Amiga Nakahara, Willmott & Espeland

Nakahara, Shinichi, Lamas, Gerardo, Tyler, Stephanie, Marin, Mario Alejandro, Huertas, Blanca, Willmott, Keith R., Mielke, Olaf H. H. & Espeland, Marianne, 2019, A revision of the new genus Amiga Nakahara, Willmott & Espeland, gen. n., described for Papilioarnaca Fabricius, 1776 (Lepidoptera, Nymphalidae, Satyrinae), ZooKeys 821, pp. 85-152 : 90-94

Amiga Nakahara, Willmott & Espeland gen. n.

Type species.

Papilio arnaca Fabricius, 1776, by present designation

Systematic placement and diagnosis.

Espeland et al. (2019) recovered Amiga arnaca comb. n. as sister to the " Pareuptychia clade", whose composition partially corresponded to that found in Peña et al. (2010), with a high support (BS and PP> 0.95). The " Pareuptychia clade" itself was also well supported (BS and PP> 0.95), including Satyrotaygetis satyrina (Bates, 1865), Magneuptychia inani (Staudinger, [1886]), Euptychoides albofasciata (Hewitson, 1869), Neonympha areolatus (Smith, 1797), Erichthodes antonina (C. Felder & R. Felder, 1867), Pareuptychia ocirrhoe (Fabricius, 1776), Megeuptychia antonoe (Cramer, 1775), Splendeuptychia doxes (Godart, [1824]), Nhambikuara mima (Butler, 1867), and Euptychoides eugenia (C. Felder & R. Felder, 1867). Amiga gen. n. is distinguished from all members of the " Pareuptychia clade" by the presence of bluish-lilac coloration on the dorsal hindwing and by the purplish sheen in the tornal half of the VHW. Furthermore, the absence of cornuti and membranous lamella antevaginalis of Amiga gen. n. appear to be unusual character states among the clade. The type species of Chloreuptychia , Papilio chloris Cramer, 1780 (= Chloreuptychia chlorimene ) was recovered as sister to a moderately supported (BS and PP> 0. 75 <0. 95), clade including the " Pareuptychia clade", " Taygetis clade", " Splendeuptychia clade" and " Archeuptychia clade".

Description.

MALE: Forewing length: 18.5-22 mm (n = 6)

Head: Eyes with sparse golden hair-like setae, with white scales along margin; frons dark brownish, covered with creamy brownish scales and hair-like scales towards antennae; first segment of labial palpi similar in width to second segment, similar in length to third segment, adorned with white long hair-like scales and brownish long hair-like scales ventrally, second segment longer than eye depth and covered with white hair-like scales, brownish hair-like scales, and white scales laterally and dorsally, with brownish hair-like scales and brownish scales along edge of distal two-thirds of dorsal surface, ventrally adorned with brownish hair-like scales and whitish hair-like scales longer than segment width, third segment roughly one-third of second segment in length and covered with brownish scales dorsally and ventrally, with white scales laterally; antennae approximately half of forewing length, with ca 34 segments (n = 1), scape about as twice as long as pedicel, white scales on each side of base of flagellomeres, distal 10-12 segments composing club.

Thorax: Brownish, dorsally scattered with grayish scales and lightly colored long hair-like scales; ventrally scattered with white scales and white long hair-like scales; foreleg (Fig. 5c) whitish, femur, tibia and tarsus similar in length; midleg and hindleg with femur white ventrally, tibia and tarsus grayish dorsally, ocher ventrally tibia and tarsus adorned with spines ventrally, pair of tibial spurs present at distal end of tibia.

Abdomen (Fig. 3a, b): Eighth tergite sclerotized in a narrow anterior band and slightly broader posterior patch, which appear as two separate plates.

Wing venation (Fig. 3): Basal half of forewing subcostal vein swollen; base of cubitus swollen; forewing recurrent vein present as small projection slightly above origin of M2; hindwing humeral vein developed; origin of M2 slightly towards M1 than M3.

Wing shape: Forewing triangular, apex rounded, costal margin slightly convex, outer margin almost straight below M2, inner margin almost straight, but curving inwards towards thorax near base; hindwing somewhat rectangular, slightly elongate, costal margin almost straight, angled inwards at base, outer margin slightly undulating, inner margin slightly curved near tornus, anal lobe convex, slightly rounded.

Dorsal forewing: Ground color light brownish, slightly translucent, thus subtly revealing ventral bands and ocelli in cell M1.

Dorsal hindwing: Ground color similar to forewing, iridescent bluish lilac reflection covering most of dorsal hindwing, area near costa and area distal to marginal band revealing ground color; slightly translucent, thus subtly revealing ventral bands and ocelli.

Ventral forewing: Ground color pale grayish brown; pale reddish-brown discal band extending from radial vein, crossing discal cell, passing origin of Cu2, terminating at 2A; concolorous scales present along discocellular vein; pale reddish-brown postdiscal band extending from radial vein towards inner margin until reaching vein 2A, slightly wider than discal band; broad, faint, iridescent bluish-lilac reflection extending just distal of postdiscal band towards outer margin, prominent between postdiscal band and umbra; sinuate, narrow submarginal band, almost concolorous to basal two bands, extending from apex towards tornus, jagged above Cu1, almost straight below this vein; concolorous marginal band, not jagged, appearing narrower than submarginal band, traversing along marginal area from apex to tornus; fringe brownish; ocellus in cell M1, spilling out from veins M1 and M2, black with two whitish pupils in center, ringed in yellowish orange, ocelli present in cell M2 and M3, appearing as two slate-gray patches surrounded by yellowish-orange ring; umbra appearing as broad rather faint band concolorous to four ventral bands, visible around ocelli, extending to cell Cu2.

Ventral hindwing: Ground color similar to forewing; general wing pattern similar to forewing except as follows: iridescent bluish-lilac reflection extending from base of wing, towards outer and inner margin, especially area where iridescent bluish scales are present on dorsal surface; discal band passing cubital vein area basal to origin of Cu2; postdiscal band passing origin of Cu1, bent inwards in cell Cu2; submarginal band broadening towards tornus after passing Cu1; five submarginal ocelli, those in cells M1 and Cu1 similar to that in VFW cell M1 but with single pupil, those in cells M2 and M3 similar to those in VFW cells Rs, M2 and M3 but slate grayish patch appearing as single patch in middle.

Genitalia (Fig. 4 c–g): Tegumen appears semi-circular in lateral view, anteriorly and dorsally convex, ventral margin rather straight; uncus longer than tegumen in lateral view, apparently without setae, middle section somewhat broadening in dorsal view, tapering posteriorly and terminating in single point; brachium tapering towards apex, apical point positioned above uncus in lateral view, parallel to uncus with apical edge curving inwards in dorsal view; combination of ventral arms from tegumen and dorsal arms from saccus slightly curved distally; appendices angulares present; saccus narrow, concavity at base of ventral margin, anteriorly rounded, similar or shorter than uncus in length; juxta present as plate with deep concavity at dorsal margin in posterior view; valva distally setose, valva appearing roughly parallelogram in lateral view, ventral margin convex, dorsal margin distal of costa curved, costa curved inwards, apical process somewhat curving upwards; phallus roughly straight, similar in length to valva plus saccus, phallobase about one-third of phallus, ductus ejaculatorius visible as illustrated, posterior portion of aedeagus somewhat curved upwards, manica covering more than half of aedeagus, cornuti absent.

FEMALE: forewing length: 19-21 mm (n = 6)

Similar to male except as follows: Five tarsomeres present in foretarsus, with spines along some tarsomeres; forewing appearing somewhat rounded and broad; dorsal hindwing submarginal band somewhat more prominent; bluish lilac reflection appearing more purplish, extending to origin of M1 or further anteriorly; feeble pearly reflection present on dorsal forewing (but see below for further information). Female genitalia and abdomen (Figs 4 h–k): Inter-segmental membrane between 7th and 8th abdominal segments pleated and expandable, with weakly sclerotized region present; lamella antevaginalis membranous; lateral side of 8th abdominal segment sclerotized (referred to as "lamella postvaginalis" by Willmott et al. 2018), this sclerotized plate fused to lamella antevaginalis at anterior margin; ductus bursae membranous, somewhat inflated around origin of ductus seminalis, located at approximately one-fifth distance from ostium bursae to corpus bursae, ductus bursae apparently weakly sclerotized at region posterior to origin of ductus seminalis; corpus bursae roughly oval in dorsal view, with two relatively narrow signa, together with ductus bursae extending to juncture of 4th and 5th sternite.

Variation.

This species exhibits geographic variation in wing pattern, some of which is recognized here with subspecific names. A broad, faint, iridescent bluish-lilac reflection between the ventral forewing postdiscal band and the umbra is present in specimens from the eastern Andes, whereas it is absent in many specimens from west of the Andes. The absence of this bluish-lilac reflection on the ventral forewing seems rather stable in specimens from western Colombia and western Ecuador. However, this character appears in a few specimens from Panama, and is present in some specimens from Costa Rica and Nicaragua, although the degree of reflection is variable. The bluish-lilac reflection seen mainly on both the dorsal forewing and hindwing is variable in color, varying from light blue to purple. Especially in female specimens, the extent of bluish-lilac reflection on the dorsal forewing is variable, being absent in some specimens, whereas covering most of the discal cell and cells Cu1 and Cu2 in others (see below for further information). There exists a feeble pearly reflection on the ventral forewing from the base to the postdiscal band in specimens from southeastern Brazil (see below for further information), although this is absent in a few specimens. The presence or absence of a ventral forewing ocellus in cell M3 is variable, appearing as a trace in some specimens. The size of the ventral hindwing ocellus in cell M1 is variable in comparison with the ventral hindwing ocellus in cell Cu1, ranging from similar in size to almost twice as large. The genitalia appear not to be informative in separating specimens from east and west of the Andes, although specimens from Central America, including A. arnaca sericeella comb. n. et stat. n., seem to have a rather curved dorsal margin of the uncus in lateral view (Fig. 4e).

Etymology.

The new generic name is derived from the feminine Spanish noun “amiga”, meaning "a (female) friend", alluding to the fact that this is a common, familiar butterfly. The generic name is regarded as feminine.

Biology.

Janzen and Hallwachs (2018) report four grass species ( Poaceae ), Ichnanthus nemorosus , Ichnanthus pallens , Lasiacis ruscifolia , and Paspalum decumbens , as hostplants for Amiga gen. n. in Costa Rica. In addition, DeVries (1987) reported three grass genera, namely Eleusine , Ichnanthus , and Oplismenus , as hostplants in Costa Rica. Singer and Ehrlich (1993) reported Ichnanthus pallens as a hostplant in Trinidad and Tobago. The egg, mature larva, and pupa of Amiga gen. n. were described and the latter two stages illustrated in DeVries (1987). Various images of the penultimate instar, ultimate instar, prepupa and pupa are figured by Janzen and Hallwachs (2018), based on material reared in Costa Rica. In Costa Rica, adult females of Amiga gen. n. were seen ovipositing late in the afternoon, and some eggs were observed to be parasitized by trichogrammatid wasps ( DeVries 1987). The species occurs from sea level to at least 1850 m, and it is common, indeed ubiquitous, in undisturbed to heavily disturbed rain and cloud forest. Both sexes fly low (0.5 m) along shady trails throughout the middle of the day (09:00-15:00), and males are often observed perching singly on tops of leaves, maintaining apparent territories, and patrolling for ca 10 m along a trail.

Distribution

(Fig. 6). This genus ranges from southern Mexico throughout virtually all of tropical Central and South America, where its southernmost distribution appears to be southern Brazil.