Hudsonimyia caissara, Silva & Wiedenbrug & Trivinho-Strixino & Oliveira & Pepinelli, 2012

Silva, Fabio Laurindo da, Wiedenbrug, Sofia, Trivinho-Strixino, Susana, Oliveira, Caroline Silva Neubern de & Pepinelli, Mateus, 2012, Two new species of Hudsonimyia Roback, 1979 (Diptera: Chironomidae: Tanypodinae) from Neotropical Region unveiled by morphology and DNA barcoding, Journal of Natural History 46 (25 - 26), pp. 1615-1638 : 1623-1626

Hudsonimyia caissara sp. nov.

( Figures 1–3 )

Type material

Holotype. Male with pupal and larval exuviae, BRAZIL, SP, Ubatuba, stream beside Ruínas da Lagoinha, 23 ◦ 30.468’ S, 45 ◦ 11.923’ W, 0 m above sea level (a.s.l.), 1 May 2009, S. Wiedenbrug.

Paratype. One male with larval and pupal exuviae, same data as holotype.

Etymology

From the indigenous Tupi language (Caiçara = inhabitants of coastal areas), refers to the region where type material was collected. The name should be regarded as noun in apposition.

Diagnostic characters

Hudsonimyia caissara sp. nov. differs from other Hudsonimyia species by the combination of the following characters.

Male imago. Head with frontal temporal setae uniserial frontally, thorax with 8–10 prealar setae, one widely separate from others anteriorly, tergite I–V and VII–VIII with brown transverse and lateral bands near proximal margin and VI pale brown.

Pupa. Surface of thoracic horn opposite to plastron plate with few spinules, corona forming a diagonal angle to the respiratory atrium.

Larva. Head with maculation on the distal margin, occupying about one-quarter length of head.

Description – adult male (n = 2 unless otherwise stated)

Dimensions. Total length 2.44–2.74 mm. Wing length 1.52–1.66 mm. Total length / wing length 1.60–1.65. Wing length / length of profemur 2.24–2.31.

Colouration. Head pale yellow; pedicel, antenna and maxillary palp pale brown. Thorax pale yellow with pale brown vittae; antepronotum pale; supra-alar callus pale brown. Wing membrane transparent without spots, veins pale brown and macrotrichia on veins. Legs pale brown. Tergite I–V and VII–VIII with brown transverse and lateral bands near proximal margin and VI pale brown. Hypopygium brown.

Head ( Figure 1A,B ). Antenna with 14 flagellomeres, AR 0.97 (1), flagellum 720 (1) µm long, diameter of pedicel 126 (1) µm, apical setae single ( Figure 1B ). Temporal setae 11 (1), uniserial ( Figure 1A ). Eyes bare, with dorsomedian extension containing three (1) terminal facets. Tentorium 158 (1) µm long, stipes not measurable. Clypeus 106 (1) µm long, 78 (1) µm wide at largest part, bearing 14 (1) setae. Cibarial pump with anterior margin concave, 202 (1) µm long. Palpomere lengths 1–5 (in µm): 38 (1); 51 (1); 88 (1), 123 (1); 134 (1).

Thorax ( Figure 1C ). Antepronotum with one or two lateral setae. Acrostichals 44–46, biserial; dorsocentrals 30–34, irregularly uniserial; prealars 8–10, one widely separate from others anteriorly ( Figure 1C ); supra-alars 1. Scutellum with [8] eight setae. Anepisternals, pre-episternals and postnotals absent.

Wing ( Figure 1D ). Width 0.41–0.49. Costa 1.40–1.52 mm long, not produced beyond R 4+5, ending very slightly beyond tip of M 3+4. R 2+3 present. Base of radial sector 0.03–0.05 mm long. VR 0.75–0.82. WW 0.27–0.30. Brachiolum with three setae. Squama with 9–17 setae.

Legs ( Figure 1E–G ). Fore leg: tibia one apical spur 19–25 µm long with four teeth ( Figure 1E ). Mid leg: tibia with two apical spurs 15–18; 11–15 µm long, longest spur with four teeth, shortest spur with three teeth ( Figure 1F ). Hind leg: tibia with one apical spur 21 µm long, with four teeth ( Figure 1G ). All legs with slender, hook-shaped claws. Pulvilli absent. Lengths and proportion of leg segments as in Table 2.

Hypopygium ( Figure 1H,I ). Tergite IX with irregular row of seven to nine dorsal setae. Anal point present. Phallapodeme long and narrow, 63 µm long. Sternapodeme curved anteriorly. Gonocoxite cylindrical, 94–97 µm long, with slightly concave inner margin. Gonostylus simple, 58–60 µm long; megaseta 11–14 µm long. HR 1.56–1.66. HV 4.04–4.13.

Description – pupa (n = 2 unless otherwise stated)

Colouration. Exuviae yellow. Thoracic horn most pale brown.

Cephalothorax ( Figure 2A,B ). Wing sheath smooth 981–1069 µm long and 319–375 µm wide. Thoracic horn as in Figure 1G , 244–256 µm long and 75–100 µm wide, with few spinules on the surface opposite to plastron plate; plastron plate large, 91–92 µm long. Corona forming a diagonal angle to the respiratory atrium. Respiratory atrium tubular, narrower than lumen. Round basal lobe present. Thoracic comb absent, rugose area present near base of thoracic horn.

Abdomen ( Figure 2C,D ). 2.59–2.74 mm long. Tergites I–VIII with shagreen composed of short spinules, with extremity sharp pointed, serially arranged individually in indistinct rows ( Figure 2D ), extending the full length of segments. T I with scar, 120–122 µm long. Chaetotaxy of segment IV as in Figure 2C. T VII with two lateral setae. T VIII with five lateral setae surpassing insertion of macrosetae. Anal lobe as in Figure 2C , 363–400 µm long and 256–263 µm wide, with two anal macrosetae; outer and inner margins with spinules. Genital sac smaller than anal lobe, with 163–181 µm long. GS / AL 0.41–0.50.

sp. nov., male (n = 2).

Description – fourth instar larva (n = 2 unless otherwise stated)

Colouration. Head pale yellow, distal margin one-quarter pale brown; postoccipital margin brown; distal tooth of mandible and apex of ligula brown. Abdomen pale yellow; procercus and anal setae pale brown. Posterior parapod claws all pale yellow.

Head ( Figure 3A ). Length 569–594 µm, 388–419 µm wide; cephalic index 0.65–0.74. Chaetotaxy as in Figure 2A .

Antenna ( Figure 3B ). Length 500–535 µm long, A 1 254–256 µm long, with ring organ placed 144–152 µm from base, A 2 68 µm long. AR 3.25–3.31.

Maxilla ( Figure 3C ). Basal palp segment 48 µm long and 7–8 µm wide, with ring organ 21 µm from base, A 1 / P 1 5.22–5.31, A 2 / P 1 1.38–1.42.

Mandible ( Figure 3D ). Length 83–97 µm, with three lateral setae. Sensillum campaniformium 63–71 µm from apex. A 1 / MD 2.63–3.01.

Mentum and M appendage ( Figure 3E ). Dorsomental teeth reduced; pseudoradula uniformly granulate, 104–116 µm long.

Hypopharyngeal complex ( Figure 3F,G ). Ligula 66–71 µm long, maximum width 37–42 µm, anterior toothed margin slightly concave. It / O 0.96–1.00. Mt / O 0.96. It / Li 0.96–1.00. Muscle attachment 20–22 long. Paraligula bifid, 28–31 µm long, inner tooth 21–24 µm long, shorter than outer tooth. Pecten hypopharyngis with 16–17 teeth almost equal in size ( Figure 3G ).

Body. Without lateral fringe. Anterior parapods with simple claws. Procercus 131–150 µm long, 19–25 µm wide, with seven anal setae 339–425 µm long. L / W 7–8. Supraanal seta 356–400 µm long. Anal tubules not measurable. Posterior parapod apex with hooklets and numerous simple claws.

Ecology

The two larvae of Hudsonimyia caissara were found in leaf litter of a small mountain stream. However, we hesitate to record this biotype as characteristic to this species, because of the small number of larvae sampled.

Figures

Figure 1. Hudsonimyia caissara sp. nov.: adult male. (A) Head, frontal view. (B) Apex of antenna. (C) Thorax. (D) Wing. (E–G) Tibial spurs of P1 (E), P2 (F), and P3 (G). (H) Tergite IX and anal point. (I) Hypopygium with tergite IX and anal point removed, left: dorsal aspect, right: ventral aspect.

Figure 2. Hudsonimyia caissara sp. nov.: pupa. (A) Thoracic horn with basal lobe. (B) Thoracic horn surface opposite to plastron plate. (C) Abdominal segments with chaetotaxy, anal lobe and male genital sac, right: ventral aspect, left: dorsal aspect. (D) Shagreen pattern on abdominal segments surface.

Figure 3. Hudsonimyia caissara sp. nov.: larva. (A) Head with chaetotaxy, left: dorsal aspect, right: ventral aspect. (B) Antenna. (C) Maxillary palp detail. (D) Mandible. (E) Mentum and M appendage. (F). Ligula and paraligula. (G) Pecten hypopharyngis.