Lobomyia, Woodley, Norman E. & Arnaud, Paul H., 2008

Woodley, Norman E. & Arnaud, Paul H., 2008, Lobomyia neotropica, a new genus and species of Tachinidae (Diptera) from the Neotropical Region, Zootaxa 1783, pp. 31-39 : 32-35

Lobomyia gen. nov.

( Figs. 1–6 )

Type species. Lobomyia neotropica Woodley & Arnaud , by present designation.

Diagnosis. The combination of the following character states will diagnose Lobomyia : body with pale tomentose areas golden yellow (flies appearing metallic green in life); eyes sparsely to moderately haired; facial ridge mostly bare with only 2–5 small setae above vibrissa; lower facial margin produced, visible in profile, extending beyond vibrissal bases; ocellar setae well-developed, proclinate; parafacial bare; genal dilation with pale hairs except for a few anteroventral major setae that are black; postpronotum with three setae nearly in a line, the middle seta only slightly displaced anteriorly; katepimeron bare; prosternum and much of pleura with white to pale yellow hairs; first postsutural supra-alar seta as long and stout as first postsutural dorsocentral seta; hind margin of hind coxa bare; at least mid and hind femora mostly yellow, usually all femora are yellow.

Lobomyia is most likely to be confused with Chrysoexorista Townsend , as individuals of this genus are also metallic green in life. However, Chrysoexorista species have more obviously pubescent eyes, the lower facial margin not protruding beyond the vibrissal bases, dark hairs on the prosternum and pleura, and dark femora.

Description. Coloration with tomentose areas metallic green in life, fading to dull golden-yellow upon drying.

Head ( Figs. 1, 2 ). Eye sparsely to moderately haired; facial ridge slightly arcuate anteriorly in medial region, bare on most of its length, only 2–5 setae or hairs above vibrissa; lower facial margin produced, visible in front of vibrissal angle in lateral view; parafacial narrower than first antennal flagellomere, bare except for one or two small hairs below lowest frontal seta; gena well developed, about 1/5 of head height, with welldeveloped dilation; 3–6 setae in frontal row, only two arising below antennal bases, all inclinate or reclinate, posterior-most often reduced; female with two proclinate orbital setae, the posterior one reduced, about ½ length of anterior; ocellar setae well developed, proclinate; outer vertical seta hairlike in male, essentially not differentiated from postocular setae, larger in female, but much smaller than inner vertical seta; male with base of the first flagellomere lobed in the type species ( Fig. 1 ), unmodified in other known species; arista with first two segments very short, third segment slightly thickened on basal 2/5; female antenna with first flagellomere shorter, not reaching oral margin, and without projecting lobe in all known species; palpus slen- der, nearly cylindrical.

Thorax. Postpronotum with three major setae in nearly a straight line, the angle formed by the slightly anteriorly placed middle seta with inner and outer setae greater than 160E; notopleuron with 2 large setae; acrostical and dorsocentral setae 3+3; first postsutural supra-alar seta as long and stout as first postsutural dorsocentral seta; scutellum with apical setae minute ( Fig. 3 ), usually crossed apically but occasionally not crossed or absent, three other pairs of marginal setae well developed, one smaller pair of discal setae; proepisternum bare; prosternum setose with white hairs; katepisternum with 3 setae (sometimes 2, with anteroventral seta absent), the anteroventral seta arising close to the anterior one ( Figs. 1, 2 ); katepimeron bare; infrasquamal region bare; femora yellow; midtibia with one anterodorsal seta near middle and one smaller anteroventral seta slightly distal to it; hind tibia with anterodorsal setae forming a fairly evenly spaced row but the setae not closely spaced, with a single enlarged, medial seta; hind coxa bare posteriorly; bifurcation of vein R2+3 with 2–4 small setae; M ending at wing margin separately from R4+5; bend in M slightly obtuse.

Abdomen ( Fig. 3 ). Median dorsal depression of tergite 1+2 extending to posterior margin, with one pair of median marginal setae; tergite 3 with one closely spaced pair of median marginal setae and no discal setae; tergite 4 with even row of marginal setae and no discal setae; tergite 5 with an even row of both discal and marginal setae.

Etymology. The generic name refers to the lobe at the base of the antennal flagellum in males of L. neotropica and is considered feminine in gender.

Remarks. Lobomyia belongs to the Exoristinae but does not show obvious affinities with any genus of Exoristinae with a strong first postsutural supra-alar seta. Eggs dissected from a wild-caught female (Nova Teutonia, Brazil) are about 0.30 mm x 0.15 mm in size, yellowish, ovoid, without a strongly sclerotized chorion (as indicated by being somewhat collapsed when observed). Microtype eggs from a specimen of Chrysoexorista Townsend , on the other hand, were found to be 0.20 mm x 0.10 mm, yellowish, and more strongly sclerotized. Also, no female specimen of Lobomyia was found with the abdomen appearing completely inflated by eggs, as is sometimes found in females bearing microtype eggs. Thus, the apparent presence of non-microtype eggs in Lobomyia indicates that the genus should possibly be placed in the tribe Eryciini. Behavioral observations are needed to confirm this beyond doubt. Lobomyia is not very similar to Chrysoexorista Townsend or other genera of Exoristinae that are metallic green in life, as these taxa all have more strongly developed apical scutellar setae and dark legs. Whether or not this metallic coloration has evolved multiple times in the Exoristinae will be determined only by more extensive phylogenetic study of the subfamily.

We have surveyed the extensive holdings of type material of Neotropical tachinids in USNM, a collection which contains the vast majority of types of C.H.T. Townsend, a prolific worker on the Neotropical fauna who described many of the genera found there. We did not find any specimens resembling Lobomyia neotropica , and therefore feel confident that Lobomyia is a generic-level taxon that is undescribed.

We are aware of two or three additional species that share all of the character states found in Lobomyia , except the expanded base of flagellomere one in males. We believe that these are congeneric. Given the vast Neotropical fauna of Tachinidae that is undescribed, it is likely that additional species will be discovered.

Figures

FIGURE 3. Lobomyia neotropica, gen. nov., sp. nov., dorsal view of female showing scutellar setation and abdominal color pattern.

FIGURES 1 – 2. Lobomyia neotropica, gen. nov., sp. nov. 1, Male, lateral view. 2, Female, lateral view.

FIGURES 4 – 6. Lobomyia neotropica, gen. nov., sp. nov., male terminalia. 3, Fifth sternite, ventral view. 4, Genital complex, posterior view. 5, Genital complex, lateral view. Abbreviations: c, cercus. dp, distiphallus. ej ap, ejaculatory apodeme. epi, epiphallus. gon, pregonite. s, surstylus.