Labrundinia multidentata 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 : 81-86

Labrundinia multidentata Silva sp. n.

( Figs 38–40 )

Material examined. Type material: Holotype male with pupal and larval exuviae, Brazil: São Paulo, São Carlos, Canchin reservoir, 02.ii.2009, F. L. Silva ( MZUSP). 2 Paratypes: 2 larvae same data as holotype except for vii.1998, S. T. Strixino ( NTNU).

Etymology. Derived from the Latin multus, meaning many, and dentatus, meaning toothed, and refers to the distinctly toothed subbasal seta on posterior larval parapod of the new species.

Diagnostic characters. Labrundinia multidentata sp. n. differs from other Labrundinia species by the combination of the following characters. Adult male: wing length 1.2 mm; R2+3 absent; abdominal tergites II–VI with continuous brown transverse band near proximal margin, T VII–VIII completely brown; hypopygium brown, sternapodeme with distinct anterior process. Pupa: thoracic horn semi globose; abdominal segment VII with 2 LSsetae; genital sac not reaching apex of the anal lobe. Larva: surface of head capsule covered with small spinules; lateroventral and posteroventral spine groups absent; subbasal seta of posterior parapod serrated; serrated claw present; bifid claw with V-shaped lower indentation.

Description. Adult male (n = 1)

Size. Total length 2.1 mm. Wing length 1.2 mm. Total length/wing length 1.91. Wing length/ profemur length 2.99.

Coloration. Head brown with dark brown occipital margin; pedicel, antenna and maxillary palp brown. Thorax brown with dark scutum. Wing membrane transparent without any marking. Legs brown. Abdominal tergites II–VI with continuous brown transverse band near proximal margin, T VII–VIII completely brown; hypopygium brown ( Fig. 38L ).

Head ( Figs 38A–E ). Temporal setae 10, uniserial ( Fig. 38B ). Eye ratio 0.88. Tentorium ( Fig. 38C ) 142 Μm long. Clypeus 103 Μm long, 57 Μm wide at largest part, bearing 14 setae. Cibarial pump 173 Μm long ( Fig. 38D ), with anterior margin concave. Lengths of palpomeres 1–2 (in Μm): 33; 53; palpomeres 3, 4 and 5 broken off. Antennal flagellum with apical setae single, not measurable ( Fig. 38E ).

Thorax. Antepronotum with 2 lateral setae. Acrostichals 46, biserial, diverging evenly posteriorly, starting close to antepronotum and almost reaching scutellum; dorsocentrals 22, irregularly biserial; prealars 9; supraalars 2. Anapleural suture ratio 0.44. Scutellum with transverse row of 8 setae and group of numerous fine anterior setae.

Wing ( Fig. 38F ). Width 0.3 mm. Costa 0.9 mm long. R2+3 absent. VR 0.77. WW 0.28. Brachiolum with 2 setae. Squama setiferous.

Legs ( Figs 38G–K ). Fore leg: width at apex of tibia 33 Μm ( Fig. 38G ), tibia with single, apical and pectinate spur 14 Μm long ( Fig. 38H ), with three lateral teeth and two preapical setae; ta1-4 without any preapical pseudospurs. Mid leg: width at apex of tibia 30 Μm long ( Fig. 38I ), tibia with single, apical and pectinate spur 15 Μm long with three lateral teeth ( Fig. 38J ) and two preapical setae; ta1-4 without any preapical pseudospurs. Hind leg: width at apex of tibia 31 Μm long ( Fig. 38K ), tibia without spur; comb with 5 bristles; ta1-4 each with two preapical pseudospurs. Claws slender, hooked; pulvilli absent. Lengths and proportion of leg segments as in Table 25.

fe ti ta1 ta2 ta3 p1 374 406 299 188 136 p2 450 415 – – –

p3 422 502 480 234 160

ta4 ta5 LR BV SV p1 90 66 0.74 2.24 2.60 p2 – – – – –

p3 104 71 0.96 2.47 1.93 Hypopygium ( Fig. 38M ). Tergite IX arched, with 12 posterior setae. Membranous anal point rounded, apical edge convex. Phallapodeme 50 Μm long. Sternapodeme with distinct anterior process. Gonocoxite cylindrical, 106 Μm long, 51 Μm wide, with slightly concave inner margin. GcR 2.07. Gonostylus simple and slender, 66 Μm long; megaseta 15 Μm long. HR 1.61. HV 3.21.

Pupa (n = 1)

Size. Abdomen 1.9 mm long in male.

Coloration. Exuviae and thoracic horn brown. Apex of anal lobe brown.

Cephalothorax ( Figs 39A–C ). Frontal apotome smooth ( Fig. 39A ). Wing sheath smooth 0.8 mm long. Thoracic horn 220 Μm long and 94 Μm wide ( Fig. 39B ), THR 2.34, preapical indentation moderately deep. Membranous preapical papilla 24 Μm long ( Fig. 39C ), PTH 0.11, aeropyle tube simple, short and robust, 20 Μm long; 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 conical tubercles ( Fig. 39B ).

Abdomen ( Figs 39D–E ). Tergite I with scar not measurable. T I–VI without shagreen, T VII–VIII with shagreen basally concentrated. Abdominal chaetotaxy as in figure 39D. Abdominal segment VII with 2 LS-setae. A VIII with 5 LS-setae. Anal lobe 268 Μm long and 132 Μm wide ( Fig. 39E ), outer margins sclerotized, with 7 spines, longest spine 17 Μm long, inner margins of lobes membranous. ALR 2.02. Male genital sac almost reaching apex of anal lobe.

4th instar larva (n = 3 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. 40A ). Length 438–496 Μm, 256–301 Μm wide. IC 0.59–0.61. Surface covered with small spinules; lateroventral and posteroventral spine groups absent. Ventral cephalic setae S9, S10 and SSm forming a straight line diagonal to longitudinal axis of head capsule ( Fig. 40A ).

Antenna ( Figs 40B–C ). Length 302 (1) Μm, A1 194–201 Μm long, with ring organ located 0.71–0.92 (2) from base, A2 95–101 Μm long. AR 1.99–2.04. Blade longer than A2 over-reached by accessory blade.

Maxilla ( Fig. 40D ). Basal palp segment 23–25 Μm long and 8 Μm wide at the middle, with ring organ located 0.76–0.81 from base. PR 2.96–3.08. APR 8.10–8.64.

Mandible ( Fig. 40E ). Length 60–65 Μm. Sensillum campaniformium located 0.60–0.70 from apex, basal tooth bifid, with seta subdentalis projecting from sloping end towards apical tooth, accessory tooth present, AMD 3.11– 3.30.

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

Hypopharyngeal complex ( Figs 40F–G ). Ligula 46–53 Μm long, 23–26 Μm wide, with row of 5 teeth. IO 0.97– 0.99, MO 1.04–1.08. Paraligula bifid, 25–28 Μm long, inner tooth 20–23 Μm long, shorter than outer tooth. Pecten hypopharyngis with 8 teeth almost equal in size.

Body ( Figs 40H–I ). Without lateral fringe. Anterior parapods with simple claws. Procercus 128–140 Μm long, 25–32 Μm wide, with 7 anal setae 369–454 (2) Μm long. L/ W 4.04 –5.44. Supraanal seta well developed. Anal tubules 194 (1) Μm long. Posterior parapod 200–268 Μm long; subbasal seta on posterior parapod serrated, with 12– 13 spines basally ( Fig. 40H ); parapod apex with numerous simple claws and one serrated claw; bifid claw with Vshaped lower indentation ( Fig. 40I ). B/C 1.04–1.06 (2).

Remarks. Adult males of Labrundinia multidentata are very similar to those of the related species L. kogilamae and L. tenata , but may be separated by having a basally brown abdominal tergite VII (in basal ¾) in contrast to the completely brown abdominal tergite VII exhibited by L. kogilamae and L. tenata . The tentorium length, shorter in L. multidentata , is enough to separate this species from L. fiorelinii , L. parareniformis and L. reniformis . The pupae of L. multidentata appear most similar to those of L. tenata , but can be distinguished from this species by the genital sac not reaching apex of the anal lobe. The larvae of L. multidentata can be separated from those of the related species L. parareniformis and L. reniformis by the basally serrated subbasal setae of the posterior parapods in contrast to the simple subbasal setae exhibited by L. parareniformis and L. reniformis . Labrundinia multidentata has been recorded only from its type locality in São Paulo. The larvae were collected in the Canchin reservoir, a small dam characterized by a predominance of the aquatic macrophyte, Salvinia auriculata .

Figures

FIGURES 38 A – M. Labrundinia multidentata 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 39 A – E. Labrundinia multidentata 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 40 A – J. Labrundinia multidentata Silva sp. n., larva. A. Head with chaetotaxy, 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. Serrated claw of posterior parapod. I. Subbasal seta of posterior parapod. J. Bifid claw of posterior parapod.