Medeventor minimus Bazyar & Silva, 2018

Bazyar, Zeinab & Silva, Vera Cristina, 2018, Two new species of Medeventor Wheeler from South America (Diptera, Chloropidae, Oscinellinae), Zootaxa 4407 (4), pp. 563-572 : 564-567

Medeventor minimus Bazyar & Silva , sp. n.

( Figures 1‒5)

Diagnosis. Small flies; colour of head somewhat different to rest of the body; frons somewhat projected laterally; first flagellomere of antenna rounded, sometimes with a distinct upper corner; eye reniform, concave posteroventrally; thorax with 2 postalar, 1 pre-scutellar acrostical setae; femora swollen; hind tarsi entirely yellow; male sternite 6 weakly developed, sensory setulae could be present or absent; phallapodeme broad in lateral view; epandrium with few setae; surstyli with a rounded tip in posterior view.

Description. Male. Total length, 1.7 mm. Wing length, 1.9 mm. Relative measurements (the depth, length and width respectively) of the head (13:10:14) and thorax including with the scutellum (10:15:13). Body light brown and head yellow. Head ( Figure 1). Ocellar triangle yellow, bare, almost indistinct, not reaching anterior margin of head; interfrontal setae on an irregular row and settled on its position with variation; ocellar tubercle dull; eye reniform, concave posteriorly, hairy; gena yellow, half height of the eye, with sparse setulae, slightly striated ventrally; vibrissal angle not projecting and exceeding the anterior eye margin, a short robust black vibrissa seta present; parafacialia rather wide; facial carina narrow, triangular, extending to ventral margin of face; clypeus light colour; frons slightly projecting (well visible above and before eye in profile); first flagellomere yellow, short, rounded with a distinct upper corner, the sense pits are undetectable; arista pubescent, dark, with yellow base; palpus yellow, elongated; proboscis yellow, short, geniculate, labellum with 4 hardly visible pseudotracheae; occiput yellow. Setulae on frons dense and reduced in size; postocellar, inner and outer vertical setae much longer and distinctly stronger than remaining cephalic setae, nearly as long as depth of first flagellomere of the antenna, ocellar and postocellar setae convergent and recurved; postocular setulae in a single row. Thorax. Scutum with 7 pale brown stripes, evenly covered with long, light brown, setulae; postpronotum pale, pubescent; anepisternum pubescent; 1 postpronotal seta; 1+2 notopleural setae; 1 pre-scutellar dorsocentral and acrostical; 2 postalars, 1 intra-postalar seta;1 apical and 4 subapical scutellar setae, not born from warts or tiny projections. Wing ( Figure 2): Elongate, membrane fine and hyaline, covered with fine microtrichia; veins pale yellow and narrow; costal sections 1:2:3:4 from humeral crossvein to M1 are as (68:100:59:38); M1 gently concave posteriorly; the chloropidtypical flexure of CuA1 curving only; anal area moderately developed; alula well developed. Legs. All femora swollen ( Figure 1); male femoral organ on dorsal side of mid femur absent (microscopical investigation with 40 fold objective magnification); mid tibia with a ventral dark apical seta; tibial organ on hind leg oval, brownish, 1/3 length of tibia; all claws and tarsi symmetrical. Abdomen. Dark brown; setulae on tergites regularly distributed; sternite 6 weakly developed, a pair of sensory setulae or patch of microtrichia could be present or absent ( Figure 5 ). Terminalia (Figures: 3‒5). Sintegosternite 7+8 present [those after the phylogenetical torsion in dorsal position behind last tergite]; hypandrium closed; pre- and postgonites fused, tip rounded with small sensillae; basiphallus elongate, sclerotized, distiphallus short; phallapodeme cylindrical, thick, tip flattened ( Figure 5 ); phallic guide broad, not fused to hypandrium; epandrium convex, with few setulae evenly distributed; surstyli simple, with a rounded tip in posterior view, and connected to distal lateral side of epandrium ( Figure 3 ), with 8 long, 4 setae placed on anterior and 4 on posterior side ( Figure 3 ); cerci well developed, broad, rounded, setulose, each with a long apical seta, and basally they are fused to each other. Female. Unknown.

Type material: Holotype ♂. BRAZIL, Mato Grosso, P.N. Chapada dos Guimarães, Transição Ciliar / Cerrado, Trilha Cachoeira Véu de Noiva , 15o24'33.5''S, 0 55o 49'59.9''W, Malaise 17, 09.iii. ‒18.iv.2012, Lamas, Nihei & eq. col. ( MZUSP) . Paratype: BRAZIL, same data as holotype, 1♂ ( MZUSP) .

Etymology: The specific epithet comes from the Latin adjective parvus with its superlative word minimus , a, um (smallest), referring to the small size of this species.

Comments. This species shares with M. tschirnhausi features such as the hairy eyes, not swollen palpus, not elongate and thickened; face with a narrow carina, closed hypandrium, long setae all over the surstylus, and an elongate seta on the cercus. The bare ocellar triangle, the presence of a single prescutellar acrostichal seta, and the rounded cerci fused basally, are characters shared with M. nubosus .

Figures

FIGURES 3‒5. Medeventor minimus, sp. n., male genitalia. 3. Posterior view.4. Lateral view.5. Ventral view. Abbreviations: basi, basiphallus; cer, cercus; dis, distiphallus; ep, epandrium; gon, gonites; hyp, hypandrium; ph-a, phallapodeme; st 6, sternite 6; sur, surstylus.Scale bar, 0.1 mm.