Labrundinia fittkaui Silva

Silva, Fabio Laurindo Da, Fonseca-Gessner, Alaide Aparecida & Ekrem, Torbjørn, 2014, A taxonomic revision of genus Labrundinia Fittkau, 1962 (Diptera: Chironomidae: Tanypodinae), Zootaxa 3769 (1), pp. 1-185 : 39-44

Labrundinia fittkaui Silva sp. n.

( Figs 16–18 )

Material examined. Type material: Holotype male with pupal and larval exuviae, Brazil: São Paulo, São Carlos, Fazzari stream, 25.viii.2008, F. L. Silva ( MZUSP). Paratype: 1 male with pupal and larval exuviae same data as holotype except for Canchin reservoir, 5.vi.2007 ( NTNU).

Etymology. Named in honour of Ernst Josef Fittkau, for his contribution to the knowledge of Neotropical Chironomidae .

Diagnostic characters. Labrundinia fittkaui sp. n. differs from other Labrundinia species by the combination of the following characters. Adult male: R2+3 absent; fore leg ratio 0.61–0.68; abdominal tergites II–VIII with continuous brown transverse band near proximal margin; hypopygium pale brown, sternapodeme rounded without anterior process. Pupa: thoracic horn club-shaped, preapical indentation shallow, aeropyle tube ending in large bulbous expansion. Larva: head capsule surface covered with small spinules, lateroventral spine group present, weakly developed, with 3–4 spines, posteroventral spine group absent; subbasal seta of posterior parapod simple; bifid claw with V-shaped lower indentation.

Description. Adult male (n = 2)

Size. Total length 2.2 (1) mm. Wing length 1.2 (1) mm. Total length/wing length 1.90. Wing length/ profemur length 3.11.

Coloration. Head pale brown with dark brown occipital margin; pedicel and antenna brown; maxillary palp brown. Thorax brown with dark scutum; antepronotum pale brown. Wing membrane transparent without any marking. Legs pale brown. Abdominal tergites II–VIII with continuous brown transverse band near proximal margin; hypopygium pale brown ( Fig. 16L ).

Head ( Figs 16A–E ). Temporal setae 10, uniserial ( Fig. 16B ). Eye ratio 1.08–1.25. Tentorium ( Fig. 16C ) 134 (1) Μm long. Clypeus 79–84 Μm long, 56–58 Μm wide at largest part, bearing 10 setae. Cibarial pump 160–175 Μm long ( Fig. 16D ), with anterior margin concave. Lengths of palpomeres 1–5 (in Μm): 33–34; 44–54; 77–112; 116 (1); 211 (1). Antennal flagellum 761 Μm long, diameter of pedicel 124 Μm, apical setae single ( Fig. 16E ), AR 1.17 (1).

Thorax. Antepronotum with 2–3 lateral setae. Acrostichals 32–40, biserial, diverging evenly posteriorly,

starting close to antepronotum and almost reaching scutellum; dorsocentrals 18–22, irregularly biserial; prealars 8; supraalars 2. Anapleural suture ratio 0.47 (1). Scutellum with transverse row of 8 setae and group of numerous fine anterior setae.

Wing ( Fig. 16F ). Width 0.3 (1) mm. Costa 1.0 (1) mm long. R2+3 absent. VR 0.71 (1). WW 0.28 (1). Brachiolum with 2 setae. Squama setiferous.

Legs ( Figs 16G–K ). Fore leg: width at apex of tibia 31–37 Μm ( Fig. 16G ), tibia with single, apical and pectinate spur 10–17 Μm long ( Fig. 16H ), with three lateral teeth and two preapical setae; ta1-4 without any preapical pseudospurs. Mid leg: width at apex of tibia 31–35 Μm long ( Fig. 16I ), tibia with single, apical and pectinate spur 14–20 Μm long with three lateral teeth ( Fig. 16J ) and two preapical setae; ta1-4 each with two preapical pseudospurs. Hind leg: width at apex of tibia 32–34 Μm long ( Fig. 16K ), tibia without spur; comb with 6 bristles; ta1-4 without any preapical pseudospurs. Claws slender, hooked; pulvilli absent. Lengths and proportion of leg segments as in Table 12.

fe ti ta1 ta2 ta3

p1 369–413 461–500 282–338 204–274 142–182 p2 519–611 470–561 575–650 247–283 138–150 p3 459–554 602–744 556–680 238–290 158–176

ta4 ta5 LR BV SV

p1 117–126 63–70 0.61–0.68 1.92–2.12 2.70–2.94 p2 82–101 71–87 1.16–1.22 2.91–2.94 1.72–1.80 p3 105–118 73–84 0.92–0.93 2.82–2.96 1.90–1.91 Hypopygium ( Fig. 16M ). Tergite IX arched, with 9 posterior setae. Membranous anal point rounded, apical edge convex. Phallapodeme 43 Μm long. Sternapodeme with anterior process absent. Gonocoxite cylindrical, 91– 95 Μm long, 33–35 Μm wide, with slightly concave inner margin. GcR 2.57–2.89. Gonostylus simple and slender, 62–67 Μm long; megaseta 10–14 Μm long. HR 1.42–1.47. HV 3.41–3.85.

Pupa (n = 2 unless otherwise stated)

Size. Abdomen 1.7–2.0 mm long in male.

Coloration. Exuviae mostly pale brown; thoracic horn and apex of anal lobe brown.

Cephalothorax ( Figs 17A–C ). Frontal apotome smooth ( Fig.17A ). Wing sheath smooth 0.8–0.9 mm long. Thoracic horn 169–213 Μm long and 43–53 Μm wide ( Fig. 17B ), THR 3.92–4.02, preapical indentation moderately deep. Membranous preapical papilla 34–44 Μm long ( Fig. 17C ), PTH 0.16–0.26, aeropyle tube simple, short, 13– 19 Μm long, ending in a large bulbous expansion; plastron plate small. Horn sac well developed, completely filling respiratory atrium. External membrane with pale spinules basally concentrated. Basal lobe wedge-shaped. Thoracic comb with 9–11 conical tubercles ( Fig. 17B ).

Abdomen ( Figs 17D–E ). Tergite I with scar 110–140 Μm long. T I–VI without shagreen, T VII–VIII with shagreen basally concentrated. Abdominal chaetotaxy as in figure 17D. Abdominal segment VII with 4 LS-setae. A VIII with 5 LS-setae. Anal lobe 253–278 Μm long and 128–132 Μm wide ( Fig. 17E ), outer margins sclerotized, with 9–14 spines, longest spine 10–11 Μm long, inner margins of lobes membranous. ALR 1.98–2.10. Male genital sac almost reaching beyond apex of anal lobe.

4th instar larva (n = 2 unless otherwise stated)

Coloration. Head pale yellow, without maculation; postoccipital margin brown. Second antennal segment 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 ( Fig. 18A ). Length 471–498 Μm, 281–284 Μm wide. IC 0.56–0.60. Surface covered with small spinules; lateroventral spine group present but weakly developed, with 3–4 spines; posteroventral spine group absent. Ventral cephalic setae S9, S10 and SSm forming a straight line diagonal to longitudinal axis of head capsule ( Fig. 18A ).

Antenna ( Figs 18B–C ). Length 273–278 Μm, A1 178–185 Μm long, with ring organ located 0.57–0.58 from base, A2 85–86 Μm long. AR 1.87–1.98. Blade longer than A2 over-reached by accessory blade.

Maxilla ( Fig. 18D ). Basal palp segment 20–24 Μm long and 7–9 Μm wide at the middle, with ring organ located 0.67–0.80 from base. PR 2.62–3.00. APR 7.51–9.16.

Mandible ( Fig. 18E ). Length 61–64 Μm. Sensillum campaniformium located 0.61–0.70 from apex, basal tooth bifid, with seta subdentalis projecting from sloping end towards apical tooth, accessory tooth present, AMD 2.88– 2.91.

Mentum and M appendage . Dorsomental teeth reduced; pseudoradula uniformly granulate.

Hypopharyngeal complex ( Figs 18F–G ). Ligula 44–51 Μm long, 24–25 Μm wide, with row of 5 teeth. IO 0.98– 0.99, MO 1.01–1.02. Paraligula bifid, 22–26 Μm long, inner tooth 17–19 Μm long, shorter than outer tooth. Pecten hypopharyngis with 6 teeth almost equal in size.

Body ( Figs 18H–I ). Without lateral fringe. Anterior parapods with simple claws. Procercus 113–119 Μm long, 21–28 Μm wide, with 7 anal setae, 333–347 Μm long. L/ W 4.09 –5.71. Supraanal seta well developed. Anal tubules not measurable. Posterior parapod not measurable; subbasal seta on posterior parapod simple, without spines ( Fig. 18H ); parapod apex with numerous simple claws; bifid claw with V-shaped lower indentation ( Fig. 18I ). B/C 1.10– 1.15.

Adult female. Unknown.

Remarks. Adult males of Labrundinia fittkaui appear most similar to those of L. longipalpis in the hypopygium coloration and absence of R2+3. However, the rounded anal point with convex apical edge separates L. fittkaui from L. longipalpis that has a trapezoidal anal point with notched apical edge. The pupae of L. fittkaui are very similar to those of L. gregi , but can be distinguished from this species by the shallow preapical indentation of the thoracic horn and the large bulbous expansion of the aeropyle tube. The larvae of L. fittkaui very closely resemble those of L. gregi and can be distinguished only by the shape of cephalic capsule, broader in L. fittkaui . Labrundinia fittkaui has so far been recorded from two localities in São Paulo State, Brazil. The larvae were collected in the Fazzari stream, a first-order stream surrounded by a well-preserved riparian forest. The water has a high level of dissolved oxygen and low conductivity. The species was also collected in the Canchin reservoir, a small dam characterized by a predominance of aquatic macrophytes.

Figures

FIGURES 16 A – M. Labrundinia fittkaui Silva sp. n., adult male. A. Head, frontal view. B. Temporal setae. C. Tentorium. D. Cibarial pump. E. Apex of antenna. F. Wing. G. Apex of fore tibia. H. Fore tibial spur. I. Apex of mid tibia. J. Mid tibial spur. K. Apex of hind tibia with comb. L. Abdominal coloration pattern, dorsal aspect. M. Hypopygium, left: ventral aspect, right: dorsal aspect.

FIGURES 17 A – E. Labrundinia fittkaui Silva sp. n., pupa. A. Frontal apotome. B. Thoracic horn with basal lobe and thoracic comb. C. Apex of thoracic horn showing preapical papilla. D. Abdominal segments with chaetotaxy, dorsal aspect. E. Anal lobe and male genital sac, ventral aspect.

FIGURES 18 A – I. Labrundinia fittkaui Silva sp. n., larva. A. Head with chaetotaxy and detail of lateroventral spine group, left: ventral aspect, right: dorsal aspect. B. Antenna. C. Apex of antenna. D. Maxillary palp. E. Mandible. F. Ligula and paraligula. G. Pecten hypopharyngis. H. Subbasal seta of posterior parapod. I. Bifid claw of posterior parapod.