Corynoneura mineira, Wiedenbrug, Sofia & Trivinho-Strixino, Susana, 2011

Wiedenbrug, Sofia & Trivinho-Strixino, Susana, 2011, New species of the genus Corynoneura Winnertz (Diptera, Chironomidae) from Brazil, Zootaxa 2822, pp. 1-40 : 17-21

Corynoneura mineira sp. n.

( Figs 10–12 )

Corynoneura -Gruppe spec. 9: Wiedenbrug 2000: 107

Type material. Holotype male with pupal and larval exuviae, BRAZIL, MG, Paraisópolis, Distrito dos Costa, 22°39´54.81”S, 45°55´38.29”W, approx. 1370 m a.s.l., 11.x.2009, S. Wiedenbrug. Paratypes: allotype female with pupal and larval exuviae, same data as holotype; one pharate male with pupal exuviae and two females with pupal and larval exuviae same data as holotype (UFSCAR MPSW 044); two pharate females with pupal exuviae and one pupal exuviae, SP, Ubatuba, stream beside Ruínas da Lagoinha, 23˚30.468´S, 45˚11.923´W, 0 m a.s.l., 10.x.2008, S. Wiedenbrug; one female with pupal exuviae, Ubatuba, Sertão da Quina, Cachoeira da Renata near parking lot, 23°31.087´S, 45°14.621´W, 39 m a.s.l., 14.i.2008, S. Wiedenbrug.

Diagnostic characters. The adult males are separable from other species by the antenna with 10 flagellomeres, AR about 0.3, eyes pubescent, aedeagal lobe triangular, attachment of the phallapodeme caudal on the lateral sternapodeme, phallapodeme posterior margin sclerotized, curved to anterior and rounded, gonocoxite with a median lobe with longer microtrichia. Adult females are separable from other species by the labia not strongly sclerotized, apparently separated not building together a funnel, copulatory burse with posterior margin not strongly invaginated, two seminal capsules subequal in size, one more sclerotized than the other. The pupae are distinguished from other species by tergites III and IV usually with median shagreen field separated from posterior shagreen, spines on posterior row relatively wide and with rounded lateral margin, anal lobe not joined medially as an inverted v but separated by a straight margin, posterior margin rounded with fringe. The larvae can be recognized by the head integument without sculptures, the mentum with 3 median and 6 lateral teeth, head elongate (post–mentum length/ head width 1.5), AR 0.88, antenna longer than frontoclypeal apotome, basal seta on posterior parapods split from the base.

Etymology. Named after mineiro, referring to the natives of Minas Gerais State, where the holotype male was collected.

Description. Male (n = 1, holotype)

Total length 0.83 mm.

Color. Thorax brownish; legs whitish; tergites I–IV whitish, V–IX brownish; gonocoxite and gonostylus brownish.

Head. AR = 0.28. Antenna with 10 flagellomeres, sensilla chaetica not possible to see. Flagellomeres 2–9, with more than one row of setae. Apical flagellomere composed of two fused flagellomeres, with one row of setae ( Fig. 10 A). Temporal setae absent. Clypeus 30 µm long, with 8 setae. Tentorium 112 µm long, 10 µm wide. Palpomere lengths (in µm): 10, 12, 17, 20, 35. One sensilla clavata on the third palpomere. Eyes pubescent.

Thorax ( Fig. 10 B). Antepronotum apparently without setae. Dorsocentrals 3, prealars 2. Scutellars 2. Antepronotal lobes dorsally reduced.

Wing ( Fig. 10 C). VR 2.94. Clavus 25 µm wide, ending 150 µm from arculus. Clavus/wing length 0.24.

Legs. Spur of front tibia 17 µm long; spur of middle tibia 10 µm long; spurs of hind tibia 37 µm long, second spur s-shaped. Width of apex of front tibia 12 µm, of middle tibia 15 µm, of hind tibia 32 µm. Front tibial scale 17 µm long; mid tibial scale 7 µm, hind tibial scale 35 µm long ( Fig. 10 D). Leg measurements (in µm) and ratios as in Table 7.

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR p1 202 240 82 62 35 15 25 0.34 3.82 5.36 1.60 p2 280 255 140 70 25 15 17 0.55 5.29 3.82 2.00 p3 200 215 120 67 25 17 25 0.56 3.96 3.46 2.75 Abdomen setation. Three setae on TVII, 3 on TVIII.

Hypopygium ( Figs 10 E–F) Tergite IX with 4 small setae. Laterosternite IX with 1 seta. Superior volsella small with small seta directed to median. Aedeagal lobe triangular. Gonocoxite with a median lobe with longer microtrichia. Inferior volsella smooth anteriorly with longer setae medially directed. Phallapodeme 30 µm long; transverse sternapodeme rounded. Gonocoxite 55 µm long. Gonostylus 15 µm long, tapering apically; megaseta 5 µm long. HR 3.67. HV 5.53.

Female (n = 1)

Thorax length 0.42 mm. Wing length 0.66 mm. Wing length/length of profemur 3.61. Color. Thorax brownish; legs whitish; tergites I–II whitish, III–IX brownish.

Head. AR 0.42. Antenna with 5 flagellomeres, apical flagellomere 45 µm long; one sensilla chaetica on flagellomere 1, two sensilla chaetica on flagellomeres 2–5. Temporal setae absent. Clypeus 40 µm long, with 8 setae. Tentorium 70 µm long, 5 µm wide. Palpomere lengths (in µm): 10, 10, 17, 20, 37. One sensilla clavata on third palpomere. Eyes pubescent.

Thorax. Antepronotal not possible to observe. Dorsocentrals 3, prealars 2. Scutellars 2. Antepronotal lobes dorsally tapering.

Wing ( Fig. 11 A). VR 2.4. Clavus 32 µm wide, ending 290 µm from arculus. Clavus/wing length 0.44.

Legs. Spur of front tibia 17 µm long; spur of mid tibia 10 µm; spurs of hind tibia 32 µm long, second spur small s-shaped. Front tibial scale 10 µm long, mid tibial scale 7 µm long, hind tibial scale 37 µm long. Width of apex of front tibia 17 µm, of middle tibia 17 µm, of hind tibia 35 µm. Leg measurements (in µm) and ratios as in Table 8.

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR p1 182 212 92 57 30 27 25 0.44 3.48 4.27 1.80 p2 257 242 122 52 25 12 22 0.48 5.53 4.08 2.25 p3 205 222 110 65 25 12 27 0.49 4.13 3.89 2.20 Abdomen setation. TVII with 3 setae, TVIII with one seta.

Genitalia ( Figs 11 B–D). Gonocoxite IX with 1 seta. Tergite IX with 2 setae. Two seminal capsules respectively 32 µm and 40 µm long, one more sclerotized than the other, one spermathecal duct with a loop, second not discernable, both ducts join together short distance before seminal eminence, which has sclerotized outer borders. Notum 30 µm long. Membrane well sclerotized V-shaped. Apodeme lobe anterior margin curved to posterior, apically pointed. Coxosternapodeme strongly curved, with a tiny lateral lamella, copulatory bursa semicircle-shaped, with rounded lateral corners. Two labia membranous, bare, separated and rounded. Gonocoxapodeme straight, gonapophyses triangular medially. Postgenital plate with microtrichia. Cercus 25 µm long.

Pupa (n = 1–3)

Total length 1.22 – 1.32 mm.

Cephalothorax. Frontal apotome smooth ( Fig. 12 A). Frontal setae 62–67 µm long. Median antepronotals 30 and 80 µm. Pc3 35 µm. Dorsocentrals Dc3 32 µm long; Dc4 42 µm long. Distance between Dc1 and Dc2 87–90 µm; Dc2 and Dc 3 30–35 µm; Dc3 and Dc4 22 µm. Dc1 displaced ventrally. Wing sheath with 1–4 row of pearls ( Fig. 12 B).

Abdomen ( Figs 12 C–F). Tergite I and sternite I without shagreen. Tergite II with few median and posterior shagreen points. Tergites III–IV with median shagreen field separated from posterior shagreen field, last with spines increasing in size, posterior spines wider than longer ( Figs 12 E–F). Tergite V similar to IV but median shagreen field not separated from posterior shagreen. Tergites VI–IX with shagreen. Sternites II–III with very fine shagreen (not drawn), IV–VIII with fine shagreen. Conjunctive TII/III with 8–9 spinules; TIII/IV with 11 – 12 hooklets; TIV/ V with 7–10 hooklets; TV/VI with 0–2 spinules; SIV/V with 8–9 spinules; SV/VI with 8–9 spinules; SVI/VII with 8–9 spinules, SVII/VIII with 7–8 spinules.

Segment I with 4 D-setae, 1 L-setae, without V-setae; segment II 3 D, 3 L-setae and 3 V-setae; segment III–VII 4 D, 3V-setae and 4 taeniate L-setae; segment VIII with 2 D, 1 V and 4 taeniate L-setae.

Anal lobe distally rounded 82–105 µm long. Anal lobe fringe without lateral setae, posterior with 24 taeniate setae 300 µm long; 3 taeniate macrosetae; inner setae taeniate.

Larva (n = 1–2)

Head ( Fig. 12 G). Head capsule integument smooth. Frontal apotome 187 µm long; head width 107 µm; postmentum 162–167 µm; postmentum/head width 1.56. SI simple. Premandible with outer lateral lamella with a brush. Mentum with three median teeth and six adjacent teeth ( Fig. 12 I). Distance between setae submenti 35 µm. Mandible ( Fig. 12 J) length 30–37 µm. Antennae ( Fig.12 H). AR 0.88. Length of segment I 140 µm, II 72 µm, III 80 µm, IV 5 µm; basal segment width 10 µm; antennal blade not visible; ring organ at 30 µm from the base of first antennal segment. Lauterborn organs inserted on second antennal segment not overreaching the distal border of this segment. Antennal segments two and three brown.

Abdomen. With ventral setae modified, wider and longer ( Fig. 12 K). Subbasal seta on posterior parapod as figure 12L.

Remarks. The larvae from Corynoneura mineira were collected from litter laying near the water surface from small mountain streams. This species was found in Minas Gerais, São Paulo and Rio Grande do Sul states.

Figures

FIGURE 10. Corynoneura mineira sp. n., male. A—terminal flagellomeres. B—thorax. C—wing. D—apex of hind tibia. E and F—hypopygium. E—tergite IX removed, sclerites hatched; left: ventral view, right: dorsal view. F—tergite IX; left: dorsal view, right: ventral view.

FIGURE 11. Corynoneura mineira sp. n., female. A—wing. B, C and D—genitalia. B—dorsal, with view of copulatory bursa. C—ventral view; left: gonapophysis removed. D—detail of labia.

FIGURE 12. Corynoneura mineira sp. n., immatures. A – F—pupa. A—frontal apotome. B—thorax, lateral view. C—tergites I – IX and anal lobe, left: without fringe. D—sternites I – VIII. E—detail of tergite IV. F—detail of posterior shagreen of tergite IV. G – L—larva. G—dorsal view of the head and antenna. H—antenna. I—mentum. J—mandible. K—abdominal setae. Lsub-basal seta of posterior parapod.