Argyrogrammana willmotti Dolibaina & Dias, sp. nov.

Argyrogrammana willmotti Dolibaina & Dias, sp. nov.

(Figs 31–34, 43, 60, 64)

Diagnosis. Argyrogrammanna willmotti sp. nov. belongs to “ stilbe complex” and can be distinguished from all species of this complex by having very small black spots on both wings and surfaces. Nevertheless, A. willmotti sp. nov. shares similarities in color pattern and morphology of the male genitalia with A. placibilis. Argyrogrammana willmotti sp. nov. can be separated from A. placibilis in forewing by the distance between the discocellular veins and the black spot of the proximal postdiscal band at M2–M3 two times longer (Fig. 43) than in both melanic (Fig. 44) and non-melanic (Fig. 45) A. placibilis specimens. Furthermore, the forewing upperside submarginal silveryblue line is more disjoint in A. willmotti sp. nov. than in A. placibilis; forewing with two distal postdiscal bands in the male of A. willmotti sp. nov., while three in males of A. placibilis; forewing underside submarginal black spots small and rectangular in A. willmotti sp. nov., large and triangular in A. placibilis; in male genitalia of A. willmotti sp. nov. the uncus is triangular in lateral view while squared in A. placibilis; the membranous area between lateral tegumen and uncus is narrow in A. willmotti sp. nov. whereas large in A. placibilis; the valvae has a deeply dorsal depression in A. placibilis while it is absent in A. willmotti sp. nov.; and the dorsal distal projection of the valvae is thin in A. willmotti sp. nov. while thick in A. placibilis.

Description. Head: uniformly pale orange; eye glabrous, brown with a black median band; antenna yellow, with black scales at the base of each segment, club mostly black, with the two last segments orange; labial palpus yellow, third segment black, thin and short. Female as in male, except by the eye without a black median band.

Thorax: uniformly orange; legs yellow with black stripes. Female as in male.

Forewing upperside: male holotype length 11.2mm, female allotype 10mm; apex rounded; ground color goldorange; two thin black spots at the base of the wing at the costal margin and on 2A; costal margin of left wing with several black flecks, reduced in right wing; discal cell with four thin black spots and two additional spots at the end of discal cell; four bands of thin black spots arranged in a “zig-zag” pattern at the postbasal, discal, and two at the postdiscal areas, from costal margin to 2A, except the distal postdiscal band, extending to anal margin; thin silveryblue submarginal line broken on the veins, spot on M1–M2 oblique; outer margin gold-orange; fringe absent. Female as in male, except by the rounder apex and shorter outer margin.

Forewing underside: ground color pale gold-orange; costal margin with pale gray scales from the base of the wing to R2; other black spots as in the upperside but larger; thin silvery-blue submarginal line reduced, surrounded by large black spots from the apex to 2A. Female as in male.

Hind wing upperside: ground color gold-orange; two thin black spots at the middle of the discal cell and one black spot at the end of discal cell; four bands of black thin spots arranged in a “zig-zag” pattern, one in the postbasal and discal areas and two in the postdiscal area; distal postdiscal band with two small black spots at Rs– M1 and M1–M 2 in right wing but absent in left wing; thin silvery-blue submarginal band broken on the veins; outer margin gold-orange; fringe absent. Female as in male, except for the rounder wing and pale brown fringe.

Hind wing underside: ground color pale gold-orange; black scales speckled at the base of the wing; other black spots as in the upperside but larger; silvery-blue submarginal band absent; submarginal black band broken on the veins, from apex to tornus. Female as in male.

Abdomen: dorsally orange with five black spots between tergum II to VII and a black line on the tergum I to III; pleura and sterna light yellow. Female as in male.

Male genitalia: tegumen dorsally squared and laterally triangular; triangular lateral membranous area between tegumen and uncus; tegumen ventral arms and saccus dorsal arms evenly narrow and fused; anterior projection of the saccus short and narrow; uncus shorter than tegumen, laterally ellipsoidal and distally bilobed; gnathos long and thin, “C” shaped and distally pointed; valvae triangular and short, with a slightly pointed distal projection; fultura inferior long; aedeagus thick, three times longer than valvae with innumerous thin and long cornuti.

Female genitalia: sterigma sclerotized, arch-shaped; lamella antevaginalis narrow; lamella postvaginalis thin, arched distally projected at the center with a pointed tip; bursae copulatrix thirteen times longer than sterigma; ductus bursae as long as one third of the length of bursae copulatrix, with a short sclerotized portion, remainder membranous; corpus bursae rounded and long, with a pair of conical and asymmetrically placed signa; papilla analis rectangular with irregular margins, a short and rounded postero-ventral projection and a median rounded glabrous area.

Type material. Holotype male with the following labels: / HOLOTYPUS / BRASIL, ACRE, MÂNCIO LIMA, P[AR]Q[UE]. NAC[IONAL]. [DA] SERRA DO DIVISOR, PORÇÃO NORTE, 7º26’50”S 73º39’52”W 200– 400m. 10–21.IX.2011 D. Dolibaina & D. Moura, leg. / DZ 21.644 / D. Dolibaina gen. prep. 2011 / Holotypus Argyrogrammana willmotti Dolibaina & Dias det. 2015 / in DZUP.

Allotype with the following labels: / ALLOTYPUS / OBIDOS – PARÁ [, Brazil] / Ex. Col. Gagarin / DZ 19.303 / Dolibaina det. 2012 / Allotypus Argyrogrammana willmotti Dolibaina & Dias det. 2015 / in DZUP.

Etymology. This new species is named after Dr. Keith R. Willmott, to honor his extensive contribution in the taxonomy, systematic, phylogeny, evolution, biogeography and ecology of the Neotropical butterflies.

Ethology. A single male specimen of A. willmotti sp. nov. was collected at the PNSD in 2011 on the edge of a natural clearing in the hilltop while resting beneath a leaf five meters above the ground, around 16:00h.

Distribution. This species is currently known only from two localities in the Amazon basin, namely, the north region of PNSD, Mâncio Lima, Acre, and Óbidos, Pará, Brazil.

Comments. The ground color and black spots pattern on the wings define A. willmotti sp. nov. as a member of the “ stilbe complex”, and the most similar species is A. placibilis. Hall & Willmott (1996) clarified the identity of several species from this complex and they considered A. perone (Westwood, [1851]) a synonymous of A. placibilis. The type of A. placibilis is markedly similar to A. iracyi P. Jauffret & J. Jauffret, 2007 which can be differentiated by the tip of the valvae without a hook process. According to those authors, the phenotype of the syntype of A. perone, with smaller black markings on the wings, is similar to the most common phenotype of A. placibilis and A. willmotti sp. nov. However, A. willmotti sp. nov. has the black spots in both wings and sides even smaller than A. placibilis and A. perone. Additionally, the distance between the discocellular veins and the black spot of the proximal postdiscal band at M2–M 3 in the forewing of A. willmotti sp. nov. are twice longer (Fig. 43) than in A. placibilis (Fig. 44) and A. perone (Fig. 45); this character is stable also on the females.

The female genitalia of species of Argyrogrammmana never were described nor illustrated in previous studies (Brévignon & Gallard 1995, Hall & Willmott 1995, 1996). Interestingly, the signa are asymmetrically placed in A. willmotti sp. nov., i.e., their position on the corpus bursae are not aligned with each other like many other riodinids. We have dissected other species of Argyrogrammana and observed different conditions for that character, including the absence of signa in A. caesarion Rebillard, 1958 and the presence of only one signum in A. venilia. Unaligned signa were also observed in A. gallardi sp. nov. (Fig. 63), A. stilbe stilbe, A. iracyi (Fig. 65), A. saulensis tunari Gallard, 2008, comb. nov. (Fig. 66) and A. rameli (Stichel, 1930). More dissections are necessary to investigate further conditions of this character within the genus and its use for the taxonomy of the group.