Leptomorphus bifasciatus (Say)

Borkent, Christopher J. & Wheeler, Terry A., 2012, Systematics and Phylogeny of Leptomorphus Curtis (Diptera: Mycetophilidae) 3549, Zootaxa 3549, pp. 1-117 : 18-19

4. Leptomorphus bifasciatus (Say)

( Figures 4, 5, 45, 94, 147, 150, 154)

Sciophila bifasciata Say, 1824: 363 .

Diomonus bifasciatus: Johannsen, 1909: 45 .

Leptomorphus bifasciatus: Procter, 1946: 359 .

Leptomorphus (Diomonus) bifasciatus: Matile, 1977: 146 .

References: Wiedemann 1828: 62 (re-description); Le Conte 1859: 246 (reprint of original description); Osten Sacken 1878: 10 (catalogue, with note from Loew as to possible placement in Empheria ); Kertész 1902: 57 (catalogue); Aldrich 1905: 140 (catalogue); Johannsen 1910: 154 (description, key reference, NH); Johnson 1925: 80 (MA, ME, NH, VT); Procter 1938: 310 (ME), 1946: 359 (ME), Shaw & Fisher 1952: 192 (key reference, MA, NH); Laffoon 1965: 223 (catalogue citation), Eberhard 1970 (natural history and behaviour), 1986 (correction to 1970); Matile 1977: 146 (subgeneric placement); Santini 1985: 239, 243–4 (comparison to L. walkeri ); Poole and Gentili, 1996: 194 (catalogue).

DIAGNOSIS: The only extant species of Leptomorphus with the following combination of characters: scutum with setae restricted to dorsocentral line and margins; R 4 present and forming a quadrilateral cell; male genitalia with gonocoxites placed apically on tergite 9 and folded dorsally at apex ( Fig. 94).

This species can be easily differentiated from other Nearctic species with R 4 by the brown coxae and brown antennae ( Fig. 4).

DESCRIPTION: Male. ( Fig. 5) Head: light-dark brown, somewhat dorsoventrally compressed in anterior view. Antenna dark brown; scape light brown, 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 brown, with 2–3 large bristles, 2–3 setae on apicodorsal margin, none ventrally; flagellomere 1 with tapered base brown remainder brown; flagellomere 6 2.0X as long as broad. Clypeus brown, circular, strongly protruding; bristles on clypeus brown, both strong, smaller bristles on entire surface, all directed ventrally, clypeus 1.5X as long as face. Face yellow to light brown; shape a slightly wider than tall triangle, covered with many strong bristles. Frons brown; bare, frontal furrow running 1/3 distance from dorsal margin towards ventral margin, frontal cleft running to lateral ocellus. Palpus with segments 2–3 light brown remainder yellow; 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 appears to have large lateral patch of fine yellow setae not clearly delimited. Labellum light brown. Eye with a number (in ~1/4 of the ommatidial junctions) of long inter-ommatidial setulae scattered on posterior half. Occiput light-dark brown with appressed, anteriorly directed setae. Ocelli in a straight line, space between ocelli 1–1.5X diameter of laterals, lateral ocelli 1.5X their own diameter from eye margin, ocellar triangle dark brown/black with electric blue green specks. Thorax: Length 2.12 ± 0.38 mm (1.89–2.38 mm, n = 10). Yellow dorsally with lateral and dorsocentral brown lines, laterally brown, sometimes almost completely brown. Scutum ranging from yellow with posteriorly pointing V of brown and lateral and posterior margins brown, to dark brown with small anteromedial yellow spot; surface of scutum bare; acrostichal setae absent; dorsocentral setae present as complete multiple lines of setae; multiple rows of lateral setae present; patch of setae on scutum at wing base small. Scutellum light to dark brown, darker anteriorly; with 8–12 large bristles and many small bristles. Prescutum brown. Mediotergite brown to dark brown with 8–12 bristles on posterolateral corners, absent. Laterotergite brown; anterior margin of laterotergite not reaching katepisternum. Anepimeron light brown to brown. Anepisternum light brown to brown. Katepisternum brown. Antepronotum and proepisternum light brown to brown. Margin of anterior and posterior spiracles yellow with light brown trichia. Metepisternum dark brown. Anapleural suture straight and clear. Halter stem yellow, knob light to dark brown. Legs: Principally yellow to light brown; hind coxa at least 1/2 brown, in northern specimens remaining coxae brown as well as central 4/5 of hind femur and sometimes centre of midfemur; extreme anteroapical corner dark brown on all femora. Midfemur with apical spine-like process. Tibia with covering of brown macrotrichia, foretibia without comb of short setae along length of anteroventral surface, tibial spurs yellow, foretibial spur length 1.75X apical thickness of foretibia, midtibia with strong, dorsal, bare patch of even thickness for 3/4 of its length, placed basally, shortest midtibial spur 0.7X length of longest, longest midtibial spur 3.5X apical thickness of midtibia, shortest hind tibial spur 0.85X length of longest, longest hind tibial spur 3.5X apical thickness of hind tibia. Foreleg first tarsomere 1.4X length of foretibia. Wing ( Fig. 45): Length 8.1 ± 1.4 mm (7.1–9.6 mm, n = 10). Hyaline; apical macula dark brown running from anterior to posterior wing margin, beginning halfway along R 5, but fading towards apex and posterior margin; medial macula extending from Sc to stem of M 1+2 with some light brown in cell cua. Macrotrichia in all cells. Setae on basal posterior margin of wing (along base of cell a) alternating long and short for margin of alula, remainder short. Calypter bare. Vein sc-r present, apical end joining R within its own length before or after origin of Rs. R 4 present. R 5 slightly concave for entire length. M 1 reaching apex before R 5, apices of M veins clearly reaching wing margin. M 4 -CuA fork arising well before origin of r-m. A 2 faintly present as crease. Abdomen: Tergites principally reddish orange, T1 brown, T2 with anteromedial brown spot. Tergite 8 smaller than all other abdominal sclerites and covered in small bristles. Genitalia ( Fig. 94): orangish yellow. Sternite 9 lightly sclerotized, posteriorly directed triangle covering most of the ventral surface (as wide as genitalia). Tergite 9 subcircular except for gonocoxal indentation and slight apicomedial indentation. Gonocoxite placed apically on T9, apical margin flat with slight dorsally directed fold, medial margin not reaching medial line, bearing gonostylus basally. Gonostylus a single lobe tapering towards apex and bearing several setae, gonocoxite III associated with dorsal margin of gonostylus but not fused to it. Aedeagus equal in length to T9, tapering towards apex and then swollen and sclerotized at apex, with two short subapicodorsal lobes, apodemes ~1/4 total length. Parameres as long as wide with single lobe lobe slightly swollen and curving laterally with apical surface covered in small spines, apodemes 1/4 length of parameres and strongly united with gonocoxal apodemes.

Female. ( Fig. 4) As for male, except as follows. Thorax: Length 1.89 ± 0.39 mm (1.48–2.13 mm, n = 10). Wing: Length 7.4 ± 1.1 mm (6.2–8.1 mm, n = 10). Legs: Midfemur without apical spine-like process. Abdomen: Cercus yellow.

Immatures. Larva and pupa described by Eberhard (1970). Egg unknown.

BIOLOGY: The biology of the immatures and adults is detailed by Eberhard (1970) and is similar to that of L. subcaeruleus .

DISTRIBUTION: British Columbia east to Maine and south to North Carolina ( Fig. 147), 25–1800 masl .

DISCUSSION: The original type specimen was collected on Major Long’s second expedition ( Say 1824), which travelled from Philadelphia through the ‘North-west Territory’ of the USA (southwest of the Great Lakes) to Lake Winnipeg and then eastward through Lake Superior and Lake Huron. In the description the only distribution data given is that this species ‘inhabits North-west Territory’ ( Say 1824: 363). Unfortunately the collections of Thomas Say were destroyed, with the exception of some syntypes that were sent to colleagues, with some Diptera being sent to Wiedemann ( Evenhuis 2006). Wiedemann (1828: 62) described specimens of L. bifasciata sent to him by Say, but the depository of these specimens at the end is stated as “Im Museum zu Philadelphia”, thus Wiedemann did not keep any but returned them to Philadelphia ( Wiedemann, 1828: 62). Given the similarity in general habitus and coloration of L. bifasciatus to other Leptomorphus species in the region (e.g. L. subcaeruleus , L. nebulosus ), a neotype is designated to fix the identity of the species.

As discussed below in the phylogeny section, the placement of Leptomorphus species in subgenera ( Matile 1977) is not supported by our phylogenetic results. This species is therefore removed from the subgenus Diomonus and placed solely in Leptomorphus .

MATERIAL EXAMINED: Neotype: ( Fig. 5) here designated, adult male, pinned, labelled “CAN: QC: Mont St Hilaire/ Stand 4, flight-intercept trap / 45°32.22’N, 73°08.91’W / 1–8.vii.2008, V. Levesque; NEOTYPE ♂ / Leptomorphus bifasciatus / (Say) / Det. C.J. Borkent, 2012” [ LEM].

Other material: CANADA, BC, Kinbasket Reservoir, Bush Arm , 10–11.viii.2009, Cooper, Beauchesne and Associates Ltd. (1♂, RBCM) ; ON, Coniston , 27.vii, E.S. Parish. (1♂, USNM) ; Foresters Falls , 14.viii.1991, J. R. Vockeroth. (1♂, CNC) ; Lake Abitibi , 4.viii.1925, N.K. Bigelow. (1♂, CNC) ; 7.viii.1925. (1♂, CNC) ; Tobermory, Dunk's Bay , 26.viii.1996, S.A. Marshall. (1♂, DEBU) ; Bruce Co., William Henry Marsh , 31.viii.1999, S.A. Marshall. (1♀, DEBU) ; Carleton Co., 8km S Richmond , 30.viii.2008, D.M. Wood. (1♂, LEM) ; QC, 2.3km SSW Rapide-Danseur , 29.vi–28.vii.2007, A. Hibbert. (1♂, LEM) ; 30.vi–29.vii.2007. (2♂, 1♀, LEM) ; Lake Duparquet Res. and Train. For. , 12.vii–1.viii.2006, A. Hibbert. (1♀, LEM) ; Mont St- Bruno , 24.vi–1.vii.2008, V. Levesque. (1♂, LEM) ; Mont St-Hilaire , 18–24.ix.2001, E. Fast. (1♂, LEM) ; 3.viii.2007, C.J. Borkent. (1♂, LEM) ; 1–8.vii.2008, V. Levesque. (1♂, LEM) ; 23–30.vi.2008. (1♂, LEM) ; Old Chelsea , 13.ix.1956, J. R. Vockeroth. (1♂, CNC) ; Rougemont , 14–21.vii.2008, V. Levesque. (1♂, LEM) ; 21–28.vii.2008. (2♂, 1♀, LEM) ; 23–30.vi.2008. (1♂, LEM) ; 30.vi–7.vii.2008. (1♂, LEM) ; SK, Belanger, Osten Sacken. (1♂, MCZ) ; USA, MA, Chester , 5.viii.1911. (1♂, MCZ) ; ME, York Co., West Lebanon , 28.viii–3.ix.1990, D.W. Barry. (1♂, UNHC) ; NC, Mason Co., Highlands , 20.vi.1957, J. R. Vockeroth. (1♂, CNC) ; 21.vi.1957, J. R. Vockeroth. (1♂, CNC) ; 24.vi.1958, J.L. Laffoon. (1♂, ISUI) ; NH, Dolly Copp, White Mtns. , 13.vii.1931, A.L. Melander. (1♀, USNM) ; Mt. Washington, A. T. Slosson. (1♂, CUIC, 1♂, USNM) ; Carr. Co, 1mi. N Wonalancet, E Fk. Spring Brk. , 18–23.vii.1985, D.S. Chandler. (1♂, UNHC) ; 24–30.vii.1985. (1♂, UNHC) ; 18.ix–1.x.1985. (1♂, UNHC) ; The Bowl , 2.5mi. NW Wonalancet, 2–10.viii.1984, D.S. Chandler. (1♀, UNHC) ; 20–26.vii.1984. (2♂, UNHC) ; 28.vi–4.vii.1984. (1♂, UNHC) ; 31.vii–6.viii.1985. (1♂, UNHC) ; Coos Co., 1mi. NE East Inlet Dam , 22.viii–12.ix.1986, D.S. Chandler. (1♂, UNHC) ; 10–24.vii.1986. (2♂, UNHC) ; 25.vi–9.vii.1986. (2♂, UNHC) ; 13–26.ix.1986. (1♀, UNHC) ; Norton Pool , 3mi. NE East Inlet Dam, 8–21.viii.1986, D.S. Chandler. (1♂, UNHC) ; 27.ix–17.x.1986. (1♀, UNHC) ; Straf Co., 1mi. SW Durham , 13.vii.1991, W.J. Morse. (1♀, UNHC) ; 4mi. W Durham , 23–26.viii.1982, R.M. Reeves. (2♂, UNHC) ; 13–15.vii.1982. (1♂, UNHC) ; Spruce Hole , 3mi. SW Durham, 7–20.viii.1987, D.S. Chandler. (1♂, UNHC) ; NY, Adirondacks, Avalanche Trl , 30.vii.1929, A.L. Melander. (1♀, ANSP) ; Albany Co., Huyck Preserve, Rensselaerville , 4.vii.1968, W.G., M.J. Eberhard. (1♂, 1♀, MCZ) ; Greene Co., viii, (1♂, CMNH) ; Hamilton Co., vic. Jockeybush Outlet , 5.viii.1961, J.L. Laffoon. (1♀, ISUI) ; PA, Centre Co., Bear Meadows , 6.ix.1979, P.H. Adler. (1♀, USNM) ; McKean Co, 4.9km S Ludlow, Pigeon Run , 4.viii.1994, M.J. Ricke. (1♂, CMNH) ; TN, Burrville , 14.vii.1953, Benesh. (1♂, MNHN) ; VA, Giles Co., Clover Hollow , 9.viii.1967, Ento. Class. (1♂, SEMC) ; Mt. Lake Biol. Sta. , 26.vi.1975, G.W. Byers. (1♀, SEMC) ; VT, Brattleboro , 1909, H. Kahl. (1♂, CMNH) ; Morrison, White Mtns. (3♂, USNM) .