Bittacus varzeanus Machado, 2018

Machado, Renato Jose Pires, Mendes, Diego Matheus De Mello & Rafael, José Albertino, 2018, The genus Bittacus Latreille (Insecta: Mecoptera) in Brazil: key to species, distribution maps, new synonym, and three new species, Zootaxa 4526 (3), pp. 303-330 : 321-326

Bittacus varzeanus Machado , sp. n.

( Figs. 4a, b , 8q , 11 , 12d )

Diagnosis. Wing membrane hyaline. Forewing apex not falcate; with 1–2 costal crossveins. Hind wing Rs 1+2 not forked. Male epandrium with two internal lobes and apex emarginated in dorsal view.

Description. Forewing length 18.4–21.3 mm, hind wing length 15.3–18.0 mm.

Head ( Figs. 11b, c ) with labrum and gena dark brown; clypeus, frons and vertex pale; ocellar triangle and palpi black. Set with blackish pubescence, particularly on the vertex. Three distinctive ocelli, lateral ocelli slightly larger. Antennae long, filiform, with yellowish pubescence; scape and pedicel pale; flagellum brown, paler towards the apex. Number of flagellomeres undetermined but with more than 18.

Thorax ( Fig. 11c ) covered with blackish pubescence. Pronotum light brown, with anterior margin slightly darker. Antepronotum and postpronotum with one and two black setae on lateral margins respectively. Mesonotum and metanotum pale but margins darker and scutellum slightly paler. Pleural region with scattered short black setae; uniformly pale except the anterior margin of mesoepisternum darker, and by black marks on the dorsal and ventral posterior corners of meso and metameron.

Legs ( Figs. 4a, b ) with coxa and trochanter pale, with yellowish pubescence slightly longer than on the other segments. Femur and tibia set with sparse short black setae, particularly numerous on basal half of hind femur. Fore and mid femur long, thin, and pale; hind femur broader and slightly darker than anterior ones. Tibia pale with apex dark brown, longer than femur, with two long apical spurs; spurs in fore and mid leg about as long as half-length of basitarsus, slightly shorter than basitarsus in hind leg. Fore and mid tarsi pale, apical tarsomeres sometimes darker; basitarsi slightly shorter than tibia half-length, and longer than the remaining four tarsomeres combined; tarsomere III about as long as half-length of tarsomere II and slightly longer than tarsomere IV; tarsomere V about as long as tarsomere IV, prehensile. Hind tarsus brown, apex of tarsomeres slightly darker; shorter than half-length of hind tibia; tarsomeres II–IV about the same length, basitarsus about twice longer than tarsomere II.

Wings ( Figs. 4a, b , 11a ) narrow with apex rounded. Membrane hyaline, pterostigma and apical margin pale and set with short black setae; thyridium present. Forewing usually with one subapical costal crossvein, a few paratypes with two; humeral crossvein present; Sc ending beyond first fork of Rs; Rs fork nearly forming a right angle; Rs 1+2 forking after end of pterostigma; Rs 3+4 forking at the level of mid distance between Sc end and pterostigma; usually one pterostigmal crossvein, a few paratypes with two; M origin basal to Rs origin; M and Rs first forking at the same level; Cu 1 ending slightly basal to the level of Rs 3+4 fork; A 1 ending basal to Rs first fork. Hind wing similar to forewing except for Rs 1+2 not forked.

Abdomen ( Figs. 4a, b ) with yellowish pubescence. Basal tergites pale with posterior margin darker; last three tergites dark brown. Sternites thin and elongated, colors similar to tergites.

Male terminalia ( Figs. 8q , 11 d–f) with epandrium pale brown, set with long blackish setae; in dorsal view, broadening towards apex; posterior margin weakly excavated medially; internal margin set with short thickened black setae becoming more numerous at the apex; inner surface with a subapical rounded lobe on each side (margin of lobes set with short thickened black setae); in lateral view, ending before the end of basistylus, convex dorsally, posterior margin excavated medially. Cercus about as long as sternite IX, dark brown, pale basally, set with yellowish setae. Basistylus set with long black setae, particularly at posterior margin; dark brown, but in ventral view with a thin medial pale line that expands towards apex; ventrally convex in lateral view. Gonostylus short, with apex rounded, set with black setae. Penisfilum broad at base, abruptly narrowed medially, tapering towards apex, curving backwards at the medial region.

Paratype female terminalia with cercus short; dark brown; set with yellowish setae. Subanal plate and tergite XI pale and set with short yellowish setae. Cercus, subanal plate and tergite XI ending about at the same level. Gonocoxosternite pale, set with yellowish setae and longer black setae at posterior margin, not fused ventrally; in lateral view with a subapical membranous concavity.

Etymology. Named after the species habitat, the várzea, an area in the Amazon forest seasonally flooded area by white water ( varzeanus = “from várzea ”).

Holotype. Male (present designation): INPA: BRASIL, Amazonas , Tefé, Várzea, 3 o 19’45’’S– 64 o 41’13’’W, 14–28.x.2017, Malaise, J.A. Oliveira, D.M.M. Mendes & J.A. Rafael—Rede Bia ( INPA).

Holotype condition. Excellent, mounted in triangle.

Paratypes. Brazil: Amazonas : Tefé, Várzea, 3 o 19’45’’S– 64 o 41’13’’W, 5–15.ix.2016, Arm. Malaise, J.A. Oliveira, D.M.M. Mendes & J.A. Rafael (6♀ — INPA) ; idem, 1–5.xi.2016 (6♀ — INPA) ; idem, (1♂, 3♀ — CEMT) ; idem, 1–13.x.2017 (1♂, 3♀ — INPA) ; idem, 14–28.x.2017 (19♂, 27♀ — INPA) ; idem (1♂, 3♀ —UFRR); idem (1♂, 3♀ —UFAC); idem (1♂, 3♀ — CZMA) ; idem (1♂, 1♀ —UNIR); idem (1♂, 3♀ — MZSP) ; idem, 15–30.xi.2017 (2♂, 10♀ — INPA) ; idem, 1–22.xii.2017 (5♀ — INPA) .

Comments. Bittacus varzeanus sp. n. does not fit in any of the species groups proposed by Collucci & Amorim (2000). The shape of the subapical lobes in the inner margin of the male epandrium of B. varzeanus is somewhat similar to B. angrensis ; however, the new species lacks the typical falcate apex of the wings of B. angrensis . The general shape of the wings is similar to that of B. flavescens , but the shape of the male epandrium easily distinguishes them. The medial excavation on the posterior margin of the male epandrium of B. varzeanus sp. n. is unique within the South American species of Bittacus .

Figures

FIGURE 4. Bittacus adult habitus images. a) Bittacus varzeanus sp. n., living female; b) B. varzeanus male; c) Bittacus ferreirai sp. n., male holotype. Scale bar = 3 mm.

FIGURE 8. Brazilian Bittacus male epandria, dorsal view. a) B. angrensis; b) B. aripuanensis; c) B. blancheti; d) B. boraceiensis; e) B. brasiliensis; f) B. cruzi sp. n.; g) B. diversinervis; h) B. femoralis; i) B. ferreirai sp. n.; j) B. flavescens; k) B. froehlichi; l) B. genicutalus; m) B. latreillei; n) B. maculosus; o) B. omega; p) B. pintoi; q) B. varzeanus sp. n.

FIGURE 11. Bittacus varzeanus sp. n. a) wings; b) head, frontal view; c) head and thorax, dorsal view; d) male terminalia, lateral view; e) male terminalia, dorsal view; f) male terminalia, posterodorsal view. Scale bars = 1 mm.

FIGURE 12. Distribution records of Bittacus species in Brazil. a) B. angrensis, B. aripuanensis, B. blancheti, B. brasiliensis, B. brunipennis; b) B. boraceiensis, B. cruzi sp. n., B. diversinervis, B. femoralis; c) B. ferreirai sp. n., B. flavescens, B. froehlichi, B. latreillei; d) B. maculosus, B. omega, B. pintoi, B. varzeanus sp. n. Bittacus geniculatus is not represented because of its imprecise location.