Pseudopostega tanygnatha Davis & Stonis 2007

Pseudopostega tanygnatha

ADULT. Figure 177. Length of forewing 2.3 mm. Small, mostly white moth with white forewings marked with 2 brown, subapical costal strigulae and a dark brown apical spot. Male with caudal lobe of gnathos extremely long and slender; basal fold absent (Figure 328). Female unknown.

Head: Vestiture white. Scape white; flagellum brown dorsally, paler ventrally, 47-segmented. Palpi white; labial palpus with light brown suffusion laterally.

Thorax: White; anterior margin of tegula with faint suffusion of light brown. Forewing almost entirely white, with 2 brown, subapical costal strigulae and a dark brown apical spot; first strigula fading well before apical spot; area immediately basal to dot suffused with pale yellow; apical strigula slightly curved around spot, fading to tornus; terminal cilia mostly white, with brownish suffusion apically beyond strigula 2; venter of forewing light brown except for basal white area. Hindwing and cilia light brown dorsally and ventrally except for white suffusion at base. Legs mostly white; foreleg with dorsal surfaces mostly cream with slight suffusion of light brown, paler on tarsomeres; midleg with light brown bands dorsally on tarsomeres 3 and 4; hindlegs missing.

Abdomen: Light golden brown dorsally, white ventrally.

Male Genitalia: Figures 328, 329. Socii a pair of small, rounded, setose lobes, very widely separated by a distance equal to length of gnathos; caudal rim of uncus undulate, with a median, triangular projection. Vinculum broad; anterior margin subtruncate, slightly concave. Gnathos triangular, with a broad base gradually constricting to form an elongate, slender, caudal lobe; anterior margin broadly concave, without basal fold (Figure 328). Valva with a moderately large cucullar lobe ~0.4× length of entire genital capsule, bearing a pectinifer consisting of 18–25 blunt spines; distal apex of cucullar lobe slightly extended, acute; pedicel curved, extremely long and slender, approximately equal to cucullar lobe in length with a width less than 0.2× length of lobe; valva short, length along sacculus ~0.75× length of entire genital capsule; saccular lobe strongly tapered, more than 2/3 length of pedicel; basal process of valva tapering to a slender base; costal lobe moderately stout, basal apex terminating at same level as basal process. Juxta undeveloped.

FEMALE, LARVA AND PUPA. Unknown.

HOLOTYPE. ♂; COSTA RICA: GUANACASTE: Estación Pitilla, 9 km S Santa Cecilia, P. N. Guanacaste, 700 m, 19–23 Jun 1993, P. Rios, slide DRD 4213 (INBIO).

HOST. Unknown.

FLIGHT PERIOD. June (unique record).

DISTRIBUTION. (Map 7) Known only from the type locality in northwestern Costa Rica.

ETYMOLOGY. The species name is derived from the Greek tany (long) and gnathos (jaw) in reference to the slender, greatly elongated caudal lobe of the male gnathos.

DISCUSSION. The gnathos of P. tanygnatha possesses the most slender, elongate caudal lobe of any member in the triangularis group. Other diagnostic features of the male include the absence of a basal fold, broadly truncate vinculum, and valva with a reduced cucullar lobe and elongate pedicel.

The saltatrix group

The saltatrix group includes those species with typically elongate valvae, which either equal or surpass the length of the genital capsule in length. The cucullar lobe is greatly enlarged (usually >0.5 the length of the genital capsule), obovate in form, and is supported by a slender pedicel. The gnathos terminates in a stout to slender caudal lobe and possesses a variably developed basal fold. The juxta is usually absent.

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

The length of the forewings is about 2.3 mm. Adults have been recorded in June.