Elaphropeza riatanae, Published, 2007

SHAMSHEV, IGOR V. & GROOTAERT, PATRICK, 2007, Revision of the genus Elaphropeza Macquart (Diptera: Hybotidae) from the Oriental Region, with a special attention to the fauna of Singapore, Zootaxa 1488 (1), pp. 1-164 : 88-89

Elaphropeza riatanae sp. nov.

( Figs. 141–144 )

Diagnosis. Occiput black, postpedicel about 5.0 times longer than wide; mesonotum yellow with brown scutellum; acrostichal and dorsocentral bristles multiserial; legs with brownish pattern, hind tibia with 1 anterodorsal bristle near middle; abdominal tergites 4 and 5 with squamiform setae.

Description. Male. Body length 2.1–2.3 mm, wing length 1.7–1.8 mm. Occiput wholly black, subshining, with yellow to brownish yellow setation. Anterior ocellars long, proclinate; posterior ocellars minute. Inner verticals long, outer ones somewhat shorter. Frons subshining. Antenna ( Fig. 141 ) with postpedicel brownish, scape and pedicel yellow. Pedicel with circlet of subequally short setulae. Postpedicel long, nearly 5.0 times longer than wide. Style normally pubescent, black, nearly as long as postpedicel and about 1.5 times shorter than scape, pedicel and postpedicel combined. Proboscis brownish yellow. Palpus yellow, small, rounded; with scattered brownish yellow setulae, bearing 1 longer subapical seta.

Thorax largely yellow, shining, with yellow to brownish yellow bristles; scutum with small brownish patch above wing base including postalar callus (sometimes very indistinct), scutellum and metanotum wholly brown, mesopleuron posteriorly and pteropleuron in upper part darkened. Prothoracic episterna lacking long upturned bristle just above fore coxa, with 1 short upturned bristle in upper part. Postpronotal bristle not prominent. Mesonotum with 2 notopleural, 1 postsutural supra-alar, 1 postalar and 4 scutellar (inner ones very long, cruciate; outer ones very short) bristles. Acrostichals and dorsocentrals multiserial, uniform (except for 1 pair of long prescutellars), extending to base of scutellum.

Legs almost entirely yellow, with yellow to brownish yellow setation; hind femur brownish near apex above, fore and mid tibiae brownish (fore tibia darker), fore and mid tarsi wholly brownish, hind tarsomeres 2–5 becoming gradually darker (from 2nd to 5th). Coxae and trochanters with unmodified setation. Fore and hind femora and tibiae somewhat thickened. Fore femur with rows of short antero- and posteroventral bristles and 2 longer bristles near base. Fore tibia lacking prominent bristles (except subapicals). Mid femur with 2 rows of spinule-like, short, ventral bristles (becoming shorter in apical part of femur), 1 long thin bristle near base and 1 anterior subapical bristle. Mid tibia with hardly prominent ventral spinules in apical part, lacking prominent bristles (except subapicals). Hind femur bearing 1 row of short anteroventrals and 3–4 erect dorsal bristles near base. Hind tibia with 1 anterodorsal bristle near middle; apical projection small, rounded, clothed in dense brownish setulae. Hind basitarsus somewhat thickened.

Wing normally developed, finely uniformly infuscate, covered with uniform microtrichia; veins yellowish to brownish yellow. Costal vein with moderately long setulae along anterior margin. Basal costal bristle moderately long, brownish. Costal index: 39/30/26/16. Vein Rs longer than crossvein bm-cu. Veins R4+5 and M1+2 divergent near wing apex, both straight. Vein CuA1 reaching wing margin. Vein A1 absent. Crossvein bm-cu transverse. Crossvein r-m before middle of cell bm. Halter yellow.

Abdomen. Tergite 1 almost entirely pale yellow, with very narrow lateral brownish spots only. Tergites 2 and 3 subequal, subtriangular laterally, deeply concave on anterior margin; with unmodified setation. Tergite 4 broadest, dark brown, with squamiform setae. Tergite 5 very narrow, with squamiform setae. Tergites 6–8 unmodified; tergites 6 and 7 with similar moderately long posteromarginal bristles. Sternites 1–3 pale yellow, sternites 4–7 subrectangular, brownish. Gland-like structures present between tergites 4–5.

Terminalia ( Fig. 142–144 ) large, brownish. Cerci almost completely fused; left cercus elongate oval, bearing numerous short bristles; right cercus hardly prominent, short, very narrow, with several long marginal bristles. Epandrium completely divided. Right epandrial lamella subtriangular, with several long and some number of short bristles, lacking spines. Right surstylus not prominent. Left epandrial lamella fused to hypandrium, with 1 long bristle apically. Left surstylus with upper lobe elongate oval, with subtriangular projection in basal part, bearing scattered short marginal bristles. Hypandrium with 2 strong bristles. Phallus very short. Two rod-shaped apodemes.

Female. Body length 2.0– 2.1 mm, wing length 1.7–1.8 mm. Mid tibia lacking ventral spinules. Segment 8 brown, somewhat elongate, with sclerites separated; sternite 8 folded apically. Cercus elongate oval. Otherwise as in male.

Material examined: Holotype male labelled: SINGAPORE, Chek Jawa , 12 September 2005, mangrove, sweeping (reg. 25343, leg. PG, E-18).

Paratypes: SINGAPORE: 1 ♂, 2 ♀♀, Chek Jawa , 26 March 2005, mangrove, sweeping (reg. 25031, leg. PG) ; 2 ♀♀, Chek Jawa , 11 October 2005, mangrove, Mal (reg. 25380, leg. PG) ; 1 ♂, 4 ♀♀, Chek Jawa , 26 October 2005, mangrove, Mal 2 (reg. 25399, leg. PG) ; 1 ♂, Semakau Island , 26 June 2005, beach, sweeping (reg. 25185, leg. PG) ; 1 ♂, Sungei Buloh , 26 August 2005, mangrove, sweeping (reg. 25321, leg. PG) .

Derivatio nominis. The present species is dedicated to Mrs Ria Tan for the great work she is doing in Singapore in popularising the marine life through excellent photography published in books, leaflets and on websites. The photo album on marine life of the mangrove of Chek Jawa may have contributed to the protection of this very interesting site.

Distribution. Singapore. Mangrove.

Singapore. This is a rare species recorded only in mangrove. The highest activity is mainly in the second half of the year. Males and females are found in almost equal numbers.

Remarks. The relationships of E. riatanae sp. nov. are unclear beyond inclusion within the monophyletic lineage of the E. ephippiata species group sharing completely fused cerci (see “Discussion” for details).

Figures

FIGURES 141–144. Elaphropeza riatanae sp. nov. 141. antenna. 142. epandrium with cerci. 143. right epandrial lamella. 144. left surstylus.