Polypedilum

Oyewo, Emmanuel Adeoye & Saether, Ole A., 2008, Revision of Polypedilum (Pentapedilum) Kieffer and Ainuyusurika Sasa et Shirasaki (Diptera: Chironomidae), Zootaxa 1953, pp. 1-145 : 11-13

Polypedilum subgenus Pentapedilum Kieffer

Pentapedilum Kieffer, 1913: 25 .

Rosenia Kieffer, 1921a: 275 , nec Rosenia Waagen et Wentzel, 1886 .

Type species: Polypedilum stratiotale Kieffer, 1913: 26 (= Chironomus tritus Walker, 1856: 162 ), by subsequent designation of Edwards (1929: 326).

Other included species: P. (Pe.) anale (Freeman) , P. (Pe.) botiense sp. n., Polypedilum (Pe.) botosaneanui sp. n., P. (Pe.) calvescens Freeman , P. (Pe.) camposense sp. n., P. (Pe.) chutteri Harrison , P. (Pe.) convexum Johannsen, P. (Pe.) daitojekeum (Sasa et Suzuki) , P. (Pe.) daitokeleum (Sasa et Suzuki) , P. (Pe.) elongatus Tokunaga , P. (Pe.) epleri Oyewo et Jacobsen , P. (Pe.) esakii (Tokunaga) , P. (Pe.) exsectum (Kieffer) nomen dubium, P. (Pe.) fanjingense Zhang et Wang , P. (Pe.) furudosecundum (Sasa et Arakawa) , P. (Pe.) hamoni Freeman, P. (Pe.) hirtiforceps Kieffer , P. (Pe.) intuber sp. n., P. (Pe.) kamosecundum (Sasa) , P. (Pe.) kasumiense (Sasa) , P. (Pe.) leei Freeman , P. (Pe.) longisetum Moubayed , P. (Pe.) macrotrichium (Guha et Chaudhuri) , P. (Pe.) mellense (Goetghebuer) , P. (Pe.) micra Freeman, P. (Pe.) muscicola (Kieffer) , P. (Pe.) nodosum (Johannsen) , P. (Pe.) nubens (Edwards) , P. (Pe.) palauense Tokunaga , P. (Pe.) pallidum (Kieffer) nomen dubium, P. (Pe.) paraconvexum Zhang et Wang , P. (Pe.) pseudosordens Zhang et Wang, P. (Pe) pygmaeum Kieffer , P. (Pe.) reei sp. n., P. (Pe.) robusticeps (Guha et Chaudhuri) , P. (Pe.) ruandae Freeman , P. (Pe.) scirpicola (Kieffer) , P. (Pe.) shirokanense (Sasa) , P. (Pe.) sordens (van der Wulp) , P. (Pe.) tissamaharense sp. n., P. (Pe.) tenuis Zhang et Wang , P. (Pe.) tigrinum (Hashimoto) , P. (Pe.) toyamadeeum (Sasa) , P. (Pe.) tritum (Walker) , P. (Pe.) trukense (Tokunaga) , P. (Pe.) tusimaefeum (Sasa) , P. (Pe.) tusimafegeum (Sasa) , P. (Pe.) unagitertium (Sasa) , P. (Pe.) uncinatum (Goetghebuer) , P. (Pe.) vittatum , P. (Pe.) wittei (Freeman) .

Diagnostic characters. The male imagines of the subgenus differ from the males of other subgenera primarily by the presence of macrotrichia, at least at the apex of the wing membrane. The superior volsella is horn-shaped, almost always with one bristle beyond the base or on a projection, but in very rare cases there may be two or it is absent. The setae on the inner subapical margin of gonostylus are long and evenly distributed. The anal point is mostly narrow, without lateral shoulders.

The known females differ from the other subgenera by having spermathecal ducts with a sharp bend, but no loop. The dorsomesal lobe is shorter than in the subgenus Tripodura ; the ventrolateral lobe is brush-like in most instances, but without the apical longer curved microtrichia; the number of setae on gonocoxite IX as well as tergite IX appear generally higher than in other subgenera, but with few on each side of segment X.

The pupa lacks well developed cephalic tubercles or frontal warts, the anal comb usually projects laterally and has anally directed teeth; the anterior, transverse band of shagreen on tergites II–VI frequently consists of unusually coarse, dark spines. The anal lobe always lacks dorsal setae.

The larva has third antennal segment almost as long as fourth or longer; Lauterborn organs small, indistinct or absent. The antennal blade is always shorter than flagellum. The premandible is almost always bifid.

Imago. Moderately small to moderately large species, wing length 0.77–3.02 mm. Abdomen pale yellow to various dark brown stripes on segments; yellow or dark apices or broadly banded. Thorax pale yellow to dark brown or with various coloration patterns on vittae, preepisternum, postnotum, antepronotum and scutellum. Wings without markings but with few (at least at apices) to very dense macrotrichia. Legs pale yellow, yellow, yellowish brown or dark brown; some with dark brown femora and/or tarsi apices.

Antenna. AR 0.33–2.23. Male with 13, females with 5 flagellomeres.

Head. Eyes bare, frontal tubercles absent. Third palpomere bearing 2–5 short blunt-tipped subapical sensilla clavata. Tentorium without microtrichia. Temporals consisting of several inner and outer verticals and few postorbitals. Clypeus often with numerous setae.

Thorax. Antepronotum reduced, widely separated, without setae, scutal tubercle usually absent. Acrostichals numerous, long and biserial; dorsocentrals long, few to many, in single row. Scutellum with few to many setae, uni- to multiserial. Supraalars absent; preepisternum and anepisternum bare.

Wing. Membrane with macrotrichia. R 1 and R 2+3 nearly parallel; R 2+3 evanescent. R and R 1 with few to many setae; R 4+5 with many or occasionally few setae; RM with 1–5 setae or occasionally bare; M with few, occasionally many or without setae. Cell m basal of RM occasionally bare. Squama with few to several setae. Brachiolum with 1–9 setae.

Legs. Foretibial scale rounded or triangular, with or without apical or subapical spur. Mid and hind tibiae with broad, unspurred anterior comb separated from posterior narrower comb with elongate spur, occasionally fused. Sensilla chaetica absent. Pulvilli present, well developed and characteristically bifurcate.

Abdomen. Densely setose with long setae.

Hypopygium. Anal tergite band moderately developed, almost always fused basal to median anal tergite setae; slightly delimited area of long median anal tergal setae; weaker apical anal tergite setae present lateral to anal point. Anal point variable, but often narrow, tapered apically to parallel-sided apex, sometimes broad with median furrow. Superior volsella with well developed base with or without microtrichia; 2–6 inner setae or setae occasionally absent; superior volsella projection bears 1 seta subapically, medially or basally, occasionally 2 or no setae. Inferior volsella mostly parallel-sided or clubbed or broadened subapically or medially, microtrichiose with a long seta directed posteriorly arising from a tubercle, very rarely 2 setae. Gonocoxite mostly medially narrowed with outer margin gradually tapering to rounded apex. Gonostylus most nearly straight on inner side, outer margin medially broadened and gradually tapering to rounded apex with short seta on tubercle.

Female genitalia. Gonocoxapodeme well sclerotized, straight to slightly curved, nearly reaching apex of dorsomesal lobe, no connections mesally anterior of vagina. Gonocoxite IX reduced with 2–17 setae. Tergite IX with numerous setae. Segment X with 2–10 setae on each side of the anterior edge of the vagina. Postgenital plate mostly U-shaped or apically pointed, a few species with rounded apex. Gonapophysis VIII with dorsomesal lobe large, broadly rounded; ventrolateral lobe distinctively small, with diverse shape but usually with brush-like microtrichia of various length. Apodeme lobe with no particular shape, often covered by dorsomesal lobe. Cerci normal. Seminal capsules rounded or ovoid with distinct sclerotized neck; spermathecal duct almost always with bend.

Pupa. Small to medium sized, 3.31–7.02 mm. Exuviae pale brown to brown or black with margins of wing sheath golden brown, mesal paratergites margins of segments VI–VII and caudal spur brown.

Cephalothorax. Frontal setae, if present either short or long. Cephalic tubercles absent or barely indicated. Frontal apotome smooth or very slightly wrinkled laterally. Prealar tubercle apparently always absent.

Abdomen. Tergite I without spines and shagreen; II–VI with large anterior band of spines; VII with anterolateral spinules or absent; VIII bare but occasionally with anterolateral spinules; IX bare; II–VI with relatively weak to strong extensive median and/or posterior band of shagreen. Tergite II and III without shagreen in P. (Pe). exsectum and II without shagreen in P. (Pe.) leei . Tergite II with coarse caudal hooklets arranged in a single row. Spinules on conjunctives III/IV may be absent, if present, spines or spinules are 2–4 or multiband and mostly anterior pointing; IV/V always with spinules. Pedes spurii A present on segment IV or occasionally absent. Pedes spurii B weak to well developed on segment II.

Segments II–IV with 1–3 hair-like L setae; V and VI with 3, VII and VIII each with 4 taeniae. Anal lobe well developed with complete fringe of medium to long taeniae confined to posterior half, dorsal seta absent.

Larva. Small to medium sized larvae. Head capsule yellowish brown or brown with postoccipital margin, mentum and mandible brownish black.

Antenna. Five segmented. Basal antennal segment with ring organ near base. Antennal segment 3 subequal, equal or slightly longer than 4; Lauterborn organ usually vestigial or small, if developed, not beyond 1/ 2 of segment 3. Blade usually shorter than flagellum.

Labrum. S I moderately expanded laterally towards apex, apex branched; S II narrow, more or less distinctly branched on both sides. Labral lamella well developed. Pecten epipharyngis usually distinctly divided into 3 platelets, each with well developed teeth. Premandible usually bifid, with prominent premandibular brush.

Mandible. Four dark brown heavily sclerotized teeth with an apparently fifth tooth fused proximally to the medial margin in some species. Teeth may bear a dorsal tooth, one apical and 2 smaller inner tooth, or 1 large apical and 3 inner tooth. Seta subdentalis well developed, base straight with apex slightly curved. Seta interna usually consisting of 4 main branches with numerous branches. Pecten mandibularis with numerous secondary filaments projecting towards teeth.

Mentum. Two median teeth and 7 pairs of lateral teeth. First lateral tooth usually shorter than median in most species; in P. (Pe.) epleri median and first lateral teeth equal, forming a straight row. Second lateral tooth may be shorter, longer or subequal to median; from third lateral teeth usually decrease progressively to the sixth and a minute seventh. Ventromental plate without posterior lobe.

Abdomen. Body setae inconspicuous. Claws of posterior parapods all simple. Procercus short, bearing several medium to long anal setae. Supraanal seta well developed. Anal tubules well developed.