Opeatocerata trilobata, Câmara & Rafael, 2011

Câmara, J. T. & Rafael, J. A., 2011, Two new species of Opeatocerata Melander (Diptera, Empididae, Empidinae) from the Brazilian Amazon Basin, Zootaxa 3062 (1), pp. 37-45 : 40-44

Opeatocerata trilobata sp. nov.

( Figs. 21–39 )

Diagnosis. Abdomen with subrectangular black spots on sides of tergites 3–6 ( Figs. 23, 24 ). Posterior cercus with dorsal and ventral projections ( Fig. 26 ). Subepandrial sclerite V-shaped dorsally ( Fig. 29 ). Phallus short, as long as hypandrium, with apex trilobate ( Figs. 31, 32 ).

Description. Holotype male ( Fig. 21 ). Head: Holoptic with upper ommatidia larger and delimited from lower ommatidia. Face parallel-sided, dark brown with grey pruinescence in ventral view, about 5X longer than upper width. Ocellar tubercle protuberant, brown with brown pruinescence and 2 pairs of divergent bristles, anterior pair longest. Ocelli light brown. Postocular bristles black, arranged in distinct complete uniseriate row and progressively longer ventrally. Postcranium brown with grey pruinescence, denser ventrally. Postgena with long yellow bristles. Antenna brown with short black bristles, inserted below middle of head; first flagellomere about 2X as long as pedicel; stylus aristiform, about 2X as long as first flagellomere. Proboscis shorter than head height, yellow with yellow bristles apically and ventrally on labellum.

Thorax ( Fig. 21 ): Yellow, shiny. Pronotum with transverse row of yellow bristles on anterior margin. Thoracic chaetotaxy: 1 acrostichal bristle placed posteriorly; dorsocentral row of uniseriate, slender yellow setulae, interrupted on posterior descendant region and posteriorly with longer bristles; 3 postpronotal setae; 2 robust notopleurals with several smaller setae in front; several supra-alar setae. 2 postalar bristles, posterior stronger; 1 pair of parallel scutellar bristles; laterotergite with 7 long yellow bristles.

Legs ( Fig. 21 ): Yellow, except last two segments of all tarsi black. All legs with distinct bristles; mid and hind tibiae and tarsi with anterodorsal and posterodorsal rows of longer bristles; hind tibia with larger number of bristles.

Wing ( Fig. 22 ): Hyaline with conspicuous brown pterostigma 2.5X as long as deep; M 1 and M 2 slightly upward curved and weak near margin. Halter yellow.

Abdomen ( Figs. 21, 23 ): Yellow with subrectangular black spots, shiny on sides of tergites 3–6 ( Figs. 21, 23, 24 ), long yellow bristles on all segments laterally and on segments 6–8 posteriorly. Tergite 8 shorter than tergite 7 divided in two subtriangular plates ( Fig. 24 ). Sternite 8 longer than sternite 7 divided in two subtriangular plates ( Fig. 24 ).

Terminalia (paratype): Anterior cercus with dorsal projection anteriorly directed ( Fig. 25 ), distal suboval projection in dorsal view ( Fig. 26 ); descendant plate of anterior cercus subrectangular, rather wider dorsally in posterior view ( Fig. 27 ). Posterior cercus subrectangular, truncated at apex ( Fig. 25 ), with dorsal acuminate projection and ventral subquadrate projection ( Fig. 26 ). Hypoproct with long bristles, subcircular in lateral view ( Fig. 25 ), comma-shaped in posteroventral view ( Fig. 27 ). Epandrium wide, membranous anteriorly, with epandrial lobe rather truncate and small spiniform bristles mesially and longer bristles distally ( Fig. 28 ). Subepandrial sclerite and bacilliform sclerite V-shaped, latter with no fold ( Fig. 29 ). Subepandrial sclerite rather narrow medially in dorsal view ( Fig. 29 ). Hypandrium membranous, longer than wide and enclosing phallus, with small setae ( Fig. 30 ). Phallus short, as long as hypandrium, with cylindrical base, expanded progressively towards apex ( Fig. 31 ); apex trilobate, inferior lobe symmetrically divided in two rounded lobes ( Fig. 32 ). Ejaculatory apodeme tetralamellar ( Figs. 25 , 31, 32 ).

Specimen length: 2.9 mm; Wing length: 3.4 mm.

Female ( Fig. 33 ): Similar to male, except dichoptic with subequal ommatidia; frons black and shiny. Wing ( Fig. 34 ) hyaline, infuscated between pterostigma and M 1. Legs with shorter bristles, restricted to hind tibia and tarsus. Abdomen with subrectangular shiny black spots on sides of tergites 3–5 ( Figs. 35, 36 ). Terminalia: Tergite 8 subrectangular with wider base ( Fig. 39 ). Sternite 8 wider at base, anterior margin with inverted shallow V-shaped sulcus ( Fig. 39 ). Genital fork with base entirely thin, arms longer than base ( Fig. 37 ). Tergite 10 shorter than half length of tergite 8, divided in two subtriangular plates ( Fig. 39 ). Sternite 10 with anterior and posterior margins concave ( Fig. 39 ). Cercus longer than segment 10, with longer bristles at apex ( Fig. 37 ). Receptacle of spermatheca hemispherical ( Fig. 38 ).

Specimen length: 2.8 mm; wing length: 2.9 mm.

Type material. HOLOTYPE ♂ labelled: BRASIL, AM [azonas], Manaus , Rod [ovia] AM 010 , Km 50, ZF2, Km 14, torre [tower], 02 ° 35'21''S; 60 ° 05'55''W. / 4.iii.2011. 00–03:00h. Arm [adilha] dossel 40 m. F.F. Xavier Filho, J. T. Câmara & P. Dias leg ( INPA) . PARATYPES: same as holotype (3 ♂, INPA) ; idem, torre, 02 ° 35'21''S; 60°05'55''W / 3–4.iii.2011, 21–00:00h (4 ♂, 5 ♀, MZUSP,) ; idem, 4.iii.2011, 03–06:00h (3 ♂, 1 ♀, MPEG) ; idem, próximo a torre / 04.iii.2011. 00–03:00h. Arm. luz móvel. J.A. Rafael & R. F. Silva leg (8 ♂, 3 ♀, INPA) ; idem, 03– 06:00h (2 ♀, INPA) ; idem, Km 24, próxima à sede CFT, 4.iii.2011, 18–21:00h. Arm. luz fixa. F.F. Filho, J. T. Câmara & J.A.Rafael leg (3 ♂, 2 ♀, BMNH) ; idem, Km 27, próxima à entrada LBA, 5.iii.2011, 18–21:00h. Arm. luz dossel 35m. F.F. Filho, R. F.Freitas leg (2 ♂, 5 ♀, INBio) ; idem, 6.iii.2011, 03–06:00h (2 ♂, 2 ♀, CNC) ; idem, 00–03:00h (4 ♂, 2 ♀, CZMA) ; idem, Km 14, próximo à torre, 3–4.iii.2011. 21–00:00h. Arm. luz móvel. J.A. Rafael & R. F.Silva (1 ♂, UFPR) ; idem, 6.iii.2011, 03–06:00h. Arm. luz móvel. J.A. Rafael, J. T. Câmara & P.Dias leg (2 ♂, 1 ♀, USNM) ; idem, 00–03:00h (3 ♀, INPA) .

Holotype condition. Good, not dissected.

Etymology. From the Latin tri = three, lobus = lobate and refers to the trilobate apex of the phallus.

Remarks. Opeatocerata trilobata differs from all other known species by the presence of subrectangular spots on the sides of tergites 3–6 (the corresponding spots are triangular or semicircular on other known species), the posterior cercus with dorsal and ventral projections, and the trilobate apex of the phallus.

Variation. Male and female specimens with body lengths from 2.8–3.5 mm. Pterostigma from 2–2.5 times as long as deep. Male abdomen with subrectangular black spots reaching tergite 7.

Figures

FIGURES 21–29. Opeatocerata trilobata sp. nov., paratype ♂. 21, habitus, lateral view. 22, wing. 23, abdomen from tergite 3 until terminalia, lateral view. 24, tergites 4–8 in dorsal view and sternites 4–8 in ventral view. 25, terminalia, lateral view. 26, lobes of the cerci, dorsal view. 27, descendant plate of anterior cercus and hypoproct. 28, epandrium, lateral view. 29, subepandrial sclerite and bacilliform sclerite, dorsal view.

FIGURES 30–39. Opeatocerata trilobata sp. nov., 30–32, paratype ♂. 30, hypandrium, ventral view. 31, hypandrium, phallus and ejaculatory apodeme, lateral view. 32, phallus and ejaculatory apodeme, dorsal view. 33–39, paratype female. 33, habitus, lateral view. 34, wing. 35, abdomen from tergite 3 until terminalia, dorsal view. 36, abdomen from tergite 3 until terminalia, lateral view. 37, genital fork. 38, terminalia, tergites 8, 10 and cerci in dorsal view, sternites 8 and 10 in ventral view. 39, receptacle of spermatheca.