Hydrobaenus olfa, Zerguine & Rossaro, 2010

Zerguine, Karima & Rossaro, Bruno, 2010, A new species of Hydrobaenus Fries, 1830 (Diptera, Chironomidae) from Algeria, Zootaxa 2507 (1), pp. 37-43 : 38-41

Hydrobaenus olfa n. sp.

Holotype: 1 pharate ♂, Algeria: Garaet Ank El Djmel, 35° 46.298' N, 6° 52.00' E, 15.I.2004 . Paratypes: 1 ♂, 4 pupal exuviae, 4 larvae, as for holotype. Type material deposited in University of Milano , DiPSA Dept., Italy .

Etymology: The species is named after Olfa, the name of the son of the first author.

Diagnostic characters: The species can be easily separated from all the other known species of Hydrobaenus for the high number of anal macrosetae (6–8) on anal lobes of pupa. The larval and adult male characters emphasize that the species is near to Hydrobaenus pilipes ( Malloch, 1915) . The male imago has a slender relatively well developed anal point, devoid of setae, gonostylus without an outer corner and a developed crista dorsalis, the larva has an AR about 2, a large bifid yellow median tooth and a narrow small dark first lateral tooth.

Male (n = 2). Medium sized species, wing length 3.22 mm.

Antenna. With 13 flagellomeres; groove beginning at flagellomere 4; sensilla chaetica on flagellomeres 2– 3 and terminal. Antennal ratio 2.33, ultimate flagellomere 828 µm long.

Head. Eye bare, with parallel-sided dorsomedian extension. Temporal setae clearly separated into two groups, with 5 inner verticals reduced in size, 3 larger outer verticals, 2 postorbitals. Cibarial pump with anterior margin concave, narrow anteriorly, broadened posteriorly. Palp normal with 5 segment; palpomeres lengths (µm): 39, 42, 140, 109, 165. Apex of 3rd palpomere with 3 sensilla clavata.

Thorax. Antepronotum moderately developed; lobes joined along a broad suture with anterior notch, in broad contact, 7 lateral antepronotals; 8 acrostichals reduced in size, placed in a row, beginning some distance from antepronotum; 11 dorsocentrals arising from a white spot; 10 strong prealars, arising from a white spot; 7 scutellars on two rows. Anterior and posterior anepisternum II and preepisternum without setae.

Wing badly preserved in type material. Membrane without setae, with distinct punctation. Anal lobe somewhat reduced. Costa moderately extended; R 2 +3 running and ending midway between R 1 and R 4 +5; R 4 +5 ending distally of M 3; An ending distally of FCu; Cu 1 slightly curved apically. R with setae, R 1 and R 4 +5 without setae. Squama fringed with more than 50 setae arranged in many rows .

Legs. Pseudospurs present on ta 1 of mid and hind legs. Sensilla chaetica on tarsomere 1 of hind leg absent. Setae on ta 1 of p 3 c. 140 µm long. Pulvilli absent. LR c. 0.57. Legs measurements in Table 1.

Abdomen. Tergites with irregularly scattered setae; T IX with about 20 setae.

Hypopygium ( Fig. 1 ). Anal point well developed 40 µm long, transparent, with parallel sides; apex without setae and microtrichia, with numerous setae at base. Phallapodeme and aedeagal lobe well developed. Anterior margin of transverse sternapodeme convex, oral projections pointed, never conspicuously thickened. Virga consisting of 2 well developed spines 30–40 µm long and 2 other slender and lighter spines. Gonocoxite with well developed inferior volsella well separable into a dorsal and a ventral lobe. Dorsal lobe squared, with short setae and microtrichia, ventral lobe developed beyond dorsal lobe. Superior volsella not developed. Gonostylus rounded apically, with a rounded outer corner, without an outer projection; crista dorsalis absent; megaseta 17 µm long.

Pupa (n = 5). Medium sized pupae, 6.06 mm long, abdomen 4.85 mm long.

Cephalothorax. Frontal apotome rugose; with well developed warts. Frontal setae present on frontal apotome. Antennal sheath above pedicel smooth. Ocular field with 1 postorbital and 1 vertical. Two antepronotals, c. 100 µm long. Thoracic horn c. 500 µm long ( Fig. 2 ), with pointed apex, sparsely covered with strong spinules. Three precorneals present, arranged in a triangle, 180, 100, 80 µm long; 4 dorsocentrals present, dc 2 closer to dc 1 than to dc 3; prealar minute. Thorax weakly rugulose. Wing sheath smooth.

Abdomen ( Fig. 2 ). Tergite I without anteromedian shagreen; T II with faint median shagreen; T III–VI with more extensive, stronger shagreen; T VII–IX with faint anteromedian shagreen. Sternites I and IX without anteromedian shagreen; faint anteromedian and posteromedian shagreen present on remaining sternites. Tergite II with posterior hooklets. Pedes spurii A present on sternites IV–VII; pedes spurii B on segment II, well developed. Apophyses dark and well delineated on both tergites and sternites. Segment I with 4–5 D setae, 2–3 L setae and 3 V setae. Segments II–VI each with 5 D setae, 4 L setae, no taeniate setae on segments IV–VI. Segment VII with 4 taeniate L setae; segment VIII with 5 taeniate L setae, 200–250 µm long.

Anal lobe ( Fig. 2 ). With 6–8 equally long anal macrosetae placed on well developed tubercles and with full fringe of about 40, 160 µm long, setae, fringe always reaching macrosetae. Apex of anal lobe rugulose, with lines. Male genital sac ending near apex of anal lobe. Genital sheath not ending in papilla but constricted at apex.

Larva (n = 4). Medium sized to large larvae, about 9 mm long.

Antenna ( Fig. 3 ). With 6 segments, segments consecutively smaller, segment 6 vestigial. Antennal segments lengths (in µm): 76.1, 16.7, 11, 6, 3, 1. Antennal ratio about 2. Ring organ near base of first segment. Blade slightly shorter than flagellum. Lauterborn organs distinct, about as long as third segment.

Labrum ( Fig. 3 ). S I coarsely plumose. Labral lamella simple, triangular, very weakly sclerotized. Pecten epipharyngis consisting of 3 simple, sclerotized smooth spines; 7–8 pairs of chaetulae laterales present, all smooth, 2 chaetulae basales present bifid at apex. Premandible with 2 apical teeth and small inner accessory tooth; brush absent.

Mandible ( Fig. 3 ). Apical tooth 18 µm long, shorter than combined width of 3 inner teeth (25 µm), with a darkened molar area resembling a 4th tooth. Seta subdentalis apically with a small indentation. Branches of seta interna smooth.

Mentum ( Fig. 3 ). With large, bifid median tooth and 6 pairs of lateral teeth. Median tooth 12 µm wide, pale; first lateral teeth 4 µm wide, darker and lower than median tooth; second lateral teeth 8 µm wide; other teeth consecutively smaller. Ventromental plate well developed; beard absent.

Maxilla ( Fig. 3 ). Anterior lacinial chaeta apparently neither longitudinally curled, nor forming nearly complete cylinder. No lamella of galea serrated. Pecten galearis not developed.

Body. Procercus well developed, sclerotized posteriorly, 50–60 µm high, 30–40 µm wide, dark with 7 apical setae (anal setae). Anal setae 580–600 µm long. Anal tubules not swollen, shorter than posterior parapods. Posterior parapods 357 µm long in one paratype, 227 µm long in the other paratype (3 instar?). Supraanal seta 262–300 µm long in one paratype, 103 µm long in the other paratype.

Habitat. The type locality, Garaet Ank El Djmel, is a big pond of about 3.5 ha and a depth of 0.6 m. It belongs to the complex wetlands of the Eastern Hauts plateaux in Algeria. Garaet Ank El Djmel has a sandy bed and is very salty of about 10 mS cm –1. The specimens were collected on 15 January 2004 where the average air of temperature was 5.2°C and the average water temperature was 6.3°C.

Figures

FIGURE 1. Hydrobaenus olfa n. sp., adult male. Hypopygium.

FIGURE 2. Hydrobaenus olfa n. sp., pupal exuviae. Abdomen, thoracic horn and anal lobes.

FIGURE 3. Hydrobaenus olfa n. sp., larva. Antenna, labrum, mandible, maxilla and mentum.