalk 130–132 µm long and in subapical part with 18–20 needle-shaped setae, 40–44 μm long; dorsal part rounded, with some long setae ( Figs. 9–10 ). Gonostylus 410 µm long, narrow crescent-shaped, slightly expanded basally, its surface with short setae, ca 8 μm long, along the inner edge with thin setae, 40–48 μm long; apex with short macroseta, 12 µm long ( Figs. 1, 4, 7 ). HR 1.16.

Pupa and larva unknown.

Diagnosis. Total length 3.2 mm. Eyes bare. Antenna with 13 flagellomeres and slightly reduced plume of setae; AR 0.70–0.74. LR 1 0.67, BV 1 3.66, SV 1 2.70. Tergite IX narrow, with short anal point, which bends under tergite IX, dark brown in basal 2/3 and light grey in distal 1/3, with rounded apex. Transverse sternopodeme wide rectangular with rounded outer angles. Gonocoxite without inferior volaellae, basally with superior volsellae consisted of ventral and dorsal parts; ventral part located on long stalk and in subapical part with 18–20 needle-shaped setae; dorsal part rounded, with some long setae. Gonostylus narrow crescent-shaped, slightly expanded basally, its surface with short setae, along inner edge with thin setae; apex with short macroseta. HR 1.16.

The new species belongs to the latitarsis group and most closely related to D. caucasica Kownacki et Kownacka , from which it is well distinguished by structures of gonostylus and superior volsellae as well as some other characters given in Table 2 .

Ecology and distribution. Adult male was collected near mountain large Achipse River ( Fig. 11 ) in a wide beech-fir valley. The bottom of this river is large stones and boulders, flow rate of 0.7–1 m /s, located at an altitude of 600 m a.s.l. Known only from the type locality in Achipse River of the Southernwest Caucasus.

Figures

FIGURE 11. Locality and habitat of Diamesa achipseensis sp. nov. on Achipse River of the Southwestern Caucasus (Photo by D.M. Palatov).

FIGURES 1–10. Adult male of Diamesa achipseensis sp. nov. 1–2, part of hypopygium in dorsal view with invisible bent gonostylus; 3, part of tergite IX in ventral view with anal point; 4, dorsally curved gonostylus; 5, part of hypopygium from ventral side; 6, endoskeleton; 7, gonostylus; 8, transverse sternapodeme; 9–10, superior volsellae. Scale bar: 50 μm.