Metriocnemus eryngiotelmatus, Donato, Mariano & Paggi, Analía C., 2005

Donato, Mariano & Paggi, Analía C., 2005, A new Neotropical species of the genus Metriocnemus van der Wulp (Chironomidae: Orthocladiinae) from Eryngium L. (Apiaceae) phytotelmata, Zootaxa 1050, pp. 1-14 : 3-10

Metriocnemus eryngiotelmatus n. sp.

Type material: Holotype male with larval and pupal exuviae number 5183/1 ( MLP), Punta Lara, 34°51.090'S 57°57.543'W, Buenos Aires, Argentina, 4­vii­2004, M. Donato, leg. Allotype female with larval and pupal exuviae number 5183/2 ( MLP), Punta Lara, 34°51.090´S 57°57.543´W, Buenos Aires, Argentina, 4­vii­2004, M. Donato, leg.

Paratypes: 2 males with larval and pupal exuviae numbers 5183/3–4 ( MLP), Punta Lara, 34°51.090´S 57°57.543´W, Buenos Aires, Argentina, 4­vii­2004, M. Donato, leg.; male with larval and pupal exuviae number 5183/5 ( MLP), Arroyo El Pescado y Ruta Nac. 11, 34°57.618´S 57°46.628´W, Buenos Aires, Argentina, 15­viii­2004, M. Donato, leg.; male with larval and pupal exuviae number 5183/6 ( MLP), Ruta Prov. 51 cerca de Coronel Pringles, 37°54´57.6««S 61ϋ15´41.2´W, Buenos Aires, Argentina, 15­ii­2005, M. Donato, leg.; 3 females with larval and pupal exuviae numbers 5183/7­9 ( MLP), Punta Lara, 34°51.090´S 57°57.543´W, Buenos Aires, Argentina, 4­vii­2004, M. Donato, leg.; female with larval and pupal exuviae numbers 5183/10 ( MLP), Arroyo El Pescado y Ruta Nac. 11, 34°57.618´S 57°46.628´W, Buenos Aires, Argentina, 15­viii­2004, M. Donato, leg.

Other material examined: male with larval and pupal exuviae ( MLP), Ruta Prov. 51 cerca de Coronel Pringles, 37°54´57.6 S 61°15´41.2´´W, Buenos Aires, Argentina, 15­ii­ 2005, M. Donato, leg.; 2 females with larval and pupal exuviae ( MLP), Balneario Ferrando, Colonia del Sacramento, Uruguay, 10­x­2004, M. Donato, leg.; 5 larvae ( MLP), Sierras de Aceguá, 31°51.429´S 54°19.230´W, Cerro Largo, Uruguay, 15­ii­2005, M. Donato, leg.

Additional material studied (in the collection of Dr. J. E. Sublette):

Metriocnemus costatus Sublette & Sasa : Holotype male, Barretal, Guatemala, number II­51, 22­i­81, Sasa, leg.; Allotype female, Barretal, Guatemala, number II­67 (on same slide with paratype male, pupal exuviae), 25­ii­81, Sasa, leg.; Paratypes: pupal male, Barretal, Guatemala, II­53, Sasa, leg.; 3 males, Barretal, Guatemala, number II­54, Sasa, leg.

Metriocnemus lautus Sublette & Sasa : Holotype male, Lavaderos, Guatemala, number II­56, 22­x­81, Sasa, leg.

Metriocnemus virgatus Sublette & Sasa : Holotype male, Rincón, Guatemala, number II­77 (larva mounted on same slide), 16­iii­81, Sasa, leg.; Allotype female, Barretal, Guatemala, number II­83 (on same slide with paratype male), 16­iii­81, Sasa, leg.; Paratype pupal male, number II­73, Sasa, leg.

Etymology: The species name “ eryngiotelmatus ” refers to Eryngium , the host plant, and telma, from Greek, meaning pool.

Male imago (n = 6, except when otherwise stated) ( Figs. 2 A, C–E)

Total length 3.13–3.92, 3.57 mm, Wing length 1.67–2.15, 1.88 mm; width 0.45–0.63, 0.53 mm. Total length/wing length 1.82–1.98, 1.89. Wing length/length of profemur 1.93–2.08, 1.99. Coloration uniformly dark brown with light spots at base of setae, mainly on thorax and abdomen.

Head. AR 1–1.25, 1.1 (n = 5). Antennae with 13 flagellomeres. Ultimate flagellomere 427.1–579.6, 503.9. Temporal setae 34–48, 39. Clypeus with 21–37, 32 setae. Cibarial pump, tentorium, and stipes as in Fig. 2 C. Tentorium 166.7–217.2, 194.9 µm long; 30.3– 45.4, 36.6 µm wide. Stipes 88.4–103.5, 96.9 µm long (n = 5); 30.3–63.1, 49.5 µm wide (n = 5). Palp segment lengths 42.9–50.5, 46.7; 35.3–65.6, 45.1; 189.4–284.7, 229.1; 138.9– 213.5, 172.7 (n = 5); 194.5–244.1, 215.1 (n = 5).

Thorax ( Fig. 2 D). Antepronotum with 9–16, 12 lateral setae. Dorsocentrals 61–102, 81; acrostichals 46–50, 48; prealars divided in two groups, anterior 13–21, 16, and posterior 13–29, 18; supraalars 2–3. Scutellum with 12–23, 16 fine setae, and 16–30, 22 coarse setae. Preepisternals 5–14, 10.

Wing ( Fig. 2 A). VR 1.19–1.28, 1.23. C extension 75.7–223.7, 158.8 µm long and with 45–74, 58 non marginal setae. Brachiolum with 6–9, 8 setae; R with 65–95, 76; R1 with 45–67, 55; R4+5 with 94–138, 122; RM with 3–9, 6; M with 16–33, 22; M3+4 with 53–70, 58; Cu with 53–95, 78; Cu1 with 31–54, 37; PCu with 117–153, 139. Wing membrane with setae covering most cells. Squama with 15–28, 21 setae.

Legs. Spur of front tibia 78.3–101.7, 88.5 µm long; spurs of middle tibia: 37.8–51, 43.0 and 42.9–53, 49.3 (n = 4); of hind tibia: 40.4–48, 44.4 and 75.7–98.5, 86.7 µm long (n = 5). Width at apex of front tibia 45.4–60.6, 53.8; of middle tibia 50.5–60.6, 55.1; of hind tibia 50.5–71.9, 63.3. Comb with 9–10 setae. Lengths (in µm) and proportions of legs in Table 1.

Hypopygium ( Fig. 2 E). Without anal point. Setae on tergum IX 46 –52, 48 (n = 3), laterosternite IX with 5–7, 6 setae. Phallapodeme 108.6–98.5, 194.2 µm long; transverse sternapodeme 116.2–101.0, 111.7 µm long with oral projections. Without virga. Gonocoxite 285.4–227.3, 261.8 µm long; inferior volsella flat, ending at 0.59–0.66, 0.62. Gonostylus 143.9–118.7, 129.6 µm long; crista dorsalis low, almost straight; megaseta 10.3–8.8, 9.8 µm long. HR 2.15–1.8, 2.01; HV 3.04–2.6, 2.76.

Female imago (n= 5, except when otherwise stated) ( Figs. 2 B, F–G)

Total length 2.7–4.2, 3.2 mm, Wing length 1.57–2.02, 1.72 mm; width 0.5–0.7, 0.6 mm. Total length/wing length 1.6–2.1, 1.8. Wing length/length of profemur 1.85–1.95, 1.91. Coloration as in male.

Head. AR 0.2–0.32, 0.26. Lengths (in µm) of flagellomeres: 65.4–101.0, 86.3; 60.6– 75.7, 68.2; 58.1–90.9, 73.7; 58.1–85.8, 69.2; 73.2–88.4, 81.3. Temporal setae 48–82, 59. Clypeus with 37–54, 44 setae. Tentorium 138.9–161.6, 148.0 long; 20.2. 25.2, 24.2 wide. Stipes 85.8–113.6, 104.8 long; 53.1–75.7, 68.2 wide (n = 5. Palp segment lengths (in µm): 30.3–58.1, 44.9; 32.8–60.6, 47.4; 146.5–232.4, 197.5; 149.0–189.4, 173.7; 181.8–242.5, 220.2.

Thorax. Antepronotum with 8–20, 13 lateral setae. Dorsocentrals 51–110, 80 in some specimens including 9 or 10 on humeral area; acrostichals 24–50, 36; prealars divided in 2 groups, anterior 8–31, 16, and posterior 14–35, 21; supraalars 2 or 3. Scutellum with 12– 20, 16 fine setae, and 14–35, 21 coarse setae.

Wing ( Fig. 2 B). VR 1.26–1.38, 1.31. Brachiolum with 8–16, 11 setae. Wing membrane with setae covering most cells. Squama with 15–22, 18 setae.

Legs. Spur of front tibia 65.6–88.4, 75.2 long; spurs of middle tibia: 27.2–40.4, 31.7 and 32.8–42.9, 35.3; of hind tibia: 30.3–41.6, 35.1 and 32.8–42.9, 38.8 m long. Width at apex of front tibia 47.9– 63.1, 54.0; of middle tibia 50.5–65.6, 55.8; of hind tibia 60.6– 83.3, 71.2. Lengths (in µm) and proportions of legs in Table 2 .

TABLE 1. Measurements (µm) and proportions of legs of male Metriocnemus eryngiotelmatus n. sp. 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; “Schenkel­Scheine­verhältnis” (SV), ratio of femur plus tibia to metatarsus.

SV

P1 2.61–2.8, 2.72

P2 3.94–4.55, 4.34

P3 3.72–3.98, 3.83

Genitalia ( Fig. 2 F). Gonocoxite IX with apicomedial projection and rounded at end, with 26–36, 32 setae (n = 3). Gonapophysis VIII as shown in Fig. 2 G. Tergite IX subrectangular with 34–60, 50 setae (n = 3). Cercus 65.6–80.8, 73.2 µm long. Seminal capsule 68.2–88.4, 79.3. Notum 126.3–184.3, 155.6 µm long.

Pupa (n = 6, except when otherwise stated) ( Figs. 3 F–J)

Total length 4.03– 5, 4.35 mm. Exuviae hyaline.

Cephalothorax ( Fig. 3 I). Frontal apotome sexually dimorphic; female apex ( Fig. 3 F) more acute than male apex ( Fig. 3 G). Distance between Dc1 and Dc2 18.9–63.1, 37.6 (n = 5); between Dc2 and Dc3 12.6–27.7, 23.04 (n = 4); between Dc3 and Dc4 7.5–15.1, 11.3 (n = 4).

SV

P1 2.72–2.84, 2.78

P2 4.52–4.82, 4.7

P3 3.58–3.94, 3.79

Abdomen ( Fig. 3 H). Tergites III–VIII with apical row of tubercles. Tergum III–VIII with tubercles as follows (n = 5); 26–33, 29; 25–29, 27; 25–29, 28; 27–32, 29; 27–29, 28; 17–26, 23. Tergites III–VIII with basal band of clustered microtrichia of 3 types: simple, with 2 microtrichia usually clustered at base, and with 3 or 4 microtrichia usually clustered at base. Total number of microtrichia on Tergum III 152–182, 167 (n = 4). Anal lobe angular with 2 pale setae. Anal lobe length 214.7–265.2, 234.9 (n = 5). Genital sac length 176.8–237.4, 209.3 (n = 4).

Larva (n = 5, except when otherwise stated) ( Figs. 3 A–E)

Total length 0.5–0.62, 0.54 mm (n = 3). Head capsule 99–120, 110 µm long. Coloration yellowish with head somewhat darker than body.

Head. Lengths of antennal segments (in µm): 20–23, 21.2; 4–7, 5.4; 1–3, 2.1; 1–2, 1.4; 0.5–1.5, 1. AR 0.4–0.5, 0.46. Basal antennal segment 8–9, 8.8 µm wide; distance from base to ring organ 5–6, 5.75 (n = 4); to basal mark of seta 8–10, 9.5; blade 9–12, 10.3 (n = 3). Setae I plumose; labral lamellae plumose. Mandible ( Fig. 3 C) 53–65, 59.2 µm long, with 7 setae in seta interna. Mentum ( Fig. 3 A) with central teeth lower than first pair of lateral teeth. Postmentum 69–80, 74.6 µm long.

Figures

FIGURE 2. Metriocnemus eryngiotelmatus n. sp. adults. Male: A, wing in dorsal view. C, head in dorsal view. D, thorax in lateral view. E, hypopygium left dorsal, right ventral. Female: B, wing in dorsal view. F, genitalia, ventral view. G, Gonapophysis VIII. Setae on veins are not illustrated. Scale bar = 100 µm.

FIGURE 3. Metriocnemus eryngiotelmatus n. sp. larva: A, mentum. B, antenna. C, mandible. D, posterior parapod claws. E, posterior parapods. Pupa: F, female frontal apotome. G, male frontal apotome. H, abdomen. I, cephalothorax. J, anal lobe. Cp = cibarial pump, Cu = cubital, M = mediana, R = radius, Sc = subcosta, St = stipes, Te = tentorium. Scale bar = 100 µm.

Tables

TABLE 2. Measurements (µm) and proportions of legs of female Metriocnemus eryngiotelmatus n. sp. Abbreviations as in Table 1.

	Fe	Ti	Ta1
P1	813.28–1088.19, 909.19	854.28–1200.06, 968.18	589.86–813.6, 673.25
P2	833.94–1139.04, 945.81	823.28–1118.7, 943.77	355.95–467.82, 400.69
P3	874.62–1139.04, 980.38	1057.68– 474.65, 1206.16	508.5–681.59, 575.62