Ropalomera aterrima Hernández

Ibáñez-Bernal, Sergio & Hernández-Ortiz, Vicente, 2012, The new genus Acrocephalomyia, and a new species of Ropalomera from Costa Rica, with additional records for other Mesoamerican species (Diptera: Ropalomeridae), Zootaxa 3478, pp. 553-569 : 558-560

Ropalomera aterrima Hernández -Ortiz & Ibáñez -Bernal, sp. nov.

Figs. 10–18

Type -locality. COSTA RICA: ALAJUELA, 20 km south of Upala.

Etymology. From Latin aterrima (fem.), black or dark colored, referring to the general black coloration of the body and wings.

Diagnosis. Ropalomera aterrima sp. nov. can be separated from other species of the genus by the following combination of characters: body predominantly black, ocellar bristle large; thorax with only one postpronotal bristle; scutum without pollinose vittae, scutellum shiny brown, flat dorsally, and angled dorsally in lateral view; hind tibia with some setae on the dorsal surface not arising from tubercles; abdomen shiny black dorsally and without pollinosity, dull black ventrally.

Description (male and female). Head: Frons length 0.42 times length (from posterior ocelli to frontal anterior margin) as maximum width, dark brown, nearly black, slightly paler over antennal insertions and sides of the ocellar tubercle, all covered with small, thin black setae; bronze pollinosity evident when light insides anteriorly excluding region above antennal insertion and around ocellar tubercle; fronto-orbital plate with brighter pollinosity; ocellar tubercle shiny black, 1 pair of long ocellar bristles; postocellars divergent; occiput with setae; 1 pair of frontal seta; inner verticals convergent and outer verticals divergent (holotype with large supernumerary bristle outside outer vertical bristle on one side). Parafacialia yellow above, brownish below with 4 stout bristles. Face shiny yellow above, brownish below, with a pale rounded tubercle at middle. Gena dark brown with silver pollinose vertical vitta that continues dorsally onto occiput behind eye; setululae black, except whitish over vitta. Clypeus shiny dark brown. Antenna brown, scape 0.5 and flagellum 3.5 times length of pedicel, flagellum length 2.0 times width at level of arista insertion; arista black with basal third yellow, with long rays. Proboscis dark brown, palpus dark brown setulose, covered with grey pollinosity.

Thorax: Postpronotal lobe shinning dark brown, nearly black. Scutum dark brown in ground color, pollinose and with uniformly spaced black setulae; scutum with pollinose patches near postpronotal lobes, on lateral margins near the transverse suture, and on prescutellar region; scutum also with a pair of small presutural dorsocentral black shiny dots. Scutellum triangular, shiny reddish brown, angled dorsally in lateral view, with apex elevated. Pleuron dark brown, with scarce pollinosity not forming vittae. Thorax chaetotaxy: 1 postpronotal, 2 notopleural, 1 presutural supra-alar, 1 postsutural supra-alar, 1 postalar, 1 intra-alar, 1 intra-postalar, 1 dorsocentral, 1 acrostical, 1 anepisternal and some setae below posterior margin, 1 katepisternal, and 1 posterior spiracle bristle; scutellum with 1 marginal and 1 apical bristle (apical bristles not seen but sockets present). Legs: front coxa with silvery pollinosity denser than that on mid and hind coxae; femora shiny brown, paler at base; tibiae concolourous with femora; tarsi comparatively yellowish, with black setae dorsally and red setae ventrally, pulvilli yellow. Front femur densely covered with black setae, with a row of 8 outstanding bristles on ventral margin and a row of 4 outstanding preapical dorsal bristles; front tibia swollen without keel and 2 outstanding bristles on preapical dorsal margin. Mid femur with no differentiated bristles, but densely covered with black setae; mid tibia swollen with row of 3 outstanding bristles on apical third of dorsal margin. Hind femur with 2 dorsal and 2 ventral preapical outstanding bristles; hind tibia swollen, nearly twice diameter of hind femur, without keels and with row of about 8 outstanding bristles along dorsal margin. No outstanding bristles originating from tubercles. Wing: fumose, darker basally and anteriorly, venation typical of family. Halter white with brown base.

Abdomen: shining black dorsally without pollinosity, dull black ventrally.

Measurements. Holotype Ƥ: Wing length: 11.0 mm, width: 4.2 mm; gena height: 1.0 mm; eye height: 2.2 mm; frons length: 1.2 mm, width: 2.0 mm; thorax length (from anterior margin of scutum to apex of scutellum): 3.7 mm, width at level of supra-alar setae: 2.6 mm. Paratype Ƥ: Wing length: 9.7 mm, width: 3.8 mm; gena height: 1.1 mm; eye height: 1.75 mm; frons length: 1.1 mm, width: 1.7 mm; thorax length (from anterior margin of scutum to apex of scutellum): 3.0 mm, width at supra-alar setae insertion level: 2.2 mm. Paratype 3: Wing length: 9.4 mm, width: 3.6 mm; gena height: 0.85 mm; eye height: 1.75 mm; frons length: 0.9 mm, width: 1.4 mm; thorax length (from anterior margin of scutum to apex of scutellum): 2.7 mm, width at level of supra-alar setae: 2.1 mm.

Comments. This species is included in the genus Ropalomera by the presence of postpronotal bristles, antennal arista with long rays, face with rounded tubercle distant from antennal bases, and posterior spiracle with bristles, but it differs in having the dorsal surface of scutellum flat, and the scutal vittae absent. Ropalomera aterrima sp. nov. is readily characterized by the general black coloration of the body, particularly of the abdomen and wings, and by the absence of pollinose vittae on scutum and pleura.

Material examined. Holotype Ƥ: COSTA RICA. ALAJUELA: 20 km S of Upala, 26/March–12/April/1991, F. D. Parker, col. Paratype Ƥ: same data as holotype except 1–10/April/1991. Paratype 3: same data as holotype except 5–18/March/ 1991 ( USU).

Figures

FIGURES 10 – 13. Ropalomera aterrima sp. nov. Holotype Ƥ. 10) Head, lateral view; 11) Head, frontal view (left antenna not drawn); 12) Antenna, lateral view; 13) Head and thorax, dorsal view, showing chaetotaxy and dorsal pattern. Scale in millimeters.

FIGURES 14 – 18. Ropalomera aterrima sp. nov. Holotype Ƥ. 14) Thorax, lateral view; 15) Wing; 16) Front leg, posterior view; 17) Mid leg, anterior view; 18) Hind leg, anterior view. Scale in millimeters.