Hygronemobius amoenus Chopard, 1920

(Figs. 13–18, Map 1)

Hygronemobius amoenus Chopard, 1920: 120 . Holotype: male, FRENCH GUIANA, Saint-Laurent-du-Maroni, St. Jean de Maroni. Depositoy: Museum National d‘Histoire Naturelle, Paris (MNHN).

Hygronemobius amoenus: Chopard, 1967: 189.

Hygronemobius amoenus: Desutter-Grandcolas, 1993: 12.

Hygronemobius amoenus: Pereira, Miyoshi, Martins, Fernandes, Sperber & Mesa, 2013: 1, 3, 16, 17, 18.

Examined material: 10 males and 10 females. Brasil [Brazil], Pará, Melgaço, FLONA Caxiuanã, ECFPnESECAFLOR; 1°43'35"S, 51°26'36"W; I.2012; D.A. Cunha leg . 3 males and 7 females. Same data as the previous, but II.2012 (MPEG) . 18 males and 16 females. Same data as the previous, but month and year collection unknown (MPEG) . 1 male. Same data as the previous, but month unknown and collected in 2012 (MPEG) . 4 males and 5 females. Same data as the previous, but I.2012 (MPEG) . 5 males and 12 females. Same data as the previous, but II.2012 . 7 males and 7 females. Same data as the previous, but III.2012 (MPEG) . 4 males and 1 female. Same data as the previous, but IV.2012 (MPEG) . 4 males and 1 females. Same data as the previous, but V.2012 (MPEG) . 2 males and 2 females. Same data as the previous, but VI.2012 (MPEG) . 5 males and 7 females. Same data as the previous, but VII.2012 (MPEG) . 1 male. Same data as the previous, but VII.2011 . 6 males and 6 females. Same data as the previous, but VIII.2012 (MPEG) . 5 males and 4 females. Same data as the previous, but IX.2012 (INPA) . 2 males and 2 females. Same data as the previous, but XI.2011 (BOTU) . 1 male and 4 females. Same data as the previous, but XII.2011 (BOTU) .

Updated diagnosis: Similar to other species of the amoenus group (except Hygronemobius torquatus Desutter-Grandcolas, 1993), the male exhibits two longitudinal whitish stripes on the pronotum; however, it is distinguishable from other species in the group by the following characteristics: the lighter color of head and pronotum (Figs. 13D–E; 14A, C), the reticulate spots in the area below the insertion of the antennae, genae, and clypeus (Fig. 13E); the whitish stripes surrounding the eyes (Figs. 13D–E); the additional whitish mark along the posterior margin of pronotal disc, sometimes forming a transverse stripe (Figs. 13B; 14A); the abdomen uniformly blackish or darkbrownish, except the supra-anal plate and the fourth tergite, which are partially whitish (Figs. 13B; 16G; 18B, G)—in males, the fourth tergite with intercalated whitish spots, two on the sides and one in the middle (Fig.13B), and in females, the fourth tergite is almost entirely whitish (Fig. 18B).

Redescription. Head. Coloration light brown, with a slightly lighter stripe extending along the inner margin of the eyes, from the dorsal portion to the inner margin of the antennal orbits, contiguous with a medial spot of the same tone, extending to the clypeal suture. Reticulated spots formed by dark brown punctuations extend laterally from the gena to the apex of the clypeus. Labrum lighter than the cephalic capsule (Fig. 13E). In frontal view, triangular, wider than tall, with prominent eyes and the antennal orbit close to the base of the eyes. Medial ocellus at the same level as the upper margin of the antennal orbits and marked with a black spot. Lateral ocelli near the end of the coronal branch of the ecdysal line (Fig 13E). In lateral view, eyes oval, taller than wide. Posterior portion of the gena and the postocular region glabrous, lighter than the rest of the cephalic capsule (Fig. 13D). First two segments of the maxillary palpomeres similar, almost equal in length, cylindrical, yellowish in color with white distal portions; third palpomeres longer than the sum of the previous two, subcylindrical, narrower proximally and lighter; fourth conical, smaller and slightly darker than the third; fifth conical, rounded distally, longer than any previous segment, and brown in color, except for the whitish tip (Fig. 13F).

Thorax. Pronotum, in dorsal view, wider than long, with almost straight anterior and posterior margins (Fig. 14A). Pronotal disc brown, with two lateral whitish stripes and an additional mid spot (sometimes forming a stripe) on the posterior margin, and ecdysal line conspicuously marked (Fig. 14A). AS formed by three almost parallel macrochaetae, two in the brown portion of the disc and one in the whitish stripe; MSG formed by three macrochaetae forming a square angle; PS formed by seven macrochaetae, four of them forming an arch, followed by three more lateral macrochaetae forming an almost straight line, extending through the lateral lobes (Figs. 14A–B). In lateral view, lateral lobes longer than tall and completely brown (Figs. 13B; 14C). LS formed by six macrochaetae, forming the pattern seen in Figs 14D. Prosternum reduced; mesosternum rectangular, with rounded corners and slightly darker anterior portion; and metasternum hexagonal, with slightly darkened anterior edges (Fig. 13G). Mesosternum and metasternum setose (Fig. 13G).

Wings. Tegmina longer than wide, light brown in color with whitish spots in the anal, postcubital, and harp regions, and at the distal portion. These spots extend from the cubital-anal region, radiating throughout the length along the medial + cubital-anal veins. The An+PCup veins well visible (Fig 15A). First and second C+Sc veins connected proximally, as well as the third and fourth C+Sc veins (Fig. 15B, white circles). Stridulatory apparatus with 44 teeth (N=1, Fig. 15C).

Legs predominantly ochre, with conspicuous setae (macrosetae), and pubescent surface covered with small setae (Figs. 16A–F). Dorsal surface of fore and mid femora with the mid-distal portion brown and a whitish spot in the middle. Dorsal surface of hind femora almost completely brown, except for the two whitish spots and the ochre distal portion. All basitarsi predominantly whitish (Figs. 16A–F). Tympana present only on the outer surface of the fore tibia (Fig. 16A). Hind legs robust, with three dorsal spurs on each margin, two apical on the inner margin, and three on the outer margin (Figs. 16E–F).

Abdomen, in dorsal view, uniformly black or dark brown, except for the supra-anal plate’s proximal half and the fourth tergite, which are partially whitish (Figs. 13B; 16G)—fourth tergite with small and intercalated whitish spots, two on the sides and one in the middle (Fig.13B). Supra-anal plate small, conical, with a rounded posterior margin (Fig. 16G). Abdominal sternites predominantly brown (Fig. 13C). In ventral view, subgenital plate wider than long, with a widely rounded posterior margin and a slightly lighter mid-distal spot (Fig. 16H); in lateral view, longer than tall (Fig. 16I). Cerci of lighter color near their base.

Phallic complex. Pseudepiphallic apical lobes triangular and acute, completely membranous, covered with bristles, and conspicuously distinctive from the pseudepiphallic sclerite and median lobes. In dorsal view (Fig. 17A), pseudepiphallic median lobes well-sclerotized, distinctive from the pseudepiphallic sclerite. Ectophallic apodeme thin, and endophallic cavity reduced. Endophallic sclerite with an invagination between the lateral appendages and the central one, although it is almost imperceptible. Endophallic sclerite symmetrical, with central part connected to lateral appendages only distally and medio-proximally separated, lateral appendages triangular. Endophallic apodeme well-sclerotized. In lateral view (Fig. 17B), pseudepiphallic parameres as well-sclerotized inward lobes. In axial view (Fig. 17C), median pseudepiphallic lobe well-sclerotized. Pseudepiphallic parameres with rounded outer margin and irregular inner margin. Ectophallic fold well-projected ventrally. In lateral view (Fig. 17D), pseudepiphallic apical lobes triangular and downcurved. Pseudepiphallic median lobe projected posteriorly. Ectophallic fold well-developed. Rami of medium thickness and well-sclerotized.

Female. Tegmina reduced (Figs. 18A–B). Base of the pronotal disc larger than males. Abdominal tergites uniformly dark brown, with the fourth tergite completely whitish (Fig. 18B). Ovipositor, in lateral view, almost straight, slightly upcurved (Fig. 18D); in dorsal and ventral views, straight, with dorsal valves bearing very small denticulations on the apex (Figs. 18E–F). Tenth tergite similar to males (Fig. 18G); Subgenital plate ochre; in ventral view, wider than long, with the posterior margin forming two lobes (Fig. 18I); in lateral view, longer than tall, with rounded posterior margin (Fig. 18H).

Measurements (mm).

Males. TL: 5.9–7.2; PL: 1.1–1.2; PW: 1.2–1.9; Tg: 2.2–3.5; HF: 3.7–4.2; HT: 2.9–3.2.

Females. TL: 5.1–7.2; PL: 1.3–2.0; PW: 1.2–1.9; Tg: 0.5–1.0; HF: 3.8–4.1; HT: 2.2–3.2; Ov: 2.3–2.9.

Distribution. This species was originally recorded in the Northern French Guiana (Chopard, 1920, Desutter-Grandcolas 1993), and this is the first record in Brazil, in the Floresta Nacional de Caxiuanã, in Pará State (Map 1).