Forcipomyia (Metaforcipomyia) truncata, Spinelli, Gustavo R., Marino, Pablo I. & Borkent, Art, 2012

Spinelli, Gustavo R., Marino, Pablo I. & Borkent, Art, 2012, A revision of Biting Midges of the Subgenera Forcipomyia (Metaforcipomyia) and F. (Saliohelea) from Costa Rica (Diptera: Ceratopogonidae), Zootaxa 3419, pp. 1-52 : 9-11

Forcipomyia (Metaforcipomyia) truncata n. sp.

( Figs. 18–23 , 140 )

Diagnosis. Male: only species of Neotropical Forcipomyia (Metaforcipomyia) with labrum truncate apically and bearing a row of transverse elongate spicules, scutum with uniformly dark pigmentation, parameres absent and aedeagus abruptly tapering to an elongate, slender posteriorly directed prong. Female: unknown.

Description. Male. Head. Brown. Eyes abutting medially for length of three ommatidia. Antenna ( Fig. 18 ) pale brown with plume setae well developed, flagellomeres 2–4 spherical, flagellomere 10 1.36–1.41 (1.39, n = 2) X longer than flagellomere 11, flagellomeres 10–13 elongate; flagellomere 13 with apical nipple, not constricted basally; AR 0.95–0.99 (0.97 n = 2). Palpus ( Fig. 19 ) pale brown; segment 3 swollen proximally, with shallow, sensory pit opening at midlength; PR 2.56–2.89 (2.72, n = 2). Labrum truncate apically with row of transverse elongate spicules.

Thorax. Uniformly brown, scutellum with 7 strong setae. Legs ( Fig. 20 ) brown except hind tibia with broad subapical pale band, femorotibial joints and apex of hind tibia darker, latter with 5–6 spines; tarsomeres pale with pectinate scales; tarsomere 1 of foreleg with two rows of spine-like bristles, tarsomere 1 of hind leg with patch of thick setae on basal portion; foreleg TR 1.86–1.88 (1.87, n = 2), midleg TR 1.00 (n = 2), hind leg TR 1.23–1.25 (1.24, n = 2); claws curved, moderately stout. Wing ( Fig. 21 ) plain, without pattern of pigmented membrane; M2 only visible near wing margin; intercalary vein faint; first radial cell obliterated; second radial cell well developed; fork of cubitus situated slightly distad to level of apex of costa; CuA2 obsolete on distal 1/3; wing length 1.64 (n = 2) mm; breadth 0.54–0.56 (0.55, n = 2) mm; CR 0.35. Halter pale brown.

Abdomen. Tergites uniformly brown. Genitalia ( Fig. 22 ): Brown. Tergite 9 short, extending to 1/3 length of gonocoxite; posterior margin truncate; cercus lobe-like, slightly produced beyond midlength of gonocoxite; sternite 9 broad, posterior margin broadly excavated, angle deeply sclerotized, with single row of setae. Gonocoxite slen- der, 2.2 X longer than greatest breadth; gonostylus 0.85 length of gonocoxite, nearly straight, tip pointed. Parameres absent, gonocoxal apodemes slightly curved with short, pointed lateral projections. Aedeagus ( Fig. 23 ) stout, triangular, lateral margins heavily sclerotized, abruptly tapering to pale, slender posteriorly prong; basal arch poorly sclerotized, extending to 1/10 of total length; lateral arms extending laterally.

Female. Unknown.

Distribution. This species is known only from the lowlands of northwestern Costa Rica at elevations of 40 meters ( Fig. 140 ). Unlike other Costa Rican species of F. (Metaforcipomyia), which are all in wet, humid habitats, F. truncata is in an area of dry deciduous forest.

Taxonomic discussion. Characters to distinguish this species from F. pluvialis and F. rivalis may be found in the key and the taxonomic discussion under the latter species.

Type material. Holotype male on microscope slide, labeled “ HOLOTYPE Forcipomyia (Metaforcipomyia) truncata Spinelli, Marino and Borkent , Costa Rica, Guanacaste prov., La Cruz, Santa Rosa NP, Sector Murciélago, 5.5 km ENE Cerro Guachipelin, 40 m, 25/ 27-VII-1996, M. Araya, Malaise tp. LN343450 320900 #7876, CD 5269” ( INBC). Paratype, 1 male as follows: Costa Rica, Guanacaste prov., Sector Murciélago, 3 km NNW Cerro Guachipelin, 40 m, 7-II-1996, M. Araya, Malaise tp., CD 5271 ( CNCI).

Derivation of specific epithet. The name truncata – truncus (cut off) refers to the truncated labrum of adult males of this species.

Figures

FIGURES 18 – 23. Forcipomyia (Metaforcipomyia) truncata sp. n., male. 18 — flagellum; 19 — palpus; 20 — legs (lateral view); 21 — wing; 22 — genitalia (ventral view); 23 — aedeagus.

FIGURES 140 – 141. Distribution map of species of Forcipomyia (Metaforcipomyia).