Pseudopostega brachybasis Davis & Stonis 2007

Pseudopostega brachybasis

ADULT. Figure 237. Length of forewing 2.3–2.6 mm. Small, mostly white to pale cream moth with cream white forewings marked with 3 dark to light brown, subapical costal strigulae, 2 light to dark brown tornal strigulae, and a small, dark brown to fuscous apical spot. Base of male gnathos broad, extremely short, abruptly constricted to a deeply furcate, caudal lobe; basal fold transverse, broadly triangular, short (Figure 415). Papillae anales of female minutely bilobed; lobes short and round; corpus bursae covered internally with numerous minute spines (Figures 495, 496).

Head: Vestiture white. Scape white; flagellum brown dorsally, cream ventrally, 46–47-segmented. Palpi white; labial palpus with suffusion of dark brown dorsally.

Thorax: White; tegula with dark brown suffusion on anterior margin. Forewing white with basal costal margin dark brown; 3 light to dark brown, subapical costal strigulae; strigula 1 moderately broad, light brown, continuing straight and obliquely to join a similar, basal tornal strigula before dark brown to fuscous apical spot; area between basal strigulae and apical spot suffused with light brown; strigula 2 dark brown, curving slightly down to junction of basal strigulae; strigula 3 usually faint, short, usually fading before apical spot and well separated from short brown, terminal strigula beyond apical spot; terminal cilia mostly cream to light brown, becoming sometimes white around tornus and light brown along dorsal margin; venter of forewing brown with basal, subhumeral white area. Hindwing and cilia brown dorsally and ventrally. Legs mostly cream; foreleg with dorsal surfaces suffused with brown, lighter on tarsus; tarsi of mid- and hindlegs faintly banded dorsally with light brown.

Abdomen: Dark brown dorsally, grayish brown laterally, with narrow cream stripe ventrally.

Male Genitalia: Figures 415, 416. Socii a pair of small, rouded, setose lobes, widely separated by a distance ~0.7× length of cucullar lobe; caudal rim of uncus deeply concave. Vinculum broadly rounded. Gnathos broad, extremely short, with well-developed lateral lobes, abruptly constricted to a deeply furcate, caudal lobe; lobe divided to base; anterior margin of gnathos mostly truncate with a shallow median cleft; basal fold mostly transverse, short, broadly triangular (Figure 415). Valva with moderately large cucullar lobe ~0.3× length of genital capsule, bearing a pectinifer consisting of a single to partially double row of 24–28 blunt spines; distal apex of cucullar lobe moderately extended, slender; pedicel broad, ~36× length of cucullar lobe; valva elongate, length along sacculus ~0.65× length of genital capsule; saccular lobe short, tapering to slender, setose apex; basal process of valva tapering to acute base, slightly longer than slender, acute costal lobe. Juxta slightly developed.

Female Genitalia: Figures 495, 496. Abdomen tapering to a narrowly rounded, minutely cleft apex. Each posterior apophysis elongate, fused for most of its length. Papillae anales consisting of a pair of minute, broadly rounded lobes (Figure 496); lobes short, length ~0.7× width, bearing ~10–12 moderately long setae. Vestibulum moderately narrow, membranous, with dense concentration of pectinations similar to and continuous with those within caudal end of ductus bursae. Ductus bursae slender, of uniform diameter to corpus bursae; inner walls densely lined with pectinations consisting of ~3–7 minute spicules arranged in short, transverse rows; pectinations becoming more sparse anteriorly and terminating caudad of separation of ductus spermathecae. Corpus bursae moderately short, elliptical, enlarging abruptly from ductus bursae; a dense scattering of slender, elongate spines arising from most of inner wall; a faint band of minute, tuberculate outgrowths extending most of length of bursa. Ductus spermathecae elongate, approximately equaling length of bursa copulatrix; membranous outer canal short, moderately broad near corpus bursae; inner canal terminating in 4–5 convolutions; vesicle composed of a slightly enlarged, moderately elongate, single coiled tube.

LARVA AND PUPA. Unknown.

HOLOTYPE. ♂; MEXICO: TAMAULIPAS: El Ensino, 250 m: 4–13 Aug 1988, V. O. Becker, slide USNM 32824 (USNM).

PARATYPES. MEXICO: TAMAULIPAS: El Ensino, 250 m: 1 ♂, 1 ♀, 4–13 Aug 1988, V. O. Becker, slides USNM 32835, DRD 4223 (USNM, VOB).

HOST. Unknown.

FLIGHT PERIOD. August.

DISTRIBUTION. (Map 18) Known only from the state of Tamaulipas in northeastern Mexico.

ETYMOLOGY. The species name is derived from the Greek brachys (short) and basis (foundation, pedestal), in reference to the extremely short base of the male gnathos.

DISCUSSION. This species closely resembles P. constricta in genital morphology but may be superficially distinguished by its more cream forewing color and darker strigulae and hindwings. The male of brachybasis differs from constricta in having a shorter, more compact gnathos base and distinctly shorter saccular lobes on the valvae.