Minilimosina (Svarciella) gracilenta Su

Su, Lixin, Liu, Guangchun & Xu, Jie, 2015, A review of Minilimosina Roháček (Diptera: Sphaeroceridae) from China, Zootaxa 4007 (1), pp. 1-28 : 13-15

Minilimosina (Svarciella) gracilenta Su sp. nov.

( Figs. 45–53 )

Diagnosis. General colour brownish black. Legs entirely pale brown. Four small subequal interfrontals. Mid tibia: proximal anterodorsal seta longer than distal anterodorsal and more than half as long as distal dorsal seta. Cs2 slightly longer than Cs3. Sternite 5 of male ( Fig. 53 ) with a pair of rod-like black lobes below the posteromedial comb which is connected with synsternite 6+7. Posterointernal lobe of gonostylus ( Fig. 47 ) with a robust spine. Distiphallus ( Figs. 49, 50 ) with a pair of thin apicodorsal sclerites.

Description. Male. Body length 2.1 mm, wing length 1.8 mm. Head and thorax dark brown, including antennae, face and gena; legs pale brown. Haltere with pale yellow stem and dark brown knob.

Head: 2 orbitals. Interfrontalia with 4 pairs of small subequal setae. A minute pair of setulae outside the lowermost interfrontals. Genal seta well developed. Eye height about 1.5 times as long as genal height. Aristal hairs twice as long as width of base of arista.

Thorax: Anterior margin of mesopleuron with a line-like black spot, the lower 1/4 area of mesopleuron with a crescent-shaped black spot, anterior corner between mesopleuron and sternopleuron also with a line-like black spot. Thoracic chaetotaxy: 1 long humeral seta; anterior dorsocentral seta 0.8 times as long as posterior dorsocentral, posterior dorsocentral slightly longer than or subequal to scutellum length; acrostichal setae in 6 rows in front of suture. Sternopleuron with a small anterior and a strong posterior sternopleural seta. Mid tibia: proximal anterodorsal seta longer than distal anterodorsal, there seem to have a row of about 5 small posterodorsal setae, ventroapical seta 1.5 times as long as width of mid tibia. Wing and veins pale brown, including C. C extended beyond apex of R4+5. Cs2 1.1 times as long as Cs3, crossveins r-m and dm-cu separated by 2.5 times the length of dm-cu. R2+3 straight, apically gently bent up to C. R4+5 straight. Alula small and narrow, apically pointed. Anal vein sinuate.

Male abdomen: Syntergite 1+2 ( Fig. 51 ) large and dark pigmented, distinctly wider than tergite 3 and distinctly longer than tergites 3 and 4 together. Tergites 3 and 4 pale pigmented, slightly desclerotized. Tergite 5 divided into 2 dark pigmented sclerites. Synsternite 1+2 and sternite 3 pale pigmented, slightly desclerotized. Sternites 4–5 uniformly dark pigmented. Sternite 5 ( Figs. 52, 53 ) with an usual posteromedial comb of blunt spines situated between two apically blunt lobes, each carrying 2 setae, median and apical parts of lobes dark pigmented; a group of thicker spine-like setae in front of the comb; with a pair of rod-like black lobes below the comb connecting with synsternite 6+7 ( Fig. 53 ). Epandrium ( Figs. 45, 46 ) medium long. Hypandrium ( Fig. 46 ) with medial rod-like part thin and long. Gonostylus ( Figs. 45, 46, 47 ) roughly trilobed; outer lobe large, with long setae; posterior inner lobe small, triangular, apically pointed, basally with a robust spine; anterior inner lobe relatively large, with two groups of short setae on its apical part. Phallophore ( Fig. 49 ) shorter than distiphallus. Postgonite ( Fig. 48 ) slender, subapically with small setulae. Distiphallus ( Figs. 49, 50 ) apically membranous and spinulose; ventral sclerite slender, apically looped ( Fig. 49 ); dorsobasal sclerite with a pair of apically bifurcate parts, dorsoapical sclerite separated in two thin parts.

Female: Unknown.

Type material. ( LKLSU, in glycerine): Holotype male: China, Jiangxi, Mt. Wuyi, Malaise trap, 1160 m, 22.Jun.2009, Yi Li & Lingli Yi.

Etymology. The species is named according to two thin rod-like black parts below posteromedial comb of male sternite 5: “gracilentus” (= Lat. slender, thin, slim).

Comments. In the key ( Roháček & Marshall, 1988; Marshall, 1985), the species runs to M. archboldi Marshall , but distinctly differing from the latter in wing with Cs2 slightly longer than Cs3, sternite 5 of male with comb-like posteromedial lobe margined by two lateral apically blunt lobes and having two dark thin rod-like lobes below it. Based on synapomorphy proposed by Roháček & Marshall (1988): tergite 5 divided into 2 parts or greatly reduced, the species should be assigned to M. fanta group. We think that based on shared characters (possible synapomorphies): gonostylus with anterior projecting lobe, phallophore shorter than distiphallus, slender postgonite and looped ventral sclerite of distiphallus, the new species could form a clade with M. fanta and M. parafanta . The species can be safely distinguished from M. fanta and M. parafanta by the following characters: general colour brownish black; legs entirely pale brown; Cs2 slightly longer than Cs3; tergites 3–4 pale pigmented and slightly desclerotized, gonostylus with a small anterior projecting lobe; dorsoapical sclerite of distiphallus with slender separated parts.

Distribution. Oriental: China (Jiangxi).

Figures

FIGURES 45 – 53. Minilimosina (Svarciella) gracilenta Su, sp. n.: 45, male genitalia, posterior; 46, male genitalia, lateral; 47, gonostylus, internal; 48 – 49, aedeagus and associated structures, lateral; 50, aedeagus, dorsal; 51, male preabdomen, dorsal; 52, male sternite 5, ventral; 53, male sternite 5 and synsternite 6 + 7, posterior.