Mesene margaretta anartia Hall & Lamas

Hall, Jason P. W. & Lamas, Gerardo, 2007, Four new symmachiine taxa from the eastern Andes of Peru and Ecuador (Lepidoptera: Riodinidae), Zootaxa 1533, pp. 41-52 : 47-50

Mesene margaretta anartia Hall & Lamas , new subspecies

(Figs. 3A,B; 7; 11)

Description: Male: Forewing length 13.5 mm. Forewing slightly elongate, with straight costal margin and angular distal margin, four forewing radial veins; hindwing rather angular, with pointed apex and tornus. Dorsal surface: Ground color of both wings dark brown, basal half of forewing reddish orange, broad creamcolored submarginal rays in each of cells Cu2 to R4+5, rays in cells Cu2 and Cu1 continuous with basal reddishorange area, remaining rays isolated, rays separated from each other by a dark brown venal stripe, with broadest dark brown venal stripe on either side of ray in cell M3; basal three-quarters of hindwing reddish orange, with costal half darker red than anal half, short and broad pale yellow rays extend distally from basal reddishorange area in each of cells 2A to M3, ray in cell 2A narrow, remaining rays broad; fringe on both wings entirely dark brown. Ventral surface: Differs from dorsal surface by having slightly paler reddish-orange scaling on both wings, with hindwing basal area of a uniform shade, forewing rays a more dirty whitish color, and hindwing rays slightly broader and longer.

Head: Labial palpi short and yellow; eyes black and bare, lateral scaling yellow; frons entirely pale yellow; antennae approximately 60% of forewing length, antennal segments entirely brown with a narrow and discontinuous nudum section lateroventrally, clubs dark brown.

Body: Dorsal surface of thorax and abdomen orange, ventral surface yellow; a broad and continuous band of concealed androconial scales present dorsally across posterior margin of abdominal tergites four, five, six and seven; forelegs entirely pale yellow, mid- and hindlegs a mixture of pale brown and pale yellow scales.

Genitalia ( Fig. 7 ): Uncus rectangular in lateral view, falces with a rounded “elbow”, tegumen typical of tribe; vinculum narrow and sinuous, formed into a large, broad saccus ventrally; valvae vertically elongate in lateral view, with a broad anterodorsal section extending dorsally over aedeagus and a long, triangular, posterior section extending slightly upwards; aedeagus short, very broad and slightly downturned anteriorly, everted vesica very short and broad, with three large, oval-shaped, anteriorly directed patches of large spinelike cornuti, one patch positioned dorsally and other two positioned lateroventrally (patch on right not visible in Fig. 7 ), and an additional patch of smaller and more sparsely distributed spines between larger patches on left side of vesica; pedicel short, narrow and strap-like.

Female: Differs from male as follows: Forewing length 14.5 mm. Both wings slightly more elongate and rounded. Ground color of both wings slightly paler brown; basal areas on both wings consistently more reddish and slightly reduced in size, especially on hindwing, increasing length of contiguous distal rays, rays on both wings more whitish in color.

Head: Palpi, frons and scaling at eye margins cream.

Body: Ventral surface of thorax and abdomen cream; no abdominal androconia present; forelegs entirely cream, mid- and hindlegs a mixture of cream and pale brown scales.

Genitalia (Fig. 11): Corpus bursae elongate, with a pair of invaginated spine-like signa, one signum nearly half size of other and slightly displaced posteriorly and laterally towards other signum; posterior portion of otherwise membranous ductus bursae hardened, U-shaped, and covered with evenly spaced creases, with a darkened and heavily sclerotized dorsal protrusion across entire width of posterior section, membranous ductus seminalis exits this sclerotized protrusion dorsally on extreme right side; after a broad membranous area of ductus bursae, ostium bursae forms a broad, semicircular, sclerotized band dorsally, and a narrow, horizontal, sclerotized band ventrally.

Type material: Holotype ɗ, PERU: Junín, Aldea, 600–700 m, 10°54’S 74°55’W, 24 Aug 2003 (J. J. Ramírez) ( MUSM).

Paratypes: PERU: Junín, 1ɗ: La Merced, [c. 11°03’S 75°19’W, 750 m] (Natural History Museum, London, England [ BMNH]). Cuzco, 1Ψ: Pilcopata, [c. 12°55’S 71°24’W], 750 m, 6–8 Feb 1975 (G. Lamas) ( MUSM). Madre de Dios, 1ɗ: 20 km. S.W. of Puerto Maldonado, 300 m, 25 Oct 1983 (S. S. Nicolay) ( USNM); Parque Nacional Manu, Pakitza, 350–400 m, 11°53’S 70°58’W, 1ɗ: 15 Oct 1990 (G. Lamas) ( MUSM), 1Ψ: 18 Sept 1988 (M. G. Pogue) ( USNM).

Etymology: This taxon is named after the Greek word for “uneven”, in reference to the characteristic uneven spacing of the distal rays on the forewing.

Diagnosis: Based on the shared possession of elongate wings and darker orange to red scaling across the costal half of the dorsal hindwing in males, this new taxon can be placed in a group with Mesene margaretta (White, 1843) and Mesene nola Herrich-Schäffer , [1853]. The new taxon and M. margaretta can be placed as each others closest relatives, and distinguished from M. nola , by having essentially identical male and female genitalia, concealed androconial scales on abdominal tergites four, five, six and seven (a unique character within Mesene ), entirely dark brown antennae without any basal whitish scaling on each segment, and entirely yellow palpi without any brown ventral scaling. Despite their considerable differences in outward appearance, because these two taxa have parapatric or allopatric geographic ranges and identical morphology, anartia is conservatively described here as a subspecies of M. margaretta . However, if anartia and margaretta are ever found to have slightly overlapping or strictly parapatric ranges, without any sign of intergradation, then anartia should be raised to species status.

Mesene margaretta anartia differs from nominotypical M. margaretta by having an entirely cream ventral surface to the abdomen, without black stripes across the distal margin of each segment, reduced reddish orange on the forewing and often to a lesser extent on the hindwing, typically a broader area of whitish scaling overlying the rays on the dorsal hindwing, and forewing whitish rays that are broader, more indistinctly defined, confined to the postdiscal area instead of extending to the distal wing margin, and unevenly spaced, with the rays in cells M2 and M 1 in males and M2 to R4+ 5 in females coalesced to form a larger spot.

FIGURE 11. Symmachiini female genitalia in dorsal view. 11. Mesene margaretta anartia , paratype Ψ, Pilcopata, Cuzco, S. Peru (MUSM). Scale bar = 1 mm.

With the description of this distinctive new subspecies, we now recognize two subspecies for M. margaretta . The name semiradiata was proposed by C. & R. Felder (1865–74) as a full species for typical Colombian specimens of M. margaretta . It was treated by Stichel (1910–11) as a subspecies of M. margaretta , and finally synonymized by Callaghan & Lamas (2004). The name oriens was proposed by Butler (1870) as a full species for northern Venezuelan specimens of M. margaretta with no whitish rays showing on the dorsal surface. It was downgraded to a subspecies of M. margaretta in Hall & Harvey (2002), and is here synonymized with M. margaretta margaretta (n. syn.) for several reasons. Similar entirely orange phenotypes recur throughout the range of this taxon, for example also in southern Mexico and eastern Colombia, some specimens exhibit intermediate wing patterns, and the male genitalia of specimens exhibiting each of these wing pattern phenotypes do not differ. Given the fact that the entirely orange phenotype repeatedly occurs only in small geographic pockets throughout the range of Mesene margaretta margaretta , intermediates are rare, and the two phenotypes present different mimetic wing patterns, it seems likely that the entirely orange phenotype represents a localized geographic form restricted to a particular habitat type.

Biology: Nothing is known about the biology of this rare taxon, except that it inhabits wet lowland and premontane forest along the base of the eastern Andes from 300 to 750 m.

Distribution: Mesene margaretta anartia is currently known to range from central (Junín) to southern (Madre de Dios) Peru, along the base of the eastern Andes. However, its distribution almost certainly extends southwards into Bolivia, and may extend slightly further northwards. Nominotypical M. margaretta is known to range from Mexico to western Ecuador and from northern Venezuela to northeastern Ecuador. It remains unclear which of the two taxa will occur in southern Ecuador and northern Peru.

Figures

FIGURES 5 – 8. Symmachiini male genitalia in lateral view. 5. Mesene leucogyna leucogyna, holotype %, Qbda. Siete Jeringas, Junín, C. Peru (MUSM). 6. Mesene leucogyna notia, holotype %, San Pedro, Cuzco, S. Peru (USNM). 7. Mesene margaretta anartia, paratype %, Pakitza, Madre de Dios, S. Peru (MUSM). 8. Symmachia pena, holotype %, Qbda. Siete Jeringas, Junín, C. Peru (MUSM). Scale bar = 1 mm.