Stenochironomus liviae Dantas, Hamada & Mendes, 2016, new species
Creators: name: Dantas, Galileu P. S.
name: Hamada, Neusa
name: Mendes, Humberto F.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Chironomidae
Stenochironomus
Stenochironomus liviae

description: Stenochironomus liviae new species
(Figs. 20–23)
Type material. Holotype male with pupal exuviae, BRAZIL: Amazonas state, Itacoatiara, Madeireira Mil, 02º 46’37.7’’ S, 58º 50’38.3’’ W, 25.v.2009, in decayed wood, G.P.S. Dantas, S.C. Escarpinati (INPA). Paratypes: 1 male with pupal exuviae, same locality as holotype collected 02º 46’43.1’’ S, 58º 38’54.0’’ W, 02.v.2009; 1 male, BRAZIL: Amazonas state, Manaus, igarapé da UFAM, 03º 05’ 57.2’’ S, 59º 58’ 0 5.8 W, 15.x.2007, P. Picanço; 1 male, BRAZIL: Santa Catarina state, São Domingos, rio Chapecó, swarm at 18:00, 07.x.2004, L.C. Pinho (MZUSP); 1 male with pupal and larval exuviae, BRAZIL, Bahia state, Camacan, Serra Bonita, 15º 23’ 28’’ S, 39º 33’56’’ W, 820m altitude, 31.vii.2008, in decayed wood, A.R. Calor, L.S. Lecci, L.C. Pinho, F.A. Moretto (MZUSP).
Diagnostic characters. Male: thorax with dark-brown patch on median region of the scutum, lateral vitta with dark pigmentation running along the anterior and median margins; anal point bulbous at apex, strongly curved in lateral view; front femur and tibia densely covered by setae. Pupa: frontal apotome elongated; frontal warts present, triangle-shaped; pedes spurii B present on T II. Larvae: ventromental plate with weak crests near the anterior margin; SI pinnate, SII bifurcated, SIII simple; labiohypopharynx with ligular lobes truncated without small projection on lateral margin; micropore located antero-laterally to setae submenti.
Etymology. the species is named in honor of Dr. Livia Fusari for her cooperation and encouragement during this study.
Male (n = 5, except when otherwise stated). Total length 6.25–7.94, 7.12 mm. Wing length 2.79–3.32, 3.14 mm. Total length/ wing length 2.13–2.39, 2.26. Wing length/ length of profemur 1.20–1.45, 1.30.
General coloration: Eyes metallic green when alive or in alcohol; flagellomere antennal setae light brown; wing yellowish with distal half of membrane slightly more dark than proximal half. Thorax with dark-brown patch on median region of the scutum; lateral vitta with dark pigmentation running along the anterior and median margins. Legs: front femur, tibia and ta1- ta2 yellowish with brownish apex; median and posterior legs yellowish. Femur and tibia of the front leg densely covered by setae that are yellowish at base and dark brown at apex.
Head (Fig. 20 A). AR 1.84–2.05, 1.95. Thirteenth flagellomerum 1084–1373, 1220 µm long. Temporal setae 13–18, 16. Clypeus with 27–39, 33 setae. Tentorium, stipes and cibarial pump as in Figure 17 A. Tentorium 197– 268, 229 µm long; 50–58, 54 µm wide at sieve pore; 24–34, 27 µm wide at posterior tentorial pit. Stipes 213–245 (2) µm long; 8–10 (2) µm wide. Palpomere lengths (in µm): 70–77, 73; 76–85, 79; 295–371, 338; 175–228, 200; 303–388, 339.
Thorax (Fig. 20 B). Acrostichals 7–13, 11; dorsocentrals 5–9, 8 in a single row; prealars 3–5, 4. Scutellum with 10–17, 14 setae in two rows. Anterior edge of scutum angled in lateral aspect.
Wing (Fig. 20 D). VR 1.07–1.10, 1.09. Brachiolum with 3–5, 4 setae. R with 58–64, 61 setae; R1 with 64–75, 70 setae; R4+5 with 77–93, 86 setae; M with 1–3, 2 setae; RM with 0–6, 3 setae; remaining veins bare. Squama with 5–12, 8 setae.
Legs. Scale of front tibia 59–74, 70 µm long, with small spine at apex; spurs of middle tibia 40–43, 42 µm and 42–52, 48 µm long; spurs of hind tibia 39–55, 46 µm and 41–60, 50 µm long. Apex of fore tibia 74–112, 92 µm wide, of mid tibia 82–115, 97 µm wide, of hind tibia 92–114, 102 µm wide. Lengths (in µm) and proportions of legs as in Table 6.
fe ti ta1 ta2 ta3 ta4
p1 2194–2625 1901–2259 2765–3331 1378–1630 1158–1384 1053–1227
p2 1847–2167 1553–1761 1000–1117 482–561 412–470 231–272
p3 2195–2547 1900–2199 1353–1484 735–824 618–733 342–366 ta5 LR BV SV BR
p1 330–364 1.45–1.47 1.75–1.78 1.46–1.48 4.5–5.3
p2 110–133 0.63–0.64 3.51–3.56 3.40–3.52 3.9–3.5
p3 130–155 0.67–0.71 2.98–3.00 3.03–3.20 4.4–4.7 Hypopygium (Figs. 20 C, 21A, 21B, 21C). Anal point bulbous at apex (Fig. 21 B); 140–156, 150 µm long; 23– 35, 28 µm wide at base; 12–15, 14 µm wide at half; 24–28, 26 µm wide at apex. Tergite IX with 54–72, 66 strong setae, caudal apex rounded with pre-apical constriction in dorsal aspect. Laterosternite IX with 4–7, 6 setae. Phallapodeme 183 (1) µm long; transverse sternapodeme 39–55, 46 µm long. Gonocoxite 248–305, 278 µm long; inferior volsella 273–345, 297 µm long, with 7–11, 9 setae, apical setae stout; superior volsella 96–125, 106 µm long, with 6–10, 8 setae distributed along most of length. Gonostylus 242–290, 268 µm long. HR 1.02–1.05, 1.04. HV 2.45–2.86, 2.66.
Pupa (n = 3) except when otherwise stated). Total length 7.74–9.73 (2) mm. Coloration: cephalothorax and abdomen light brown.
Cephalothorax (Figs. 22 A, 22B). Frontal apotome elongated; frontal warts present, triangle-shaped (Fig. 22 B). Precorneal setae 36–38 µm long. Dorsocentrals (Dc) 58–85 µm long. Distance between Dc1 and Dc2 (1) 6 µm; between Dc2 and Dc3 (1) 249 µm; between Dc3 and Dc4 (1) 5 µm. Median suture granulose.
Abdomen (Figs. 17 E, 22C, 22D). T I bare; T II–V with large field of shagreen; T VI with field of shagreen restricted to posterior margin; T VII–VIII without shagreen; anal segment with anterior pair of shagreen patches. TII with posterior row of hooklets extending to lateral margin of tergite, divided medially into two groups by a distance of 160 µm. Abdominal setation: S I without L setae; S II–IV with 3 L setae; S V–VII with 4 LS setae; S VIII with 5 LS setae. Pedes spurii B present on II segment (Fig. 22 C). Spur on S VIII with 5 brownish teeth (Fig. 22 E). Genital sac 498 (1) µm long, overreaching the posterior margin of the anal lobe by 51 µm; anal lobe rounded at apex, with fringe of about 100 filaments.
Fourth-instar larva (n = 1). Head (Fig. 20 F). Antenna as in Figure 23 A; length of antennal segments (in µm): 97; 34; 13; 13; 6. Blade 32 µm long. Labral lamella with two groups of spicules in a comblike arrangement, pecten epipharyngis not visible. S1 pinnate, not measurable; S2 bifurcated, 28 µm long; S3 simple, 22 µm long. Premandible 110 µm long. Mandible (Fig. 23 B) 253 µm long, with with 3 inner teeth. Mentum concave (Fig. 23 D), 192 µm wide, with 12 blackish teeth; micropore located antero-laterally to setae submenti; ventromental plate with weak crests near anterior margin. Base of dorsolateral strip originating on posterior ⅓ of dorsomedian strip. Labiohypopharynx (Fig. 23 C) with ligular lobes truncated, with cleft between lobes very narrow, nearly parallel sided.
Female unknown.
Systematic remarks. The larva of S. liviae sp. nov. is similar to S. roquei and S. jubatus. However, S. liviae sp. nov. can be distinguished from S. roquei by the absence of small tubercles on the lobes of labiohypopharynx. The larvae of S. liviae sp. nov. can be distinguished from S. jubatus by the position of the micropore, which is anterolateral to the setae submenti.
Notes on biology of the species. The larvae of S. liviae sp. nov. are wood miners and adults were reared from wood with width ranging from 20 to 2 centimeters in diameter, all still with bark. Some specimens of S. liviae sp. nov. and S. roquei Dantas, Hamada & Mendes were obtained from the same piece of wood.
The species has a wide distribution in Brazil, registered in the Amazon and Atlantic forest. Probably this apparently disjunct distribution is a reflection of the studies focusing on chironomid fauna performed in these two biomes, which does not happen in the intermediate areas, consisting of the Cerrado, Caatinga and Pantanal (see discussion in Pinho et al. 2009). Future collections in these poorly sampled areas could help us to better understand the distribution of this and other chironomid species.
description: Published as part of Dantas, Galileu P. S., Hamada, Neusa & Mendes, Humberto F., 2016, Contribution to the knowledge of Stenochironomus Kieffer (Diptera, Chironomidae) from Brazil: seven new species and description of females and immatures of some previously known species, pp. 1-47 in Zootaxa 4117 (1) on pages 28-32, DOI: 10.11646/zootaxa.4117.1.1, http://zenodo.org/record/266257