Pseudopostega dorsalis Davis & Stonis 2007

Pseudopostega dorsalis dorsalis

ADULT. Figures 127, 128, 191. Length of forewing 2.2–3.3 mm. Small, mostly white moth with white forewings marked by a large, dark brown to fuscous dorsal spot extending most of the length of hind margin, a prominent, dark brown to fuscous, a subapical costal strigula extending obliquely along base of cilia, and 1–2 much more slender, dark brown, costal strigulae through terminal cilia; apical spot indistinct. Male gnathos with slender, attenuated caudal lobe; basal fold well developed, triangular (Figures 338, 339). Papillae anales of female bilobed, lobes short and usually truncate (Figure 462).

Head: Vestiture white. Scape white; flagellum light to dark brown, ~57–67-segmented. Maxillary palpus cream. Labial palpus white to dull white, dark brown to fuscous dorsally and laterally.

Thorax: White; anterior margin of tegula brown. Forewing white, sometimes with suffusion of light golden brown along costal margin, prominently marked by a large, dark brown to fuscous dorsal spot extending most of length of hind margin; a prominent, dark brown to fuscous, subapical costal strigula extending obliquely across base of cilia, broadest on costal margin then broadening again at termination in area of apical spot near tornus; a second, short, slender brown costal strigula located immediately more distad, closely parallel to prominent basal strigula 1 and occasionally confluent with it; a third, equally short, brown, costal strigula located midway across terminal cilia; apical spot indistinct; terminal cilia white to grayish white between strigulae and at tornus, light brown beyond strigulae and along hind margin; an elongate white spot at base of cilia immediately above apical dark streak; venter of forewing medium to dark brown except for short, basal white patch. Hindwing and cilia brown dorsally and ventrally except for white suffusion at base. Legs mostly white to cream; foreleg with lateral and dorsal surfaces dark brown; midleg with dark brown banding dorsally on terminal 3 tarsomeres; hindleg cream with light grayish brown dorsal spot at apex of tibia and two light grayish brown bands on tarsomeres 2 and 3.

Abdomen: Medium to dark brown dorsally, white to cream ventrally with brownish suffusion laterally.

Male Genitalia: Figures 338, 339. Socii a pair of relatively long rounded, setose lobes, widely separated by a distance ~0.4× length of cucullar lobe; caudal rim of uncus deeply concave. Vinculum broad, tapering to rounded anterior margin. Gnathos with broad base that constricts abruptly to form a slender, elongate, straight, caudal lobe; apex of lobe minutely rounded; anterior margin of gnathos convex; basal fold broadly triangular, laterally narrow (Figure 338). Valva with an elongate cucullar lobe ~0.6× length of genital capsule, bearing a pectinifer consisting of ~42–45 blunt spines; distal apex of cucullar lobe rounded, not extended; pedicel slender, approximately 0.1× length of cucullar lobe; valva elongate, length along sacculus ~0.75× length of genital capsule; saccular lobe stout, moderately long with a rounded, setose apex; basal process of valva tapering to acute apex, approximately equaling length of costal process. Juxta undeveloped.

Female Genitalia: Figures 461–463. Abdomen tapering to a narrowly rounded, minutely cleft apex. Each posterior apophysis divided slightly more than half its length with anterior fused section relatively short. Papillae anales bilobed, consisting of a pair of broad, usually truncate but sometimes minutely cleft, divergent lobes (Figures 462, 463); lobes short, length ~1.1× width, bearing ~8–10 moderately long setae. Vestibulum narrow, membranous. Ductus bursae approximately same diameter to corpus bursae; inner walls densely lined with pectinations consisting of usually 2–5 minute spicules arranged in short, transverse rows; pectinations continuing almost half the length of corpus bursae. Corpus bursae elongate, slender, enlarging slightly anterior to separation of ductus spermathecae; a narrow, elliptical, faint band of external tubercles extending through anterior half of bursa. Ductus spermathecae relatively short, ~0.33× length of bursa copulatrix; membranous outer canal slender, short; inner canal terminating in 3–4 convolutions; vesicle composed of enlarged, partially coiled sac; lagena absent.

LARVA AND PUPA. Unknown.

HOLOTYPE. ♂; COSTA RICA: SAN JOSé: San Pedro de Montes de Oca, UCR, Reserva Ecológica Leonel Oviedo, 10°26'N, 84°01'W, 1150 m: 5 Jun 2000, K. Nishida, slide USNM 32793 (USNM).

PARATYPES. COSTA RICA: CARTAGO: Turrialba, 600 m: 2 ♂, Jul 1981, V. O. Becker, slides DRD 4331, USNM 31803 (USNM, VOB). GUANACASTE: Estación Cacao, lado SO Volcán Cacao, P. N. Guanacaste, 1000–1400 m: 5 ♂, 2 ♀, 23 Oct–9 Nov 1990, C. Chaves, slides DRD 4335, DRD 4336, DRD 4340, DRD 4341, USNM 32255, USNM 32424 (INBIO, USNM). PUNTARENAS: Finca Cafrosa, Estación Las Mellizas, P.N. Amistad 1300 m: 1 ♀, Mar 1991; 1 ♀, Apr 1991, M. Ramirez, slides DRD 4333, DRD 4334 (INBIO). SAN JOSé: San Pedro de Montes de Oca, UCR, Reserva Ecológica Leonel Oviedo, 1150 m: 1 ♀, 5 Jun 2000, K. Nishida, slide USNM 33099 (USNM).

HOST. Unknown.

FLIGHT PERIOD. Adults probably occur throughout much of the year, with records known for March to April, June to July and October to November.

DISTRIBUTION. (Map 9) Currently known from only Costa Rica from elevations of 600 to1400 m.

ETYMOLOGY. The species name is derived from the Latin dorsualis (of the back, dorsal) in reference to the large, dark brown to fuscous spot present along the dorsal margin of the forewing.

DISCUSSION. This is one of the few Costa Rican Pseudopostega species yet to be found at La Selva, although the subspecies P. dorsalis fasciata, mentioned below, is known from La Selva. Known records show the species to occur at slightly higher elevations in Costa Rica, which may explain its absence at La Selva. The large forewing dorsal spot present in P. dorsalis dorsalis differs from that in P. colognatha and P. latifurcata latifurcata by extending across the forewing to the costal margin. The male genitalia of all three species differ greatly, as illustrated.

Pseudopostega dorsalis is believed to consist of two subspecies possessing identical male genitalia but with distinctly different wing patterns. No intermediate pattern variation is known to exist between the subspecies with a large forewing dorsal spot (Figure 191), herein named P. dorsalis dorsalis, and P. dorsalis fasciata, which possesses a dark brown fascia extending obliquely across the forewing (Figure 192). Because adults of both subspecies were collected within the same area at Estación Cacao and Turrialba, the status of these proposed taxa is subject to question. Sympatry in this case suggests that either (a) two distinct species possessing identical genital morphology may be involved or (b) these two morphs represent more recently derived subspecies, perhaps as a result of sympatric speciation associated with, for example, a significant shift in host plants (Doebeli and Dieckmann, 2000). Two Costa Rican specimens representing a male dorsalis dorsalis from San Jose (D181; 493 base pairs sequenced) and a female dorsalis fasciata (D195; 397 base pairs) from La Selva were submitted for DNA analysis of the mitochrondrial gene CO1. Although the number of base pairs sequenced was not optimal, greater genetic difference (~3%) was observed between these samples than resulted in the comparison of the vicariant populations of P. duplicata. Because the ~3% difference that resulted is more typical of individuals from different hosts (P. Hebert, Biodiversity Institute of Ontario, University of Guelph, Guelph, Ontario, Canada, personal communication) and considerably less than that normally exhibited between morphologically distinct, congeneric species (Hebert et al., 2004), the two superficially distinct forms with identical genitalia have been considered subspecies. Landry et al. (1999) also caution that simple percent sequence divergence between closely related sister species of Lepidoptera can be highly variable and may not necessarily be a reliable predictor of whether two unknown populations constitute reproductively isolated species.

A similar example of subspeciation apparently has evolved within another, similarly marked species proposed herein, P. latifurcata. However, in this case the two subspecies are allopatric, with the one possessing a large dorsal spot, P. latifurcata latifurcata, restricted to the West Indies, and the banded subspecies, P. latifurcata apoclina, known only from Costa Rica.

Pseudopostega dorsalis is a moth of the family Opostegidae. It was described by Donald R. Davis and Jonas R. Stonis, 2007. It is known from Costa Rica.

The length of the forewings for ssp. dorsalis is 2.2–3.3 mm. Adults have been recorded throughout much of the year, with records known for March to April, June to July and October to November. The length of the forewings for ssp. fasciata is 2.4–2.9 mm. Adults of this subspecies have been collected from May to July and September to November.