Corynoneura mediaspicula, 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 : 12-16

Corynoneura mediaspicula sp. n.

( Figs 7–9 )

Type material. Holotype male with pupal and larval exuviae, BRAZIL, SP, São Paulo, Parque Estadual do Jaraguá, stream near playground, 9.ix.2007, S. Wiedenbrug. Paratypes: allotype female with larval and pupal exuviae, Ubatuba, stream beside Ruínas da Lagoinha, 23˚30.468´S, 45˚11.923´W, 0 m a.s.l., 16.x.2008, S. Wiedenbrug; male with pupal and larval exuviae, same data as holotype, but spring on the way to the Jaraguá peak; female with pupal and larval exuviae same data as allotype; one male and one female with pupal and larval exuviae ( UFS- CAR MPSW 0 37 and 040), 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; one male and one female with pupal and larval exuviae, SP, Jundiaí, Serra do Japí, 23°14´30´´S, 46° 57´16´´W, 18.xii.2007, S. Wiedenbrug.

Diagnostic characters. The adult males are separable from other species by the antenna with 7 flagellomeres, 6 distinct and the last composed of 5 fused flagellomeres, not very plumose with one row of seta each flagellomere, AR about 1.2, eyes pubescent, abdominal segments I–IV whitish, V usually whitish, not as dark as following segments, VI–IX brownish, attachment of the phallapodeme caudal on the lateral sternapodeme, phallapodeme posterior margin sclerotized, rounded and curved to anterior, gonostylus slender tapering apically. Adult females are separable from other species except from C. hermanni by the shape of the labia funnel, seminal capsules size subequal, abdominal segments III–IX brownish. The pupae are distinguished from other species by the shagreen of relatively strong spines even distributed, on tergite IV median spines slightly longer than on posterior field, 4 small taeniate lateral setae on segments III–VIII, anal lobe rectangular separated from each other through a perpendicular margin, anal lobe fringe restricted to posterior margin. The larvae can be recognized by the head integument without sculptures, the mentum with 3 median and 6 lateral teeth, antenna longer than post-mentum, AR 0.81–0.97, second antennal segment longer than the third, basal seta on posterior parapods split from the base.

Etymology. From Latin medius meaning central and spiculum meaning sharp, referring to the spines of the median shagreen field on the pupal tergites being stronger than the rest.

Description. Male (n = 1–4)

Total length [1.00]– 1.27 mm. Wing length 0.52–[0.58]. Total length/wing length [1.73]–2.29. Wing length/ length of profemur 2.65–[3.11].

Color. Thorax brownish; legs whitish; tergites I–IV whitish, V usually whitish, if brown not as dark as following segments, VI–IX brownish.

Head ( Fig. 7 A). AR = [1.16]–1.23. Antenna with [7] flagellomeres, flagellomeres 1–6 distinctly separated from each other, ultimate flagellomere [105]–160 µm long, composed of 5 distinct but fused flagellomeres, two sensilla chaetica at the last flagellomere ( Fig. 7 B). All flagellomeres, except the first and last, with one row of seta each. Temporal setae absent. Clypeus [32] µm long, with 6–7setae. Tentorium [102]–107 µm long; 7–[10] µm wide. Palpomere lengths (in µm): [7]–10, [10], [15], [17], 35–[45]. Third palpomere with one sensilla clavata. Eyes pubescent.

Thorax ( Fig. 7 C). Antepronotum with 1 lateral seta. Dorsocentrals 4, prealars 2. Scutellars 2. Antepronotal lobes dorsally reduced, tapering.

Wing ( Fig. 7 D). VR 3.17–[3.36]. Clavus [25] –27 µm wide, ending 130–[132] µm from arculus. Clavus/wing length [0.23] –0.25. Anal lobe absent.

Legs. Spur of front tibia [20]–22 µm long; spur of middle tibia [10] and 7–[10] µm long; spurs of hind tibia [37] µm long, second spur S-shaped. Width of apex of front tibia 15–[17] µm, of middle tibia 12–[15] µm, of hind tibia 27–[35] µm. Front tibial scale [7] µm long; hind tibial scale [32]–37 µm long ( Fig. 7 E). Leg measurements (in µm) and ratios as in Table 5.

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR p1 185–187 235–240 90–93 62–65 32–35 17 22 0.37–0.43 3.57 4.40–4.72 2.25–2.50 p2 255–280 237–245 130 65–68 33 17 20–25 0.53–0.55 4.45–4.76 3.78–4.04 2.25–2.50 p3 197–200 210–225 125 67–70 27 15 25 0.55–0.59 3.87–4.07 3.26–3.40 4.25–4.75 Abdomen setation. Tergite VI 0–1, VII 3–4, VIII 1.

Hypopygium ( Figs 7 F–H) Tergite IX with 2–4 setae. Laterosternite IX with 2 setae. Superior volsella absent. Inferior volsella smooth with longer microtrichia directed to median. Phallapodeme [20] µm long, rounded and sclerotized on posterior margin; transverse sternapodeme [15] µm long. Gonocoxite 55–[60] µm long. Gonostylus tapering apically [22] µm long; megaseta [6] µm long. HR 2.44–[2.67]; HV [4.43]–4.76.

Female (n = 1)

Total length 1.01 mm (n = 1). Wing length 0.56 mm. Total length/wing length 1.82. Wing length/length of profemur 3.37.

Color. Thorax light brown, brownish vittae, postnotum and anepisternum and preepisternum; legs whitish except for brownish ring anterior on tibia; tergites I–II whitish, III–IX brownish.

Head. AR 0.48. Antenna with 5 flagellomeres, apical flagellomere 50 µm long; two sensilla chaetica on flagellomeres 3–5. Temporal setae absent. Clypeus 37 µm long, with 7 setae. Tentorium 70 µm long, 5 µm wide. Palpomere lengths (in µm): 12, 12, 17,-, 35. Sensilla clavata not possible to see. Eyes pubescent.

Thorax. Antepronotal 1. Dorsocentrals 5, prealars 2. Scutellars 2. Antepronotal lobes dorsally tapering.

Wing ( Fig. 8 A). VR 2.45. Clavus 30 µm wide, ending 225 µm from arculus. Clavus/wing length 0.40.

Legs. Spur of front tibia 10 µm long; spur of middle tibia 7 µm and 7 µm long; spurs of hind tibia 35 µm long, second spur small s-shaped. Front tibial scale 10 µm long. Hind tibial scale 40 µm long. Width of apex of front tibia 15 µm, of middle tibia 15 µm, of hind tibia 30 µm. Leg measurements (in µm) and ratios as in Table 6.

fe ti ta1 ta2 ta3 ta4 ta5 LR BV SV BR p1 165 217 87 55 27 15 25 0.40 3.84 4.37 2.40 p2 250 235 120 62 27 12 20 0.51 4.94 4.04 2.50 p3 195 205 112 65 25 15 22 0.55 4.0 2 3. 56 2.20 Abdomen. One seta on TVI, 3 on TVII, 1 on TVIII.

Genitalia ( Figs 8 B–D). Gonocoxite IX with 1 seta. Tergite IX with 2 setae. Two seminal capsules respectively 32 µm and 37 µm long, one spermathecal duct with a loop, second straighter, both ducts join together short distance before seminal eminence, which has sclerotized outer borders. Notum 70 µm long. Membrane well sclerotized. Apodeme lobe well sclerotized, apically pointed. Coxosternapodeme strongly curved, with one tiny lateral lamellae, coxosternapodeme with one end at the roof of copulatory bursa, the latter semicircle-shaped. Labia membranous, bare, separated, dorsal funnel shaped, apically building the accessory gonopore(?), ventral divided in two lobes (fig.8D). Gonocoxapodeme straight, gonapophyses medially slightly lobed. Post genital plate inconspicuous. Cercus 37 µm long.

Pupa (n = 1–3)

Total length 1.32–1.42 mm.

Cephalothorax. Frontal apotome with granulation ( Fig. 9 A). Frontal setae 55–60 µm long. Median antepronotals 40 µm. Dorsocentrals Dc1 27 µm long; Dc2 25 µm long; Dc3 30 µm long; Dc4 27 µm long. Distance between Dc1 and Dc2 67–77 µm; Dc2 and Dc3 32–37 µm; Dc3 and Dc 4 12–17 µm. Dc1 displaced ventrally. Wing sheath with about 4 rows of pearls.

Abdomen ( Figs 9 B–E)). Tergite I and sternite I–II without shagreen. Tergites II, VIII–IX with fine shagreen. Tergites III–VII with relative strong points evenly distributed, median field of shagreen with slightly stronger shagreen points as posterior ( Fig. 9 D–E). Sternite III with very fine shagreen (not drawn); Sternites IV–VIII with fine shagreen. Conjunctive TII/III with 0–9 spinules; TIII/IV with 18–20 hooklets; TIV/V with 15–19 hooklets; TV/VI with 10–13 hooklets; TVI/VII without hooklets; SIV/V with 10–11 spinules; SV/VI with 8–12 hooklets; SVI/VII with 8–12 hooklets, SVII/VIII with 7–8 hooklets.

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

Anal lobe rectangular 90–105 µm long. Anal lobe fringe without lateral setae, posterior with 11–13 taeniate setae 375–400 µm long and median1–3 shorter and thinner fringe setae; 3 macrosetae taeniate; inner setae taeniate.

Larva (n = 1–4)

Head ( Fig. 9 F). Head capsule integument smooth. Frontal apotome 160 – 185 µm long; head width 110–137 µm; postmentum 130–135 µm; postmentum/head width 0.98–1.18. SI simple ( Fig. 9 G). Premandible with an outer lateral lamella with a brush ( Fig. 9 H). Mentum with three median teeth, intermediate teeth minute, and six adjacent teeth ( Fig. 9 J). Distance between setae submenti 37–42 µm. Mandible length 40–42 µm with outer sclerotized protuberance ( Fig. 9 I). Antennae ( Fig. 9 K). AR 0.81–0.97. Length of segment I 75 –82 µm, II 42 –50 µm, III 37 –40 µm, IV 2–5 µm; basal segment width 12 µm; antennal blade 30–42 µm long; ring organ at 17–25 µm from the base of first antennal segment. Antennal segments two and three brown.

Abdomen. Ventral setae modified, wide and longer ( Fig. 9 L). Subbasal seta on posterior parapod split from the base ( Fig. 9 M).

Remarks. The larvae of Corynoneura mediaspicula were collected from litter laying near the water surface from small mountain streams. This species was found in Minas Gerais and São Paulo states.

Figures

FIGURE 7. Corynoneura mediaspicula sp. n., male. A—head, dorsal view, left, sclerites hatched. B—terminal flagellomeres. C—thorax. D—wing. E—apex of hind tibia. F and G—hypopygium. F—tergite IX; left: dorsal view, right: ventral view. Gtergite IX removed, sclerites hatched; right: dorsal view, left: ventral view. H—gonostylus.

FIGURE 8. Corynoneura mediaspicula sp. n., female. A—wing. B, C and D—genitalia. B—dorsal with view of labia. Cventral view; left: gonapophysis removed. D—ventral view of labia.

FIGURE 9. Corynoneura mediaspicula sp. n., immatures. A – E—pupa. A—frontal apotome. B—tergites I – IX and anal lobe, left: without fringe. C—sternites I – VIII. D—detail of tergite IV. E—detail of posterior shagreen of tergite IV. F – M—larva. Fdorsal view of the head and antenna. G—dorsal view of labrum. H—premandible. I—mandible. J—mentum. K—antenna. Labdominal seta. M—sub-basal seta of posterior parapod.