Parapsectrocladius setosus, Donato, Mariano, Mauad, Melina & Fuentes, María Cecilia, 2015

Donato, Mariano, Mauad, Melina & Fuentes, María Cecilia, 2015, A new species of Parapsectrocladius Cranston (Diptera: Chironomidae: Orthocladiinae) from Patagonia, Argentina, Zootaxa 3911 (4), pp. 547-559 : 549-552

Parapsectrocladius setosus sp. nov.

Type material. ARGENTINA: Holotype male, Río Negro, P. N. Nahuel Huapi, C° Catedral, Laguna Toncek, 41º11’54.2’’S – 71º29’12’’W, 1747 m a.s.l., 20.i.2007, sweep net, M. Donato col. ( MLP). Paratypes: male, same data as holotype; 2 males, same data as holotype except A. Garré and F. Montes de Oca cols. (NHM and ZSM); 2 males with pupal exuviae, same data as holotype except A. Garré and F. Montes de Oca cols., drift net ( MLP and NHM); 1 male, Río Negro, Meseta de Somuncurá , Laguna Puesto de Lata, Paraje Chasicó, Estancia Jaguar Musso, 41°09’18.6’’S – 67°34’40.3’’W, 1.055 m a.s.l., M. Donato col. ( MLP).

Etymology. Named after the strong and numerous setae in the inner margin of the inferior volsella.

Diagnosis. The male of Parapsectrocladius setosus is clearly differentiated from the rest of the species of the genus except P. escondido by having the anal point tapering triangular without setose protuberances at base and the inferior volsella simple and apically bluntly triangular. It can be separated from P. escondido by having the inner margin of the inferior volsella with strong setae. The pupa of P. setosus is separated from the rest of the members of the genus by having the thoracic armament comprising long blunt spines (>30pm), thoracic horn covered with fine spinules and with a basal swelling, median spine patches of tergites IV–VI weakly defined and apex of anal lobe with small tubercles.

Male (n = 7). Total length 3.86–5.40, [4.98] (6) mm. Wing length 2.22–2.84, [2.74] (5) mm. Total length/wing length 1.74–2.03, [1.82] (5). Wing length/length of profemur 2.37–2.52, [2.43] (5). Coloration (specimen preserved in alcohol) uniformly brown; thorax somewhat light brown with vittae, postnotum and preepisternum darker; legs light brown.

Head. Antennae with 12–13, 13 (6) flagellomeres; AR 1.2–1.5, [1.41] (5), ultimate flagellomere 489–584, [568] (5) long. Temporal setae 8, divided in 1, [1] inner verticals, 1–2, [1] outer verticals, and 3–5, [4] postorbitals. Clypeus with 18–28, [28] (6) setae. Tentorium 220–254, [230] (6) long and 46–100, [48] (6) wide. Palpomere lengths (1–5) (5): 40–60, [40]; 50–80, [62]; 100–150, [124]; 118–148, [130]; 172–224, [186] (4).

Thorax. Antepronotum with 9–15, [11] (5) lateral setae. Acrostichals absent. Dorsocentrals 18–22, [22] (4); prealars 6–9, [8] (5); supraalar 1, [1] (5). Scutellum with 9–18, [18] (5) setae.

Wing. VR 1.13–1.2, [1.16] (5). C extension 20–78, [20] (5) long. Brachiolum with 2, [2] (5) seta. R with 10–12, [10] (4); R1 with 0–1, [0] (5); R4+5 with 0–2, [2] (5). Squama with 12–28, [23] (5) setae.

Legs. Spur of front tibia 60–154, [62] long; spurs of mid tibia 24–40, [40] and 32–44, [44]; of hind tibia: 30–42, [42] (6) and 76–98, [90] long. Width at apex of front tibia 60–88, [70]; of mid tibia 70–154, [74]; of hind tibia 80–106, [84]. sensilla chaetica of tarsomere 1 of midleg 3–6, [4] (6). Comb with 11–13, [11] (6) setae. Lengths and proportions of legs in Table 1.

Hypopygium ( Figs.1–3 ). Tergum IX with 18 setae, divided in 4–7, [4] (6) small setae and 7–11, [7] (6) big setae. Laterosternite IX with 3–6, [3] (5) setae. Anal point 162–196, [162] (6) long, width at base 30–60, [44] (6), and with 14–24, [16] (6) setae. Phallapodeme 130–162, [162] (5) long; transverse sternapodeme 94–114, [114] (5) long. Virga represented by a broad and diffuse area of fine spinules. Gonocoxite 362–462, [450] long; length from base of gonocoxite to apex of inferior volsella/length of gonocoxite 0.53–0.55, [0.53]. Inferior volsella subtriangular with strong setae on inner margin ( Fig. 3 ). Gonostylus 168–202, [180] long; megaseta 18–26, [20] (6) long. HR 2.15–2.5, [2.5]; HV 2.30–2.77, [2.77] (6).

Pupa (n = 2) ( Figs. 4–5 ). The pupae examined fit the description by Cranston (2000) of P. longistylus except for the presence of an anteromedian patch of spines present on T III ( Fig. 4 ). In the drawing of the pupal abdomen ( Fig. 4 A of Cranston, 2000) the tergites IV–VI have an anteriomedian patch of spines.

Female and larva. Unknown.

Distribution and biology. The species is known from Chile and Argentina. The altitude range is from about 1000 to 1.700 m a.s.l. Collection sites show that this species prefers standing water environments. The geographic distribution of the genus is extended eastward in Patagonia since P. setosus was collected in the Somuncurá Plateau, a vast basalt plateau of over 25,000 km 2 located in north eastern Patagonia, with an average altitude of 1000 m a.s.l. The terrestrial vegetation is predominantly herbaceous and shrub forms ( León et al., 1998). This plateau would not have suffered the Patagonian glaciations and subsequent marine ingressions, thereby acting as a refuge and dispersal center ( Ringuelet, 1975). The Somuncurá Plateau is also an area of endemism, with numerous endemic species such as the fish Gymnocharacinus bergi Steindachner ( Menni & Gomez, 1995) , the frogs Atelognathus reverberii (Cei) and Pleurodema somuncurensis (Cei) (Cei, 1980) , the scorpions Urophonius somuncura Acosta (Acosta, 2003) and Bothriurus ceii Ojanguren-Affilastro (Ojanguren-Affilastro, 2007) , among others.

TABLE 1. Lengths (in Μm) and proportions of legs of Parapsectrocladius setosus sp. n. (male, n = 5). Measurements of the holotype in square brackets. Abbreviations: Femur (fe); Tibia (ti); Tarsomeres 1–5 (ta1-5); Leg Ratio (LR), ratio of metatarsus to tibia; «Beinverhältnisse» (BV), combined length of femur, tibia, and basitarsus divided by combined length of tarsomeres 2–5; «Schenkel-Scheine-verhältnis» (SV), ratio of femur plus tibia to metatarsus.

Figures

FIGURES 1 – 3. Parapsectrocladius setosus sp. nov., male. 1, Hypopygium, dorsal aspect; 2, Hypopygium with tergite IX removed, dorsal aspect to the left, ventral aspect to the right; 3, Inferior volsella.

FIGURES 4 – 5. Parapsectrocladius setosus sp. nov., pupa. 4, Tergite III; 5, Tergite VIII.