Parapentaneura bentogomensis, Stur, Elisabeth, Fittkau, Ernst Josef, Da, Mirian A. & Serrano, Silva, 2006

Stur, Elisabeth, Fittkau, Ernst Josef, Da, Mirian A. & Serrano, Silva, 2006, Parapentaneura bentogomensis gen. n., sp. n., a new Tanypodinae (Diptera, Chironomidae) from Brazil, Zootaxa 1384, pp. 59-68 : 61-64

Parapentaneura bentogomensis , gen. n., sp. n.

( Figs 1–10 , 13–15 , 17–23 )

Type material: Holotype male, slide mounted in Euparal. Brazil, Mato Grosso, Bento Gomes River near Poconé, on Eichhornia sp., 28.viii.1994, M.A. Serrano ( ZSM). Paratypes: 1 larva as holotype; 2 adult males with pupal exuviae (reared), 1 pharate male, 1 adult female (damaged) with associated pupa, 1 larval and pupal exuviae (reared but imago lost), Brazil, Mato Grosso, Bento Gomes river near Poconé, among Salvinia roots, 14.x.1993, M.A. Serrano; 1 male imago (damaged) with associated pupa, Brazil, Mato Grosso, Bento Gomes river near Poconé, among Salvinia roots, viii.1993, M.A. Serrano; 1 larva (prepupa), Brazil, Mato Grosso, Bento Gomes river near Fazenda Periquito, among floating leaf litter, 15°54’S, 56°33’W, 11.v.1993, E. Stur.

Etymology. Named after the type locality, the Bento Gomes River.

Diagnosis. Male imago as given in generic diagnosis. Pupa with alveolar horn atrium filling most of lumen, thoracic comb consisting of 6–8 rounded tubercles. Anal lobe 1.6 (female) or 1.8 (male) times longer than broad. Larval paraligula with 3 teeth, pecten hypopharyngis with 10–11 teeth, AR about 4.

MALE. Head pale brown. Eyes with dorsal extension; temporals uniserial, orbitals 3, inner verticals 1, outer verticals 3, postorbitals apparently 1. AR 1.2–1.3; pedicel with 3 setae; antenna with 13 flagellomeres, apical flagellomere indistinctly offset ( Fig. 8 ), about 2 times longer than basal width.

Thorax brownish. Antepronotal lobes separated medially; humerals 1; dorsocentrals 9–12, uniserial; supraalars 1; prealars 3–5; acrostichals 18–23; lateral antepronotal, anepisternal, preepisternal and postnotal setae absent; scutal tubercle absent.

Wing ( Fig. 1 ) 1.1–1.3 mm long; membrane evenly covered with pale macrotrichia; costa produced beyond R4+5, ending about midway between M1+2 and M3+4; R2+3 present; R2 branch absent; R2+3 reaching costa; anal lobe well developed.

Legs ( Figs 4–6 ) pale brown. Fore tibia without comb, hind tibia with comb of 5–6 setae; tibial spurs lyrate, with 3–4 teeth; hind tibia with single spur; pulvilli absent; claws pointed ( Fig. 7 ). Lengths and proportions of legs as in Table 1 .

Abdomen brownish; Tergite IX with posterior row of 4–5 strong setae. Hypopygium ( Fig. 2 ) with anal point broadly triangular; gonocoxite robust, 1.5 times longer than broad, with slightly concave inner margin; dorsal surface with longer marginal setae and anteromedian short bristles; inferior volsella absent; gonostylus ( Fig. 3 ) simple, elongate, with swollen base, about half the length of gonocoxite.

PUPA. Small, total length 2.5–3.0 mm, brownish. Thoracic horn ( Fig. 10 ) flattened, apically rounded, 3 times longer than maximum apical width; with week spinules; horn atrium with alveolar area filling most of lumen, connected to branched central duct distally joined to enlarged plastron plate; corona present, more than half the length of horn; plastron plate about 0.6 times the length of corona. Thoracic comb with 6–8 (n = 6) well developed rounded teeth, longest tooth more than 2 times longer than broad; thoracic seta Dc 1 and Dc 2 taeniate, Dc 3 broken ( Fig. 9 ).

Abdomen ( Fig. 15 ): Scar on tergite I elongate, pigmented; tergites with short, blunt spinules, partially serially arranged in groups of 2 and 3; abdominal D setae all filamentous, robust, apically round; remaining D and V setae of varying sizes; segments I–VI with 2 L setae; segment VII with 1 L setae, and 3 LS setae, shorter than length of segment; segment VIII with 5 LS setae. Anal lobe of female ( Fig. 13 ) about 1.6 (n = 2) times, of male ( Fig. 14 ) about 1.8 (n = 4) times longer than broad; outer margin sclerotized, with spinules beyond distal macroseta; inner margin smooth; anal lobe medially membranous; anal macrosetae with adhesive sheaths, apical macrosetae dorsal; male genital sac reaching onethird of anal lobe length ( Fig. 13 ).

LARVA. Small, 3.6–4.6 mm, greenish when alive, pale when preserved in alcohol. Head capsule ( Fig. 23 ) pale brown, in forth instar larvae about 600 µm long (n = 2). Antenna ( Fig. 17 ) 4 segmented, 4 times longer than mandible, basal segment 13 times longer than basal width, ring organ at apical half, AR about 4.0. Mandible slender ( Fig. 18 ), basal tooth distinct; basal segment of maxillary palp ( Fig. 20 ) about 4 times longer than wide, ring organ in distal one-third. Dorsomentum ( Fig. 22 ) with 3 teeth on each side, lateral margin weekly notched. Ligula ( Fig. 19 ) with 5 subequal teeth; row of teeth straight to slightly convex, inner teeth with apices turned outwards; paraligula trifid; pecten hypopharyngis with 10–11 teeth. Anal tubules slender, longer than posterior parapodes, supraanal setae dark, situated on small humps, stronger and longer than anal setae ( Fig. 21 ); claws of posterior parapods simple.

Figures

FIGURES 1 – 8. Parapentaneura bentogomensis gen. n., sp. n., male. 1, wing. 2, tergite IX and hypopygium, dorsal view. 3, gonostylus. 4, apex of fore tibia. 5, apex of mid tibia. 6, apex of hind tibia. 7, tarsal claw. 8, apex of antenna.

FIGURES 9 – 12. Parapentaneura bentogomensis gen. n., sp. n. (9 – 10) and Parapentaneura sp. (11 – 12), pupae. 9, ecdysial margin of mesonotum with dorsocentrals. 10 & 11, thoracic horn with thoracic comb. 12, points on ventral side of thoracic horn.

FIGURES 13 – 16. Parapentaneura bentogomensis gen. n., sp. n. (13 – 15) and Parapentaneura sp. (16), pupae. 13, tergite VIII and anal lobe, male. 14, tergite VIII and anal lobe, female. 15, tergites I – VII. 16, anal lobe, female.

FIGURES 17 – 24. Parapentaneura bentogomensis gen. n., sp. n. (17 – 23) and Pentaneura sp. (24), larvae. 17, antenna. 18, mandible. 19, paraligula and ligula. 20, basal segment of maxillary palp. 21, posterior abdominal segments. 22, mentum and mentum appendage. 23 & 24 – head capsule, with position of cephalic setae and sensory pores.

Tables

TABLE 1. Lengths (in μm) and proportions of legs of Parapentaneura bentogomensis gen. n., sp. n., male (n = 2, holotype and paratype).

	fe ti ta1 ta2	ta3	ta4	ta5	LR	BV
p1	522–562 574–670 528–630 260–318	192–228	120–140	56–68	0.92–0.94	2.47–2.59
p2	562–638 658–770 540–674 220–290	124–172	84–98	52–58	0.82–0.88	3.37–3.67
p3	500–558 744–878 512–596 260–320	176–202	116–136	56–68	0.68–0.69	2.80–2.89