Beardius arawak, Pinho & Mendes & Andersen, 2013

Pinho, Luiz Carlos, Mendes, Humberto Fonseca & Andersen, Trond, 2013, Revision of Beardius Reiss et Sublette, 1985 (Diptera: Chironomidae), with the description of twenty new species, Zootaxa 3742 (1), pp. 1-78 : 20-24

Beardius arawak sp. n.

( Figs 16–25 )

Type material. Holotype male, BRAZIL, Acre State: Mâncio Lima, Serra do Divisor National Park, Igarapé Ar Condicionado , 17.iii.2006, light trap, A.R. Calor ( MZSP) . Paratypes: 2 males, as holotype except Igarapé Amor , 18.iii.2006 ( MZSP) . 1 pupa with pharate male, Amazonas State: Rio Cuieiras, na foz do Rio Branquinho , 21.xii.1961, Brundin net, A308, E.J. Fittkau ( ZSM) . 1 pupa with pharate male, Igarapé Cachoeira , 12.iv.1961, A150–1, E.J. Fittkau ( MZSP) . 1 pupa, Lago Cabaliana, Baixo Rio Solimões , Brundin net, F. Reiss ( MZSP) . 1 pupa, Lago do Calado, Baixo Rio Solimões , 10.v.1971, Brundin net, F. Reiss ( ZSM) ; 1 pupa, as previous except 30.xi.1971 ( ZMBN) . 1 male, Pará State: Rurópolis, Cachoeira do Grin , S04°05', W55°00', 24.x.2007, Pennsylvania trap, N. Hamada et al. ( INPA) . 1 male, as previous except 09.x.2008, L.M. Fusari & N. Hamada ( INPA) .

Diagnostic characters. The species belongs in the xylophilus group. The male can be separated from all other members of the genus by the combination of the following characters: acrostichals present; anal point broadly triangular, moderately long, covered with microtrichia; and basal projection of inferior volsella subquadrate and transverse. The pupa differs from that of other known species by the combination of the following characters: tergites VII–VIII with anterolateral patches of shagreen; and paratergite VIII lacking lateral spines.

Etymology. The name refers to the Arawak Indians, an ethnic group from Central and South America. The name is to be regarded as a noun in apposition.

Description

Male (n = 3, except when otherwise stated). Total length 2.37–2.66 mm. Wing length 1.04–1.27 mm. Total length / wing length 2.09–2.28. Wing length / length of profemur 1.95–2.13.

Coloration. Head, thorax and abdomen pale. Legs pale.

Head ( Fig. 16 ). AR 0.87–1.30, ultimate flagellomere 449–552 µm long. Inner verticals 3, outer verticals 3–4, postorbitals 3–4. Clypeus with 10–15 setae. Tentorium 127–139 µm long, 24–30 µm wide. Stipes 100–106, 103 µm long. Palpomere lengths (in µm): 25–40, 20–30, 96–124, 134–159, 134–233 (2). Third palpomere with 2–3 sensillae subapically, longest 10–15 µm long.

Thorax ( Fig. 17 ). Scutal tubercle absent. Antepronotum without setae. Dorsocentrals 7; acrostichals 5–8, prealars 2–3. Scutellum with 4–6 setae.

Wing ( Fig. 18 ). VR 1.48–1.54. R with 4 setae; R 4+5 with 2–4 setae at apex. Brachiolum with 2 setae. Remaining veins bare.

Legs. Spur of fore tibia (including scale) 43–54 µm long, spur of mid tibia (including comb) 51–70 µm long, spur of hind tibia (including comb) 59–75 µm long. Width at apex of fore tibia 43–48 µm, of mid tibia 45–51 µm, of hind tibia 48–54 µm. Lengths and proportions of legs as in Table 3.

Hypopygium ( Figs 19–21 ). Anal point strong, bluntly triangular, 30–46 µm long. Tergite IX without setae, tergal bands present. Laterosternite IX with 2–3 setae. Phallapodeme 48–63 µm long. Transverse sternapodeme 38–53 µm long. Gonocoxite 83–101 µm long. Superior volsella digitiform, weakly curved, 48–51 µm long, with 5– 7 dorsal, 2 apical, and 2 ventral setae, without microtrichia. Median volsella absent. Inferior volsella clavate, 46–58 µm long, with 2 apical thin setae and 4–8 short, lanceolate setae subapically; projection subquadrate, transverse, sometimes digitiform in dorsal aspect, arising from base of volsella, 23–28 µm long. Gonostylus 91–116 µm long. HR 0.85–0.92. HV 2.47–2.81.

Pupa (n = 5, except when otherwise stated). Total length 2.71–3.36 (4) mm.

Coloration. Cephalothorax and abdomen pale.

Cephalothorax ( Fig. 23 ). Frontal apotome conical ( Fig. 22 ), frontal setae 31–72, 49 µm long. Thorax with fine dorsal granulation. Thoracic horn with about 3 branches; anterior stout branch with spinules in distal 2/3. Distance between Dc1 and Dc2 4–6, 5 µm; between Dc2 and Dc3 144–167, 156 µm; between Dc3 and Dc4 4–6, 5 µm. Median antepronotal 1, precorneal 1, prealars absent.

Abdomen ( Fig. 25 ). Tergite I with or without shagreen. Tergites II–V with anterior transverse band of shagreen slightly stronger than contiguous posterior shagreen. Tergite VI with anterior transverse band of shagreen only. Tergites VII and VIII with shagreen in two anterolateral patches. Row of hooklets on tergite II about 1/3 of tergite width. Conjunctive IV/V with spinules in two patches. Paratergite V with row of spinules in posterior 1/2; paratergite VI with or without spinules. Pedes spurii A and pedes spurii B present. Segment I without L setae; segments II–IV with 3 L setae; segment V with 3 taeniate L setae; segments VI–VIII with 4 taeniate L setae. Segment VIII without lateral spines, spur simple ( Fig. 24 ). Anal lobe 143–164 (3) µm long, with 6–12, 10 taeniate setae.

Female and larva. Unknown.

Distribution. The species is collected in the Acre, Amazonas, and Pará states in Brazil.

Figures

FIGURES 16–21. Beardius arawak sp. n., male. 16—head; 17—thorax; 18—wing; 19—anal point and tergite IX and dorsal aspect of left gonocoxite and gonostylus; 20—hypopygium with anal point and tergite IX removed, left dorsal aspect, right ventral aspect; 21—hypopygium, lateral view.

FIGURES 22–25. Beardius arawak sp. n., pupa. 22—frontal apotome; 23—thorax; 24—paratergite VIII; 25—abdominal segments I–IX and anal lobe, dorsal view.