Leptomorphus furcatus Borkent, 2012

Borkent, Christopher J. & Wheeler, Terry A., 2012, Systematics and Phylogeny of Leptomorphus Curtis (Diptera: Mycetophilidae) 3549, Zootaxa 3549, pp. 1-117 : 35-36

15. Leptomorphus furcatus Borkent , new species

( Figures 17, 56, 104, 148, 150, 155)

DIAGNOSIS: The only extant species of Leptomorphus with the following combination of characters: foretibia with dense row (comb) of short anteroventral bristles; wing with apical spot very pale and restricted to apical ¼ of cell r1; medial spot absent ( Fig. 56); male genitalia with sternite 9 bearing a medial invagination for posterior 2/3 and with 2 dark, apical points ( Fig. 104).

This species can be distinguished from most other Nearctic species by the lack of R 4. It can be separated from L. hyalinus based on the yellow scutellum, the presence of small setae on the entire surface of the scutum, and the apically placed gonocoxites ( Fig 104).

DESCRIPTION: Male. ( Fig. 17) Head: yellow-orange, circular in anterior view. Antenna brown; scape yellow, with brown setae in single apical row extending from dorsum laterally into thick patch covering apicoventral process, basal third and entire medial surface bare, anterobasal patch of setulae present; pedicel yellow, with 1–2 large bristles, several setae on apicodorsal margin, a few fine setae on apicoventral margin; flagellomere 1 with tapered base yellow, remainder brown; flagellomere 6 1.7X as long as broad. Clypeus yellow, slightly laterally compressed oval; bristles on clypeus yellow, both strong, smaller bristles on entire surface, all directed ventrally, clypeus 1.5X as long as face. Face ivory to light brown; shape a subequal triangle, with fine bristles covering face. Frons yellow; with few bristles medioventrally, frontal furrow running 1/2–full distance from dorsal margin towards ventral margin, frontal cleft more than 1X diameter of median ocellus anterior of median ocellus. Palpus light brown; segment 1 small but visible below eye, segments increasing in length, segment 5 1.5X length of segment 4 with even width from base to apex, segment 3 with fine yellow setae laterally but not in distinct patch. Labellum brown. Eye with few, short inter-ommatidial setulae scattered on surface. Occiput yellow with appressed, anteriorly directed setae. Ocelli in a straight line, space between ocelli less than diameter of laterals, lateral ocelli 3X their own diameter from eye margin, ocellar triangle dark brown/black. Thorax: Length 1.24 ± 0.33 mm (0.94–1.39 mm, n = 10). Brown dorsally, yellow laterally. Scutum yellow, some northern specimens light brown with dorsocentral lines and lateral margins yellow; surface of scutum covered with small setae; acrostichal setae vaguely present; dorsocentral setae probably present but not clearly distinguishable from other setae; multiple rows of lateral setae present; patch of setae on scutum at wing base present. Scutellum yellow; without large bristles and many small bristles. Prescutum yellow. Mediotergite yellow with 8–10 bristles on posterolateral corners, small bristles covering. Laterotergite yellow; anterior margin of laterotergite not reaching katepisternum. Anepimeron yellow. Anepisternum yellow. Katepisternum yellow. Antepronotum and proepisternum yellow. Margin of anterior and posterior spiracles yellow with yellow trichia. Metepisternum yellow. Anapleural suture with anterior portion slightly curved dorsally. Halter stem yellow, knob light brown. Legs: principally yellow; extreme anteroapical corner brown on hind femur, on other femora yellow. Midfemur without apical spine-like process. Tibia with covering of brown macrotrichia, foretibia with comb of short setae along length of anteroventral surface, tibial spurs brown, foretibial spur length 2X apical thickness of foretibia, midtibia with faint, dorsal, bare patch of even thickness for 2/3 of its length, placed basally, shortest midtibial spur 0.9X length of longest, longest midtibial spur 5X apical thickness of midtibia, shortest hind tibial spur 0.85X length of longest, longest hind tibial spur 4X apical thickness of hind tibia. Foreleg first tarsomere 1.6X length of foretibia. Wing ( Fig. 56): Length 5.2 ± 1.2 mm (4.0– 6.1 mm, n = 10). Hyaline; apical macula very light, restricted to apical 1/4 of cell r 1; medial macula absent. Macrotrichia in all cells. Setae on basal posterior margin of wing (along base of cell a) alternating long, short. Calypter with a few short setae. Vein sc-r present, apical end joining R within its own length prior to origin of Rs. R 4 absent. R 5 straight, slight posterior turn near tip. M 1 reaching apex at same level as R 5, apices of M veins reaching wing margin. M 4 -CuA fork arising apically of origin of r-m. A 2 absent. Abdomen: Tergites principally yellow, T2–5 with posterior 1/4–1/3 brown, T6 with posterior 1/3 dark brown, T7 dark brown. Tergite 8 smaller than all other abdominal sclerites, without bristles. Genitalia ( Fig. 104): yellow. Sternite 9 sclerotized, mostly circular but with medial invagination on posterior 2/3 and 2 dark apical points, 2/3 the width of genitalia. Tergite 9 slightly longer than wide oval with a subapical dorsal process tapering apically into lateral points and a medial U-shaped indentation. Gonocoxite placed centrally on T9, medial margin not reaching median line, bearing gonostylus halfway along medial margin. Gonostylus a single club-shaped lobe with several setae, gonocoxite III associated with dorsal margin of gonostylus but not fused to it. Aedeagus 2/3 length of gonocoxite, tapering towards apex, apodemes 1/5 total length. Parameres a laterally curved taper, 1.1X length of apodemes.

Female. As for male, except as follows. Thorax: Length 1.35 mm (1.31–1.39 mm, n = 2). Wing: Length 5.9 mm (5.4–6.3mm, n = 2). Legs: Foretibia without comb of short setae on anteroventral surface. Abdomen: Cercus yellow.

Immatures. Unknown.

BIOLOGY: Unknown.

DISTRIBUTION: New Mexico and Arizona south to Northern Mexico ( Fig. 148), 915–2255 masl .

ETYMOLOGY: The species name refers to the strongly forked nature of sternite 9, particularly the strongly sclerotized apicolateral points, a condition unique within Leptomorphus .

MATERIAL EXAMINED: Holotype: here designated, adult male, pinned, labelled “ USA; NM; Grant Co. 14mi N/ Silver City , Cherry Cr. Campgrnd / 11–14.viii.2007, el 7400’/ (32°54.8’N 108°13.6’W)/ Malaise trap, J.E. O’Hara; HOLOTYPE ♂ / Leptomorphus furcatus / Borkent, new species / Det. C.J. Borkent 2012” [ LEM]

Paratypes: labelled as for holotype (3♂, LEM) ; except 14–16.viii.2007. (1♂, LEM) ; MEXICO, SI, 15mi. W El Palmito , 3.viii.1964, W. R.M. Mason. (2♂, CNC) ; 20.vii.1964. (1♂, CNC) ; 30.vii.1964. (1♀, CNC) ; 20mi. E Concordia , 4.viii.1964. (2♂, CNC) ; Portrerillos , 15mi. W El Palmito, 11.vii.1964, J.F. McAlpine. (4♂, CNC) ; 16.vii.1964. (3♂, CNC) ; USA, AZ, 15mi. S Sierra Vista , vii.1967, R.F. Sternitzky. (2♂, CNC) ; 15mi. S Sierra Vista , 2.vi.1967. (2♂, CNC) ; Cochise Co., 8km W Portal , 24.ix.1966, P.H. Arnaud, Jr. (1♀, CAS) ; 14.viii.1985. (1♂, CAS) .