Leptomorphus subcaeruleus (Coquillett)

Borkent, Christopher J. & Wheeler, Terry A., 2012, Systematics and Phylogeny of Leptomorphus Curtis (Diptera: Mycetophilidae) 3549, Zootaxa 3549, pp. 1-117 : 60-61

30. Leptomorphus subcaeruleus (Coquillett)

( Figures 36–37, 72, 84, 117, 130, 146, 150, 154)

Sciophila subcaerulea Coquillett, 1901: 595 .

Sciophila pulchra Johannsen, 1903: 14 . Synonymized by Shaw (1947).

Diomonus subcaeruleus: Johannsen, 1909: 45 .

Diomonus pulcher: Johannsen, 1909: 45 .

Leptomorphus subcaeruleus pulcher: Shaw, 1947: 157 .

Leptomorphus subcaeruleus subcaeruleus: Shaw, 1947: 157 .

Leptomorphus (Diomonus) subcoeruleus: Matile, 1977: 146 (lapsus).

References: Johannsen 1910: 154–157 (description, key reference, NH); Johnson 1925: 80 (distribution; MA, ME, NH, RI, VT); Brimley 1938: 326 (NC); Procter 1946: 359 (ME); Shaw & Fisher 1952: 192 (key to species, MA, ME, NH, NY, RI, VT); Laffoon 1965: 223 (catalogue); Cole & Schlinger 1969:120 (distribution: AB); Wray 1967: 75 (North Carolina); Eberhard 1970 (complete 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 on entire surface; thorax completely dark brown/black and the legs completely yellow, scutum with setae on entire surface; R 4 present; male genitalia with two long sickle-like structures (aedeagus) curving dorsally ( Fig. 117).

This species can easily be distinguished from other species with R 4 present, based on the completely dark brown or black body (sometimes tergite 4 light brown or reddish in female, Fig. 37), yellow legs (including the coxae) and completely brown antennae ( Fig. 36).

DESCRIPTION: Male. ( Fig. 36) Head: dark brown to black, somewhat dorsoventrally compressed in anterior view. Antenna dark brown; scape medium to dark brown, with brown to black 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, several setae on apicodorsal margin, none ventrally; flagellomere 1 with tapered base dark brown remainder dark brown; flagellomere 6 1.6X as long as broad. Clypeus dark brown, circular, strongly protruding; bristles on clypeus dark brown, both strong, smaller bristles on entire surface, all directed ventrally, clypeus 1.5X as long as face. Face dark brown; shape a slightly wider than tall triangle, covered with many strong bristles. Frons dark brown; bare, frontal furrow running 1/3 distance from dorsal margin towards ventral margin, frontal cleft initially running to lateral ocellus then barely in front of median ocellus. Palpus with segments 1–3 light brown, remainder 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 without distinct lateral patch of fine setae. Labellum brown. Eye with a number (in ~1/4 of the ommatidial junctions) of long inter-ommatidial setulae scattered on posterior half. Occiput 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 ± 0.56 mm (1.72–2.54 mm, n = 10). Dark brown. Scutum dark brown/black with blue-green specks; surface of scutum covered with small setae; acrostichal setae absent; dorsocentral setae present as complete multiple lines of setae; double row of lateral setae present; patch of setae on scutum at wing base present. Scutellum dark brown; with 8–10 large bristles and many small bristles. Prescutum brown. Mediotergite dark brown with 18–24 bristles on posterolateral corners, absent. Laterotergite brown; anterior margin of laterotergite not reaching katepisternum. Anepimeron brown. Anepisternum dark brown. Katepisternum dark brown. Antepronotum and proepisternum dark brown. Margin of anterior and posterior spiracles brown with brown trichia. Metepisternum anterior ventral corner yellow remainder dark brown. Anapleural suture straight and clear. Halter with basal 1/3 of stem ivory, apical portion and knob dark brown. Legs: Principally yellow; femora with apex brown; extreme anteroapical corner dark brown on all femora; foretibia with apical 1/2 brown, midtibia with apex brown, hind tibia brown except for base; tarsi brown. Midfemur with apical spine-like process. Tibia with covering of brown macrotrichia, foretibia without comb of short setae along length of anteroventral surface ( Fig. 84), yellow to light brown, foretibial spur length 1.7X apical thickness of foretibia, midtibia with strong, dorsal, bare patch of even thickness for 3/4 of its length, placed basally, shortest midtibial spur 0.8X length of longest, longest midtibial spur 3X apical thickness of midtibia, shortest hind tibial spur subequal to length of longest, longest hind tibial spur 3X apical thickness of hind tibia. Foreleg first tarsomere 1.4X length of foretibia. Wing ( Fig. 72): Length 8.0 ± 1.7 mm (6.9–9.4 mm, n = 10). Hyaline; apical macula brown, only on anterior half of wing, beginning halfway along R 5 but not reaching wing tip; 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) all the same length. Calypter bare. Vein sc-r present, apical end joining R within its own length prior to 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 all dark brown to black. Tergite 8 smaller than all other abdominal sclerites and covered with many bristles. Genitalia ( Fig. 117): dark brown. Sternite 9 sclerotized, rounded rectangle, 2/3 the length of T9 but wider than genitalia. Tergite 9 as wide as long, with basal half of lateral margins parallel, remainder tapering to rounded medial apex. Gonocoxite placed apically on T9, tapering to a point on apicolateral margin, 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 1.5X length of T9, tapering to middle and then becoming a lateral sclerotized sickle-like hook with serrated tip, apodemes sclerotized and 1/7 total length. Parameres a swollen lobe with apex covered in small spines, apodemes 1/4 length of parameres and strongly united with gonocoxal apodemes.

Female. ( Fig. 37) As for male, except as follows. Thorax: Length 2.03 ± 0.34 mm (1.8–2.3 mm, n = 10). Wing: Length 7.8 ± 1.2 mm (6.8–8.6 mm, n = 10). Legs: Midfemur without apical spine-like process. Abdomen: Tergite 4 often light brown or reddish. Cercus dark brown.

Immatures. Pupa, larva ( Fig. 130) and egg are described by Eberhard (1970).

BIOLOGY: A detailed description of immature and adult behaviour is given by Eberhard (1970). The larvae feed on the underside of polypore fungi where they spin a silken sheet that traps the fungal spores, which they then eat and fill in the hole in the sheet. Larvae pupate by anchoring a line underneath or adjacent to the fungus. They then crawl to the middle of this line and pupate attached to the line hammock-style. Adult males are known to find and guard female pupae from other males. The guarding male fights off challengers using his forelegs while hanging on with his four hind legs. The ability of the male to hang on while under attack is probably aided by the presence of the midfemoral apical process ( Fig. 84) which is placed in such a way that it interacts with the tibia to lock the joint. This applies to the other species with the midfemoral apical process as well.

DISTRIBUTION: Nearctic; South Dakota east to New Brunswick, and from Ontario south to North Carolina ( Fig. 146), 5–1830 masl .

DISCUSSION: After studying the type of L. pulcher we agree with the previous synonymization with L. subcaeruleus . Males and females were associated based on the collection of a mated pair.

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 the genus Leptomorphus .

MATERIAL EXAMINED: Holotype: adult male, pinned on paper point, genitalia in glass vial on pin, labelled “FRANCONIA, N.H.; Mrs Slosson / Collector ; [Red label] Type / No. 5444/ U.S. N.M; Sciophila / subcaerulea/ Coq.; HOLOTYPE ♂ / Leptomorphus / subcaeruleus (Coquillett) / Det. C.J. Borkent, 2012” [ USNM].

Other material: CANADA, NB, Newcastle , 6.vii.1971, B. V. Petersen. (1♀, CNC) ; ON, 6mi. W Richmond , 6.vii.1971, J.E.H. Martin. (1♀, CNC) ; Algonquin Park , Swann Lake, 1–10.vii.1994, E. R. Barr. (1♂, DEBU) ; Bouck's Hill , 18.vi.2003, R. Zeran. (3♂, LEM) ; Greenbush , 10.vii.1999, R. Hainault. (1♂, CNC) ; Hall’s Lake , 19.vii.1961, G.K. Morris. (1♂, DEBU) ; Innisville , 5.vii.1963, W. R. M. Mason. (1♀, CNC) ; 16.vii.1963. (1♂, CNC) ; Lancaster , 1.vii.2003, R. Zeran. (4♂, LEM) ; Morrisburg , 18.vi.2003, R. Zeran. (1♂, LEM) ; Niagara Falls , 10.ix.1910, M.C. VanDuzee. (1♀, CAS) ; One sided Lake, 12.vii.1960, S.M. Clark. (1♂, CNC) ; Ottawa. (1♂, USNM) ; Bruce Co., Little Cove , 4.ix.2004, S.A. Marshall. (1♂, DEBU) ; Dunks Bay , 22.viii.2003, S.A. Marshall. (1♂, DEBU) ; Carleton Co., 8km S Richmond , 30.viii.2008, D.M. Wood. (1♂, LEM) ; Dufferin Co., nr. Mansfield , 19–20.ix.1992, J Skevington, A Goering. (1♀, CNC) ; Lanark Co., N. Burgess Twp. , 1.viii.1970, D.M. Wood. (2♀, CNC) ; 24.viii.1972. (1♀, CNC) ; QC, 2.3km SSW Rapide-Danseur , 30.vi–29.vii.2007, A. Hibbert. (1♂, 1♀, LEM) ; 28.v–30.vi.2007. (1♂, LEM) ; Aylmer , 15.vii.1924, C.H. Curran. (1♂, CNC) ; Kirk's Ferry , 22.viii.1924, E.P. Ide. (1♀, CNC) ; Lake Duparquet Res. and Train. For., 12.vii–1.viii.2006, A. Hibbert. (3♂, 1♀, LEM) ; Mont St-Bruno , 1–8.vii.2008, V. Levesque. (2♂, LEM) ; 24.vi–1.vii.2008. (3♂, LEM) ; Mont St-Hilaire , 11–18.ix.2001, E. Fast. (1♂, LEM) ; 18–24.ix.2001. (2♂, LEM) ; 15–22.vii.2008, V. Levesque. (1♂, LEM) ; 17–23.vi.2008. (2♂, LEM) ; 30.vi–7.vii.2008. (2♂, LEM) ; 23–30.vi.2009. (1♂, LEM) ; Norway Bay , 30.viii.1938, G.E. Shewell. (1♀, CNC) ; Rougemont , 16–23.vii.2008, V. Levesque. (1♂, LEM) ; Ste-Anne-de-Bellevue, Morgan Abrtm. , 31.vii.2007, C.J. Borkent. (1♂, LEM) ; 3.vii.2010. (4♂, 5♀, LEM) ; 30.vi.2010. (4♂, 2♀, LEM) ; USA, CT, Redding , 17.vii.1931, A.L. Melander. (1♀, USNM) ; Stamford , 3.vii.1944. (1♂, USNM) ; MA, Holliston, 2.vii, N. Banks. (1♂, MCZ) ; Petersham , vii.1926, A.L. Melander. (1♂, ANSP) ; Petersham , vi.1941. (1♀, MCZ) ; MD, Garrett Co., New Germany St. Pk. , 7.vi.1977, Byers, May, Young. (1♂, SEMC) ; ME, York Co., West Lebanon , 5–9.vii.1990, D.W. Barry. (1♂, UNHC) ; MI, Isle Royale , 3–7.viii.1936, C.W. Sabrosky. (1♀, USNM) ; Berrien Co., St Joseph , 15.vi.1975, D.D. Wilder. (1♂, CAS) ; NC, Highlands , 26.vi.1957, W. R. M. Mason. (1♂, 1♀, CNC) ; Sunburst , 6.v.1912. (1♂, NCSU) ; NH, Dover , 30.vi.1974, A.H. Mason. (1♀, UNHC) ; Hampton , 25.vii.1903, S.A. Shaw. (1♀, CUIC) ; Carr. Co., 1mi. N Wonalancet, E Fk. , Spring Brk., 29.viii–5.ix.1985, D.S. Chandler. (1♀, UNHC) ; 2.5mi. NW Wonalancet , 28.vi–4.vii.1984, D.S. Chandler. (1♂, UNHC) ; Rock. Co., 1mi. W Odiorne Pt. , 22–24.vi.1983, D.S. Chandler. (1♂, UNHC) ; Straf Co., 1mi. SW Durham , 24.vii–6.viii.1987, D.S. Chandler. (1♂, UNHC) ; 4mi. W Durham , 14–20.ix.1982, R.M. Reeves. (1♂, UNHC) ; Durham , 14.viii.1957, W.J. Morse. (1♂, 1♀, UNHC) ; 22.vii.1984. (1♂, UNHC) ; 10.vii.1989. (1♂, UNHC) ; NY, Axton , 12–22.vi.1901, A.D. MacG, C.O. H. (1♀, CUIC) ; Beaver Creek , McLean Res., 30.viii.1924. (1♀, CUIC) ; 1.ix.1925. (1♂, CUIC) ; East Aurora , 30.vii.1922, M.C. Van Duzee. (1♂, CAS) ; Erie Co., Protection , 18.vii.1915, M.C. Van Duzee. (1♀, CAS) ; PA, Ohiopyle , viii.1907, H. Kahl. (1♂, CMNH) ; State College , 6.viii.1949, C.W. Sabrosky. (1♂, USNM) ; Clarion Co., Cook Forest St Pk. , 11.viii.1961, J.L. Laffoon. (1♂, ISUI) ; Forest Co., nr. Marienville , 27.ix.1994, W. Metheny. (1♀, CMNH) ; Huntingdon Co., Cornpropstsmills , 28.vi.1973, D.J. Shetlar. (1♂, CAS) ; Moreland Co., Powdermill Nature Reserve , 20.vii.1956, H.K. Clench, N. Richmond. (1♂, CMNH) ; SD, Harney Peak , Harney Nat. For., 24.vii.1951, G.W. Byers. (1♂, SEMC) ; Lawrence Co., 6.2mi. SW Lead , 10.vii.1959, G.W. Byers. (1♂, SEMC) .