A new species of the genus Mesosmittia Brundin, 1956 (Diptera: Chironomidae) from the Neotropics with a cladistic analysis of the genus using quantitative characters Author Donato, Mariano text Zootaxa 2011 2836 51 61 journal article 10.5281/zenodo.206685 feeed475-6788-4a58-8400-70bc2b7fec2b 1175-5326 206685 Mesosmittia museophila n. sp. Material examined. Holotype male, MLP number 5307/1, ARGENTINA , Buenos Aires, La Plata, 34º 54’ 30.9’’S – 57º 56’ 21.8’’W , 8–IV–2005 , sweep net, M. Donato; paratypes : 7 males , MLP numbers 5307/2–6 and 2 males in ZMBN , same data as holotype . Other material examined. Mesosmittia mina Saether , holotype male, U.S.A. , Georgia , Clarke Co., Athens, Oconee River ( ZMBN ). Examined by Professor Ole A. Saether. Etymology. Referring to the species swarming in the forest surrounding the La Plata Museum, using the Greek philus = friend as a suffix. Diagnosis. distinguished from all other species of the genus by the presence of a notch on the ventral margin of the gonocoxite, except for Mesosmittia mina . M. museophila is separable from this species by the shorter and blunter preapical projection of the gonocoxite instead of the preapical projection sharply pointed and triangular in M. mina . Male imago ( n = 8–10) FIGURES 1–4. Mesosmittia museophila sp. n. Male adult. (1) Tentorium, stipes and cibarial pump. (2) Wing. (3) Hypopygium dorsal view. (4) Hypopygium with tergite IX removed, right ventral view, left dorsal view. FIGURES 5–6. Mesosmittia museophila sp. n. Male adult. Hypopygium general view. (5) dorsal view. (6) ventral view. Total length 1.96–2.43, 2.13 [2.36] mm. Wing length 1–1.13, 1.08 [1.11] mm. Total length/wing length 1.81– 2.23, 2.00 [2.13]. Wing length/length of profemur 2.29–2.76, 2.51 [2.47]. Coloration uniformly dark brown with legs light brown. Head. Antennae with 13 flagellomeres, AR 1.17–1.48, 1.34 [1.43], ultimate flagellomere length 350–430, 400 [430]. Temporal setae 6–9, 7 [6], divided in 1–3, 2 [1] inner verticals and 4–6, 5 [5] outer verticals. Clypeus with 4– 9, 8 [6] setae. Cibarial pump, tentorium and stipes as in Figure 1 . Tentorium 123–152, 137 [152] long and 17–27, 24 [25] wide. Stipes 100–118, 110 [118] long and 7–12, 7 [7] wide. Palpomere lengths: 24–29, 27 (9) [27]; 39–56, 49 [56]; 69–86, 78 [78]; 64–83, 69 [78]; 93–113, 100 [100]. Thorax. Antepronotum with 0–2, 1 [0] lateral setae. Dorsocentrals 6–9, 7 [8]; acrostichals 8–12, 10 [10]; prealars 3–5, 4 [3]; supraalars 1; scutellars 5–8, 5 [6]. Wing ( Fig. 2 ). VR 1.26–1.45, 1.39 [1.43]. C extension 12–24, 20 [22] long. Brachiolum with 1 seta; R with 0– 2, 1 [0]; R1 with 0–1, 0 [0]; R4+5 with 0–1, 0 [0]; squama with 2–7, 4 [4] setae. Legs. Spur of fore tibia 32–44, 39 [32] long (9); spurs of mid tibia: 15–17, 17 [17] and 17–24, 20 [24]; of hind tibia: 12–17, 16 [15] and 29–42, 37 [39] long. Width at apex of fore tibia 24–32, 29 [27]; of mid tibia 24–37, 29 [29]; of hind tibia 32–47, 38 [39]. Comb with 9–12, 9 [9] setae. Lengths (in mm) and proportions of legs in Table 1 . TABLE 1. Lengths (in μm) and proportions of legs of Mesosmittia museophila sp. n. (male) ( n = 8–10)..

p1 p2 p3	fe 380–450, 435 [420] 430–500, 470 [460] 450–540, 490 [490]	ti 520–630, 575 [530] 470–550, 495 [490] 540–630, 580 [570]	ta1 240–290, 260 [260] 200–220, 210 [200] 300–320, 310 [300]	ta2 140–170, 155 [150] 100–120, 110 [120] 150–170, 170 [160]
p1 p2 p3	ta3 100–120, 115 [110] 80–100, 85 [90] 130–150, 140 [130]	ta4 70–90, 80 [70] 50–70, 60 70–80, 75 [80]	ta5 60–70, 70 [70] 50–70, 60 60–70, 70 [70]	LR 0.43–0.49, 0.46 [0.49] 0.38–0.43, 0.41 [0.41] 0.49–0.58, 0.53 [0.53]
p1 p2 p3	BV 2.90–3.16, 3.05 [3.03] 3.55–3.94, 3.81 2.93–3.27, 3.11 [3.09]	SV 3.65–4.00, 3.76 [3.65] 4.57–5.00, 4.75 [4.75] 3.19–3.77, 3.51 [3.53]

Hypopygium ( Figs. 3–6 ). Without microtrichia on apex of “anal point”. Setae on tergite IX 9–15, 11 [9], laterosternite IX with 4–7, 5 [5] setae. Phallapodeme 37–54, 46 [54] long; transverse sternapodeme 74–103, 92 [96] long. Virga 27–42, 29 [29] long. Gonocoxite 169–203, 195 [196] long; length of gonocoxite to apex of inferior volsella/ length of gonocoxite 0.16–0.24, 0.22 [0.22], distance along inner margin from gonocoxite to apex of inferior volsella 71–91, 86 [91]. Ventral margin of gonocoxite with a notch. Gonostylus 83–105, 91 [91] long; crista dorsalis low, almost straight; megaseta 5–7, 5 [5] long. HR 1.86–2.23, 2.09 [2.15]; HV 2.07–2.61, 2.34 [2.59].