Larsia hamadae, Oliveira, Caroline Silva Neubern De & Silva, Fabio Laurindo Da, 2011

Oliveira, Caroline Silva Neubern De & Silva, Fabio Laurindo Da, 2011, Two new species of Larsia Fittkau, 1962 (Diptera: Chironomidae: Tanypodinae) from Neotropical Region, with a checklist of Larsia species of the world, Zootaxa 2786, pp. 27-41 : 35-40

Larsia hamadae sp. n.

( Figs 14–26 )

Type material. Holotype male with larval and pupal exuviae, BRAZIL: Amazonas State, Manaus, Igarapé Cabeça Branca, 15/vii/2008, C. S. N. Oliveira & L. M. Fusari. Paratypes: 3 males with larval and pupal exuviae, same data as holotype.

Etymology. Named in honour of Dr. Neusa Hamada, entomologist of the Instituto Nacional de Pesquisas da Amazônia.

Diagnostic characters. Larsia hamadae differs from other Larsia species by combination of the following characters. Male: abdomen yellowish with brown spots; tergite IX with three dorsal setae; anal point bilobed. Pupa: respiratory atrium with distinct central duct. Abdomen pale brown without spots. Tergite IV with pores located lateral to D1. Anal lobe without shagreenation. Larva: head capsule with caudal maculation; second antennal segment and maxillary palp yellow; paraligula pectinate.

Description. Adult male (n = 4 unless otherwise stated)

Dimensions. Total length [1.88] 1.88–2.03 (3) mm. Wing length [1.18] 1.16–1.30 (3) mm. Total length/wing length [1.59]1.51–1.74 (3). Wing length/length of profemur [1.99] 1.99–2.18 (3).

Coloration. Head pale with dark brown occipital margin; pedicel and antenna pale brown; maxillary palp pale brown. Thorax pale with pale brown vittae; antepronotum pale; supraalar callus brown. Wing membrane transparent without spots, veins pale brown and macrotrichia on veins. Legs pale brown. Abdomen yellowish with brown spots. Hypopygium pale brown.

Head ( Fig. 14 ). Antenna with 14 flagellomeres, AR [1.53] 1.40–1.65, flagellum [931] 884–994 μm long, apical seta single, [37] 25–50 long μm. Temporal setae [13] 13–16 (3), uniserial ( Fig. 14 ). Eyes bare, with dorsomedian extension containing [5] 5 (3) terminal facets. Tentorium [151] 138–151 μm long, stipes not measurable. Clypeus [89] 80–89 (3) μm long, [69] 68–69 μm wide at largest part, bearing [12] 12–13 (3) setae. Cibarial pump with anterior margin concave, [211] 186–211 (3) μm long and with orifice [58] 57–58 (3) from apex. Labrum [45] 40– 45 (3) μm wide, with two setae. Palpomere lengths 1–5 (in μm): [39] 39–46; [75] 66–75; [108] 100–117; 130–142 (3); 200–225 (3).

Thorax ( Fig. 15 ). Antepronotum with [2] 2 (2) lateral setae ( Fig. 15 ). Acrostichals [17] 17 (1), biserials; dorsocentrals [23] 23–19 (2), irregularly biserials; prealars [12] 7–14 (3); supraalar 1 (3). Scutellum with [10] 10–15 (3) setae. Anepisternals, preepisternals and postnotals absent.

Wing ( Fig. 16 ). Width [0.30] 0.28–0.31mm. Costa [1.15] 1.00– 1.20 mm long, not produced beyond R4+5, ending very slightly beyond tip of M3+4. R2+3 present. VR [0.90] 0.88–0.93. WW [0.25] 0.22–0.26. Brachiolum with 3 setae. Squama with [12] 9–12 (3) setae.

Legs. Fore leg: tibia with single preapical seta [92] 77–100 (3) μm long and one apical and pectinate spur, teeth unobserved. Mid leg: tibia with single preapical seta [132] 132–136 μm long; two apical and pectinate spurs 19 (2) and 24–32 (2) μm long, with 19–21 (2) and 15–17 teeth respectively. Hind leg: tibia with single preapical seta [111] 85–115 μm long; two apical and pectinate spurs [23] 23–25 and [21] 21–25 μm long, with 10 (1) and 9 (1) teeth respectively. All legs with slender, hook-shaped claws. Pulvilli absent. Lengths and proportion of leg segments in Table 3.

fe ti ta1 ta2 ta3

p1 [594] 531–594 (3) [700] 600–700 (3) [613] 513–613 (3) [294] 275–294 (3) [207] 200–207 (3) p2 [625] 550–625 [588] 500–625 [469] 398–469 (3) [194] 194–200 (3) [131] 130–131 (3) p3 [588] 544–594 [744] 638–813 [619] 563–682 [288] 288–331 [200] 200–210 (3)

ta4 ta5 LR BV SV

p1 [138] 138 (3) [88] 88–94 (3) [0.88] 0.85–0.88 (3) [2.63] 2.33–2.63 (3) [2.11] 2.08–2.21(3) p2 [94] 94 (3) [69] 69–75 (3) [0.80] 0.77–0.80 (3) [3.45] 2.93–3.45(3) [2.59] 2.59–2.74 (3) p3 [131] 131–138 (3) [81] 81–83 (3) [0.83] 0.83–0.88 [2.79] 2.47–2.79 (3) [2.15] 2.06–2.17 Hypopygium ( Fig. 17 ). TIX arched, with three dorsal setae. Anal point bilobed. Phallapodeme 37–38 (2) μm long. Sternapodeme pointed anteriorly. Gonocoxite elongate, [154] 143–154 μm long, with slightly concave inner margin; inferior volsella absent. Gonostylus simple, [100] 95–112 μm long; megaseta [11] 8–11 μm long. HR [1.54] 1.32–1.54. HV [1.88] 1.75–1.88.

Pupa (n = 3 unless otherwise stated)

Dimensions. Male abdomen [2.20] 2.00– 2.35 mm long.

Coloration. Exuviae and most of thoracic horn pale brown.

Cephalothorax ( Figs 18–20 ). Frontal apotome dome-shaped. Wing sheath smooth [831] 763–875 mm long and [281] 263–294 mm wide ( Fig. 18 ). Thoracic horn as in figures 19–20, [189] 169–206 μm long and [48] 35–48 μm wide; plastron plate [35] 23–35 μm long. Horn sac alveolar, filling most of the respiratory atrium. Basal lobe wedge-shaped. Thoracic comb with [13] 13–15 conical teeth.

Abdomen ( Figs 21–22 ). Tergites I–VIII with shagreen composed of groups of 3–8 small spinules, serially arranged in transverse arched rows. T I with scar, [138] 138–162 (2) μm long. Chaetotaxy on segment IV as in figure 21. T VII with 4 lateral filaments. T VIII with 5 lateral filaments. Anal lobe as in figures 21–22, [340] 331–358 μm long and [175] 166–185 μm wide, with two anal macrosetae, outer margins spinulate, inner margins without spinules. Genital sac smaller than anal lobe, [222] 215–243 long, shagreen present. GS/AL [0.65] 0.65– 0.68.

4th instar larva (n = 3 unless otherwise stated)

Coloration. Head pale yellow, with caudal maculation; postoccipital margin brown. Second antennal segment and maxillary palp yellowish; distal tooth of mandible and apex of ligula brown. Abdomen pale yellow; procercus and anal setae pale brown. Posterior parapod claws pale yellow.

Head ( Fig. 23 ). Length [425] 419–431 μm, [400] 375–405 μm wide; IC [0.94] 0.89–0.94. Chaetotaxy as in figures 21.

Antenna. Length [286] 286–298 μm long, A1 [228] 228–238 μm long, with ring organ placed [135] 92–137 μm from base, A2 [49] 49, 49 μm long. AR [3.89] 3.89–3.97.

Maxilla ( Fig. 24 ). Basal palp segment [48] 40–48 μm long and [9] 7–9 μm wide, with ring organ [22] 22–23 μm from base, A1/P1 [5] 5–6, A2/P1 [1.03] 1.03–1.23.

Mandible. Length [83] 62–83 μm, with 3 lateral setae and 1 sensillum campaniformium. A1/MD [2.74] 2.74– 3.88.

Mentum and M appendage. Dorsomental teeth [15] 15–16 μm long; pseudoradula uniformly granulate.

Hypopharyngeal complex ( Fig. 25 ). Ligula [68] 65–69 μm long, maximum width [34] 32–34 μm, anterior toothed margin concave. It/O [1.00] 1.00–1.05. Mt/O [0.78] 0.78–0.84. It/Li [0.13] 0.13–0.14. Muscle attachment [9] 9 (2) long. Paraligula pectinate. Pecten hypopharyngis with 10 teeth.

Body ( Fig. 26 ). Without lateral fringe. Anterior parapods with simple claws. Procercus [111] 109–118 μm long, [23] 20–25 μm wide, with 7 anal setae [391] 391–406 μm long. L/W [4.80] 4.44–5.92. Supraanal seta [323] 308– 445 μm long. Anal tubules not measurable. Posterior parapod apex with hooklets and numerous simple claws.

Remarks. The male of L. hamadae resembles L. fittkaui Sublette & Sasa and L. planensis Johannsen , but can be separated based on abdominal coloration with brown spots, on higher number of teeth on tibial spurs of legs II and III, and on bilobed anal point. The pupa of L. hamadae is similar to pupa of L. reissi Sublette & Sasa distinguishing by the thoracic horn morphology, presence of shagreen on genital sac and chaetotaxy of tergite IV. The larva of L. hamadae seems to be closely related to L. gelhausi except for pectinate paraligula and coloration pattern of cephalic capsule.

Figures

FIGURES 14 – 17. Larsia hamadae sp. n., adult male. 14. Temporal setae. 15. Antepronotal lobe. 16. Wing. 17. Hypopygium, left: ventral aspect, right: dorsal aspect. Scales: Figs 14 – 15, 17 = 100 μm; 16 = 500 μm.

FIGURES 18 – 22. Larsia hamadae sp. n., pupa. 18. Wing sheath. 19. Thoracic horn with basal lobe and thoracic comb. 20. Thoracic horn. 21. Abdominal segments with chaetotaxy, left: ventral aspect, right: dorsal aspect. 22. Anal lobe and male genital sac, ventral aspect. Scales: Figs 18 = 500 μm; 19 – 21 = 100 μm; 22 = 1000 μm.

FIGURES 23 – 26. Larsia hamadae sp. n., larva. 23. Head with chaetotaxy, left: ventral aspect, right: dorsal aspect. 24. Maxillary palp. 25. Ligula, paraligula and pecten hypopharyngis. 26. Apical claws of posterior parapods. Scales: Figs 23 = 500 μm; 24 = 50 μm; 25 – 26 = 100 μm.