Argyrophorus idealis Pyrcz & Cerdeña, 2019

Pyrcz, Tomasz W., Gutiérrez, José Cerdeña & Florczyk, Klaudia, 2019, Two remarkable new species of Argyrophorus Blanchard from the Peruvian high Andes (Lepidoptera, Nymphalidae, Satyrinae), Zootaxa 4656 (2), pp. 375-383 : 376-377

Argyrophorus idealis Pyrcz & Cerdeña , n. sp.

( Figs. 1 A–F, 2B, 3B, 4A–D)

Type locality. Tingo Pampa , 10 km N Ocros, Ancash, Peru .

Type material. Material examined: HOLOTYPE ♂: PERU, Depto. Ancash, 10 km N Ocros, Sector Tingo Pampa, 4000–4100 m, 11–12. VI .2019 , T. Pyrcz, leg., to be deposited in MUSM: PARATYPES (155 ♂ and 28 ♀): same data, leg. T. Pyrcz, P. Boyer, J. Cerdeña, J. Farfán, prep. genit. ♂ H_13_ 28.06.2019 / K.Florczyk, prep. genit. ♀ H_14_ 28.06.2019 / K.Florczyk, prep. mol. 20190768A/B, 20190769A/B; in MUSM, MUSA, PBF, CEP-MZUJ .

Diagnosis. Most similar, in size and wing shape to A. lamna and Argyrophorus rubrostriata n. sp., but immediately recognized by all silver hindwing dorsal surface, in this respect only similar to the Chilean A. argenteus Blanchard ; on turn, the reddish overcast of the forewing ventral surface, in the latter respect most similar to Argyrophorus rubrostriata n. sp.

Description. MALE ( Figs. 1A, B ): Head: eyes chocolate brown, naked; palpi twice the length of head, dorsally black, laterally light grey, covered with grey and black hair; antennae to half costa, entirely covered with scales, dorsally brown and steely grey, ventrally snow white, club darker, spoon like, composed of 9–10 segments. Thorax: dorsally black, covered with dense, chestnut hair, ventrally blackish grey; legs grey brown. Abdomen: dorsally and laterally chestnut, ventrally light grey covered with dense silver scales. Wings: FW length 17–19 mm; apex blunt, outer margin slightly concave; HW oval with a smooth outer margin; fringes brown, long. Venation: FW Sc and R arise independently, R1 arises before branching of M1, R2, R3 and R4 arise from the same stem, approximately the same distance from each other, rs-m1 short but noticeable, m1-m2 curved inside discal cell at straight angle, twice as long as m2-m3, m2-m3 straight. HW humeral vein absent, m1-m2 long and bent inside discal cell, M1 arises three times closer to Rs than to M2. FWD: Shiny silver, except for a narrow, dark brown marginal line. HWD: Shiny silver, except for a narrow, dark brown marginal line. FWV: ground colour dark brown with a wide brownish red overcast covering most of the wing surface; a series of four black submarginal oval spots, with>shaped distal and basal borders; a narrow marginal line; costal and apical areas suffused with yellow and silver scales. HWV: ground colour steely grey brown; a series of zigzagging black lines extending from costa to anal margin, postbasal, postme- dian and submarginal; a series of elongated submarginal dots, each in every cell; a thin, black marginal line parallel to outer margin; all the veins marked with light grey.

MALE GENITALIA ( Fig. 2B ): Tegumen dorsal surface slightly arched; uncus massive, one and half the length of tegumen, with a prominent dorsal buldge and a sharp tip curved downwards; gnathos stout, half the length of uncus; pedunculus prominent four-fifths the length of gnathos; vinculum slightly arched, same length as from tegumen anterior edge; saccus rather short, same length as pedunculus; valvae elongate, two times the length of tegumen dorsum, with a serrate costa, a prominent basal cavity, a bulbous basal prominence and an acute tip; aedeagus the length of tegumen+uncus, tubular, slender, slightly arched and thicker in median part, anterior entrance half the length of entire aedeagus, no apparent serration.

FEMALE ( Figs. 1C, D, E, F ): Sexual dimorphism slight (FW length: 18–20 mm), female’s wings upperside are generally duller, without the strong sheen of the males, which is probably due to different reflectance qualities of male and female scales. There is generally some brown scaling on the FW apex, not apparent in the males. Also, females wings a slightly more elongated. One female ( Fig. 1E, F ) is exceptional as it presents a mostly brown hindwing dorsal surface.

FEMALE GENITALIA ( Fig. 3B ): Papillae anales flattened in lateral view, extremely pilose, apophyse posterior prominent, wide and terminated in a blunt tip, approximately the length of papillae width; lamellae postvaginalis forming a wide hoop, partly enclosed from above by two wide flaps; ductus bursae wide and short, weakly sclerotized gradually opening into bursa with ductus seminalis emerging from basal part of ductus bursae; corpus bursae oval with two prominent signa approximately two-thirds the length of bursae.

Etymology. The epithet of this species, idealis , means « perfect » in Latin, and is an allusion to the beautiful, uniform silver upperside, matched among world butterflies only by Argryrophorus argenteus from Chile.

Bionomics. Both sexes fly on well exposed slopes covered with abundant grasses belonging to native species of Calamagrostis , intermixed with secondary Festuca and Poa , with dense cover of bushy Lupinus ( Figs. 4E, F ). It was, therefore, impossible to identify at this stage the host plant because the area where the new species was observed is covered with at least five species of Poaceae . However, contrary to the localities in north-central where other Argyrophorus were observed, the predominant species was not Stipa ichu , which in fact was not seen anywhere near. It is quite surprising because elsewhere the most frequent high Andean biotopes of Argyrophorus , and also of several species of Pampasatyrus and Faunula are dominated by Stipa . Moreover, it was impossible to identify the host plant because females have been observed to present a very unusual oviposition behaviour. They land on sandy places and dig holes in the substrate where they lay eggs one by one, not directly on any host plant ( Fig. 4B ).

Adults are very active during particularly hot and sunny periods of the day, mostly from 10–12 AM. They do not spend long periods on the wing but intermittently present patrolling and perching behaviour. They warm up their bodies by lateral basking on the ground, especially on small rocks and directly on the ground (Fig. 5). They do no display an open wing behaviour. They occasionally visit flowers of various species, mostly Asteraceae ( Fig. 4D ). They show a very strong predilection for rather dry slopes and avoid open areas devoid of grasses, nor do not, in opposition to some other species of the ground, such as A. angusta , seek humid meadows along water courses. During their flight period this species can be very common in its natural habitat. Several dozens of individuals can be observed within minutes.

Figures

FIG. 1. Adults: A. Argyrophorus idealis n. sp. male, HOLOTYPE, dorsal; B. Argyrophorus idealis n. sp. male, HOLOTYPE, ventral; C. Argyrophorus idealis n. sp. female, PARATYPE, dorsal; D. Argyrophorus idealis n. sp. female, PARATYPE, ventral; E. Argyrophorus idealis n. sp. female (individual form), PARATYPE, dorsal; F. Argyrophorus idealis n. sp. female (individual form), PARATYPE, ventral; G. Argyrophorus rubrostriata n. sp., male, HOLOTYPE, dorsal; H. Argyrophorus rubrostriata n. sp., male, HOLOTYPE, ventral; I. Argyrophorus rubrostriata n. sp., female, PARATYPE, dorsal; J. Argyrophorus rubrostriata n. sp., female, PARATYPE, ventral

FIG. 2. Male genitalia (in lateral view, aedeagus extracted in lateral and ventral view). A. Argyrophorus rubrostriata n. sp.; B. Argyrophorus idealis n. sp.

FIG. 3. Female genitalia (in lateral view). A. Argyrophorus rubrostriata n. sp.; B. Argyrophorus idealis n. sp

FIG. 4. Adults in the field and biotopes. A. A. idealis n. sp., female in resting posture; B. A. idealis n. sp., female egg laying behaviour; C. A. idealis n. sp., lateral basking on the ground; D. A. idealis n. sp., male feeding on Paranephelius sp. (Asteraceae); E. A. idealis n. sp., biotope, type locality; F. A. idealis n. sp., biotope, type locality; G. A. rubrostriata n. sp., female in resting posture; H. A. rubrostriata n. sp., biotope, type locality (photos A, B, H. T. Pyrcz; photos C, D, E, F, G. P. Boyer).