Trigonometopus assisensis, Lima & Silva, 2015

Lima, Ângela Maria Alves de & Silva, Vera Cristina, 2015, Four new Neotropical species of Trigonometopus Macquart, 1835 (Diptera, Lauxaniidae), Papéis Avulsos de Zoologia (São Paulo) 55 (9), pp. 131-142 : 133-135

Trigonometopus assisensis sp. nov.

( Figs. 1 A-I)

Diagnosis: Grey integument. Ocellar setae long, longer than posterior fronto-orbital seta; proclinate setulae covering anterior third of frons to base of anterior fronto-orbital seta; scape shorter than pedicel; first flagellomere long, oval, with recurved apex. Scutum, abdomen and femora covered by setigerous spots; dorsocentral setae arranged 0+2; proepisternal and anepisternal setae absent. Anterior two third of the wing totally covered by brown bands. Female terminalia telescopic, hypoproct and epiproct present, well developed; sternite 8 narrow; 4 spermathecae. Male terminalia: sternite 6 reduced; sternites 7 and 8 almost fused; hypandrium reduced to a stripe; phallus pear-shaped.

Description: Male: Head ( Figs. 1A, 1B, 1C ): Rounded vertex, grey; posterior edge of vertex slightly concave from dorsal view; ocellar triangle placed slightly anterior of vertex, slightly raised. Frons rectangular, short, longer than wide; flat in profile, a shallow dark grey groove running longitudinally from base of ocellar triangle through middle of frons to anterior margin; proclinate setulae from anterior margin to almost half way to vertex, including base of anterior fronto-orbital seta; anterior margin, in dorsal view, concave; lunule exposed. Face grey, almost flat; lower facial margin narrow. Parafacial grey, narrow. Gena grey with setigerous spots. Eye oval, longer than high, brownish red. Antenna brown, inserted in a facial depression: scape shorter than pedicel; first flagellomere long, oval, with recurved apex, pruinose; arista pubescent. Chaetotaxy: outer vertical seta divergent, ⅔ length of inner vertical seta, convergent; ocellar seta ⅔ lenght of postocellar setae, proclinate, divergent; postocellar setae strong, cruciate; anterior fronto-orbital seta and posterior fronto-orbital seta both reclinate, anterior seta ⅔ length of posterior seta; 2 genal setae. Thorax: Scutum flat; grey, with setigerous spots; pleural region grey; scutellum triangular, grey. Chaetotaxy: dorsocentral setae 0+2 (anterior seta away from suture); 1 postpronotal seta; 2 notopleural setae; 1 prescutellar acrostichal seta; 4 rows of acrostichal hairs; intra-alar seta absent; 1 pre- and 1 postsutural supra-alar setae; 2 postalar setae; 1 katepisternal seta; many katepisternal hairs; anepisternal seta absent; proepisternal seta absent; 2 pairs scutellar setae, apical pair parallel. Legs: Coxae and femora brown with grey pruinosity; apex of femora dark yellow; tibiae and tarsi brownish yellow; apical segments of tarsi dark brown. Chaetotaxy: fore coxa with preapical seta; fore femur with posterodorsal and posteroventral rows of setae; mid coxa with 2 basal setae; mid femur with 2 strong apical setae; mid tibia with 1 strong apical anterior seta; hind coxa with 1 apical seta; hind femur with anterior and anteroventral rows of setae; hind tibia with strong 1 posteroventral and 1 anteroventral setae. Wing ( Fig. 1D ): Hyaline; anterior two thirds with brown bands, spotted at crossveins; costa sapromyziform; R bare; crossvein r-m located before midpoint of discal medial cell; crossvein dm-cu before midpoint of cell r 4+5; longitudinal veins parallel; vein A 1 short. Halter whitish yellow. Abdomen: Grey, with setigerous spots; dorsally with black spots; in males, sternite 6 reduced to a small plate, tergites 7 and 8 almost fused. Terminalia ( Figs. 1H, 1I ): Epandrium almost rectangular. Surstylus not well developed, fused to epandrium. Hypandrium as an almost complete ring around phallus base, narrow; with median projection, forked. Phallus pear-shaped; phallapodeme U-shaped laterally and forked in ventral view, strongly sclerotized; ejaculatory apodeme small and bell-shaped, in ventral view. Female: As male, except for abdominal apical segments, telescopic, membranous areas widely folded; sternite 8 narrow ( Figs. 1E, 1F ). Terminalia: With hypoproct and epiproct present. Cercus long. Spermathecae with configuration 2+2; pair of spermathecae united with no differenciation of a commom duct; very short duct linking paired spermathecae ( Fig. 1G ).

Etymology: The specific epithet assisensis was used as a homage to the type-locality, the city of Assis, where a large number of the type specimens were collected. To be treated as a noun in apposition.

Type material: Holotype: male; Brazil: São Paulo. Assis , 06.iv.2001, A.M.A. Lima col. ( DZUP) . Paratypes: Brazil: São Paulo. Assis, Horto Florestal, 05.ix.1992, S.M.D. Mello col., 1 male ( MZUSP) ; Assis, 10.v.1995, V. C. Silva col., 2 males, 1 female ( MZUSP) ; Assis, 27.iv.1999, A.M.A. Lima col., 3 males, 2 females ( MZUSP) ; Assis, 06.iv.2001, A.M.A. Lima col., 2 males, 9 females ( DZUP) ; Santa Catarina. [Seara], Nova Teutônia, ix.1967, F. Plaumann col., 1 male ( MZUSP) .

Comments: Some specimens of this new species were collected on grass fields. It should be noted that, besides the adaptation to life to an open vegetationas noticed by Collin (1948: 227) and Stuckenberg (1971: 516) but queried by Shewell (1977) and Davies et al. (2012) the specimens were collected close to water source, preferably just before sunset.

Figures

FIGURE 1: Trigonometopus assisensis sp. nov. (A) Head, lateral view. (B) Head, dorsal view. (C) Head, frontal view. (D) Wing. (E) Female abdomen, ventral view. (F) Female abdomen, lateral view. (G) Spermathecae and genital chamber. (H) Male terminalia, lateral view. (J) Male terminalia, ventral view.