Leptomorphus obscurus Matile

Borkent, Christopher J. & Wheeler, Terry A., 2012, Systematics and Phylogeny of Leptomorphus Curtis (Diptera: Mycetophilidae) 3549, Zootaxa 3549, pp. 1-117 : 51-52

24. Leptomorphus obscurus Matile

( Figures 28, 66, 113, 136, 150, 153)

Leptomorphus (Gymnoscutum) obscurus Matile, 1977: 152 .

References: Crosskey 1980: 1221 (catalogue appendix); Matile 1997: 147–149 (figures, new records, morphological variation, key).

DIAGNOSIS: The only extant species of Leptomorphus with the following combination of characters: laterotergite, anepisternum and anepimeron yellow; scutellum brown, male genitalia with tergite 9 gradually tapering on apical quarter (tergal evagination), apex bearing medial spur and often a secondary small bump or point, also with strong, ventrally-produced, thin ridge running across ventral surface at the anterior margin of the tergal evagination, creating a semicircular dorsal margin when viewed caudally ( Fig. 113).

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. crosskeyi and L. obscurus by the gradually tapering shape of the tergal evaginations ( Fig. 113) rather than the almost square posterior margin in these two other species.

DESCRIPTION: Male. ( Fig. 28) Head: yellow with some brown spots, 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 absent; pedicel light brown/yellow, with 2 large bristles, several setae on apicodorsal margin, a few fine setae on apicoventral margin; flagellomere 1 with tapered base either brown or yellow remainder brown; flagellomere 6 1.1X as long as broad. Clypeus yellow, slightly laterally compressed oval; bristles on clypeus brown, 4–6 strong bristles on ventral margin directed ventrally, remaining setae directed medioventrally, clypeus 2X as long as face. Face yellow; shape a just longer than wide triangle, with few bristles ventrolaterally. Frons yellow; with few bristles medioventrally, frontal furrow running 1/2 distance from dorsal margin towards ventral margin, frontal cleft just anterior of median ocellus. Palpus with 1–3 yellow, remainder brown; segment 1 hidden behind eye, segments increasing in length, segment 5 2X 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 light brown. Eye with very few, short inter-ommatidial setulae scattered on surface. 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/black with electric blue green specks. Thorax: Length 1.08 ± 0.14 mm (0.98–1.23 mm, n = 10). Dark brown dorsally, yellow laterally. Scutum dark brown/black with blue-green specks, pair of yellow mediolateral and smaller posterolateral spots; surface of scutum bare; acrostichal setae absent; dorsocentral setae present as fine setae for most of length; single row of lateral setae present; patch of setae on scutum at wing base present. Scutellum brown; with 8–10 large bristles and many small bristles. Prescutum yellow. Mediotergite dark brown 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 trichia. 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; hind femur light brown at very apex; 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 faint, dorsal, bare patch of even thickness for 1/3 of its length, placed basally, shortest midtibial spur 0.8X 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 1.8X length of foretibia. Wing ( Fig. 66): Length 5.1 ± 0.7 mm (4.5–5.7 mm, n = 10). Hyaline; apical macula absent or very light at R 5 apex; 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 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 fading before wing margin. M 4 -CuA fork arising before origin of r-m. A 2 faintly present as crease. Abdomen: Tergites principally dark brown, T2–6 with lateral yellow spots. Tergite 8 smaller than all other abdominal sclerites, with 2–3 bristles on each apicolateral corner. Genitalia ( Fig. 113): yellow. Sternite 9 sclerotized, oval/rounded diamond, 3/5 the width of genitalia at widest point, overlapping medial margin of gonoxite. Tergite 9 longer than wide, lateral margins widening slightly to apex and then tapering sharply into pointed lobes with medial U-shaped indentation, a ventrally extending sclerotized band running along the base of posterior lobes. Gonocoxite placed basally on T9, medial margin just 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 gonocoxite, tapering towards apex, apodemes 2/5 total length. Parameres a simple taper, apodemes ~1/2 length of parameres.

Female adult. As for male, except as follows. Thorax: Length 1.32 ± 0.20 mm (1.19–1.48 mm, n = 9). Wing: Length 6.1 ± 0.9 mm (5.3 – 6.8 mm, n = 9). Abdomen: Cercus yellow.

Immatures. Unknown.

BIOLOGY: Unknown.

DISTRIBUTION: Guinea, Ivory Coast, Ghana, Gabon, the Central African Republic and the Republic of the Congo ( Fig. 136), 120–750 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 the genus 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)/ obscurus n. sp. ♂ ht/ L. Matile det. 1974; HOLOTYPE ♂ / Leptomorphus obscurus / Matile / Det. C.J. Borkent, 2012” [MNHN].

Paratypes: labelled as for holotype (3♂, 4♀ (1 labelled allotype )); except 24.IX.1970 (1♀); 26.IX.1970 (1♂) ; 27.IX.1970 (2♂, 1♀). All paratypes in MNHN .

Other material: CENTRAL AFRICAN REPUBLIC, La Maboke , 26.ix.1970, L. Matile. (1♂, MNHN) ; same except 27.ix.1970. (2♂, MNHN) ; 29.ix.1970. (3♂, MNHN) ; GABON, Makokou m'passa, Bale Affl., 7–16.v.1979, J. Legrand. (2♂, MNHN) ; GHANA, Kakum National Park , 8.xi.1994 (2♂, ZMUN) ; 31.x–8.xi.1994 (2♂, ZMUN) ; 8–15.xi.1994 (1♂, ZMUN) ; 8–15.x.1994 (1♀, ZMUN) ; Western Region , Ankasa game prod. reserve, 8.xii.1993, J. Kjaerandsen, T. Anderson (1♂, 1♀, ZMUN) ; GUINEA, Mt. Nimba , 18–29.vi.1991, Girard et Legrand. (1♂, MNHN) ; IVORY COAST, Taї , 5.v.1980, G. Couturier. (1♂, MNHN) ; REPUBLIC OF THE CONGO, Mayombe Dimonika , 14.xi.1975, L. Matile. (1♂, MNHN) .