Hybobathus obsoletus ( Curran, 1941 ) Miranda, 2017

Miranda, Gil Felipe Gonçalves, 2017, Revision of the Hybobathus arx and Pelecinobaccha summa species groups (Diptera: Syrphidae), Zootaxa 4338 (1), pp. 1-43 : 14-17

Hybobathus obsoletus ( Curran, 1941) comb. nov.

Fig. 5

Baccha obsoleta Curran, 1941: 23 . Type locality: Paraguay, San Bernardino. Holotype male (AMNH). Hull, 1949: 97 (citation), 123 (key), 223 (fig. 150, abdomen), 283 (fig. 383, wing); Fluke, 1956: 256 (catalog citation).

Ocyptamus obsoletus . Thompson et al. 1976: 23 (catalog citation).

Baccha nectarina Hull, 1942: 94 . Type locality:Paraguay, Villarica. Holotype male (MCZ). Hull, 1949: 97 (citation), 123 (key), 124 (key), 196 (fig. 30, abdomen); Fluke, 1956: 254 (catalog citation). syn. nov.

Ocyptamus nectarinus . Thompson et al. 1976: 22 (catalog citation).

Baccha myrtella Hull, 1960: 70 . Type locality: Peru, Chanchamayo. Holotype male (CNC). syn. nov.

Ocyptamus myrtella . Thompson et al. 1976: 22 (catalog citation).

Redescription. MALE ( Figs 5a & e–i ). Head ( Fig. 5e ). Yellow; face with slight medial darkening, more visible on the sides of the tubercle, with sparse white microtrichosity except concentrated close to eye margin, with black pile, absent medially. Gena with white pile. Lunule with central black marking, with diffuse large brown area until the crease ventral to the frontal triangle. Frontal triangle with central dark triangular spot that reaches the eye contiguity, and with black pile. Base of antenna protuberant. Vertical triangle with shiny white microtrichia, except on ocellar triangle and dorso-posteriorly to it, which are dull black, with several irregular rows of black pile ending dorsal to the anterior ocellus; ocellar triangle separated by 1.5 times its length from the posterior margin of the head. Eye contiguity shorter than the vertical triangle length. Eye with weak sub-triangular indentation on posterior margin positioned around the level of antennal insertions. Antenna with black pile; postpedicel oval, with darkened dorsal 1/3. Occiput homogeneously covered by white microtrichia, with white pile, dorsal 1/3 with one row of flattened pile, ventral 2/3 with 1–3 rows, posterior row with longer and flattened pile, medial 1/3 with a few black pile anteriorly. Thorax ( Fig. 5a ). Scutum black, but yellow laterally from postpronotum to scutellum; mostly covered by white microtrichosity, denser on a medial narrow and a pair of sub-medial vittae, except for areas between and beside the vittae that do not present microtrichosity, the areas between the vittae extend from the anterior margin to the middle, the areas beside them extend from the anterior to the posterior margin; pile long, white and erect, with anterior continuous row of slightly longer pile not densely arranged. Scutellum yellow, with slightly darker medial region, with short, black and appressed pile, erect and longer on margin; subscutellar fringe with long and black pile. Pleuron yellow, dark on anterior 1/3 of posterior anepisternum, ventral 2/3 of katepisternum, meron and postero-ventral margin of katatergum, and with some small slightly darker areas on anterior anepisternum; white pilose (proepimeron, anterior and posterior anepisternum, dorsal and ventral katepisternum, anterior anepimeron, katepimeron and metaepisternum), katatergum with long microtrichia giving it a ‘velvet’ appearance. Plumula white and short. Calypter yellow, pile long and pale on margin of the ventral lobe and very short and dark on margin of the dorsal lobe. Halter yellow, capitulum orange. Wing ( Fig. 5a ). Dark yellow, lighter on most of bm, middle of dm, small apico-anterior portion of cup, and most of cua1; entirely microtrichose; alula light yellow, wide and convex, apically 3.5 times as broad as c cell, entirely microtrichose. Legs. Pro- and mesolegs yellow with yellow pile, longer on postero basal margin of the femora, and dark anteriorly on mesocoxa and on several rows of longer pile on postero-apical 1/2 of the mesofemur. Metaleg light brown on most of metafemur and dark brown on a sub-apical small area, and metatibia dark brown except for basal and apical 1/5, remaining yellow, with dark pile on the metacoxa (a few) and on darker regions, remaining pale; metabasitarsomere 1/2 the length of the metatibia. Abdomen ( Fig. 5a ). Dark brown and petiolate, 3.5 times the length of the thorax. Tergite 1 yellow on basal 1/2 and dark brown on apical 1/2, with long and erect pile, yellow basally and black apically, and mostly bare dorso-medially; sternite 1 yellow with long, pale and erect pile. Tergite 2 long, slightly compressed medially, 5.5 times longer than smallest width, yellow baso-laterally and on two small sub-apical lateral markings; with short, black and appressed pile, except erect and long on baso-lateral 3/4; sternite 2 yellow on basal 1/2, brown on apical 1/2, pile short, black and appressed. Tergite 3 trapezoidal long, 1.4 times longer than apical width and apical margin 1.8 times wider than basal margin, with a pair of sub-lateral, basal, short, triangular, yellow markings and a pair of very narrow, central, yellow vittae that end on the apical 1/4 of the tergite and join the middle of the baso-lateral triangular markings; pile short, black and appressed; sternite 3 dark brown, pile short, black and appressed. Tergite 4 sub-quadrate, central vittae join baso-lateral triangular markings at their base, remaining characteristics as on segment 3. Tergite 5 rectangular short, wider than long, with a pair of central yellow vittae and two sub-lateral, basal, vittate spots; remaining characteristics as on 4. Genitalia ( Figs 5f– i ). Cerci with 4 rows of pile but with more pile concentrated dorso-medially. Surstylus oval and elongated, in lateral and ventral views, dorsally pilose except on apex, with ventral setulae on apex, lateral margin and a few sparse medially; subepandrial sclerite quadrate, apical quadrate indentation very short, with a pair of distinct concave indentations baso-medially, baso-lateral extensions distinct. Hypandrium quadrate, ventral notch extending on apical 2/3, with slightly concave basal margin, and with medial-lateral indentations extending dorsally and not so sharp; phallapodeme unsclerotized on basal 1/4; basiphallus drop-shaped and smoothly tapering on basal 1/2, in ventral view, and distiphallus slightly undulated, in lateral view, base slightly extending laterally but not joining ventrally, anterior sclerotized surface tapering apically, with wider membranous area on apex, ventral surface completely membranous; postgonite large, with anterior margin almost straight, apico-ventral extremity as a long acute projection; apico-dorsal extremity as a small and short acute projection, with pile on basal 4/5 of the ventral margin.

FEMALE ( Figs 5b–d & j–m ). Like male except for the following characters: Face with distinct medial, wide (1/3 of the width of the face), dark brown vitta. Frons with central wide dark brown vitta, which might expand apico-laterally, pile absent medially, dark areas covered with pale microtrichosity, differently oriented medially. Ocellar triangle separated by twice its length from the posterior margin of the head, and from the eye margin by 1– 2 times an ocellus-width. Vertex covered in white microtrichosity, differently oriented medially posterior to ocellar triangle, and absent on ocellar triangle, which is dull black. Scutum with very short black pile. Scutellum without longer pile; subscutellar fringe absent or with inconspicuous black pile. Plumula distinctly short. Wing may be lighter with wider pale areas. Pro- and mesofemora brown dorsally; most of the metafemur might be dark brown. Metabasitarsomere slightly longer than 1/2 the length of the metatibia. Abdomen between 2.5–3 times longer than thorax. Tergite 1 with shorter, appressed and mostly black pile; sternite 1 with very short pile. Tergite 2 4.5 times longer than smallest width, and without erect pile; sternite 2 mostly brown. Tergite 3 slightly shorter than apical width. Tergite 4 sub-lateral markings more elongated. Tergite 5 with four complete vittae. Tergite 6 is 1/3 of the length of 5 and without any visible pattern. Genitalia ( Figs 5j–m ). Tergite 7 as four sclerotized strips, the lateral ones joining basally to the medial ones, pilose on apical 1/2 and apico-lateral 2/3 and with a few longer pile apically; sternite 7 mostly membranous, with sclerotized spots around pile insertions, wholly pilose. Eight tergite as a basal sclerotized fascia with medial extension ending as a triangular apex, base concave, pilose on apical 1/2, with a few longer pile apically; sternite 8 with long, narrow, lateral sclerotizations that connect as a fascia basally, wholly pilose, with a few longer pile on a medial transverse row. Epiproct as pair of narrow, sclerotized, short strips, pilose, with apodeme longer than the epiproct; hypoproct triangular and membranous, pilose. Cerci membranous, pilose, positioned apically and on a slightly perpendicular plane to the epiproct. Spermathecae not observed.

Variation. MALE. Pleuron might have wider pale areas. The type of B. nectarina does not have the central vittae on abdominal tergite 3. FEMALE. Face dark vitta might be much lighter but still distinct from the lateral pale area; lateral yellow areas of frons might be very reduced (e.g. USNMENT01288171); specimens with lighter facial vitta have black pile on the dorsal occiput. Notopleuron and postalar callus might be more distinctly pale; pleuron with more extensive dark areas (e.g. USNMENT01288171). Basal 1/4 of the profemur might be brown (i.e. DZUP048291). Abdominal tergite 2 may range until 5.5 times longer than smallest width.

Length. Body: male 14.1–18mm (n = 7), female 13.3–16.4mm (n = 11); wing: male 12.6–14.1mm, female 11.9–14.4mm.

Distribution. Argentina (Misiones), Brazil (Minas Gerais, Paraná, Santa Catarina), Colombia (Antioquia, Boyaca, Quindio, Risaralda), Paraguay (Cordillera, Guairá), Peru (Junín).

Comments. The holotype of Baccha obsoleta is in poor conditions, with broken wings, and head and abdomen glued on the specimen, but the observable characters were the same as those of B. nectarina , noticeably the large dark triangular marking on the frontal triangle. The central vittae of abdominal tergite 3 seem to be absent on B. nectarina , however, due to the very narrow nature of these markings, it is assumed that this is an intraspecific variation, since the extension of pale markings in Syrphidae is known to vary, as was reported, for example, in Eupeodes (Metasyrphus) Matsumura and Episyrphus balteatus ( De Geer, 1776) ( Dušek & Láska 1974; Holloway et al. 1997). Furthermore, it is common for internal tissues to obscure patterns in pinned specimens. Thus, B. nectarina is hereby synonymized under H. obsoletus . Baccha myrtella was mentioned as related to B. nectarina in Hull (1960) , and since the holotype of B. myrtella fits the above redescription, it is also synonymized under H. obsoletus .

The sex association for this species was based on the size of the dark areas of the frons/frontal triangle. The male types with large dark triangular areas on the frontal triangle were assumed to be conspecific with the female specimens who shared a similar pattern, i.e., with a wide dark central area on the frons. Furthermore, the males have a slight medial darkening on the face, which on some females would be present as a very distinct dark medial vitta (e.g. DZUP048291).

Besides the external morphological characters, H. obsoletus differs from H. phaeopterus by the characteristics of the male sub-epandrial sclerite, hypandrium and phallus, and the female differently shaped tergite 8 and epiproct.

Examined material. ARGENTINA. Misiones, Alto Paraná river, 18–23.i.1920, leg. Schrottky (CNC_ Diptera 188771) [1 ♀, CNC]. BRAZIL. Paraná, Ponta Grossa, Vila Velha-IAPAR, 18.iii.2002, leg. Ganho & Marinoni (DZUP048291) [1 ♀, DZUP]. Minas Gerais, Pouso Alegre, i.1946, leg. P. Pereira (JSS32813) [1 ♀, CNC]. Santa Catarina, Nova Teutônia [Seara], xii– ii.1938 |1948|1960|1965|1967, leg. F. Plaumann (CNC_ Diptera 178723, JSS32984–6, USNM01288170–1) [3 ♀ & 1 ♂, CNC, 2 ♀ USNM]. COLOMBIA. Antioquia, Bello, Las Baldias, 16.viii.2015, leg. A.L. Montoya (CEUA92920) [1 ♀, CEUA, only studied from photopgraphs]; Fredonia, Vereda La Toscana, 16.x.2009, leg. C. Bota (CEUA47315) [1 ♀, CEUA, only studied from photopgraphs]. Boyaca, Muzo, 1936, leg. J. Bequaert (JSS32807) [1 ♂, CNC]. Quindio, Filandia, Granja Experimental Bengala, 13.xi.2009, leg. A.L. Montoya (CEUA47490) [1 ♀, CEUA, only studied from photographs]. Risaralda, Pereira, Santuario de Flora y Fauna Otún Quimbaya, 7–8.v.2001, 05.viii.2001, leg. Grupo de Entomologia Universidad de Antioquia (CEUA27949 & 47316) [2 ♀, CEUA, only studied from photographs]. PARAGUAY. Cordillera, Fiebrig [1 ♂ holotype Baccha obsoleta , AMNH]. Guaíra, Villarica, iii, leg. F. Schade (MCZ type 26152) [1 ♂ holotype Baccha nectarina , MCZ]. PERU. Junin, Chanchamayo, 7.v.1948, leg. J. Schunke (CNC_ Diptera 188770) [1 ♂ holotype Baccha myrtella , CNC].

Figures

FIGURE 5. Hybobathus obsoletus (Curran, 1941) comb. nov. a. Male, Baccha nectarina holotype, habitus, dorsal [copyright President and Fellows of Harvard College (MCZ)]. b. Female, abdomen, dorsal. c. Female, head, frontal. d. Female, head, dorsal. e. Male, Baccha obsoleta holotype, head, oblique dorsal (photo courtesy AMNH). f – i. Male genitalia: f. Epandrium, lateral. g. Epandrium, ventral. h. Hypandrium, lateral. i. Hypandrium, ventral. j – m. Female genitalia: j. Dorsal. k. Apex, dorsal. l. Ventral. m. Lateral. bph: Basiphallus, cerc: Cercus, drk: Dark marking on the face, ep: Epiproct, ind: Ventro-lateral indentation of the hypandrium, pgt: Postgonite, sscl: Subepandrial sclerite, s 2: abdominal segment 2, srs: Surstylus.