Alychna argenteus Medeiros, Dolibaina & Casagrande, 2020

Medeiros, Adalberto Dantas De, Dolibaina, Diego Rodrigo, Mielke, Olaf Hermann Hendrik & Casagrande, Mirna Martins, 2020, Two new Andean species of Alychna Grishin, 2019 (Hesperiidae, Hesperiinae Hesperiini, Moncina) from Bolivia and Peru, Zootaxa 4751 (1), pp. 181-186 : 184-186

Alychna argenteus Medeiros, Dolibaina & Casagrande sp. nov.

( Figs 3–4 , 6 , 8 )

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Diagnosis. Alychna argenteus sp. nov. can be easily distinguished from the other species in the genus by the presence of a grayish postdiscal band on the ventral surface of both wings, which exhibit silvery luster when observed under light in a diagonal position.

Description of the male ( Figs 3–4 , 6 , 8 ). Forewing length: 17 mm.

HEAD: dorsally dark brown, scattered by yellow to rufous scales (the head of the unique specimens is damaged). Antennae more than 2/3 length of forewing costa, dorsally black, ventrally yellowish at apiculus, base of the club and segments of the haste; nudum 2/9, black. Labial palpi lost.

THORAX: dorsally brown, ventrally pale brown mixed with some yellowish scales. Legs dark brown dorsad, with some yellowish to rufous brown scales ventrad; foretibia with epiphysis; midtibia spined and with a single pair of spurs; hind tibia spined, and with two pairs of spurs.

DFW ( Figs 3 , 6 ): ground color uniformly dark brown, with scarce yellowish scales along costa; a black tripartite stigma, with one elongated part in CuA 1 –CuA 2, contiguous with the posterior margin of discal cell, and two small parts, in CuA 2 –2A, above and below anal fold ( Fig. 6 ); one white, semi-hyaline apical spot at the end of proximal third of R 5 –M 1; two white, semi-hyaline discal spots, one rounded, at the end of the proximal third of M 3 –CuA 1, the other elongated, oblique and arched, in CuA 1 –CuA 2; two faint postdiscal spots in M 1 –M 2 (the smallest) and M 2 –M 3 (the largest), both as few yellowish scales; marginal line slightly darker than the ground; fringe yellowish.

DHW ( Fig. 3 ): ground color dark brown, unmarked; marginal line darker than the ground color; fringe yellowish.

VFW ( Fig. 4 ): ground color slightly paler than above, with rufous scales concentrated along costa and at apex; three diffuse, greyish apical spots, between R 3 –M 1, aligned toward the mid of outer margin; five diffuse, discal spots, in an oblique line, from M 1 to mid of CuA 2 –2A, greyish between M 1 –CuA 1, yellowish between CuA 1 –2A; the spot in CuA 1 –CuA 2 as a narrow and arched stripe; semi-hyaline spots as in DFW but more evident; all spots above mentioned have a silvery luster when observed under light, in a diagonal position; marginal line slightly darker than the ground; fringe yellowish.

VHW ( Fig. 4 ): ground color slightly paler than above, with rufous scales concentrated beyond distal end of discal cell; discal cell with a triangular, diffuse and greyish spot, at inferior portion of its distal end; an arched band of seven rectangular, diffuse postdiscal spots between Sc+R 1 –2A, all proximately well delineated, becoming diffuser distally; as in VFW, these spots also have a silvery luster when observed under light, in a diagonal position; marginal line darker than the ground color; fringe brown.

ABDOMEN: dorsally and ventrally dark brown, lighter ventrally and scattered by few ochre scales.

Genitalia ( Fig. 8 ): tegumen trapezoid, with a long and narrow distal projection, proximal margin with a conspicuous median U-shaped indentation ( Fig. 8a ). Ventral arms of tegumen narrowed ventrally and fused with the uniform narrow dorsal arms of saccus ( Fig. 8b ). Saccus triangular, broad, constrict laterally and shorter than tegumen+uncus ( Fig. 8c ). Uncus about triangular, 1.5 times as long as tegumen (without the median projection), distal margin slightly bifid, about 2/5 as wide as base, and with a ventral short pointed projection ( Fig. 8a, d ). Fenestra broad, triangular, as long as half of the uncus ( Fig. 8a ). Gnathos divided, similar in structure to that of A. chulumani sp. nov., except to be more projected ventrally, with ventral margin rounded, tip narrower and membranous area ellipsoid ( Fig. 8b, d ). Valva rectangular, about 2.3 as long as wide, wider at median portion; sacculus triangular and broad, half the width of the valva, narrowing towards harpe; costa undistinguished; ampulla with a constriction at dorsal margin of its base, slightly upcurved, not reaching the distal margin of harpe, distally rounded, separated from harpe by a cleft; harpe slightly longer than half of valva, distally upcurved, tip as a three vertical flattened-layers converging to a somewhat pointed structure, with an internal line bearing a median longitudinal row of tooth-like processes, laterally flattened ( Fig. 8b, e ). Aedeagus longer than valva, cylindrical, nearly straight in dorsal view, slightly arched in lateral view; coecum short, slightly flattened dorso-ventrally; ejaculatory bulb opening ovoid, dorsal; area proximal to insertion of manica slightly longer than distal portion of aedeagus; distal opening for vesica extending dorsoproximally; cornuti as two plates bearing robust spines at base of vesica, the first one fused with aedeagus ( Fig. 8 f–i). Fultura inferior developed, heart-shaped, formed by two broad ventral plates, longitudinally separate in the middle by a thin membranous path, in lateral view with a thin proximo-dorsal projection, proximal half with two lateral folds, ventrally projected and contiguous with the antero-dorsal margin of sacculus ( Fig. 8 b–c).

Female. Unknown.

Distribution and phenology. Alychna argenteus sp. nov. is only known from its type locality in the eastern slopes of the Peruvian Andes. The holotype was collected in May.

Discussion. Although the skippers belonging to Moncina generally do not have attractive colors, there are exceptions such as A. argenteus sp. nov.. The grayish silvery lustered markings of both ventral wings of A. argenteus sp. nov. are unique among Alychna species, though this pattern is also found in three additional Andean skippers: Viridina viridenex (Weeks, 1901) , V. viridis (E. Bell, 1942) , and Wahydra graslieae A. Warren, Carneiro & Dolibaina, 2018 . In fact, these four ventrally flashy skippers, albeit some of them not related, occur very locally in moderate to high elevation habitats of eastern Andean slopes and are poorly represented in collections. As argued by Carneiro et al. (2018), the skipper fauna from this area is more difficult to be investigated due to a conjuncture of climatic conditions and fewer number of researchers studying the group. Thus, further studies are necessary to determine the relation between the distributional range and the ventral pattern of these skippers.

Even with a discrepant ventral wing pattern, A. argenteus sp. nov. is here proposed as a species belonging to Alychna based on the general morphology, including the black tripartite forewing stigma, hyaline spot distad of stigma on the forewing, and a curved line of spots in discal area of VHW ( Cong et al. 2019). Alychna argenteus sp. nov. resembles A. exclamationis most in the general shape of the uncus, valvae and aedeagus

Etymology. The name is a Latin word for silver in reference to the presence of the grayish postdiscal band on ventral wings that exhibit a silvery luster when observed under light.

Type material. Holotype male with the following labels: / Holotypus / V-1996 Carpish Huanuco, Peru Büche leg. / OM 43.180 / gen. prep. A. Medeiros 2018 / Holotypus Alychna argenteus Medeiros, Dolibaina & Casagrande det. 2019 /. Deposited at the OM-DZUP.

Figures

FIGURES 1–4. Alychna species in dorsal (left) and ventral (right) views. 1–2. Alychna chulumani sp. nov., holotype: 3–4. Alychna argenteus sp. nov., holotype.

FIGURES 5–6. Forewing stigma of Alychna species 5. Alychna chulumani sp. nov., holotype, 6. Alychna argenteus sp. nov., holotype.

FIGURES 7–8. Male genitalia of Alychna species. 7. Alychna chulumani sp. nov., holotype. 8. Alychna argenteus sp. nov., holotype. a) dorsal view of tegumen and uncus. b) lateral view of tegumen, saccus, uncus, gnathos, valva and fultura inferior. c) ventral view of saccus and fultura inferior. d) ventral view of tegumen, uncus and gnathos. e) left view of the right valva. f) dorsal view of aedeagus. g) left lateral view of aedeagus. h) ventral view of aedeagus. i) right lateral view of aedeagus.