Allocladius quadrus, 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 : 17-19

Allocladius quadrus sp. n.

( Figs 38–44 )

Type material. Holotype male, CHILE: Región XII, Punta Arenas, Lago El Parrillar, 53º24.444'S, 71º15.823'W, 246 m a.s.l., 10.iii.1999, hand net, T. Andersen ( ZMBN Type No. 424) . Paratype: 1 male, as holotype ( ZMBN) .

Diagnostic characters. The presence of a square single pars ventralis much wider than long and without setae together with the tongue-like, strongly projecting inferior volsella and the high antennal ratio will separate the species from other species with pars ventralis.

Etymology. From Latin, quadra, a square, referring to the rectangular pars ventralis.

Male (n = 2). Total length 2.65–2.67 mm. Wing length 1.67–1.73 mm. Total length / wing length 1.53– 1.60. Wing length / length of profemur 3.05–3.16.

Coloration. Fully brown.

Head. AR 1.40–1.44. Ultimate flagellomere 463–491µm long. Temporal setae 6–7, consisting of 3–4 weak inner verticals, 2 strong outer verticals, and 1 postorbital. Clypeus with 9–12 setae. Tentorium, stipes, and cibarial pump as in Figure 38 . Tentorium 135–143 µm long, 34 µm wide. Stipes 150 µm long, 41–49 µm wide. Palpomere ( Fig. 39 ) lengths (in µm): 26–30, 45–53, 94–98, 143–146. Third palpomere with 2 lanceolate sensilla clavata, 19–21 µm long.

Thorax ( Fig. 40 ). Median antepronotal lobes comparatively well developed, antepronotum with 1 very weak lateral seta. Dorsocentrals 10–11, acrostichals 6, prealars 3–4, supraalar 1. Scutellum with 10 setae.

Wing ( Fig. 41 ). VR 1.31–1.32. Anal lobe distinct, slightly projecting. Costal extension absent, but indication of 190–200 µm long false vein. R ending slightly proximal to apex of M 3+4, Cu 1 sinuous. Brachiolum with 1 seta, R with 2 setae, other veins bare.

4+5

Legs. Spur of fore tibia 53 µm long, spurs of mid tibia 23–26 µm and 15 µm long, of hind tibia 45–49 µm and 23–26 µm long. Width at apex of fore- and mid tibia 30–36 µm, of hind tibia 45–49 µm. Comb of 14–15 setae, longest 38–45 µm long, shortest 23–30 µm long. Length and proportions of legs as in Table 6.

Hypopygium ( Figs 42–43 ). Anal point 45–49 µm long, including 34 µm long basal sclerotized part with 10–14 setae and 11–15 µm long bare, hyaline distal part. Tergite IX with 8–9 setae in addition to those on anal point. Laterosternite IX with 4–6 setae. Phallapodeme 71–75 µm long. Transverse sternapodeme 45–60 µm long, with weak oral projections. Virga 8–11 µm long, 11 µm wide, thumbnail-like. Pars ventralis ( Fig. 44 ) single, subquadrangular, 71–75 µm long, 101–113 µm wide, one specimen with slight median concavity. Gonocoxite 184–206 µm long. Superior volsella barely indicated as dorsal swelling of inner margin of gonocoxite, reaching to 0.41–0.45 gonocoxite length. Inferior volsella well developed, reaching to 0.61–0.64 gonocoxite length; no apparent posterior lobe. Gonostylus 79–83 µm long; megaseta 9–11 µm long. HR 2.33–2.50. HV 3.19–3.39.

Distribution and biology. The species is known from southernmost Chile, where it was netted on a lake shore at about 250 m altitude in an area with Notofagus forest.

Figures

FIGURES 38–44. Allocladius quadrus sp. n., male. 38—tentorium, stipes, and cibarial pump; 39—palp; 40—thorax; 41—wing; 42—hypopygium, dorsal aspect; 43—hypopygium with anal point and tergite IX removed, dorsal aspect to the left, ventral aspect to the right; 44—pars ventralis.