Leptomorphus crosskeyi Matile, 1229

Borkent, Christopher J. & Wheeler, Terry A., 2012, Systematics and Phylogeny of Leptomorphus Curtis (Diptera: Mycetophilidae) 3549, Zootaxa 3549, pp. 1-117 : 27-28

10. Leptomorphus crosskeyi Matile

( Figures 11, 51, 99, 136, 150, 153)

Leptomorphus (Gymnoscutum) africanus Matile, 1977: 147 . Preoccupied by Meunier, 1907.

Leptomorphus crosskeyi Matile, 1980: 1229 (new replacement name for africanus ).

References: Crosskey 1980: 1221 (catalogue appendix as L. africanus ); Matile 1997: 143, 147–150 (figures, new records, morphological variation, key, lapsus as nom. nov.).

DIAGNOSIS: The only extant species of Leptomorphus with the following combination of characters: laterotergite, anepisternum and anepimeron yellow; scutellum brown; male genitalia with posterolateral projection of tergite 9 (tergal evagination) bearing distinct thin point on medial corner, gonostylus with shortest lobe gradually tapering to thick point ( Fig. 99).

This species can be distinguished from most other Afrotropical species by the brown scutellum and lack of small setae covering the scutum (except along dorsocentral lines). It can be separated from L. gracilis by the larger width of the posteromedial concavity of tergite 9 and thin point on the medial corner of the tergal evagination and from L. obscurus by the almost square posterior margin of the tergal evaginations ( Fig. 99).

DESCRIPTION: Male. Head: yellow with some brown spots, circular in anterior view. Antenna brown; scape dark 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 2 large bristles, several setae on apicodorsal margin, number of fine setae on apicoventral margin; flagellomere 1 with tapered base brown remainder brown; flagellomere 6 1.8X as long as broad. Clypeus yellow, dorsoventrally elongate oval; bristles on clypeus brown, 6–8 strong bristles on ventral margin directed ventrally, remaining setae directed medioventrally, clypeus 2X as long as face. Face yellow; shape a subequal triangle, with few bristles ventrolaterally. Frons ventral half brown rest yellow; with few bristles medioventrally, frontal furrow running full distance from dorsal margin towards ventral margin, frontal cleft just anterior of median ocellus. Palpus with segments 1–2 yellow, 3–5 light brown; segment 1 hidden behind eye, segments increasing in length, segment 5 2.5X length of segment 4 with central half thinner than base and apex, segment 3 with apicolateral patch of fine yellow setae encircled by strong dark setae. Labellum yellow. Eye with interommatidial setulae absent. Occiput yellow with some adventitious brown spotting anteriorly, with appressed, anteriorly directed setae. Ocelli in a straight line, space between ocelli less than diameter of laterals, lateral ocelli 2X their own diameter from eye margin, ocellar triangle dark brown. Thorax: Length 1.19 mm (1.15–1.23 mm, n = 4). Dark brown dorsally, yellow laterally. Scutum dark brown/black with blue-green specks, pair of yellow mediolateral and posterolateral spots; 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 brown; with 8–10 large bristles and few small bristles. Prescutum yellow. Mediotergite brown, lighter posteriorly with 6–8 bristles on posterolateral corners, anteromedial patch of small bristles. 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 light brown and yellow trichia respectively. Metepisternum yellow. Anapleural suture with anterior portion slightly curved dorsally. Halter with basal 1/3 of stem ivory, apical portion and knob dark brown. Legs: principally yellow; extreme anteroapical corner dark brown on all femora; midfemur without apical spine-like process. Tibia with covering of brown macrotrichia, foretibia without comb of short setae along length of anteroventral surface, hind tibial spur yellow, remainder brown, foretibial spur length 2X apical thickness of foretibia, midtibia with strong, dorsal, bare patch of even thickness for 3/4 of its length, placed centrally, shortest midtibial spur 0.78X length of longest, longest midtibial spur 4.5X apical thickness of midtibia, shortest hind tibial spur 0.8X length of longest, longest hind tibial spur 6.7X apical thickness of hind tibia. Foreleg first tarsomere 1.8X length of foretibia. Wing ( Fig. 51): Length 5.5 mm (5.3–5.7 mm, n = 4). Hyaline; apical macula absent or, if present, very light, restricted to apical 1/4 of cell r1; medial macula absent. Macrotrichia in all cells, though absent from posterobasal margin of cell a. Setae on basal posterior margin of wing (along base of cell a) alternating long, short. Calypter with group of macrotrichia. Vein sc-r present, apical end joining R at 1–2X 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 margin. M 4 -CuA fork arising just apically of origin of r-m. A 2 faintly present as crease. Abdomen: Tergites 1–2 yellow with posterodorsal brown triangle, 3–6 with anterior 1/2 yellow remainder dark brown, T7 yellow. Tergite 8 smaller than all other abdominal sclerites, with 3 bristles on each apicolateral corner. Genitalia ( Fig. 99): yellow. Sternite 9 sclerotized, circular, 1/3 width of genitalia at widest point, overlapping medial margin of gonocoxite. Tergite 9 longer than wide, margins parallel on apical 2/3 ending in lateral squared off lobe with medially directed spine and medial U-shaped indentation, one thick and one thin, ventrally extending point at base of posterior lobe. Gonocoxite placed basally on T9, medial margin not reaching medial line, bearing gonostylus apically. Gonostylus with two lobes, dorsal lobe a broad based point, ventral lobe half the width of dorsal but 2.5X length and barely tapering until apex, gonocoxite III fused to dorsolateral margin. Aedeagus 2/3 length of T9, tapering towards apex, apodemes ~1/4 total length. Parameres a simple taper, apodemes ~1/2 length of parameres.

Female. ( Fig. 11) As for male, except as follows. Thorax: Length 1.5 mm (1.44–1.56 mm, n = 2). Wing: Length 6.5 mm (6.4–6.6 mm, n = 2). Abdomen: Tergites 1–6 with anterior 1/3 yellow remainder dark brown, T7 dark brown with pair of small lateral yellow spots. Cercus yellow.

Immatures. Unknown.

BIOLOGY: Unknown.

DISTRIBUTION: Ghana, Central African Republic, and Uganda ( Fig. 136), 180–1250 masl.

DISCUSSION: 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 Gymnoscutum and placed solely in Leptomorphus .

MATERIAL EXAMINED: Holotype: adult male, pinned on double mount minuten, genitalia in glass vial on pin, labelled “[Blue label] REP. CENTRAFRIC./ LA MABOKE/ 29.IX.1970 / L. MATILE rec.; [Red label] HOLOTYPE; Leptomorphus / (Afroleptomorphus)/africanus n. sp. ♂ ht/ L. Matile det. 1974; HOLOTYPE ♂ / Leptomorphus crosskeyi / Matile / Det. C.J. Borkent, 2012” [MNHN].

Paratypes: Labelled as for holotype (1♀, labelled as Allotype, MNHN); except 2.x.1970 (1♀, MNHN); 20.viii.1967 (1♂, MNHN); UGANDA, Kibale Forest , 12.xii.1971 – 9.i.1972, R . L. Mason (1#m, BMNH) .

Other material: CENTRAL AFRICAN REPUBLIC, La Maboke , 20.viii.1967, L. Matile. (1♂, MNHN) ; same, except 2.x.1970. (1♀, MNHN) ; GHANA, Kakum N.P., 8–15.x.1994. (1♂, ZMUN) ; UGANDA, Kibale Forest , 12.xii.1971 – 9.i.1972, R . L. Masou. (1♂, BMNH) .