Allocladius scrotus, Andersen & Saether & Mendes, 2010

Andersen, Trond, Saether, Ole A. & Mendes, Humberto F., 2010, Neotropical Allocladius Kieffer, 1913 and Pseudosmittia Edwards, 1932 (Diptera: Chironomidae) 2472, Zootaxa 2472 (1), pp. 1-77 : 19-21

Allocladius scrotus sp. n.

( Figs 45–51 )

Type material. Holotype male, ECUADOR: Pichincha Province, Amaguaña, near Volcano Pasochoa , 0 o 22'S 78 o 27'W, 3.000 m a.s.l., 4.ii.1997, hand net, J. Skartveit. ( ZMBN Type No. 425) . Paratypes: 2 males as holotype ( ZMBN) .

Diagnostic characters. The presence of a single pars ventralis about half as wide as long and without setae together with the tongue-like, strongly projecting inferior volsella will separate the species from all other Allocladius species with pars ventralis.

Etymology. From Latin, scrotum, pouch containing the testicles, referring to the pars ventralis.

Male (n = 3, except when otherwise stated). Total length 2.65–2.83 mm. Wing length 1.76–1.89 mm. Total length / wing length 1.47–1.51. Wing length / length of profemur 3.07–3.13.

Coloration. Fully brown.

Head. AR 0.78–0.92. Ultimate flagellomere 406–487 µm long. Temporal setae 7–8, consisting of 3 weak inner verticals, 1 strong outer vertical, and 3–4 postorbital. Clypeus with 13–17 setae. Tentorium, stipes, and cibarial pump as in Figure 45 . Tentorium 139–203 µm long, 34–38 µm wide. Stipes 176–191 µm long, 34–53 µm wide. Palpomere ( Fig. 46 ) lengths (in µm): 23–34, 41–45, 79–101, 88–98, 101–128. Third palpomere with 1 (1) lanceolate sensilla clavata, 15 µm long.

Thorax ( Fig. 47 ). Median antepronotal lobes comparatively well developed, antepronotum with 2 weak lateral setae. Dorsocentrals 9, acrostichals 5–7, prealars 4–7, supraalar 1. Scutellum with 6–8 setae.

Wing ( Fig. 48 ). VR 1.25–1.38. Anal lobe distinct, slightly projecting. Costal extension absent, but indication of 100 µm long false vein. R 4+5 ending slightly distal to apex of M 3+4, Cu 1 sinuous. Brachiolum with 1 seta, R with 1–2 setae, other veins bare.

Legs. Spur of fore tibia 45–53 µm long, spurs of mid tibia 23–26 (2) µm and 19–23 (2) µm long, of hind tibia 56 µm long and 19–23 µm long. Width at apex of fore- and mid tibia 30 µm, of hind tibia 38–41 µm. Comb of 13 setae, longest 30–41 µm long, shortest 19–23 µm long. Length and proportions of legs as in Table 7.

Hypopygium ( Figs 49–50 ). Anal point 30–41 µm long, including 19–26 µm long basal sclerotized part with 6 setae and 8–15 µm long distal part with weak microtrichia basally and bare, hyaline apex. Tergite IX with 8–15 setae in addition to those on anal point. Laterosternite IX with 7 setae. Phallapodeme 71–101 µm long. Transverse sternapodeme 45–60 µm long, without oral projections. Virga 8–11 µm long, 8–11 µm wide, thumbnail-like. Pars ventralis ( Fig. 51 ) single, 45–60 µm long, 26–34 µm wide. Gonocoxite 161–173 µm long. Superior volsella barely indicated as dorsal swelling of inner margin of gonocoxite, reaching to 0.35– 0.37 gonocoxite length. Inferior volsella well developed, reaching to 0.60–0.70 gonocoxite length, free part 30–38 µm long; no apparent posterior lobe. Gonostylus 64–68 µm long; megaseta 8–9 µm long. HR 2.39– 2.71. HV 3.89–4.09.

Distribution and biology. The species is only known from the type locality in Ecuador where it was netted in an area with grassland at 3.000 m altitude.

Figures

FIGURES 45–51. Allocladius scrotus sp. n., male. 45—tentorium, stipes, and cibarial pump; 46—palp; 47—thorax; 48—wing; 49—hypopygium, dorsal aspect; 50—hypopygium with anal point and tergite IX removed, dorsal aspect to the left, ventral aspect to the right; 51—pars ventralis.