Beardius cristhinae Trivinho-Strixino et Siqueira

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 : 29-32

Beardius cristhinae Trivinho-Strixino et Siqueira

( Figs 37–48 )

Beardius cristhinae Trivinho-Strixino et Siqueira, 2007: 281 .

Beardius cristhinae Trivinho-Strixino et Siqueira ; Pinho et al. (2009: 262).

Beardius sp. 4 Sonoda & Trivinho-Strixino (2000: 746).

Material examined. Type material as in Trivinho-Strixino & Siqueira (2007). Additional material: BRAZIL, Amazonas State : Manaus , Adolfo Ducke Forest Reserve, Poça, S02°55'21" W59°58'44", in pool, 2 females with larva and pupa, 1 pharate female with larva, 2 males with pupa, 05.ii.2010, L.C. Pinho & H.F. Mendes .

Diagnostic characters. The species belongs in the parcus group. The male can be separated from all other members of the genus by having superior volsella fused with inferior volsella. The female by the combination of the following characters: acrostichals absent; R and R 1 with setae; and ventrolateral lobe with short microtrichia. The pupa by: tergite II with stronger shagreen orally; tergites VII and VIII without shagreen; paratergite VIII with long spines; and conjunctive IV/V with spinules arranged in two patches. The larva by: antenna with 5 segments; pecten mandibularis conspicuous; distance between ventromental plates of about the same width as median tooth of mentum; mandible with outer margin wrinkled; and mentum with last lateral tooth at about the same level as penultimate tooth.

Description

Male. The male was described in detail by Trivinho-Strixino & Siqueira (2007). Below we give new illustrations of the hypopygium ( Figs 37–38 ). The tergal bands must be regarded as absent. The type series was not enough cleared and shadows of muscles was erroneously interpreted as tergal bands by Trivinho-Strixino & Siqueira (2007). This was evidenced by examination of the type series, coupled with additional cleared material. Further, the superior volsella has ventral microtrichia only.

Female (n = 2–3, except when otherwise stated). Total length 2.09–2.40 mm. Wing length 1.41–1.45 mm. Total length / wing length 1.44–1.70. Wing length / length of profemur 1.82–1.91.

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

Head. AR 0.28–0.30, ultimate flagellomere 106–109 µm long. Temporal setae 8–10, not well separated in inner and outer verticals and postorbitals. Clypeus with 10–15 setae. Tentorium 137–177 µm long, 15–20 µm wide. Stipes 129 (1) µm long. Palpomere lengths (in µm): 25–38, 30–35, 83–104, 109–134, 152–200. Third palpomere with 3–4 sensillae subapically, longest 15–18 µm long.

Thorax ( Fig. 40 ). Scutal tubercle present. Dorsocentrals 6–9, including 1–2 near antepronotum; acrostichals absent; prealars 2. Scutellum with 4 setae.

Wing ( Fig. 39 ). VR 1.19–1.32. R with 12–13 setae, R 1 with 8–11 setae, R 4+5 with 17–19 setae. Brachiolum with 2 setae. Remaining veins bare.

Legs. Spur of fore tibia (including scale) 48–54 µm long, spur of mid tibia (including comb) 80–86 µm long, spur of hind tibia (including comb) 75–80 µm long. Width at apex of fore tibia 51–56 µm, of mid tibia 54–59 µm, of hind tibia 59–64 µm. Lengths and proportions of legs as in Table 7.

Genitalia ( Figs 41–42 ). Tergite IX with 17–29 setae. Cercus 66–76 µm long, 33–43 µm wide. Notum 89–127 µm long. Gonocoxite IX with 1–2 setae. Seminal capsule 40–68 µm long, excluding 10–15 µm long neck.

Pupa. The pupa was described in detail by Trivinho-Strixino & Siqueira (2007).

Larva (n = 6, except when otherwise stated). Total length 3.08–3.62 (3) mm. Head capsule 329–372, 347 µm long.

Coloration. Light red.

Head dorsum ( Fig. 48 ). Frontoclypeal apotome and labral sclerite 2 present. Frontoclypeal apotome with anterior granulation, extending to S4.

Antenna ( Fig. 47 ). With 5 segments. AR 1.00–1.24, 1.10. Length of segments (in µm): 53–66, 58; 19–21, 20; 13–18, 15; 10–13, 12; 5–8, 6. Blade 58–99, 81 µm long, 1,5 times longer than flagellum. Lauterborn organs 13–15, 14 µm long, alternating on segments 2 and 3.

Labrum. Pecten epipharyngis ( Fig. 46 ) with 3 plates, mid with 3 teeth, laterals with 3–4, 3 teeth each. Premandible 78–96, 86 µm long.

Mentum ( Figs 43–44 ). Pale median tooth about 1/2 length of first lateral tooth. Ventromental plate 83–101, 91 µm wide, distance between plates 9–14, 12 µm. Postmentum 154–170, 164 µm long, with granulose area between ventromental plates.

Mandible ( Fig. 45 ). 127–147, 137 µm long. Seta subdentalis 33–46, 38 µm long. Seta interna with 3 major branches. Pecten mandibularis distinct. Mola without spines. Outer margin granulose.

Abdomen. Procercus about 25 µm long, with 8 anal setae, longest about 450 µm long. Seta supraanalis about 330 µm long. Posterior prolegs about 75 µm long.

Biology. The larvae were collected in tubes constructed of leaf debris between decaying leaves in a temporary pool in the Adolfo Ducke Forest Reserve near Manaus, Brazil. The larvae of other Beardius species have been found in superficial mines in wood or are associated with macrophytes, so the habit of this species expands the range of substrate types for Beardius larvae.

Distribution. The species is collected in the São Paulo, Mato Grosso, and Amazonas states in Brazil.

Figures

FIGURES 37–38. Beardius cristhinae Trivinho-Strixino et Siqueira, male. 37—tergite IX and dorsal aspect of left gonocoxite and gonostylus; 38—hypopygium with tergite IX removed, left dorsal aspect, right ventral aspect.

FIGURES 39–42. Beardius cristhinae Trivinho-Strixino et Siqueira, female. 39—wing; 40—thorax; 41—genitalia, ventral view; 42—tergite IX.

FIGURES 43–48. Beardius cristhinae Trivinho-Strixino et Siqueira, larva. 43—mentum and ventromental plates; 44— mentum and ventromental plates, variation; 45—mandible; 46—pecten epipharyngis; 47—antenna; 48—dorsal sclerites of head capsule.