Labrundinia longipalpis ( Goetghebuer, 1921 )

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 : 67-73

Labrundinia longipalpis ( Goetghebuer, 1921)

( Figs 31–33 )

Tanypus longipalpis Goetghebuer, 1921: 18 (description of male); Goetghebuer 1927: 61 (description of male).

Pentaneura longipalpis ( Goetghebuer, 1921) : Edwards 1929: 294 (description of male).

Ablabesmyia longipalpis ( Goetghebuer, 1921) : Goetghebuer 1936: 43 (description of male, new combination).

Labrundinia longipalpis ( Goetghebuer, 1921) : Fittkau 1962: 376 (description of male and pupa, new combination); Silva et al. 2011: 294 (description of adults and immatures, new synonym).

Labrundinia maculata Roback, 1971:271 (description of adults); Roback 1987: 192 (description of immatures).

Material examined. Type material: Labrundinia longipalpis : 3 syntype males, Belgium: Flandres, Broeck d’Overmeire, Étang d’Overmeire, 25.v.1913, M. Goetghebuer ( IRSNB). Labrundinia maculata : Holotype male, USA: California, Inland Empire, Riverside County, 11–14.ix.1962, Frommer ( CAS). 7 Paratypes: 2 males and 2 females same data as holotype; 1 male and 2 females, USA: California, Santee-San Diego, 27.vii.1962, Perry ( ANSP).

Additional material: 2 pupal exuviae, Canada: Ontario, Kingston, Lake near Parham, 23.vii.1980, F. Reiss ( ZSM). 1 male, Greece: Corfu, Temploni, 13.vi.1977, H. Malicky. ( ZSM) 3 pupal exuviae, Mexico: Laguna Alberga, 3.i.1954, L. Brundin( ZSM); 1 larva, Coahuila, ditch S. of Palau, 19/v/78, Dunn & Bereza ( ANSP). 1 larva, Netherlands: Noord-Holland, s'Graveland, 10.v.1982, H. Steenbergen ( ZSM). 1 male, Romania, P. Albu ( ZSM). 1 male, Spain: Andalusia, Huelva, Riv. d. Tamujoso, 24–28.iv.1981, W. Schacht ( ZSM). 1 pupal exuviae, Sweden: Götland, Småland, Grimsgöl Lake, 15.vi.47, L. Brundin. 1 male, USA: California, Orange County, Irvine, Woodbridge village, from spider webs, v.1993, M. Spies ( ZSM); 1 male with larval and pupal exuviae, Georgia, Glynn County, pond at Plantation Village, Demere RD, St. Simons Isl., 20.ii.1992, B. A. Caldwell; 1 male with larval and pupal exuviae as previous except for 28.xi.1990; 1 male with larval and pupal exuviae as previous except for 7.v.1991; 1 female with larval and pupal exuviae as previous except for 27.ii.1991; 1 male with pupal exuviae, 1 prepupa and 1 larva, Kansas, Cherokee, Short Creek, 1.6 mi W, 1.0 mi N Galen, 9.ix.86, L. C. Ferrington ( ANSP); 1 male and 1 pupal exuviae, North Carolina, Belews Lake, 10.v.1976 ( ANSP).

Diagnostic characters. Labrundinia longipalpis differs from other Labrundinia species by the combination of the following characters. Adult male: abdominal tergite I pale brown, T II–VI with continuous brown transverse band near proximal margin, T VII–VIII completely brown; hypopygium pale brown, sternapodeme with reduced anterior process. Pupa: thoracic horn wedge-shaped, preapical indentation absent, external membrane with pale spinules basally concentrated. Larva: surface of head capsule usually covered with spinules, lateroventral spine group present but weakly developed; subbasal seta of posterior parapod serrated; bifid claw with U-shaped lower indentation.

Description. Adult male (n = 12 unless otherwise stated)

Size. Total length 2.0–2.6 (7) mm. Wing length 1.2–1.6 (6) mm. Total length/wing length 1.56–1.84. Wing length/ profemur length 2.43–2.90 (8).

Coloration. Head pale brown with dark brown occipital margin; pedicel and antenna brown; maxillary palp pale brown. Thorax brown with dark scutum; antepronotum pale. Wing membrane transparent without any marking. Legs pale brown. Abdominal tergite I pale brown, II–VI with continuous brown transverse band near proximal margin, T VII–VIII completely brown; hypopygium pale brown ( Fig. 31L ).

Head ( Figs 31A–E ). Temporal setae 12–14 (11), uniserial ( Fig. 31B ). Eyes ratio 1.10–1.39 (7). Tentorium ( Fig. 31C ) 128–145 (4) Μm long. Clypeus 65–100 (7) Μm long, 50–88 (7) Μm wide at largest part, bearing 16–24 setae. Cibarial pump 157–185 Μm long ( Fig. 31D ), with anterior margin concave. Lengths of palpomeres 1–5 (in Μm): 23–50 (10); 46–82 (10); 100–129 (9), 100–149 (8); 146–237 (5). Antennal flagellum 559–754 (10) Μm long, diameter of pedicel 103–114 (10) Μm, apical setae single ( Fig. 31E ), AR 0.97–1.27 (10).

Thorax. Antepronotum with 4–9 (5) lateral setae. Acrostichals 33–48 (10), biserial, diverging evenly posteriorly starting close to antepronotum and almost reaching scutellum; dorsocentrals 22–28 (11), irregularly uniserial; prealars 8–13; supraalars 3–4 (10). Anapleural suture ratio 0.38–0.65 (7 Scutellum with transverse row of 8–12 setae and group of numerous fine anterior setae.

Wing ( Fig. 31F ). Width 0.3–0.4 (10) mm. Costa 0.9–1.3 (10) mm long. R2+3 absent. VR 0.63–0.91 (10). WW 0.26–0.31 (10). Brachiolum with 2 setae (9). Squama with 13–16 (2) setae.

Legs ( Figs 31G–K ). Fore leg: width at apex of tibia 31–47 (10) Μm ( Fig. 31G ), tibia with single, apical and pectinate spur 12–17 (7) Μm long ( Fig. 31H ), with three lateral teeth and two preapical setae; ta1-3 each with two preapical pseudospurs. Mid leg: width at apex of tibia 31–44 (11) Μm long ( Fig. 31I ), tibia with single, apical and pectinate spur 18–23 (8) Μm long with three lateral teeth ( Fig. 31J ) and two preapical setae; ta1-4 each with two preapical pseudospurs. Hind leg: width at apex of tibia 31–56 (31) Μm long ( Fig. 31K ), tibia without spur; comb with 5 (11) bristles; ta1-4 without any preapical pseudospurs. Claws slender, hooked; pulvilli absent. Lengths and proportion of leg segments as in Table 20.

fe ti ta1 ta2 ta3

p1 398–519 431–581 263–338 194–269 (6) 131–194 (6) p2 406–650 414–563 400–625 206–294 (5) 140–170 (5) p3 436–630 555–800 550–694 238–306 (3) 175–213 (3)

ta4 ta5 LR BV SV

p1 94–125 (5) 69–82 (6) 0.56–0.63 (6) 2.06–2.37 (6) 2.97–3.34 (6) p2 94–125 (5) 60–88 (5) 0.71–1.23 (5) 2.70–3.06 (5) 1.90–2.98 (5) p3 94–138 (3) 69–94 (3) 0.90–0.99 (3) 2.72–2.87 (3) 1.84–1.97 (3) Hypopygium ( Fig. 31M ). Tergite IX arched, with 10–17 (11) posterior setae. Membranous anal point trapezoidal, apical edge slightly notched. Phallapodeme 35–66 (11) Μm long. Sternapodeme with reduced anterior process. Gonocoxite cylindrical, 88–125 (11) Μm long, 35–65 (11) Μm wide, with slightly concave inner margin; dorsomedian surface with shorter marginal setae scarcely distributed. GcR 1.80–2.60 (11). Gonostylus simple and slender, 59–80 (11) Μm long; megaseta enlarged, 12–15 (11) Μm long. HR 1.36–1.71 (11). HV 3.16–3.74 (7).

Adult female (n = 4 unless otherwise stated)

Size. Total length 2.0 (1) mm. Wing length 1.1–1.4 (2) mm. Total length/wing length 1.58 (1). Wing length/ profemur length 2.82 (1).

Coloration. Head, pedicel and antenna brown; maxillary palp pale brown. Thorax brown with dark scutum. Wing membrane without any marking. Legs pale brown. Abdomen brown with tergites II, IV and VI lighter apically. Seminal capsules brown.

Head. Temporal setae 12–14, uniserial. Eyes bare, dorsomedian extension with 2–3 (3) terminal facets; eye ratio 0.81–1.41 (3). Tentorium 110 (1) Μm long. Clypeus 83 (1) Μm long, 50 (1) Μm wide at largest part, bearing 20–32 setae. Cibarial pump 141–151 (2) Μm long, as in male. Lengths of palpomeres 1–5 (in Μm): 26–27 (2); 38– 51 (2); 85–100 (2); 108 (1); 129 (1). Antennal flagellum 360 (1) Μm long, diameter of pedicel 50 (2) Μm, AR 0.35 (1).

Thorax. Antepronotum with 4 (1) lateral setae. Acrostichals 50–52 (2), irregularly biserial, starting close to antepronotum; dorsocentrals 31–41, irregularly uniserial; prealars 12–16 (5); supraalars 3–4 (3). Scutellum with transverse row of 8 (3) setae and group of numerous fine anterior setae.

Wing. Width 0.3–0.4 (2) mm. Costa 0.9 (1) mm long. R2+3 absent. VR 0.72 (1). WW 0.31–0.36 (2). Brachiolum with 2 setae (2). Squama with 14 (1) setae.

Legs. Fore leg: width at apex of tibia 39–44 (2) Μm, tibia with single, apical and pectinate spur 16–18 (2) Μm long, with three lateral teeth and two preapical setae; ta1-4 without any preapical pseudospurs. Mid leg: width at apex of tibia 31–38 (2) Μm, tibia with single, apical and pectinate spur 12–23, 18 (3) Μm long, with 2–3 lateral teeth and two preapical setae; ta1 with one preapical pseudospur. Hind leg: width at apex of tibia 36–39 (2) Μm, tibia without spur; comb with 4–5 (2) bristles; ta1 with one preapical pseudospur. Legs with slender, hook-shaped claws. Pseudospurs indistinct. Pulvilli absent. Lengths and proportion of leg segments as in Table 21.

fe ti ta1 ta2 ta3

p1 406–414 391–419 260 169 113

p2 475–547 436–550 475 206 144

p3 519–531 578–625 391–480 234–238 156–175

ta4 ta5 LR BV SV

p1 94 69 0.64 2.46 3.07

p2 106 63 0.86 2.89 2.16

p3 117–119 69–70 0.68–0.84 2.59–2.78 2.18–2.84 Genitalia. Gonapophysis VIII broadly rounded, 63 (1) Μm long. Tergite IX 175 (1) Μm long, 100 (1) Μm wide at the middle, without setae. Coxosternapodeme 75 (1) Μm long. Tergite X with 8 lateroventral setae on each side. Postgenital plate rounded. Cerci quadrate to oval-quadrate, 38 (1) Μm long and 13 (1) Μm wide; with 10 setae (1). Labia with inconspicuous microtrichia. Notum length 133 (1) Μm long. Seminal capsules oval, 40 (1) Μm long, 33 (1) Μm wide, with conical shaped necks. Length ratio SCa/No 0.30.

Pupa (n = 12 unless otherwise stated)

Size. Abdomen 1.7–2.6 (7) mm long in male, 2.0–2.1 (5) mm long in female.

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

Cephalothorax ( Figs 32A –C ). Frontal apotome smooth ( Fig.32A ). Wing sheath smooth 0.7–1.0 mm long. Thoracic horn 211–328 Μm long and 86–203 Μm wide ( Fig. 32B ), THR 1.61–2.64, preapical indentation absent. Membranous preapical papilla 18–57 Μm long ( Fig. 32C ), PTH 0.08–0.18, aeropyle tube simple, short and robust 28–35 (8) Μm long; plastron plate much reduced. Horn sac well developed, completely filling respiratory atrium. External membrane with pale spinules basally concentrated. Basal lobe wedge-shaped. Thoracic comb with 10–12 conical tubercles ( Fig. 32B ).

Abdomen ( Figs 32D–E ). Tergite I with scar 113–143 (8) Μm long. T I–VI without shagreen, T VII–VIII with shagreen basally concentrated. Abdominal chaetotaxy as in figure 32D. Abdominal segment VII with 4 LS-setae. A VIII with 5 LS-setae. Anal lobe 180–368 Μm long and 150–186 Μm wide ( Fig. 32E ), outer margins sclerotized, with 8–12 (8) spines, longest spine 8–17 (9) Μm long, inner margins of lobes membranous. ALR 1.14–1.80 (9). Male genital sac almost reaching apex of anal lobe.

4th instar larva (n = 8 unless otherwise stated)

Coloration. Head pale yellow, without maculation; postoccipital margin brown. Second antennal segment pale 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. 33A ). Length 398–555, 491 Μm, 260–406, 337 Μm wide. IC 0.50–0.80, 0.69. Surface usually covered with spinules; lateroventral spine group present but weakly developed, with 5–6 (6) spines; posteroventral spine group absent. Ventral cephalic setae S9, S10 and SSm forming a straight line diagonal to longitudinal axis of head capsule ( Fig. 33A ).

Antenna ( Figs 33B–C ). Length 236–284 (4) Μm, A1 163–205 (4) Μm long, with ring organ located 0.65–0.84 (4) from base, A2 63–80 (4) Μm long. AR 2.28–2.56 (4). Blade longer than A2 over-reached by accessory blade.

Maxilla ( Fig. 33D ). Basal palp segment 20–29 Μm long and 7–11 Μm wide at the middle, with ring organ located 0.73–0.87 from base. PR 2.08–3.67. APR 7.45–8.90.

Mandible ( Fig. 33E ). Length 63–75 Μm. Sensillum campaniformium located 0.57–0.83 Μm from apex, basal tooth bifid, with seta subdentalis projecting from sloping end towards apical tooth, accessory tooth present, AMD 2.39–3.28.

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

Hypopharyngeal complex ( Figs 33F–G ). Ligula 51–63 (7) Μm long, 23–32 (7) Μm wide, with row of 5 teeth. IO 0.98–1.05 (7), MO 1.09–1.17 (7), muscle attachment 13–20 (7) Μm long. Paraligula bifid, 22–27 (7) Μm long, inner tooth 19–23 (7) Μm long, shorter than outer tooth. Pecten hypopharyngis with 9 (5) teeth almost equal in size ( Fig. 33G ).

Body ( Figs 33H–I ). Without lateral fringe. Anterior parapods with simple claws. Procercus 109–166 Μm long, 23–34 Μm wide, with 7 anal setae 500–749 Μm long. L/ W 3.39 –5.43 (7). Supraanal seta well developed. Anal tubules 163–206 (3) Μm long. Posterior parapod 231–396 (3) Μm long; subbasal seta on posterior parapod serrated, with 5–8 spines basally ( Fig. 33H ); parapod apex with numerous simple claws; bifid claw with U-shaped lower indentation, lower spur arched down toward base of claw ( Fig. 33I ). B/C 0.87–0.95.

Remarks. Adult males of Labrundinia longipalpis appear most similar to those of L. fittkaui and were fully discussed in the remarks of the latter. The pupae of L. longipalpis are very similar to those of L. separata , but can be distinguished from this species by having weak and simple spinules on sternite II, in contrast to the prominent and usually bifid spinules present in L. separata . Larvae of L. longipalpis may be distinguished from those of the related species L. fittkaui , L. gregi , L. parafittkaui and L. neopilosella by the combination of the following characters: subbasal setae of posterior parapods serrated basally, bifid claw with U-shaped lower indentation, inner tooth of ligula smaller than outer tooth and pecten hypopharyngis with 9 teeth. Labrundinia maculata , which is known from the Nearctic region, was considered as junior synonym of the Palaearctic Labrundinia longipalpis by Silva et al. (2011). The synonymization was based on a high level of similarities exhibited by all major life stages. However, the North American larvae differ from the European larvae by having the head capsule surface covered with spinules. Recently, the examination of additional material also has indicated that adult males ascribed to L. maculata may have a narrower brown transverse band on tergite VI than those of L. longipalpis . Despite these differences, we regard L. longipalpis and L. maculata as synonyms. Labrundinia longipalpis is widespread in the West Palaearctic region ( Silva et al. 2011, above). In North America the species is recorded from California, Coahuila ( Mexico), Georgia, North Carolina and Ontario. According to Brundin (1949) and Saether (1979), this species is characteristic of oligotrophic, mesohumic and polyhumic lakes.

Figures

FIGURES 31 A – M. Labrundinia longipalpis (Goetghebuer), 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 32 A – E. Labrundinia longipalpis (Goetghebuer), 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 33 A – I. Labrundinia longipalpis (Goetghebuer), 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.