Sigmoitendipes susanae, Andersen & Mendes & Pinho, 2017

Andersen, Trond, Mendes, Humberto Fonseca & Pinho, Luiz Carlos, 2017, TWO NEW NEOTROPICAL CHIRONOMINAE GENERA (DIPTERA: CHIRONOMIDAE) Abstract, CHIRONOMUS Journal of Chironomidae Research 30 (30), pp. 26-54 : 41-45

Sigmoitendipes susanae new species

http://zoobank.org/ 5F79CF91-9117-4B94-8804- 1D4D7DE88CAE

Type material: Holotype: BRAZIL, São Paulo, Ribeirão Preto, Lago Monte Alegre , 21°11’S 47°43’W, 9.v. 2000, 500 m a.s.l., HF Mendes, 1 male with larval and pupal exuviae (reared) ( MZUSP) . Paratypes: BRAZIL, São Paulo, Parque Estadual da Serra do Mar, São Luís do Paraitinga, Núcleo Santa Virgínia , 14.iv.2009, light trap, R Mariano, LS Lecci, G Schulz, 1 male ( UFSC) . Amazonas: Coari ( BOGPM) , Urucu, igarapé Martha , 04°51’50”S 65°04’45”W, 05–06. xi.2007, Pensylvannia trap, SRM Couceiro, 9 males ( MZUSP, ZMBN) ; as previous except: 16– 21.xi.2007, 1 male ( UFSC) . Mato Grosso: Nova Xavantina area, igarapé Garapuat , expedition camp I, 24–27 viii.1965, Brundin net, EJ Fittkau, 1 male ( ZSM - A565-4 ) . Pará: near border to Suriname, Parque Indígena Tumucumaque, igarapé Okueima , 18.iv.1962, at light, EJ Fittkau, 1 male ( ZSM - A371-1 ) ; as previous except: Parque Indígena Tumucumaque , “Kumadueni”, onça site, 19.iv.1962, 1 male ( ZSM - A377 ) ; as previous except: Rio Paru, Malloca Apicó , 14.iv.1962, 1 male ( ZSM - A366-1 ) ; as previous except: between Furo Maripanema and Rio Curuçá near the Atlantic Ocean , igarapé 7 km from Curuçá , 13.viii.1953, H Sioli, 1 male ( ZSM) .

Etymology: Named in honor of Professor Dr. Susana Trivinho-Strixino for her numerous contributions to the knowledge of Brazilian chironomids.

Diagnostic characters: See key.

Description

Male (n = 7–9, except when otherwise stated). Total length 4.44–5.15, 4.89 mm. Wing length 1.87–2.12, 2.00 mm. Total length / wing length 2.34–2.51, 2.44. Wing length / length of profemur 1.40–1.48, 1.44.

Coloration. Thorax brown, head and abdomen light brown, legs pale brown. Wing translucent.

Antenna. AR 2.13–2.27, 2.20. Ultimate flagellomere 882–972, 927 µm long.

Head ( Fig. 7A ). Temporal setae 20–29, 22; including 2–4, 3 inner verticals, 8–14, 10 outer verticals, partly biserial, and 8–13, 10 postorbitals. Clypeus with 14–25, 21 setae. Frontal tubercle indicated as paler area to small knob. Tentorium, stipes and cibarial pump as in Figure 7B . Tentorium 144–160, 152 µm long; 39–49, 44 µm wide. Stipes 129–160, 142 µm long; 6–10, 8 µm wide. Palp segment lengths (in µm): 37–41, 40; 45–57, 53; 82–90, 87; 92–113, 106; 123–148, 136. Third palpomere with 3–5, 4 sensilla, longest 23–27, 25 µm long.

Thorax ( Fig. 7C ). Antepronotum without setae. Dorsocentrals 5–7, 6; acrostichals apparently 6–10, 8, erect, starting some distance from antepronotum; prealars 3. Scutellar setae 10–13, 11, partly biserial.

Wing ( Fig. 8A ). VR 1.09–1.13, 1.10. Brachiolum with 2 setae; R 26–34, 29; R 1 with 21–26, 25; R 4+5 with 30–37, 34 setae, other veins and cells bare. Squama with 6–11, 9 setae.

Legs ( Figs 7D–F ). Scale of fore tibia 47–55, 52 µm long; spur of mid tibia 57–62, 59 µm long including 29–36, 32 µm long comb; spurs of hind tibia 46–52, 50 µm and 40–46, 42 µm long including 29–33, 30 µm long comb. Width at apex of fore tibia 59–65, 63 µm; of mid tibia 61–68, 64 µm; of hind tibia 66–75, 70 µm. Lengths and proportions of legs as in Table 3 .

Hypopygium ( Figs 8B, C ). Tergite IX covered with microtrichia; laterosternite IX with 2–5, 3 setae. Anal point 29–33, 31 µm long, 5–7, 6 µm wide at base, 11–14, 13 µm wide subapically, with 3–8, 6 setae to each side of the base, of which about half on the ventral side. Transverse sternapodeme 46–55, 50 µm long, concave. Phallapodeme 99–108, 103 µm long. Gonocoxite 164–178, 170 µm long. Superior volsella ( Fig. 8D ) boot-shaped, 94–108, 101 µm long, medially with partly double, rounded, setose lobe, apical part sparsely setose, with 10–14, 12 setae, apex recurved. Inferior volsella 131–149, 138 µm long; 23–26, 24 µm wide at base; 11–14, 12 µm wide at its narrowest; with 19–23, 21 µm long dorsal, bluntly triangular projection, starting 69–77, 73 µm from base; apically subrectangular, 18–21, 20 µm wide; with 14–19, 16 simple setae, longest apical seta 76–87, 80 µm long. Gonostylus 201–230, 219 µm long. HR 0.73–0.85, 0.78. HV 2.16–2.46, 2.28.

Female. Unknown.

Pupa (exuviae, n = 1). Total length 3.54 mm.

Coloration. Exuviae with light brown cephalothorax, wing sheath pale brown with slightly darker margins, abdominal segments VI–VII pale brown, caudolateral spur brown.

Cephalothorax ( Fig. 9B ). Frontal apotome ( Fig. 9A ) subtriangular, with wrinkles, 368 μm long, 332 μm wide. Cephalic tubercle conical, 36 μm long, frontal setae 65 μm long. Median antepronotal slightly taeniate, about 83 μm long. Precorneals close together, both slightly taeniate, anterior precorneal about 48 μm long, posterior precorneal about 83 μm long. Dc 1 62 μm long, Dc 2 76 μm long, Dc 3 73 μm long, Dc 4 78 μm long; Dc 1 54 μm in front of Dc 2, Dc 2 225 μm in front of Dc 3, Dc 3 39 μm in front of Dc 4. Wing sheath 1.44 mm long, without nose or pearl row.

Abdomen ( Fig. 9C ). Tergite I bare, tergites II–VI each with 4 rows of strong spinules in anteriomedial band, tergites II–V each with medial anterior to posterior patches of finer shagreen, tergite VI with posterior patch of fine shagreen, tergites VII–VIII without spinules. Tergite II with 38 caudal hooklets in single, 388 μm wide row. Spinules on conjunctive III/IV in 3–4 rows; on conjunctive IV/V in 5–6 rows in separate, lateral patches. Pedes spurii A well-developed posterior on segment IV; indicated on segment V. Pedes spurii B well-developed posterior on segment II. Caudolateral spur ( Fig. 9D ) 145 μm long, with 1 strong apical tooth and 3 weaker teeth.

Abdominal setation. Segment I without lateral setae; segments II–IV each with 3 short, hair-like lateral setae; segments V–VI each with 3 taeniae; segment VII with 4 taeniae; segment VIII with 5 taeniae.

Anal lobe. Anal lobe fringe with 47 taeniae. Male genital sac overreaches anal lobe by 82 μm.

Larva (exuviae, n = 1). Total length not measurable. Head capsule 420 µm long. Postmentum 180 µm long.

Coloration. Head capsule brown with teeth of mentum and mandible and postoccipital margin dark brown.

Head. AR 0.93; antennal ( Fig. 10B ) segment lengths (in µm): 57, 22, 10, 8, 11, 10. Basal antennal segment 30 µm wide; ring organ 18 µm from base; blade 67 µm long; accessory blade 7 µm long; Lauterborn organ 18 µm long. Pecten epipharyngis and premandible not discernible. Mandible ( Fig. 10C ) 135 µm long, with 1 dorsal, 1 apical and 4 inner teeth; seta subdentalis 36 µm long, slender and straight; setae interna prominent. Mentum ( Fig. 10A ) 124 µm wide, with 8 pairs of teeth; pair of median teeth 19 µm wide, first lateral tooth larger than median tooth, second lateral tooth smaller than first lateral tooth, third lateral tooth larger than second lateral tooth, fourth to sixth lateral teeth decrease progressively to a minute seventh tooth. Ventromental plate ( Fig. 10A ) 142 µm wide; distance between plates 39 µm; median apices of plates pointing towards each other. Ratio of ventromental plate / mentum 1.15. Setae submenti 55 µm long.

Abdomen. Not measurable.

Distribution and ecology

Found in São Paulo, Mato Grosso, Amazonas and Pará states. Fittkau collected the species using Brundin nets in shallow Amazonian forest streams of first, second or third order in evergreen tropical inundation forest. The streams were 1–2 m wide, shallow, flowing, and with bottoms of sand and leaves. During the flood season the water level in the streams rose up to approximately 4 m higher.

Figures

Figure 7. Sigmoitendipes susanae n. sp., male.A, Head. B, Tentorium, stipes and cibarial pump. C, Thorax. D, Scale of fore tibia. E, Comb of mid tibia, lateral view. F, Comb of mid tibia, posterior view.

Figure 8. Sigmoitendipes susanae n. sp., male.A, Wing. B, Hypopygium, dorsal view. C, Hypopygium with anal point and tergite IX removed, dorsal aspect to the left and ventral aspect to the right. D, Superior volsella.

Figure 9. Sigmoitendipes susanae n. sp., pupa.A, Frontal apotome. B, Thorax. C, Abdomen. D, Caudolateral spur.

Figure 10. Sigmoitendipes susanae n. sp., larva.A, Antenna. B, Mandible. C, Mentum and ventromental plates.