Leptomorphus hyalinus Coquillett

Borkent, Christopher J. & Wheeler, Terry A., 2012, Systematics and Phylogeny of Leptomorphus Curtis (Diptera: Mycetophilidae) 3549, Zootaxa 3549, pp. 1-117 : 39-40

18. Leptomorphus hyalinus Coquillett

( Figures 20, 59, 107, 126, 132, 149, 150, 152)

Leptomorphus hyalinus Coquillett, 1901: 598 .

Leptomorphus ypsilon Johannsen, 1912: 265 . new synonym.

References: Aldrich 1905: 143 (catalogue); Johnson 1910: 724 (NJ, reported as L. walkeri [specimen seen]); Johannsen 1909:72 (catalogue), 1912: 250, 252, 264–266, 323, 327, Fig. 177 (key, re-description, wing); Johnson 1925: 82 (NH); Brimley 1938: 327 (NC); Shaw 1946: 156–7 (comparison to L. nebulosus ); Shaw & Fisher 1952: 192 (key to species, NH, NJ, NY, RI); Laffoon 1965: 223 (catalogue); Khalaf 1971: 19 (MS, reported as L. ypsilon ); Matile 1977: 144 (subgeneric placement); Poole and Gentili, 1996: 194 (catalogue); Bertone et al. 2008: 674 (exemplar in molecular phylogeny).

DIAGNOSIS: The only extant species of Leptomorphus with the following combination of characters: laterotergite, anepisternum and anepimeron yellow; scutellum brown; gonostylus with single large, hook-tipped lobe ( Fig. 107).

This species can be distinguished from most other Nearctic species by the lack of R 4. It can be separated from L. furcatus based on the dark brown scutellum, the lack of setae on the surface of the scutum (with exception of dorsocentral setae) and the basally placed gonocoxites ( Fig. 107).

DESCRIPTION: Male. ( Fig. 20) Head: brown dorsally yellow ventrally, circular in anterior view. Antenna with basal 2–3 flagellomeres lighter brown, darkening apically; 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, few small setae on apicodorsal margin, none ventrally; flagellomere 1 with tapered base light brown remainder light brown; flagellomere 6 1.7X as long as broad. Clypeus yellow, slightly laterally compressed oval; bristles on clypeus brown, strong bristles on ventral half, smaller bristles on entire surface, all directed ventrally or medioventrally, clypeus 2X as long as face. Face yellow to brown; shape a just longer than wide triangle, with few bristles ventrolaterally. Frons brown to dark brown; bare, frontal furrow running 3/4–full distance from dorsal margin towards ventral margin, frontal cleft just anterior of median ocellus. Palpus yellow to brown; segment 1 hidden behind eye, segments increasing in length, segment 5 2X length of segment 4 with central portion somewhat thinner than base and apex, segment 3 with apicolateral patch of fine yellow setae encircled by strong dark setae. Labellum yellow. Eye with very few, short inter-ommatidial setulae scattered on surface. Occiput brown with appressed, anteriorly directed setae. Ocelli in a straight line, space between ocelli less than diameter of laterals, lateral ocelli 1.5X their own diameter from eye margin, ocellar triangle dark brown/black. Thorax: Length 1.19 ± 0.19 mm (0.98–1.35 mm, n = 10). Dark brown dorsally, yellow laterally. Scutum ranging from dark brown with anterio- medio- and posterolateral yellow spots, to yellow with spot at wing base and thick Y-shape originating posteriorly both dark brown; surface of scutum bare; acrostichal setae absent; dorsocentral setae present as fine setae for most of length; multiple rows of lateral setae present; patch of setae on scutum at wing base present. Scutellum dark brown; with 6–8 large bristles and many small bristles. Prescutum yellow. Mediotergite light brown to brown with 16–24 bristles on inverted U, few medially. 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 with tip of knob brown, remainder yellow. Legs: principally yellow; extreme anteroapical corner light brown on forefemur, on other femora dark brown. Midfemur without apical spine-like process. Tibia with covering of yellow macrotrichia, foretibia without comb of short setae along length of anteroventral surface, yellow to light 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 0.75X length of longest, longest midtibial spur 5X apical thickness of midtibia, shortest hind tibial spur subequal to length of longest, longest hind tibial spur 4X apical thickness of hind tibia. Foreleg first tarsomere 1.5X length of foretibia. Wing ( Fig. 59): Length 5.3 ± 0.9 mm (4.7–6.1 mm, n = 10). Hyaline; apical macula absent or, if present, very light; 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 at 2–3X its own length prior to origin of Rs. R 4 absent. R 5 straight, slight posterior turn near tip. M 1 reaching apex before R 5, apices of M veins thinning towards wing margin. M 4 -CuA fork arising well before origin of r-m. A 2 absent. Abdomen: Tergites principally yellow, T1 light to dark brown, T2–7 with posterior 1/3–1/ 2 ranging from light to dark brown. Tergite 8 smaller than other abdominal sclerites, with 5–15 bristles on each apicolateral corner. Genitalia ( Fig. 107): light yellow. Sternite 9 membranous. Tergite 9 longer than wide oval tapering apically into two short rounded lobes and shallow medial indentation. Gonocoxite placed basally on T9, medial margins not touching, apicomedial lobe covering base of gonostylus, apicolateral corner with medial facing surface covered in short, thick setae, bearing gonostylus on apical 1/3. Gonostylus a single broad-based lobe tapering towards pointed, dorsally pointing apex, gonocoxite III fused to dorsolateral margin. Aedeagus 4/5 length of gonocoxite, swelling from base3 to middle and then tapering towards apex, apodemes 1/10 total length. Parameres a simple taper (sometimes with a secondary bump or step at half the length), apodemes ~1.3X length of parameres.

Female. As for male, except as follows. Thorax: Length 1.3 ± 0.22 mm (1.07–1.48 mm, n = 10). Wing: Length 6.1 ± 1.5 mm (4.3–6.9 mm, n = 8). Abdomen: Cercus yellow.

Immatures. Undescribed.

BIOLOGY: Larvae were found feeding under the brackets of Cerrena unicolor ( Fig. 126), a soft polypore that grows on dead wood. The larvae pupate under these same brackets or adjacent to them on the underside of the dead log. The pupae hang from a line attached near their head and hind end ( Fig. 132), usually forming a hammock. Over several hours of observation of the numerous pupae at a single site, no males guarding pupae were found. More than 80 immatures were collected over the course of 1.5 weeks from the fungi on a single log and reared to adulthood. Many of the pupae produced hymenopteran parasitoids ( Orthocentrus sp. ( Ichneumonidae : Orthocentrinae ) and a species of Diapriidae ).

DISTRIBUTION: Alaska and BC east to Maine and Florida ( Fig. 149), 5–915 masl.

DISCUSSION: The colour of the scutum ranges from completely dark brown to a dark brown background with a yellow Y-shape. This colour difference led to the description of L. ypsilon by Johannsen (based on our examination of the type). However all specimens agree in the shape of the components of the male genitalia. There is some variation in the shape of parameres ranging from a single spine to a spine with a secondary rounded lobe arising a third of the distance from the apex. However, this variation was not associated with any other particular morphology, coloration, or distribution.

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 Leptomorphus and placed solely in the genus Leptomorphus .

MATERIAL EXAMINED: Holotype: adult male, pinned, labelled “ White Mts. / Morrison.; [red label] Type / No. 5451/ U.S. N.M.; Leptomorphus / hyalinus/ Coq.; HOLOTYPE ♂ / Leptomorphus hyalinus / Coquillett / Det. C.J. Borkent, 2012” [ USNM].

Other material: CANADA, BC, Hixon , 10.viii.1966, E.D.A. Dyer. (1♂, CNC) ; MB, Aweme , 18.viii.1912, E. Criddle. (1♀, ANSP) ; ON, 7.5km W Carleton Place , 14.x.2000, L. Masner. (2♀, CNC) ; Lancaster , 1.vii.2003, R. Zeran. (1♀, LEM) ; Ottawa , 1.ix.1968, J. R. Vockeroth. (1♂, CNC) ; 1.ix.1993. (1♂, CNC) ; 23.ix.1993. (1♂, CNC) ; Tobermory , Dunk's Bay, 12.viii.1996, S.A. Marshall. (1♂, DEBU) ; Bruce Co., Dunk's Bay , 25.viii–1.ix.2005, S.A. Marshall. (1♀, DEBU) ; QC, 2.3km SSW Rapide-Danseur , 29.vi–28.vii.2007, A. Hibbert. (3♂, 1♀, LEM) ; 30.vi–29.vii.2007. (3♂, 1♀, LEM) ; 27.v–29.vi.2007. (1♂, LEM) ; Lake Duparquet Res. and Train. For., 11–31.vii.2006, A. Hibbert. (1♂, 2♀, LEM) ; 19.vi–11.vii.2006. (1♀, LEM) ; Old Chelsea , 2.vii.1959, J. R. Vockeroth. (1♀, CNC) ; Ste-Anne-de-Bellevue, Morgan Abrtm. , 12.vii.2007, C.J. Borkent. (1♂, LEM) ; 17.vii.2007. (9♂, 4, LEM) ; 18.vii.2007. (5♂, 7, LEM) ; 21.ix.2007. (1♀, LEM) ; 20.viii.2008. (1♀, LEM) ; Terrasse- Vaudreuil , Molson Reserve, 15–18.vii.1999, S.E. Brooks. (1♂, LEM) ; USA, AK, 11mi. S Anderson Jct., Rte 3mi. 270, 23.vi–11.viii.1984, S. & J. Peck. (1♀, CNC) ; FL, Flamingo , 4.vi.1963, G. R. Sutter. (1♂, ISUI) ; Gainesville , 8–22.xii.1986, W. Mason. (2♂, 1♀, CNC) ; IA, Ames , 1.xi.1946, D.E. Hardy. (1♂, ISUI) ; Sioux City , 5.ix.1949, J.L. Laffoon. (1♀, ISUI) ; 8.ix.1951. (2♂, 1, ISUI) ; Boone Co., Ledges State Park , 13.x.1950, J.L. Laffoon. (1♂, ISUI) ; 18.ix.1951. (1♂, ISUI) ; 3.vii.1961. (1♂, ISUI) ; Polk Co., Alleman , 27.viii.1952, J.L. Laffoon. (1♂, ISUI) ; Van Buren Co., Lacey–Keosauqua St. Pk., 9.ix.1949, J. Laffoon, J. Slater. (1♂, ISUI) ; 10.ix.1949. (1♂, ISUI) ; IN, La Fayette , 18.viii.1916, J.M. Aldrich. (1♀, USNM) ; KS, Riley Co., Manhattan , 14.vi.1968, G.F. Hevel. (1♂, USNM) ; MA, Barre , 16.ix.2008, C. Eiseman. (1♀, LEM) ; MD, Laurel , 25.vi.1965. (1♂, CNC) ; Plummers Island , 21.vii.1971, K. V. Krombein. (1♂, USNM) ; ME, York Co., West Lebanon , 31.vii–6.viii.1990, D.W. Barry. (1♂, UNHC) ; 11–17.ix.1990. (1♀, UNHC) ; MN, Clearwater Co., Lake Itasca , 3.ix.1950, J.L. Laffoon. (1♀, ISUI) ; MO, Wayne Co., Williamsville , x.1987, J. Becker. (3♀, CNC) ; NC, Looking Glass Rock Nr. Pisgah Forest , 19.vii.1957, J.G. Chilcott. (1♂, CNC) ; Rainbow Falls , Gr. Sm. Mtns N.P., 28.v.1999, L. Quate. (1♂, CNC) ; NH, Jefferson Notch , 20.vii.1961, W.W. Wirth. (1♀, USNM) ; Rock. Co., Seabrook , Backdunes, 7–12.vii.1989, D.S. Chandler. (1♂, UNHC) ; NJ, Trenton , 23.viii.1909. (1♀, USNM) ; NY, Ft. Montgomery , 16.ix.1923, F.M. Schott. (1♂, MCZ) ; Ithaca , (1♂, 1♀, types of L. ypsilon, CUIC ); Poughkeepsie, 23.viii.1936, H.K. Townes. (1♂, ANSP) ; OH, Summit Co., 28.viii.1937, L.J. Lipovsky. (1♀, SEMC) ; SC, Anderson Co., Pendleton , Tanglewood Sprg., x.1987, J. Morse. (2♂, 1♀, CNC) ; 30.viii.1987. (1♂, CUAC) ; TN, Sevier Co., Twin Creeks , 14–29.viii.2006, J. Gulbransen. (3♂, 1♀, LEM) ; 31.vii–15.viii.2006. (2♀, LEM) .