Pagastia (Pagastia) kadi Makarchenko, 2024

Makarchenko, E. A., 2024, DESCRIPTION OF PAGASTIA (PAGASTIA) KADI SP. N. (DIPTERA: CHIRONOMIDAE: DIAMESINAE) FROM THE AMUR RIVER BASIN, Far Eastern Entomologist 506, pp. 1-6 : 2-6

Pagastia (Pagastia) kadi Makarchenko , sp. n.

https://zoobank.org/NomenclaturalActs/ 90D86438-E4F8-44C0-BF8E-F4D213EA822A

Figs 1–9

TYPE MATERIAL. Holotype: 1 pharate adult ♂ extracted from mature pupa, Russia: Khabarovsk Territory, Ulchsky District, Kadi River of the Amur River basin, 51.758528°N, 140.985861°E, 13.VIII 2004, leg. N. Yavorskaya. Paratypes: 3 mature pupae, the same data as holotype .

DESCRIPTION. Pharate adult male (n=1). Total coloration brown to darkbrown; head, thorax, legs, and abdomen brown to dark brown; antennae light brown.

Head. Eyes bare and extended dorsomedially. Temporal setae 15. Clypeus with 13 setae. Antenna with 13 flagellomeres and well developed plume; pedicel with 4 setae 48–50 μm long; terminal flagellomere with 1 subapical setae 40 μm long. AR 1.43–1.45. Palpomere lengths (in μm): 40; 76; 150; 140; 160.

Thorax. Antepronotum with 4–5 median and 4 lateral setae. Acrostichals 16 (in 1 row), dorsocentrals 11–12 (in 1–2 rows), prealars 8, scutellars 43 (in 2–3 rows).

Wings and legs absent.

Hypopygium ( Figs 1–3 ). Tergite IX with 12–15 setae on each side and with anal point 80 μm long, parallel-sided, with rounded apex and pore in apical part ( Fig. 3 ). Laterosternite IX with 7–14 setae. Transverse sternapodeme narrow, arcuate, 232 μm long. Phallapodeme 48 μm long. Median aedeagal lobe absent; lateral aedeagal lobe 80–88 μm long. Gonocoxite 232 μm long, with basal plate and lobe-like median field. Gonostylus 160 μm long, apical part angular-rounded, with megaseta 10 μm long. HR 1.45.

Pupa (n=3). Total length 4.9–5.0 mm (♂) and 5.8 mm (♀). Exuviae light brown.

Cephalothorax. Frontal apotome with 2 setae, 192–220 µm long. Thorax slightly granulated, with 2 dorsocentral setae, 40–48 µm long. Antepronotum with 2 median setae, 108–160 µm long and 1 lateral seta, 140 µm long. Precorneal setae lengths (μm): Pc 1 96, Pc 2 140, Pc 3 140. Bases of three precorneals in form of triangle.

Abdomen. Tergite I without shagreen. Tergite II with easily visible fine shagreen in anterior part and more extensive shagreen of larger spinules along posterior edge; middle part of tergite with very small and sparcely located spinules. Tergites III– VIII fully covered with shagreen of spinules which become larger near the posterior edge ( Figs 4, 6, 9 ). Spinules of the shagreen of tergites III–VII along posterior edge are directed anteriorly ( Fig. 5 ). Tergite IX with fine shagreen only anteriorly. Sternites without shagreen. Segment I with 3 pairs of lateral setae: L 1 simple, 40 μm long; L 3 divided into 2–3 branches, 80 μm long and L 4 divided into 3 branches, 112 μm long. Segments II–VI with 4 pairs of lateral setae: L 1 simple, 40–48 μm long; L 2 divided into 2–3 branches, 56–60 μm long; L 3 simple, 32–44 μm long; L 4 divided into 3–5 branches, 88–109 μm long. Segment VII with 4 pairs of lateral setae, located in posterior half and divided into 5–7 branches, 60–64 μm long. Segment VIII with 4 pairs of lateral setae, located in posterior 1/3 and divided into 3–5 branches, 72–84 μm long. Anal lobe 394 µm long (♂) and 328 µm long (♀), with triangular apical tubercle in apical part, and with 3 anal macrosetae 144–160 µm long and without median setae ( Figs. 6, 9 ). Male genital sac not or only slightly extending beyond anal lobe ( Fig. 9 ).

DIAGNOSIS. Antenna with 13 flagellomeres and well developed plume, AR 1.43– 1.45. Antepronotum with 4–5 median and 4 lateral setae. Acrostichals 16 (in 1 row), dorsocentrals 11–12 (in 1–2 rows), prealars 8, scutellars 43 (in 2–3 rows). Tergite IX with 12–15 setae on each side and with parallel-sided and rounded apex anal point, 80 μm long, with pore in apical part. Transverse sternapodeme narrow, arcuate, 232 μm long. Lateral aedeagal lobe 80–88 μm long. Gonocoxite with basal plate and lobe-like median field. Apical part of gonostylus angular-rounded, HR 1.45. Thorax of pupa slightly granulated, with 2 dorsocentral setae. Tergite I without shagreen. Tergite II with easily visible fine shagreen in anterior part and more extensive shagreen of larger spinules along posterior edge. Tergites III–VIII fully covered with shagreen of spinules which become larger near the posterior edge and directed anteriorly. Segment I with 3 pairs of lateral setae, segments II–VIII with 4 pairs of lateral setae, from which L 1 and L 3 of segments II–VI mostly simple while other lateral setae are divided into several branches. Lateral setae of segment VII are located in posterior half, lateral setae of segment VIII are located in posterior 1/3. Anal lobe with triangular apical tubercle in apical part, and with 3 anal macrosetae, without median setae.

The new species is closely related to Pagastia (P.) orthogonia Oliver , but differs well from it in the shape of the gonostylus, size of basal lobe of male gonocoxite, and absence of median setae of anal lobe in pupa. The absence of median setae of anal lobe was recorded for pupae of the genus Pagastia Oliver for the first time and this character must be included in the diagnosis of genus.

ECOLOGY. Pupae were collected from large, small and medium pebbles, mixed with detritus, at a flow rate of 0.8–1 m /s, with water temperatures 5.9°C, at a depth of 0.5–1.2 m.

DISTRIBUTION. Known only from the type locality in Kadi River ( Fig. 10 ).

ETYMOLOGY. The species is named as kadi after the type locality in Kadi River. The name is a noun in apposition.

Figures

Figs 1–9. Adult male (1–3) and pupa (4–9) of Pagastia (P.) kadi sp. n. 1 – hypopygium with tergite IX in dorsal view; 2 – hypopygium without tergite IX in dorsal view; 3 – anal point; 4 – tergite IV; 5 – spinules of posterior edge shagreen of tergite IV; 6 – tergites VII– VIII and anal lobe (♀); 7 – L4 of segment III; 8 – L3-4 of segment VIII; 9 – tergites VII–VIII and anal lobe (♂).

Fig. 10. Locality of Pagastia (P.) kadi sp. n. Russia: Khabarovsk Territory, Ulchsky District, Kadi River (Amur River basin).