Macropelopia (Macropelopia) patagonica Silva & Pinho, 2020

Silva, Fabio Laurindo Da & Pinho, Luiz Carlos, 2020, Macropelopia (Macropelopia) patagonica, a new Tanypodinae (Diptera: Chironomidae) from the Patagonian Andes, Zootaxa 4731 (4), pp. 574-580 : 576-578

Macropelopia (Macropelopia) patagonica Silva & Pinho , sp. n.

( Figure 1 )

Type material. Holotype male, slide-mounted: Argentina, Rio Negro, San Carlos de Bariloche, Gutierrez Lake , 41°9’59.07”S 71°24’54.46”W, 15.iii.2014, FL Silva, ( MZSP) . Paratype 1 male: same data as holotype, except: ( INPA) .

Etymology. From the type locality, Patagonian Andes.

Diagnosis. The male of M. (M.) patagonica sp. n. differs from those of other Macropelopia species in the combination of the following characters: temporals bi- to triserial; tibial comb of four long bristles present on foreleg; wing translucid, but darkened only around Cu, MCu, RM and bases of R 1, R 2+3 and R 4+5; hypopygium with gonostylus broad basally and constricted in apical 1/3; and gonocoxite lacking inferior volsella.

Description.

Adult male (n = 2).

Size. Total length 4.0– 4.3 mm. Wing length 2.4–2.6 mm. Total length / wing length 1.66–1.67. Wing length / length of profemur 2.57–2.59.

Coloration. Head brown; thorax dark brown, except for pale anterior anepisternum II and halter; abdomen dark brown with narrow paler stripe between segments. Legs light brown with dark brown base of tibia and apices of femur and tibia. Wing translucid, darkened only around Cu, MCu, RM and bases of R 1, R 2+3 and R 4+5.

Head ( Fig. 1A ). Antenna lost. Eye bridge nearly parallel-sided with 5–6 ommatidia width. Temporal setae 28– 30, bi to triserial. Clypeus 103–108 μm long, 108–113 μm wide at broadest point, bearing 16–18 setae. Tentorium 162–179 μm long, 34–49 μm wide; stipes 157–162 μm long. First to fifth palpomere lengths (μm): 49–54, 64–69, 118–132, 157–181, 245–265.

Thorax ( Fig. 1B ). Scutal tubercle distinct. Antepronotum with 10–11 setae. Dorsocentrals 39–45, uni- to triserial; acrostichals 51–58; prealars 16–19; supraalar 1; preespisternals 3; anepisternals absent; postnotals 5–6. Scutellum with 32–36 setae multiserially.

Wing ( Fig. 1C ). Width 0.72–0.79 mm, membrane completely covered with macrotrichia. VR 0.94–0.95. WW 0.30. Costal vein produced beyond R 4+5, its protrusion 118–128 μm long. R 2 present; R 2+3 distinct, R 3 not reaching costa. MCu just beyond FCu. Anal lobe weakly developed. Brachiolum with 4–5 setae; Rs, M and Cu with setae. Squama with 24–26 setae.

Legs ( Figs 1 D–F). Fore leg: apex of tibia 59–64 μm wide, with single spur 59 (1) μm long, bearing 8–9 lateral teeth ( Fig. 1D ); comb with 5–6 strong bristles, longest 108–129 µm long; ta 1–4 without preapical pseudospurs. Mid leg: apex of tibia 59–64 μm wide, with two spurs 59–64 and 44–49 μm long, each bearing 8–11 lateral teeth ( Fig. 1E ); ta 1–4 without preapical pseudospurs. Hind leg: apex of tibia 64–69 μm wide, with two spurs 69–74 and 49–54 μm long, each bearing 8–11 lateral teeth ( Fig. 1F ); comb with 5–12 strong bristles, longest 49–54 µm long; ta 1–4 without preapical pseudospurs. Claws on all legs long, slender, distally pointed and spinulate in basal ⅓. Pulvilli very small. Lengths (μm) and proportions of legs as in Table 2 .

Hypopygium ( Figs 1G ). Tergite IX with 20–25 setae in double row. Membranous anal point broad and rounded. Phallapodeme short but distinct. Transverse sternapodeme 140–150 µm long. Gonocoxite cylindrical, 197–204 µm long, 82–85 µm wide at middle; GcR 2.40–2.41. Inferior volsella absent. Gonostylus broad basally and constricted in apical 1/3, 117– 120 µm long; megaseta 10–13 µm long. HR 1.68–1.70, HV 3.42–3.59.

Adult female, pupa and larva. Unknown

Remarks. The male of Macropelopia (Macropelopia) patagonica sp. n. possesses a tibial comb consisting of long bristles on the foreleg, which is unique among the species of this genus. Partial COI gene sequences were obtained from 18 specimens of 5 species belonging to the genus Macropelopia ( Figure 2 ). The aligned sequences were partially (88.9 %) 658 base pairs long with 161 variable sites (24.5%), of which 86 (47.5%) were potentially parsimony informative. The specimens identified morphologically as Macropelopia were divided into at least five separate barcode species ( Figure 2 ). However, we did not observe all the material in order to differentiate the species in these clusters into subgenera. Specimens of Macropelopia were collected in Argentina, France, Norway and United Kingdom ( Table 1 ). The analysis of partial DNA barcode sequences supports Macropelopia (Macropelopia) patagonica sp. n. as valid species. Moreover, we found COI suitable for summarizing the sequence diversity and detecting taxonomically challenging species within the genus Macropelopia .

Ecology. Adult males of Macropelopia (Macropelopia) patagonica sp. n. were collected at a high altitude in the margins of a glacial lake, located at Parque Nacional Nahuel Huapi, on the Patagonian Andes.

Figures

FIGURE 1. Macropelopia (Macropelopia) patagonica sp. n., adult male. (A) Head, frontal view. (B) Thorax. (C) Wing. (D–F) Tibial spurs of P 1 (D), P 2 (E) and P 3 (F). (G) Hypopygium with tergite IX, dorsal view (left) and ventral view (right).

FIGURE 2. Neighbor joining tree for species of the genus Macropelopia based on partial COI sequences (DNA barcodes) and the Kimura-2-parameter. Numbers on branches are bootstrap values.

Tables

TABLE 2. Lengths (μm) and proportions of leg segments in Macropelopia (Macropelopia) patagonica Silva & Pinho, sp. n., adult male (n = 1–2).

	fe	ti	ta1	ta2	ta3
p1	95–102	112–129	92 (1)	50 (1)	35 (1)
p2	105–122	107–117	72 (1)	37 (1)	27 (1)
p3	95–102	129–149	105 (1)	55 (1)	37 (1)
	ta4	ta5	LR	BV	SV
p1	22 (1)	15 (1)	0.82 (1)	2.45 (1)	2.24 (1)
p2	17 (1)	12 (1)	0.67 (1)	3.00 (1)	2.93 (1)
p3	22 (1)	15 (1)	0.81 (1)	3.05 (1)	2.19 (1)