Hydrobaenus dentistylus Moubayed, 1985

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 : 348-349

Hydrobaenus dentistylus Moubayed, 1985

( Figs 1–9 , 23–24 )

Type material examined. PARATYPES: LEBANON: Litany River, Bekaa plain, 800–850 m a.s.l., 29.iii.1982, 5 ♁♁, J. Moubayed-Breil lgt. (2 ♁♁ IBNC, 2 ♁♁ JBMF, 1 ♁ ZSMC).

Diagnostic characters. The differentiating characters provided in the original paper ( MOUBAYED 1985) can be summarized and supplemented by the following main distinguishing characters found in the male adult: antenna, palp and legs not reduced; lobes of antepronotum gaping; acrostichals 4–5 in total, reduced, starting some distance from antepronotum; anal point drop-like, tergite IX and anal point densely covered with about 60–70 setae reaching apex of anal point; virga consisting of 3 curved unequal teeth (median one shorter); inferior volsella consisting of 2 unequal large lobes with proximal lobe broader; gonostylus bulb-like, globular and bearing a distinct pre-apical pointed tooth placed close to the megaseta.

Redescription. Male adult (n = 5; Figs 1–9 , 23–24 ). Small to medium sized Hydrobaenus species. Total length 2.85–3.00 mm. Wing length 2.20–2.40 mm. General colouration contrasting brown to blackish. Head dark brown, antennae pale; thorax contrasting brown to blackish, mesonotal stripes distinctly blackish; wing pale; legs dark brown to blackish. Tergites I–VIII brown; anal segment brown to dark brown, crista dorsalis dark brown.

Head. Eyes bare. Temporals consist of 9–11 setae including 5–6 inner and 4–5 outer verticals.Antenna and palp are not reduced. Antenna 810–830 μm long, 13-segmented, length (μm) of segments: 1, 50; 2–12, 30–35 (nearly sub-equal), last flagellomere 420–430; distal part of last flagellomere ( Figs 35–36 ) moderately clubbed ending with forked rounded apex; antennal groove beginning on segment 1 and reaching ultimate flagellomere; AR 1.10. Clypeus with 8 setae. Palp 5-segmented, palpomere 3 ( Fig. 1 ) with 3–4 sensilla clavata.

Thorax. Acrostichals reduced, consisting of 4–5 uniserial setae beginning some distance from antepronotum; antepronotum with 6–7 lateral antepronotals, lobes well gaping as in H. simferopolus sp. nov. ( Fig. 28 ); prealars 4–5 in 1 row. Scutellum with 8 uniserial setae. Wing. Brachiolum with 1 seta. Distribution of setae on veins: R, 8–12; R 1, 25–7; remaining veins bare. Squama with 9 uniserial setae. Legs. Sensilla chaetica present on tibia and tarsomeres ta

1

–ta

5 of PI, PII and PIII.

Hypopygium in dorsal view with gonostylus removed ( Fig. 2 ). Tergite IX ( Figs 2–3 ) broadly rectangular, narrowing distally, slightly sinuous in lateral view ( Fig. 3 ), 60–70 setae present on both tergite IX and anal point. Anal point (dorsal, Figs 2, 4 ; lateral, Fig. 3 ) about 40–45 μm long, 30 μm maximum width at base, drop-like and densely covered with setae. Virga ( Figs 2, 5 ) consisting of 3 long spines about 45 μm long, fused at base, median one shorter. Gonocoxite 250–260 μm long, maximum width 120–125 μm, with rounded apex; inferior volsella (dorsal, Figs 2, 7 ; lateral, Fig. 6 ) 95–105 μm long, 30–35 μm maximum width, consisting of 2 large lobes; proximal lobe distinctly larger. Gonostylus ( Figs 8–9 ) 115 μm long, maximum width 65–70 μm, massively spherical to bulb-shaped medially and distally; hyaline area present on posterolateral side; anterior margin swollen and bearing 5–6 setae placed on proximal part; crista dorsalis consisting of 1 triangular characteristic and strong pre-apical teeth, orally directed and placed close to megaseta, clearly visible in both dorsal and lateral view ( Figs 8–9 ); megaseta dark brown, conspicuous and slightly bent inwards.

Ecology. Large material composed of adults and pupae of H. dentistylus is recorded from shallow flowing water with rich aquatic vegetation. Emergence reported in early springtime: from March to April. Chironomid species encountered in the type locality of H. dentistylus include: Potthastia gaedii (Meigen, 1838) , P. longimanus Kieffer, 1922 , Sympotthastia zavreli Pagast, 1947 , Smittia durandae Moubayed, 1989 , Polypedilum anjarum Moubayed, 1989 , P. aegyptium Kieffer, 1925 , P. longisetum Moubayed, 1992 , P. yammounei Moubayed, 1992 , Micropsectra lindrothi Goetghebuer, 1931 , M. sofiae Stur & Ekrem, 2006 , Rheotanytarsus curtistylus (Goetghebuer, 1921) , R. rhenanus Klink, 1983 and R. ringei Lehman, 1970 .

Distribution. Hydrobaenus dentistylus is considered a typical biogeographic representative of the Levantine Province. This species is only known from its type locality: middle basin of the Litany River, Bekaa plain, Lebanon, alt. 800– 850 m.

Figures

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).

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.