Pelecinobaccha summa ( Fluke, 1936 )

Miranda, Gil Felipe Gonçalves, 2017, Revision of the Hybobathus arx and Pelecinobaccha summa species groups (Diptera: Syrphidae), Zootaxa 4338 (1), pp. 1-43 : 35-39

Pelecinobaccha summa ( Fluke, 1936)

Fig. 11

Baccha summa Fluke, 1936: 59 . Type locality: Brazil, Rio de Janeiro, Guanabara. Holotype male (AMNH). Curran, 1941: 263 (key); Hull, 1949: 95 (citation), 117 (key), 215 (fig. 113, abdomen), 276 (fig. 368, wing); Fluke, 1956: 264 (catalog citation).

Ocyptamus summus . Thompson et al., 1976: 28 (catalog citation).

Pelecinobaccha summa . Miranda et al., 2014: 12 (species list), 13 (key), 102 (fig. 2i, dorsal habitus of holotype).

Baccha susio Hull, 1941: 61 . Type locality: Brazil, São Paulo, Avanhandava. Holotype female (CNC). Hull, 1949: 95 (citation), 112 (key), 171 (redescription), 221 (fig. 138, abdomen); Fluke, 1956: 264 (catalog citation). syn. nov.

Ocyptamus susio . Thompson et al., 1976: 28 (catalog citation).

Pelecinobaccha susio . Miranda et al., 2014: 72 (redescription).

Baccha ada Curran, 1941: 278 . Type locality: Brazil, Santa Catarina, Nova Teutônia. Holotype male (AMNH). Hull, 1949: 95 (citation), 112 (key), 135 (redescription), 195 (fig. 20, female abdomen), 217 (fig. 116, male abdomen); Fluke, 1956: 235 (catalog citation); Miranda et al., 2014: 72 (junior synonym of P. susio ).

Ocyptamus ada . Thompson et al., 1976: 12 (catalog citation).

Redescription. MALE ( Figs 11a, c, e–g & i–n ). Head ( Fig. 11i ). Dark brown. Face pale on lateral 1/3, covered with white microtrichosity, with white pile except black dorso-laterally, bare medially. Gena with white pile. Lunule light brown around and above the central black marking, and marking connected to the frontal triangle color by a brown central vitta. Frontal triangle pale laterally until eye contiguity, homogenously covered with sparse white microtrichia and with a small dorso-lateral region of more concentrated microtrichia visible only from a dorso-posterior view. Only frontal prominence protuberant. Vertical triangle homogeneously covered by white microtrichia, with most of its pile restricted to a single row ending behind anterior ocellus; ocellar triangle separated by 1.5 times its length from the posterior margin of the head. Eye contiguity as long as vertical triangle length. Eye with sub-triangular indentation on posterior margin positioned slightly dorsal to antennal insertion. Antennal insertions confluent, ventral sclerotized margin slightly extended dorsally. Antenna light brown, with black pile; postpedicel oval. Occiput homogenously covered with white microtrichosity and dorsal portion with slight brown tones, dorsal 1/4 with 2 rows of simple black pile, anterior row shorter, ventral 3/4 with 2–3 rows of white, flattened pile, anterior rows slightly shorter. Thorax ( Figs 11a, c, e & f ). Scutum dark brown, pale on notopleuron, slightly dorsal to wing base, and on postalar callus, with a pair of golden microtrichose sub-median vittae tapering posteriorly and not reaching scutellum, a short median narrow golden microtrichose vitta on the posterior 1/2, and between the central and sub-median vittae there is another pair of white microtrichose vittae that are 2/3 the length of the golden pair, the rest of the scutum is covered by a dull pale sparse microtrichosity; with black pile, except white and longer laterally from the postpronotum to the notopleuron and on anterior row interrupted in the middle. Scutellum yellow and with a slightly darker median fascia, pile black and very short, slightly longer on base and laterally; subscutellar fringe with long white pile. Pleuron dark brown, pale on posterior 1/3 of the posterior anepisternum, dorso-posterior portion of katepisternum and slightly medially on the katatergite; with pale pile on anterior anepisternum, posterior 1/2 of posterior anepisternum, on separate dorsal and ventral patches on katepisternum, anterior anepimeron, katepimeron, and metaepisternum, with very short pile on proepimeron, katatergum with long microtrichia giving it a ‘velvet’ appearance. Plumula white. Calypter pale, margin of ventral lobe with long pile, margin of dorsal lobe with short pile. Halter yellow, capitulum orange. Wing. Light brown, darker on cells c, sc, and most of r1; entirely microtrichose; alula light brown, convex, basally 2 times and apically 3 times as broad as c cell, entirely microtrichose. Legs ( Fig. 11g ). Proleg light brown, profemur darker, protibia paler except for slight darkening sub-apically, pile black except pale dorsally on protibia and protarsus. Mesoleg light brown, mesofemur darker, mesotibia mostly pale except for a slight darkening subapically, pile black, longer on posterior row of the mesofemur, and pale dorsally on mesotarsus, Metaleg dark brown, pale on base and apex of metafemur, base and apex of metatibia and whole metatarsus. Abdomen ( Fig. 11a ). Dark brown, 3 times as long as thorax. Tergite 1 mostly black pilose but pile longer and white baso-laterally, bare medially; sternite 1 light brown, with erect white pile. Tergite 2 long, 3.8 times its minimum width, with slight pale markings central-laterally, with subapical central triangular region of dull brown microtrichosity, with black appressed pile, much shorter dorsally; sternite 2 brown with black appressed pile. Tergite 3 trapezoidal and long, 1.2 longer than apical margin and apical margin 2.2 times the width of the basal margin, with baso-lateral pale triangular markings and central pair of pale short vittae; with large central triangular region of dull brown microtrichosity, and with black appressed pile; sternite 3 with pair of quadrangular central markings of dull brown microtrichosity, and with black appressed pile. Tergite 4 sub-quadrate, slightly longer than wide, central spots longer and reach the baso-lateral triangular markings, remaining characteristics as on 3; sternite 4 with sub-apical fascia of dull brown microtrichosity. Tergite 5 rectangular, wider than long, with faint central vittae that connect to baso-lateral fasciate markings; remaining characteristics as on 3. Genitalia ( Figs 11j–n ). Cercus with a regular row of pile on medial margin and two regular rows on lateral margin. Surstylus directed apicoventrally, short, with rounded apex, dorso-medial 1/4 as thin lamina, with weak setulae (around 8) on apicoventral margin and row with sparse setulae medially (at margin of lamina), pilose on dorsal surface. Subepandrial sclerite quadrate, more sclerotized laterally, with shallow medial concavity on apical margin. Hypandrium with ventral notch extending on anterior 1/2 and with straight basal margin. Basiphallus with short and acute posterior projection. Distiphallus with anterior surface tapering and curved anteriorly on apex, and with baso-lateral extensions that meet ventrally (forming a tube), ventro-apical membranous area with microtrichia. Phallapodeme well sclerotized and slightly enlarged on base. Ventral surface of postgonite straight, dorsal surface slightly concave with small convexity before apex; postgonite apex slightly convex anteriorly, with small rounded ventral extremity and acute dorsal extremity, with pile mainly on ventral surface.

FEMALE ( Figs 11b, d, h & o–q ). Like male except for the following characters: Pale area of lunule might be yellow. Frons pale laterally, with pale area ending anterior to the ocellar triangle, with sparse microtrichosity oriented differently only in front of the ocellar triangle and white lateral microtrichia with no patch of differently oriented microtrichia; vertex with shorter pile; ocellar triangle twice its length from posterior eye margin and an ocellus-width from lateral eye margin, pile shorter posterior to ocellar triangle. Scutum pale laterally, sometimes with a few black pile anterior to transverse suture on notopleuron; subscutellar fringe pile very short and black to inconspicuous. Wing darker on r and base of r2+3. Apical pro- and mesotarsomeres might be darker; base of metabasitarsomere dark. Tergite 1 paler; sternite 1 with much shorter pile. Abdominal tergite 2 shorter than on male, 2.5 times minimum width, with smaller dull microtrichose region, and lateral pile much shorter than on male. Tergite 3 shorter than on male; sternite 3 with sub-apical fascia of dull brown microtrichosity. Tergite 4 rectangular and wide. Segment 6 conical, divided into separate tergite and sternite inconspicuously on most of its extension but distinctly fused at apex, as long as basal margin and 1.3 times as long as 5. Genitalia ( Figs 11o–q ). Tergite 7 triangular, with acute apex, with basal apodeme extending for 2/3 of the length of segment 6; segment 7 lateral sclerite rectangular, slightly tapering towards apex; segment 7 mostly membranous, with sparse sclerotized areas, and pilose, except bare on a small baso-medial area. Tergite 8 unsclerotized medially appearing as a pair of separate sclerites, basal crest weakly sclerotized and uniform, without extended ridges; sternite 8 as a pair of rectangular sclerotized plates with a short apical projection, the projection folding inward when the segment is at rest, and a pair of baso-medial rounded projections, pilose on membranous area. Epiproct as pair of separate sclerites fused to dorsal margin of cerci. Cercus with a row of pile on apical margin.

Length. Body: male 12.4–15.4mm (n = 20), female 8.5–14.7mm (n = 19); wing: male 10.3–11.6mm, female 8.0– 12.6mm.

Variation. MALE. Face might have only lateral 1/4 pale; pale area of lunule might be distinctly yellow; antennal insertions might seem slightly separate (e.g. DZUP 051484); scape and pedicel might be paler; dorsal occiput pile varies from a mixture of black and white to wholly white pile (e.g. DZUP044079). Whole lateral side of the scutum might be paler; there might be some pale pile laterally between the transverse suture and the postalar callus; subscutellar fringe might have some black pile medially. Darker regions of the wing can also reach the basal 1/2 of the r cell . Metabasitarsomere might have only apical 2/3 to 3/4 pale and metatarsomere 5 might be light brown. Abdominal tergite 1 might have more white pile (e.g. DZUP 051484); tergite 2 might have baso-lateral 1/3 pale; sternite 3 microtrichose markings might join medially; vittate markings of the abdominal tergites might be more or less distinct and connect to baso-lateral markings or not. FEMALE. Lateral pale area of the frons might be distanced equal to or shorter than the length of the ocellar triangle; vertex with pile the same length as the male; ocellar triangle might be distanced until 2.5 times its length from posterior eye margin and 1.3 times an ocelluswidth from lateral eye margin; dorsal occipital pile may fade to a pale yellow. Metabasitarsomere might have until basal 2/3 dark and metatarsomere 5 might be light brown. Abdominal tergite 2 might be until 3 times longer than minimum width. Tergite 7 apex not well defined and merging into membrane (e.g. USNMENT01288149); segment 7 lateral sclerite baso-ventral apodeme might be slightly longer (i.e. DZUP45471); segment 7 might be sclerotized ventrally and with apical triangular indentation; tergite 8 with sclerotized sub-apical bridge between the pair of sclerites (e.g. DZUP45471), or more sclerotized medially (i.e. USNMENT01288148).

Distribution. Brazil (Distrito Federal, Mato Grosso do Sul, Paraná, Rio de Janeiro, Santa Catarina, São Paulo).

Comments. Comments on B. ada and B. susio synonymy can be found in Miranda et al. (2014). Hull (1949) separated B. summa (only male) and B. susio (only female), in the step that separates males from females (couplet 65, p. 109), ending by contrasting B. summa to B. ada (couplet 126, p. 116), with most characters used reflecting simple intraspecific variation in extensions of dark and pale on the body (e.g. central vittae of B. ada that are supposed to connect to basal marking but are only slightly connected in tergite 3 of the holotype, furthermore in the holotype of B. summa the tergite 3 vittae join the basal markings as a subshining area in a very similar fashion as on the holotype of B. ada ). The characters on couplet 126 regarding the metabasitarsomere (presence or not of dorsal black pile) and the dorsal occiput (black or white pile) were observed in the specimens currently studied, but were noted as intraspecific variations (see above) since the genitalia did not show any further differences between them. The differences Curran (1941) used in his key (couplet 76, p. 263), where B. ada and B. summa diverge, were based on the level of contrast of the metabasitarsomere with the remaining metatarsomeres, which have already been shown to vary in the redescription above. Neither Curran nor Hull further tried to distinguish B. summa from B. ada and B. susio . Thus, since the variations observed were not further supported by either genitalia or distribution records, and B. summa being the oldest name available (article 23 of the International Code of Zoological Nomenclature-ICZN), B. ada and B. susio are hereby considered junior synonyms of B. summa .

A male (GFGM-MNRJ0001) from Distrito Federal, Brazil (northernmost record for this species), seemed to lack markings on the abdomen, but this was considered an artefact of preservation. Furthermore, the specimen just seemed to be more sclerotized in some structures. However, other diverging characters were found: Ocellar triangle separated by its length from the posterior margin of the head, subscutellar fringe with mostly black pile (very few white pile), subepandrial sclerite more sclerotized apically and postgonite with a slightly convex ventral margin and a more acute antero-ventral extremity. I refrained from naming it a separate species until more specimens are found with these characteristics to ascertain these were not just atavisms of this one specimen.

There were females with a few differences on the genitalia (i.e. shape of tergite 7, segment 7 sclerotized ventrally and more sclerotized tergite 8) but even distinct characters such as the extent of the dark on the metabasitarsomere did not separate them clearly (e.g. DZUP45471, with a mostly pale metabasitarsomere, and USNMENT0128148, with basal 2/3 dark on the metabasitarsomere, both have a tergite 7 with well defined apex, ventrally sclerotized segment 7, and a sub-apical bridge on tergite 8).

Examined material. BRAZIL. Distrito Federal, Açude da solidão, 8.i.1957, leg. N. Santos (GFGM- MNRJ0001) [1 ♂, MNRJ]. Mato Grosso, Maracajú, v.1937 (CNC_ Diptera 161392) [1 ♀, CNC]. Paraná, Foz do Iguaçu, 16.xii.1965 | 11.xii.1966 | 18.ii.1969, leg. Exc. Dept. Zoo|Moure & Mielke|V. Graf & L. Azevedo (DZUP045471, 0 51484, 051643) [1 ♀ & 2 ♂, DZUP]; [Foz do Iguaçu], xii.1941, F. Plaumann|E.N.V. (CNC_ Diptera 161393, 190658) [1 ♀ & 1 ♂, CNC]; Jundiaí do Sul, Fazenda Monte Verde, 7.iii.1988, leg. Lev. Ent. PROFAUPAR (DZUP044079) [1 ♂, DZUP]; Ponta Grossa, Vila Velha-IAPAR, 6.ix.1999, leg. Ganho & Marinoni (DZUP 041717) [1 ♀, DZUP]; Prudentópolis, 1.xii.1968, leg. Moure & Dressler (DZUP045483) [1 ♂, DZUP]. Rio de Janeiro, Jardim Botânico, viii.1934, leg. M.S. Lopes (GFGM-MNRJ0005–6, 0011) [3 ♂, MNRJ]; Guanabara [1 ♀ holotype Baccha summa , AMNH]. Santa Catarina, Nova Teutônia [Seara], x–iii, leg. F. Plaumann (CNC_ Diptera 161384–91, 161394–401, 225251, USNMENT01288146–7, 01288148–9, 01288151–2) [1 ♂ holotype Baccha ada , AMNH, 10 ♀ & 7♂, CNC, 4 ♀ & 2♂, USNM]. São Paulo, S. Avanhadava, 28.iv.1908 (CNC_ Diptera 203526) [1 ♀ holotype Baccha susio , CNC].

Figures

FIGURE 11. Pelecinobaccha summa (Fluke, 1936). a. Male, holotype, habitus, dorsal (photo courtesy AMNH). b. Female, habitus, dorsal. c. Male, Thorax, oblique dorsal. d. Female, detail of dorsal occiput, oblique dorsal. e – f. Male, scutellum, posterior. g – h. Metatarsus, dorsal: g. Male. h. Female. i. Male, head, frontal. j – n. Male genitalia: j. Hypandrium, ventral. k. Hypandrium, lateral. l. Postgonite, lateral. m. Epandrium, lateral. n. Epandrium, ventral. o. Female, abdominal segment 6 and genitalia, dorsal. p. Female, abdominal segment 7, lateral. q. Female, abdominal segment 8 and proctiger, lateral. bph: Basiphallus, crc: Cercus, ep: Epiproct, lscl: abdominal segment 7 lateral sclerite, mtb: Metabasitarsomere, oc: Occiput, pgt: Postgonite, sscl: Subepandrial sclerite, sct: Scutellum, srs: Surstylus.