Eosphaerophoria Frey, 1946

Mengual, Ximo & Ghorpadé, Kumar, 2010, The flower fly genus Eosphaerophoria Frey (Diptera, Syrphidae), ZooKeys 33 (33), pp. 39-80 : 42-44

Genus Eosphaerophoria Frey

Eosphaerophoria Frey, 1946: 169 . Type-species, marginata Frey (original designation). Vockeroth 1969: 134, map 26 (distribution), Figs 11 (wing), 89 (male genitalia) (key reference, description, distribution); Knutson et al. 1975: 313 (catalog citation); Thompson and Vockeroth 1989: 443 (catalog citation); Ghorpadé 1994: 3, 5 (citation, key); Mengual et al. 2009: 7, 8, 23 (citation, morphological characters, phylogenetic analysis).

Tambavanna Keiser, 1958: 202 . Type-species, dentiscutellata Keiser (original designation). Synonymy by Vockeroth (1969: 134).

Description (adapted from Vockeroth 1969: 134). Small slender species with male narrowly dichoptic, mesonotum bright yellow laterally, scutellum usually subacute or acute apically, abdomen of male very slightly petiolate, abdomen of female slightly broadened from base to near apex. Length from 4.9 mm to 6.8 mm.

Head. Eye bare. Face slightly broadened below, yellow, with or without medial black vitta, with a tubercle small but well defined, rather compressed in male. Antenna short, less than head width; scape about as broad as long; pedicel broader than long; basoflagellomere oval to slightly elongate, not more than 1.3 times as long as broad; arista dorsobasal, bare. Frons of male very narrow, at antenna about 1/5 head width, narrowed to 1/8 to 1/10 head width a little below anterior ocellus, then very slightly broadened to vertex; frons of female broader, narrowed gradually to posterior ocellus, then parallel-sided to vertex. Ocellar triangle, especially in male, well before posteromedian angle of eye; anterior ocellus separated from eye by much less than its diameter.

Thorax. Scutum black, with postpronotum, broad presutural stripe (notopleuron) and narrower postsutural stripe yellow; black dorsomedial area usually with opaque margin and shining or sub-shining centre. Postpronotum bare. Notopleuron with posterolateral angle sometimes produced postero-laterad into a strong blunt tubercle which extends distinctly caudad of suture (Fig. 28). Scutellum with basal black triangle and yellow margin, subtriangular in outline with apex bluntly rounded, subacute, or produced into a short, acute, sometimes upcurved tubercle. Subscutellar fringe very short and present only laterally or entirely absent. Pleura yellow (propleuron, anepisternum, anepimeron, katepimeron and katatergum), except katepisternum black with a dorsal yellow macula and meron black. Thoracic pile extremely short and sparse. Katepisternum with dorsal and ventral pile patches broadly separated, the pile in the dorsal patch extremely short or absent, scarcely distinguishable. Metasternum bare. Legs. Simple; metafemur near apex sometimes with a ventral row of short strong black spine-like setae. Wing. Vein M 2 short, perpendicular or nearly so to M 1; vein M 1 (apical crossvein) straight or slightly sinuate, meeting R 4+5 at approximately a right angle at more than half its own length from wing base (see Figs 22 and 23); posterior margin without black sclerotized puncta. Alula narrow, narrower than cell BM, anal lobe greatly reduced. Wing partially bare basomedially: 2nd costal cell bare; cells R 1, R 2+3, R 4+5, DM, CuA 1 and CuP bare basally; cells BM and R bare; anal lobe sparsely microtrichose distally; alula usually microtrichose (see Fig. 22). The proportion bare on each cell can vary slightly between species.

Abdomen. Abdominal pattern variable; terga without marginal sulcus; in male very slender and slightly to rather strongly narrowed on segments 2 and 3, 2nd abdominal tergum narrower than thorax; in female broader, narrowest near base of segment 2. Male genitalia. Usually large reaching the posterior margin of 4th sternum; typical syrphine form; cercus elongate oval; surstylus elongate, broad basally; lingula absent; aedeagus two-segmented, with apical segment flared apically; superior lobe variable, articulated with aedeagal base and with lateral surface covered with short black blunt bristles.

Etymology. Eosphaerophoria is derived from the prefix “ eos ”, from the Greek (heos), meaning “east, eastern, oriental” ( Brown 1956: 303) and the name Sphaerophoria . Thus Eosphaerophoria means eastern or oriental Sphaerophoria , clearly referring to the similar adult habitus in both genera. On the other hand, Sphaerophoria is a combination of “ sphaera ”, from the Greek (sphaira), meaning “ball, globular, sphere” ( Brown 1956: 736) and “ phoras ”, from the Greek (phero), meaning “bearing, carrying” ( Brown 1956: 604). Accordingly, Sphaerophoria adduces to the globular, spherical male genitalia of most of the species of this genus ( Vockeroth 1969; Knutson 1973). Eosphaerophoria species also have large rounded male genitalia.

Frey (1946) did not establish the gender of his new genus, Eosphaerophoria , nor Keiser (1958) for Tambavanna , but both authors used a feminine form for species epithet ( marginata and dentiscutellata respectively). According to the article 30.2.3 of the International Code of Zoological Nomenclature (ICZN 1999), and in agreement with the article 30.2.4, Eosphaerophoria must therefore treated as feminine, and new species names follow this gender.

Biology. Nothing is known of the biology of these flies. Keiser (1958: 204) merely stated that he collected his specimen in grass in a swampy locality. No other biological details have been published about Eosphaerophoria .

Distribution. Eosphaerophoria is only found in Oriental (Indomalayan) and Australasian biotic regions (see Fig. 21). Specimens from Nepal, Sri Lanka, Thailand, Malaysia, Vietnam, Indonesia, Philippines, and Papua New Guinea have been reported (see below in each species description).

Diagnosis. As mentioned above, the genus Eosphaerophoria is recognized among the syrphines (subfamily Syrphinae , tribe Syrphini ) by this combination of characters: 1) nearly vertical apical vein M 1 (see Figs 22 and 23); 2) subtriangular scutellum; 3) male narrowly dichoptic; 4) slightly narrowed abdominal base in males; and 5) reduced alula and anal lobe.

Vockeroth (1969) considered this genus the most aberrant of the Syrphini based on the presence of uncommon morphological characters, such as wing venation and dichoptic males (see figs 26 and 27), but noting also the asymmetry of the superior lobes of the male genitalia. This character cannot be considered diagnostic because there are species with symmetrical superior lobes too, as pointed out by Vockeroth (1969) (see Figs 44 , 45 , 47 and 49 ).

No closely related taxa have been previously proposed. Mengual et al. (2008a) analysed the current tribal classification of the subfamily Syrphidae , but Eosphaerophoria was not included due to the absence of suitable material for DNA extraction. Mengual et al. (2009) in their cladistic analysis of Allograpta using morphological characters, included representatives of Episyrphus , Meliscaeva , Anu , Citrogramma , Exallandra , Giluwea , Sphaerophoria and Eosphaerophoria based on adult morphological similarity. Eosphaerophoria was resolved in a polytomy with the Allograpta subgenera Antillus , Allograpta , Costarica and Rhinoprosopa in the strict consensus tree. Consequently, its phylogenetic position remains incognito but if the overall morphological similarity with Sphaerophoria is taken under consideration, the genus might be a member of the Allograpta-Sphaerophoria clade recovered by Mengual et al. (2008a, 2008b). Thus we include a generic key for Eosphaerophoria and related genera here below.

Ghorpadé (1994: 5) placed together Rhinobaccha de Meijere, 1908 and Eosphaerophoria in couplet 13 of his identification key. Although Rhinobaccha was not included in previous molecular or morphological analyses and its relationships with other genera are unclear, we decided to include this genus in the following key.

Figures

Figure 44. Eosphaerophoria bifida, male genitalia: a left lateral view b right superior lobe, dorsal view c tergite 9, cerci and surstyli, dorsal view.

Figure 45. Eosphaerophoria brunettii, male genitalia a left lateral view b right superior lobe, dorsal view c tergite 9, cerci and surstyli, dorsal view.

Figure 47. Eosphaerophoria luteofasciata, male genitalia a left lateral view b right basal appendix of aedeagus c right superior lobe, dorsal view d tergite 9, cerci and surstyli, dorsal view.

Figure 49. Eosphaerophoria symmetrica, male genitalia a left lateral view b right superior lobe, dorsal view c tergite 9, cerci and surstyli, dorsal view.