Hydrobaenus simferopolus, Moubayed-Breil & Baranov, 2018

Moubayed-Breil, Joel & Baranov, Viktor, 2018, Taxonomic notes on the genus Hydrobaenus with description of H. simferopolus sp. nov. from Crimea (Diptera: Chironomidae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 58 (2), pp. 347-355 : 352-354

Hydrobaenus simferopolus sp. nov.

( Figs 29 , 35–37, 39–47 )

Type material. HOLOTYPE: ♁ ( SIZK), ʻ UKRAINE: CRIMEA: leg. V. Baranov; Simferopol, Salgir River , 29.XI.2010, handnetʼ . PARATYPE: ♁ ( JBMF) (mounted on the same slide), same locality as for holotype.

Diagnosis. Based on some typical and specific characters found in the hypopygium of H. simferopolus sp. nov., in particular the singular shape of its phallapodeme, this new species apparently belongs to a separate group. This new species can be easily distinguished from all members of the genus by having: acrostichals not reduced, consisting of 5–6 long markedly curved setae; tergite IX without setae, dorsal margin sinuous; laterosternite IX with 7 setae on each side; anal point large, drop-shaped, proximal half with 12 setae, distal half bare and ending with a thumb-like apex; virga composed of 3 strong equal teeth; phallapodeme characteristic, terminating in 2 unusual and characteristic spirals; inferior volsella consisting of a large plain lobe ending with a hyaline and bare nose-like apex which is projecting downwards; gonocoxite with a swollen ventral lobe placed distally; gonostylus linearly elongated and slender, posterior part hyaline and bare; crista dorsalis large tooth-like, smooth apically and nearly hyaline, orally projecting and placed pre-apically close to the megaseta. Description. Male adult (n = 2; Figs 28 , 35–37, 39–47 ). Medium sized Hydrobaenus species. Total length 3.50– 3.60 mm; wing length 2.45–2.50 mm. General colouration contrasting brown to dark brown. Thorax dark brown with blackish mesonotal stripes. Legs dark brown. Tergites I– VIII and anal segment dark brown; crista dorsalis distinctly hyaline to yellowish.

Head. Eyes bare. Temporals consisting of 10–11 setae including 6–7 inner and 4 outer verticals. Palp 5-segmented, not reduced; length (in μm) of segments: 35, 45, 63, 136, 225; palpomere 3 ( Fig. 35 ) with 3 sensilla clavata, palpomere 4 ( Fig. 36 ) with 2 circular area of microtrichia placed proximally and distally. Clypeus with 6 setae in 2 rows.

Thorax. Antepronotum with gaping lobes ( Fig. 28 ), lateral antepronotals 3–4; acrostichals ( Fig. 37 ) not reduced, composed of 6–7 distinctly pin-like setae starting some distance from antepronotum; dorsocentrals 10 in 1 row; prealars 5–7 in 1 row. Scutellum with 10 uniserial setae. Wing. Brachiolum with 1 seta. Distribution of setae on veins: R 4–5 placed on proximal part; remaining veins bare. Squama with 12–13 setae in 1–2 rows. Legs. Tarsomeres ta 2 –ta 5 of PI are missing; sensilla chaetica present on tibia of PI and tarsomeres ta 1 –ta 5 of PII–PIII. Length (μm) and proportions of legs as in Table 3.

Hypopygium in dorsal, ventral and lateral view as in Figs 39, 40 , and 47. Tergite IX broadly semi-circular, narrowing distally, dorsal margin sinuous (clearly visible in lateral view, Fig. 41 ); posterior area ( Fig. 39 ) with 12–14 dorsal setae placed near the base of anal point (6–7 setae on each side). Laterosternite IX with 7 setae on each side. Anal point ( Figs 39, 41–42 ) 75–85 μm long, 60 μm maximum width in median part; broad drop-shaped ending with thumb-like apex; distal part hyaline and lacking microtrichia. Virga ( Figs 39, 44 ) 45–50 μm long, consisting of 3–4 equal pointed teeth, entirely fused except for distal part. Phallapodeme unusually shaped, characteristic, terminating in 2 characteristic spirals ( Fig. 40 ). Gonocoxite 285–300 μm long, with rounded apex; ventral margin with large swollen lobe. Inferior volsella (dorsal, Figs 39, 43 ; lateral, Fig. 47 ) 100–105 μm long, consisting of 2 unequal elongated lobes, proximal one nearly plain larger and covered with setae, distal lobe nose-like, hyaline and bare. Gonostylus ( Figs 45–46 ) 120–125 μm long, maximum width 50–55 μm, linearly elongated and slender, bearing distinct hyaline and bare posterior area; crista dorsalis strong tooth-like, hyaline with smooth and rounded apex, orally projecting and placed pre-apically close to megaseta. Taxonomic position. Male adult of H. simferopolus sp. nov. can be keyed near that of H. dentistylus based on the following resembling characters: lobes of antepronotum not in contact ( Fig. 28 ); acrostichals not reduced; virga composed of 3 strong pointed teeth; inferior volsella bilobed; crista dorsalis large tooth-like, orally projecting and placed pre-apically. However, the newly described species can be easily distinguished by the following combination of characters: acrostichals consisting of 6–7 long pin-like setae; tergite IX without setae while densely covered with setae in H. dentistylus ( Fig.2 ; MOUBAYED 1985: Fig. 1b ); anal point large, drop-shaped, with a thumb-like apex ( Figs 39, 42 ), while densely covered with setae in H. dentistylus ( Figs 2, 4 ; Fig. 1b, MOUBAYED 1985) and differently figured in lateral view ( Fig. 41 for H. simferopolus sp. nov., Fig. 3 for H. dentistylus ); phallapodeme ( Fig. 40 ) unusually shaped and terminating in 2 characteristic spirals; basal lobe of inferior volsella ( Figs 39, 47 ) ending with a noselike lobe which is hyaline, bare and projecting downwards; gonostylus ( Figs 45–46 ) linearly elongated and slender, while bulb-like and spherical in H. dentistylus ( Figs 8–9 ; MOUBAYED 1985: Figs 1b, 2 ); crista dorsalis large toothlike, hyaline and smooth ( Figs 45–46 ) while triangular with pointed apex and consistently chitinous in H. dentistylus .

Etymology. The new species is named ‘ simferopolus ’ after the Ukrainian city of Simferopol where the type material was collected; adjective.

Ecology. A typical rheophilic and oxybiontic species occurring in pristine section of streams and rivers. Species is active in winter, observed in a few swarms over water and on the grass at the near zero to sub-zero temperatures (from 5°C to -1°C). Specimens were active before the sunset in December and January.

Distribution. Only known from the type locality which is situated in the Crimean Peninsula (Crimea, Ukraine), Salgir River, Gagarin City Park, Simferopol City.

Figures

Figs 21–34. Male adult of Hydrobaenus spp. 21 – H. lugubris: last flagellomere and two preceding segments; 22 – palp, reduced. 23–26 – last flagellomere and preceding segment: 23–24 – H. dentistylus; 25–26 – H. korneyevi. 27–29 – antepronotum: 27 – H. lugubris; 28 – H. simferopolus sp. nov.; 29 – H. korneyevi. 30 – H. lugubris, tergite IX and anal point, lateral view; 31–32 – hypopygium with gonostylus removed (31 – dorsal view; 32 – lateral view); 33 – virga; 34 – gonostylus, lateral.

Figs 35–47. Male adult of Hydrobaenus spp. 35–36 – H. simferopolus sp. nov.: 35 – palpomere 3; 36 – palpomere 4. 37–38 – distribution pattern of acrostichals: 37 – H. simferopolus sp. nov.; 38 – H. lugubris. 39–40 – H. simferopolus sp. nov., hypoygium, gonostylus removed (39 – dorsal view; 40 – ventral view, tergite IX and anal point removed). 41–42 – tergite IX and anal point (41 – lateral; 42 – dorsal). 43 – inferior volsella, dorsal; 44 – virga, two aspects; 45–46 – gonostylus (45 – dorsal view; 46 – ventrolateral view). 47 – gonocoxite and inferior volsella, lateral.

Figs 1–9. Male adult of Hydrobaenus dentisylus Moubayed, 1985. 1 – palpomere 3; 2 – hypopygium, dorsal view with gonostylus removed; 3 – tergite IX and anal point in lateral view; 4 – anal point, dorsal; 5 – virga, two aspects; 6–7 – inferior volsella (6 – lateral view; 7 – dorsal view); 8–9 – gonostylus (8 – dorsal view; 9 – lateral view).