Oukuriella pesae, Fusari, Lívia Maria, Roque, Fabio O. & Hamada, Neusa, 2009

Fusari, Lívia Maria, Roque, Fabio O. & Hamada, Neusa, 2009, Oukuriella pesae, a new species of sponge-dwelling chironomid (Insecta: Diptera) from Amazonia, Brazil, Zootaxa 2146, pp. 61-68 : 62-64

Oukuriella pesae sp. n.

Type material. Holotype male with pupal and larval exuviae; BRAZIL: Pará State, Rurópolis, Tambor River, Cachoeira do Grin (04°05’35”S, 55°00’29”W) 28.x.2007. L. M. Fusari, N. Hamada. Paratypes: 2 males with pupal exuviae, 1 pharate female with larval exuviae, 2 last-instar larvae; same data as holotype, except 09.x.2008. L. M. Fusari, N. Hamada, J. O. Silva, A. M. O. Pes.

Etymology. Named in honour of Dr. Ana Maria de Oliveira Pes, for her contributions to the understanding of biodiversity patterns involving aquatic insects and freshwater sponges in Brazil, and in recognition of her help with our fieldwork.

Diagnosis. The male of Oukuriella pesae can be separated from other species in this genus by the following character combination: no setal tufts on anterior portions of abdominal tergites II–VII, T IX with two long projections posteriomedially; and superior volsella with slender digitus. The pupa without pedes spurii B and armament on conjunctive IV/V. The larva is distinguished by its head capsule conical, mandible strongly concave without inner teeth and mentum with a serrated median tooth and the fourth to sixth lateral teeth progressively receding to posterior.

Description. Male (n = 3, except where otherwise stated).

Total length 3.3–4.6 mm. Wing length 1.7–1.8 mm, width 0.5–0.6 mm. Total length/wing length ratio 1.9–2.4. Wing length/profemur length ratio, 1.5 (2). Colour: Head yellowish brown, antennae brownish. Abdomen with tergites II, VII, VIII and IX brown, remainder yellowish brown. Legs with brownish rings on basal 3/5 and apex of femur, base and apex of tibia, ta1 and ta2.

Head ( Fig. 2 B) AR 1.31. Apical flagellomere 620 µm long. Temporals 3. Clypeus with 21–23 setae. Lengths of palpomeres 1–5 (in µm): 37–47; 35–42; 95–137 (2); 122 (1); 170 (1).

Thorax ( Fig. 2 C). Without scutal tubercle. Chaetotaxy: Ac 8–12, Dc 8–9, Pa 1, Scts 7–8.

Wing ( Fig. 2 A). Mostly infuscate, with contrasting light and dark markings in cells r4+5, m1+2, m3+4, an, and cu. VR 1.2–1.5. Squama bare. Brachiolum with 2 setae. R with 11–12; R1 with 12–15; R4+5 with 12 21 setae, remaining veins and cell membranes bare.

Lengths (in µm) and proportions of leg segments as in Table 1. Tibial spur lengths (in µm): fore 55 (1); middle 52–70, hind 52–70.

Abdomen. Tergites without setal tufts.

Hypopygium ( Figs. 1 A, 1B; 2D). T IX with two long projections posteriomedially. Phallapodeme 87.5–90 µm, transverse sternapodeme 50–55 µm long. Superior volsella 62.5–100 µm long, with 7–8 dorsal–distal setae and 7 setae near bend of upper arm, digitus slender, bare, 25–27.5 µm long. Inferior volsella 145–162.5 µm long, with 2 basal setae, 8 dorsal and 1 ventral setae. Gonocoxite 155–165 µm long. Gonostylus slender, 195–200 µm long. HR 0.80–0.82. HV 1.64–2.30.

fe ti ta1 ta2 ta3

p1 1280 (1) 620(1) - - -

p2 1160–1200(3) 720 (2) 600–720(2) 300 (1) 220 (1)

p3 1160–1320 (3) 800–820 (3) 580–640 (2) 460 (1) 340 (1)

continued.

ta4 ta5 LR BV SV p1 - - - - 3.38 (1) p2 140 (1) 80 (1) 0.83 (1) 3.40 (1) 3.20 (1) p3 220 (1) 120 (1) 0.72–0.80 (2) 2.40 (1) 3.31 (1) Female (n = 1, pharate)

Similar to male, except as follows.

Total length about 6.4 mm. Colour: similar to male.

Head: AR = 0.29. Flagellomere lengths (in µm): 175, 125, 130, 100, 152. Clypeus with 11 setae. Palpomere lengths (μm): 50, 45, 120, 152, 162.

Thorax: Without scutal tubercle. Chaetotaxy: Ac 12, Dc 9, Scts 8.

Wing: not observable on pharate specimen.

Legs: not observable on pharate specimen.

Genitalia: Seminal capsule ovoid, about 85 µm long. Spermathecal duct straight. Notum 187 µm. Gonocoxapodeme 227 µm. Dorsomesal lobe, ventrolateral lobe and apodeme lobe as in Figure 3 A. Gonocoxite IX 97 µm long, with 4 setae. Tergite IX with 31 setae. Cerci about 157 µm long.

Pupa (n = 3, except where otherwise stated)

Exuviae yellowish brown. Cephalothorax length 1.34–1.48 mm, abdomen length 3.78 mm.

Cephalothorax. Frontal apotome with low and rounded cephalic tubercles. Dorsal region granular. Two lateral antepronotals, two precorneals, and two separated pairs of dorsocentrals, distances Dc1–Dc2, Dc2–Dc3, Dc3–Dc4 (in µm): 17(1), 190(1), 27(1). Basal ring oval. Prealar tubercle absent.

Abdomen ( Fig. 3 B). Tergites II–VI with shagreen; T V, VI with extensive central shagreen; T I, VII and VIII without shagreen. Hook row continuous, occupying 2/3 width of segment. Pedes spurii B absent; vortex present on segment IV. All conjunctives unarmed. Anal comb with several small teeth on margin and ventral surface ( Fig. 3 C). Segments II–IV with 1 L seta, V–VIII with 4 lateral taeniae. Anal lobe well developed, with approximately 160 long taeniae ( Fig. 3 B).

4th -instar larva (n = 4, including 2 exuviae, unless otherwise stated)

Head ( Fig. 2 E, 2F). Width 230–290(3) µm, length 470– 500(3) µm. IC = 0.49–0.58(3) Antenna 28–55 µm long, with 5 segments; AR = 1.2; ring organ near antennal base; blade longer than flagellum, accessory blade short; Lauterborn organs on apex of segment 2 ( Fig. 3 F). Premandible distally bifid, with brush. Pecten epipharyngis with 3 scales. Mandible strongly concave, 65–90 µm long, without inner teeth, apex black; seta subdentalis slender ( Fig. 3 E). Mentum 47–62 µm with a light-coloured, serrated median tooth and 6 pairs of lateral teeth, the first smaller than the remaining lateral teeth, the first and second light-coloured and nearly level with the median tooth, the fourth to sixth lateral teeth dark and progressively receding to posterior; ventromental plates 42–55 µm wide, medially separated by no more than width of median tooth ( Fig. 3 D). Setae submenti simple, long and slender.

Abdomen 6.7–7.0(2) mm long, reddish, with short posterior parapods carrying strong claws. Anal tubules 25(2) µm long, without constriction. Procerci with 6 coarse anal setae ( Fig. 2 G).

Figures

FIGURE 1. Oukuriella pesae n. sp. Male: A—hypopygium in dorsal view, B—hypopygium with tergite IX removed, left: dorsal view, right: ventral view.

FIGURE 2. Oukuriella pesae n. sp. Male: A—wing, B—head, C—thorax, D—posterior part of abdomen. Larva: E—head in lateral view, F—head in ventral view, G—posterior part of abdomen.

FIGURE 3. Oukuriella pesae n. sp. Female: A—genitalia in ventral view. Pupa: B—abdomen in dorsal view, C—anal comb. Larva: D—mentum and ventromental plate, E—mandible, F—antenna.