Ablabesmyia akemiae, Dantas & Hamada, 2019

Dantas, Galileu P. S. & Hamada, Neusa, 2019, Three new neotropical species of Ablabesmyia Johannsen, 1905 (Diptera: Chironomidae), Zootaxa 4567 (1), pp. 111-129 : 112-119

Ablabesmyia akemiae sp. n.

Type material. Holotype: male with pupal exuviae, BRAZIL: Rio Grande do Norte, Parnamirim, Pitimbu river , 05°57'30.5"S / 35°10'02.0"W, 01.ix.2015, G.P.S. Dantas . Paratypes: 1 male with pupal exuviae, 1 female with pupal and larval exuviae, as holotype; 1 male with pupal exuviae, as holotype, except for 10.xii.2016.

Diagnostic characters. Adult male: Tergite IX with 2–3 dorsal setae on each side; dorsal lobe with apical brush; aedeagal blade striated, strongly curved at apex. Forefemur with 2 bands; fore tibia with 5 bands, 3rd small and incomplete. Mid femur with 2 bands, mid tibia with 4 bands. Hind femur with 1 band, hind tibia with 4 bands.

Pupa: Cephalothorax brown; wing sheath brown along margin and veins, with dark spots. Thoracic horn lumen with hexagonal pattern; aeropyle tube simple, apically club-shaped. Thoracic comb with 14–15 teeth. Genital sac ending beyond the insertion of the second anal macrosetae. Larva: Ventral surface of head capsule with one circular brown spot between tentorial lines; S10 simple. Inner teeth of ligula directed outwardly. Postoccipital margin with well-developed projections.

Etymology: The new species is dedicated to Raissa Akemi Kamada Hosokawa, in recognition of her precious friendship, kindness and continuous support.

Adult male (n = 1–3). Total length 3.68–3.73 mm. Wing length 1.79–1.80 mm. Total length/wing length 2.06– 2.08. Wing length/length of forefemur 2.29–2.31.

Coloration. Thorax brown ( Fig. 1B ). Wing with patterns of brown spots as in figure 1C. Forefemur with 2 bands; foretibia with 5 bands, third band small and incomplete. Mid femur with 2 bands, mid tibia with 4 bands. Hind femur with 1 band, hind tibia with 4 bands. Abdomen ( Fig. 2A ) pale yellow with dark markings; tergites I with 2 dark brown spots anteromedially; tergites II–IV with 2 dark brown spots anterolaterally; tergites V with 1 anterior dark brown cross band; VI–VIII mostly dark brown; hypopygium with light brown gonocoxite apex and gonostylus base.

Head ( Fig. 1A ). Antennal flagellum 1169–1178 µm long; apical flagellomere 110–117 µm long, 18–24 µm wide; preapical seta 38–40 µm long, pedicel 153–158 µm wide, with 8–9 setae. AR 1.99–2.21. Eyes bare; dorsomedial extension well developed, 126–128 µm long, 70–72 µm wide, medially separated by distance of 121 µm. Temporal setae 53–55, multiserial anteriorly and uniserial posteriorly. Clypeus 111–150 µm long, 87–90 µm wide at maximum, with 41–50 setae. Cibarial pump with anterior margin strongly concave, 280–302µm long; orifice located 133 µm from apex. Tentorium 160–177 µm long. Palpomeres 1–5 (µm): 58–65; 88–110; 139–140; 141–143; 165–282. Third palpomere with 1 campaniform sensilla.

Thorax ( Fig. 1B ). Antepronotum with 16–20 lateral setae. Acrostichals about 60–70, biserial, diverging posteriorly; dorsocentrals 31–40, multiserial anteriorly and uniserial posteriorly; prealars 26–31, multiserial; supraalar 1. Scutellum with 40–46 setae.

Wing ( Fig. 1C ). Width 0.55–0.56 mm. Costal vein 1.65–1.66 mm long, not produced beyond apex of R 4+5, ending before apex of M 1+2. Brachiolum with 4–5 setae. Squama with 42–48 setae. Anal lobe well developed. VR 0.82–0.84. WW 0.30–0.31.

Legs ( Figs. 1 D–F). Foretibia 55–62 µm wide at apex, with one apical spur 60–61 µm long, bearing 12 lateral teeth. Mid tibia 56–59 µm wide at apex, with two apical spurs, 48–55 and 62–71 µm long, bearing 5 and 10 lateral teeth, respectively. Hind tibia 60–70 µm wide at apex, with two apical spurs, 58 and 76 µm long, bearing 5 lateral teeth in short spur; tibial comb indistinct, with 5–6 bristles. Lengths and proportions of leg segments as in Table 1.

Hypopygium ( Figs. 2 B–E). Tergite IX with 2–3 setae on each side; anal point completely covering aedeagal complex; phallapodeme 60–73 µm long; transversal sternapodeme robust and somewhat rectangular ( Fig. 2D ), 50– 51 µm long; gonocoxite 174–176 µm long; gonostylus 162–164 µm long, with 5 apical teeth and tapered megaseta; HR 1.07; HV 2.27. Aedeagal complex with striated blades 52–57 µm long, strongly curved and pointed at apex; dorsal lobe 17–18 µm long and 18–19 µm wide, rounded, bearing apical brush (2B–C, E); lateral lobe reduced; lateral filaments well developed; basidorsal lobe not evident.

Adult female (n = 1). Wing length 1.49 mm. Wing length/length of forefemur 1.95 mm.

Coloration. Forefemur with 2 bands; foretibia with 5 bands, third band small and incomplete. Mid femur with 2 bands, mid tibia with 4 bands. Hind femur with 1 band, hind tibia with 4 bands.

Head. Antenna with 11 flagellomeres; flagellum 524 µm long, apical flagellomere 112 µm long, 33 µm wide; AR 0.27. pre-apical seta 32 µm long, pedicel 78 µm wide, with 11 setae; scape with 12 setae. Eyes bare, medially separated by distance of 130 µm; dorsomedial extension well developed, 89 µm long, 71 µm wide. Temporal setae about 50, multiserial anteriorly and uniserial posteriorly. Clypeus 120 µm long, 108 µm wide at maximum, with 51 setae. Cibarial pump with anterior margin concave, 272 µm long; orifice located 127 µm from apex. Tentorium 186 µm long. Lengths of palpomeres 1–5 (µm): 57; 91; 135; 130; 247. Third palpomere with 1 campaniform sensilla.

Thorax. Antepronotum with 17 lateral setae. Acrostichals biserial, diverging posteriorly; dorsocentrals 56, multiserial anteriorly and uniserial posteriorly; prealars 39, multiserial; supraalar 1. Scutellum with about 65 setae.

Wing. Width 0.59 mm. Costal vein 1.39 mm long, not produced beyond apex of R 4+5, ending before apex of M 1+2. Brachiolum with 8 setae. Squama with about 30 setae. Anal lobe well developed. VR 0.92. WW 0.40.

Legs. Apical width of tibia 58 µm in foreleg, 56 µm in mid leg, 64 µm in hind leg. Hind tibial comb indistinct, with 5 bristles. Lengths (µm) and proportions of leg segments as in Table 2.

Abdomen. Lost.

Pupa (n = 1–3). Total length 4.37–4.90 mm.

Coloration. Exuviae brown ( Fig. 3C ). Wing sheath brown along margin and veins, with dark spots ( Fig. 3B ). Thoracic horn dark-brown, aeropyle hyaline. All abdominal tergites brown, each with anterior darker patches.

Cephalothorax. Dorsal surface slightly roughened. Frontal apotome apically truncated. Wing sheath smooth ( Fig. 3B ), 1310–1396 µm long, 470–473 µm wide. Thoracic horn ( Fig. 3A ) 468 µm long, 166 µm wide, with hexagonal pattern, spines present on the base; apical nipple with aeropyle tube club-shaped apically. Thoracic comb with 14–15 apically blunted teeth.

Abdomen ( Fig. 3C ). Tergite I with shagreen of spinules in transversal rows, with a distinct, elongate scar 200– 234 µm long; TII–VII with extensive shagreen of spinules in arc; TVIII–IX with extensive shagreen of scattered spinules. Segment VII with 4 LS setae. Segment VIII with 5 lateral filaments. Anal lobe ( Fig. 3D ) 385–391 µm long, 390–395 µm wide at the base, with 2 lateral macrosetae; outer margin straight anteriorly and slightly concave posteriorly, with 5 small spines; inner margin somewhat sinuous, without spines. Male genital sac 306–339 µm long, 255–260 µm wide at the base, extending beyond the insertion of the second macrosetae. GS/AL 0.79–0.87.

Larva (n = 1). Coloration. Head capsule yellow with circular brown spot between tentorial lines; postoccipital margin light brown. Apex of mandible and ligula teeth dark brown.

Head ( Fig. 4A ). Head capsule oval; cephalic index 0.64. VP closer to S10 than to S9, posterolateral to S9 and mesial to S10; lines S9–VP and S10–VP making obtuse angle ( Fig. 4B ). S9 apparently bifid, S10 simple, SSm multi-branched. Postoccipital margin with well-developed projections ( Fig. 4C ).

Antenna. Total length 611 µm; A 1 508 µm long, 17 µm wide at base; ring organ placed 269 µm from base; A 2 95 µm long. AR 4.93.

Maxilla. Basal segment of maxillary palp ( Fig. 4E ) subdivided into 2 parts; basal part (P 1) 45 µm long and 15 µm wide, apical part (P 2) 55 µm long and 10 µm wide. A 1 /P 1 11; A 2 /P 1 2.11.

Mandible ( Fig. 4D ). Length 199 µm; 3 lateral setae present; ring organ placed 52 µm from base. Apical tooth 54 µm long; mola projection large, blunt at apex, 9 µm long; inner tooth large, rounded at apex, partly overlying seta subdentalis. A 1 /MD 2.97.

Mentum and M appendage. M appendage rounded apically, with pseudoradula 161 µm long, 14 µm wide, granulated uniformly.

Hypopharyngeal complex ( Fig. 4F ). Ligula 93 µm long, 67, 44 and 71 µm wide at toothed, middle and basal widths, respectively, granulated at base, with 5 teeth; row of teeth concave, inner teeth directed outwardly. Paraligula bifid and robust, 52 µm long and 15 µm wide. Pecten hypopharyngis damaged.

Body. Missing

Taxonomic remarks. The male of A. akemiae sp. n. will not key past couplet 26 in the Neubern et al. (2013: 8) because of the antepronotum with 17 lateral setae, the aedeagal complex with a short dorsal lobe and the gonostylus with the same length as the gonostylus, and somewhat resembles those of A. cauame Neubern and A. commata Neubern. However , the male can be easily distinguished from them by the general coloration pattern of the legs. The numbers of bands in the fore-, mid and hind femurs are 2, 2, 1, respectively, in A. akemiae sp. n., whereas 2, 2, 2, respectively, in A. cauame , and 3, 3, 3, respectively, in A. commata . Likewise, the numbers of bands in the tibiae are 5, 4, 4, respectively, in A. akemiae sp. n., whereas 4, 3, 3, respectively, in A. cauame and 4, 4, 4, respectively, in A. commata . In addition, the transversal sternapodeme of A. akemiae sp. n. is straight, and it is inconsistent with the rounded transverse sternapodeme in A. cauame and A. commata . From A. cauame , the new species also differs by the number of antepronotal setae (9 in the former and 16–20 in the latter) and relative length of Gonostylus/Gonocoxite.

The pupa of the new species resembles that of A. reissi Paggi & Suarez by the wing sheath with spots, genital sac ending beyond the insertion of the second anal macrosetae and outer side of thoracic horn and of anal lobe with spines. However, the two species differ each other in the total length and in the number of teeth of the thoracic comb, which is respectively 4.37–4.90 mm and 14–15 teeth in A. akemiae sp. n. and 3.20–3.72 mm and 8–9 teeth in A. reissi .

The larva of the new species seems closer to that of A. reissi by the value of AR, postoccipital margin with central projections and the presence of a circular spot on head capsule located between the scars. However, in A. akemiae sp. n. VP is mesial to S10 and closer to S10 than to S9, contrasting with A. reissi , in which VP is posteior to S10 and equidistant from S9 and S10.

Notes on biology. The larva and pupae of A. akemiae sp. n. were collected in a small river located on the outskirts of a densely populated urban area and associated to the aquatic vegetation.

Distribution. The species is known only from the type locality in Rio Grande do Norte State, Brazil ( Fig. 5 ).

Figures

FIGURE 1. Ablabesmyia akemiae sp. n., adult male. (A) Head. (B) Thorax, lateral view. (C) Wing. (D) Front femur and tibia. (E) Mid femur and tibia. (D) Hind femur and tibia.

FIGURE 2. Ablabesmyia akemiae sp. n., adult male. (A) Abdomen, dorsal view. (B–C) Hypopygium, dorsal view. (C) Transversal sternapodeme. (D) Aedeagal complex, dorsal view.

FIGURE 3. Ablabesmyia akemiae sp. n., pupa. (A) Thoracic horn. (B) Wing sheath. (C) Abdomen, dorsal view. (D) Anal lobes, ventral view.

FIGURE 4. Ablabesmyia akemiae sp. n., larva. (A) Head, ventral view. (B) Ventral cephalic setae. (C) Postoccipital margin. (D) Mandible. (E) Basal maxillary palp. (F) Ligula and paraligula.

FIGURE 5. Distribution map of A. akemiae sp. n., A. monticola sp. n. and A. adamantis sp. n.