Aedokritus platycnemis Edwards, 1931

Pinho, Luiz Carlos, Dantas, Galileu P. S. & Hamada, Neusa, 2019, Some notes on taxonomy and distribution of Neotropical Aedokritus Roback and Axarus Roback (Diptera: Chironomidae: Chironominae), Zootaxa 4668 (4), pp. 535-542 : 536

Aedokritus platycnemis Edwards, 1931

( Figure 1 )

Examined material. Holotype: male, slide-mounted, “Posadas, Misiones Territory, Argentina, 13-15.i.1927 ” ( NHM) . Additional material. 1 male, BRAZIL, Amazonas State, Manaus , INPA, Campus II, 03°05’47”S 59°59’22”W, light, 14.x.2013, GPS Dantas leg. 1 male, Amazonas State, Manaus, Reserva Soka Gakkai , small lake, 03°06’44”S 59°54’22”W, light, 15.viii.2013, GPS Dantas leg. 1 male, Amazonas State, Itacoatiara, Rio Amazonas / Madeira , 03°21’31”S 58°46’31”W, 11-12.viii.2015, light, AMO Pes leg. 1 male, Pará State, Santarém , 02°25’10”S 54°42’24”W, 31.iv.2015, light, GPS Dantas leg. 1 male, Espírito Santo State, Marilândia, Lagoa do Batista , 19°31’38”S 40°26’38”W, 04.v.2016, light, P Barcelos leg.

Diagnostic characters. The species can be separated from other Aedokritus species by the wings with two dark crossbands, basal band forked toward hind margin, and large anal point.

Redescription. Male (based on holotype and additional material, n= 5): total length 5.20–5.95 mm. Wing length 2.15–2.58 mm. Total length/ wing length 2.30–2.44. Wing length/ length of profemur 1.99–2.06.

Coloration. Head brown. Thorax dark brown; vittae indistinct; halteres brown. Wing ( Figure 1A ) with two dark crossbands, basal band forked toward hind margin, apical band strongly tapered toward hind margin; squama, alula, anal lobe and whole area between C and R veins light brown. Legs with coxae, trocanthers, femora and tibiae dark brown; tarsomeres 1–2 yellowish brown; tarsomeres 3–5 brownish. Abdominal segments brown.

Antenna. AR 1.96–2.31. Ultimate flagellomere 0.88–1.08 mm long.

Head. Frontal tubercles present.Temporal setae 14–17, uniserial. Clypeus with 19–27 setae. Tentorium 250–290 μm long; 45–52 μm wide. Stipes 207 μm long; 12 μm wide. Palpomere lengths (in μm): 50–66; 65–70; 187–206; 230–235; 317–350. Third palpomere without sensilla clavata.

Thorax. Scutum without tubercle.Antepronotum with 5–7 lateral setae. Acrostichals 20–27; dorsocentrals 6–8; prealars 3–5; supraalar 1. Scutellum with 15–20 setae.

Wing ( Figure 1A ). VR 0.99–1.0. Brachiolum with 1–3 setae; R with 7–13 setae, other veins bare. Squama with 11–22 setae. Anal lobe moderately developed.

Legs. Spur of foretibia 60–71 μm long; spurs of midtibia 33–34 μm and 38–40 μm long; spurs of hind tibia 34–36 μm and 42–45 μm long. Apex of foretibia 63–77 μm wide; of midtibia 68–78 μm wide; of hind tibia 72–81 μm wide. Lengths and proportions of legs as in Table 1 .

Hypopygium ( Figures 1 B–D). Tergite IX with 40–50 dorsal setae, posterior margin without lateral projections. Anal point 48–72 μm long; 47–72 μm wide at its widest point, with 12–16 dorsal setae; apex blunt or slightly acute ( Fig. 1C ). Transverse sternapodeme 82–106 μm long. Gonocoxite 175–260 μm long. Superior volsella 65–80 μm long; 24–24 μm wide subapically; with 15–20 setae at basal microtrichiose part, apex rounded. Median volsella 42–50 μm long, 11–12 μm wide, with an apical fringe. Inferior volsella digitiform; 75–76 μm long; 73 μm wide at base, 30–37 μm wide at apex, with about 15 short, curved apical setae. Gonostylus 156–196 μm long, 75–78 μm wide at its widest point. HR 1.12–1.36. HV 3.04–3.33.

Female, pupa and larva. Unknown.

Distribution. The species was known only for its type locality in northeastern Argentina, southwestern limit of Atlantic Forest, and it is now recorded from central Atlantic Forest (Espírito Santo, Brazil) and Brazilian Amazon (Amazonas and Pará, Brazil) ( Figure 3 ).

Remarks. Edwards (1931) originally described the coloration of Aedokritus platycnemis as “Body black; legs black, with pale tarsi, ... wings with an extensive black pattern”, possibly based on pinned material. Additional material in alcohol could be described as that ( Fig. 1A ), but the black is indeed a very dark brown, fading to dark brown or brown when slide-mounted. The coloration of the slide-mounted holotype does not seem to be affected by its long age and is the same of the additional specimens in recent slides, as redescribed. Roback (1960) considered the median volsella “slender with a few long hairs at tip” a diagnostic character of species, but it is no longer true because of more recently described species (e.g. Aedokritus coffeatus ) with very similar median volsella.

Figures

FIGURE 1. Aedokritus platycnemis Edwards, male. A, left lateral habitus. B, hypopygium, dorsal view. C, variation in apex of anal point. D, hypopygium with tergite IX and anal point removed, dorsal view left, ventral view right.

FIGURE 3. Distribution of some Aedokritus Roback species in South America.