Fulgenta MacGowan

Macgowan, Iain, 2017, A new genus and species within the tribe Earomyiini (Diptera, Lonchaeidae), Zootaxa 4216 (3), pp. 201-224 : 202-205

Fulgenta MacGowan , gen. nov.

Type-species: Fulgenta pretoria MacGowan , sp. nov.

Diagnosis. Small metallic green-blue flies (wing length: 2.5–3.1 mm), body with rather sparse and short chaetotaxy, within the Earomyiini adults are distinguished from all genera apart from Lamprolonchaea by their metallic body colour and from Lamprolonchaea by the distinctive structure of the male genitalia.

Description. Male: Head: Eyes bare. Frons subshining to matt black dulled with microsculpture or slight pollinosity, frontal and interfrontal setulae very short. Orbital plate shining black, bare apart from orbital seta. Lunule bare, basal colour dark brown to orange, covered in sparse to dense silver pollinosity as are parafacials and face. Anterior genal setulae in single row of 4–8 along mouth margin. Antennae usually entirely black, 1st flagellomere occasionally slightly orange-brown on medial base, 1st flagellomere length to depth ratio ranging from 1.5–2.0:1. Arista pubescent to short plumose, ratio of plumosity at maximum extent to depth of 1st flagellomere in range of 0.25–0.9:1.

Thorax: mesonotum, shining dark emerald green, bronze green or blue-black, anepisterum and, katepisternum shining metallic green, blue-black or black, anepimeron and other sclerites subshining black. Anepisternum with 1 anterodorsal and 2 posterior setae. One seta on both proepimeron and proepisternum. Katepisternum with 1 seta placed centrally near dorsal margin with a scattering of setulae anterior to the seta, these usually short but in some species are up to 0.5x length of the seta. Scutellum; disc bare, shining green, on margin between lateral and apical setae with 1–2 setulae, 0–1 between apical setae. Calypteres pale, white or yellowish with whitish fringes. Wings clear or occasionally with apical brown shading. Wing length 2.5–3.1mm. Legs black, all basal and 2nd tarsomeres pale, apical tarsomeres darker.

Abdomen: tergites brightly shining dark green to blue green, apical segment occasionally with semi-circular excavation at apex.

Male terminalia: lying within abdomen with posterior margin of epandrium orientated ventrally, laminate surstyli situated ventral to epandrium lying parallel to abdominal sternites ( Fig 2 ) as compared to L. smaradgi (Walker, 1849) in which the ventral margins of the epandrium are orientated ventrally and the cerci lie posterior to the epandrium ( Fig. 3 ). Epandrium; flattened in the posterior-anterior plane, 9th and 10th terga not completely fused, 9th tergite a rounded or angular lobe attached to the anterior surface of the 10th terga ( Fig. 4 t9, t10). Posterior margin, just ventral to base of cerci, with an incurved medial lobe of varying size, surface with or without a scattering of small spicules ( Fig. 5 , Ilobe).

Cerci usually lying flat along posterior surface of epandrium, forming large to moderately sized laminate processes, often partly fused, often with setulae or setae on dorsal and ventral surfaces ( Figs. 4 & 5 , C). Surstyli small and rudimentary, ranging in structure from a simple narrow process bearing a group of long setulae to a small rounded lobe covered in long, fine setulae; completely enclosed within the epandrium ( Fig. 4 , Sur).

Hypandrium extending anteriorly for almost half its length, mostly within the epandrium, before extending ventrally out beyond margin of epandrium, the hypandrial apodeme continues in this plane.

Pregonites and postgonites simple. Phallus often sinuous or angular, with or without interior spurs or flanges, occasionally simple ( Figs. 4 & 5 , Ph)

Etymology. The generic name is derived from the Latin fulgent meaning shining brightly in reference to the bright shining green/blue colour of the thorax, scutellum and abdomen.

Distribution and habitat. Afrotropical, 15 species currently known from South Africa north to Ethiopia and from Nigeria in the west to Kenya in the east. Based on the details recorded on the data labels it would appear that adults are found in habitats such as secondary woodland and lowland evergreen primary forest and at altitudes of up to 1200m.

Relationships. Although adult Fulgenta are externally very similar to Lamprolonchaea in body colouration and chaetotaxy the position and detailed taxonomy of the male genitalia indicate that this is a distinct genus within the Earomyiini . Key features in defining the genus are;

In Fulgenta the male terminalia are orientated with the posterior margin in a ventral position within the abdomen ( Fig. 2 ). This is a situation similar to that found in the basal genus Dasiops rather than in Protearomyia , Lamprolonchaea , Earomyia and genera within the Lonchaeini where the epandrium has its ventral margin in a ventral position.

The male genitalia are also distinctly flattened in the posterior-anterior plane; this is evident not only in the shape of the epandrium but also in the alignment of the hypandrium and hypandrial apodeme. In Fulgenta the hypandrium articulates basally with the area on the medial surface of the epandrium located just dorsal of the surstyli, it then extends anteriorly for almost half its length, mostly within the epandrium, before extending ventrally out beyond the shell of the epandrium, the hypandrial apodeme continues in this plane ( Figs. 4 & 5 ). In general in Lamprolonchaea species such as L. s maragdi the hypandrium extends posteriorly from the shell of the epandrium with the hypandrial apodeme being articulated at an angle ( Fig. 3 ).

The surstyli in Fulgenta are notably poorly developed ( Fig. 4 , Sur) when compared to the larger more laminate structures found in Earomyia and Lamprolonchaea . This may well represent a derived condition linked to the flattening of the epandrium. In what are considered the basal genera of the family Dasiops , Chaetolonchaea and Protearomyia the surstyli are well developed and usually bear prensisetae.

A further almost unique feature in Fulgenta is evident in the structure of the epandrium where the 9th and 10th tergites, although fused are evident as separate, well-developed entities, the shapes of the two sclerites and the suture between them being visible ( Fig. 4 , t9 & t10). Although this development of t9 has been noted in Earomyia viridana (Meigen, 1826) , it is otherwise almost unknown within the Lonchaeidae where in almost all species t9 is very narrow ( McAlpine 1962: 36,191).

Within Fulgenta there is a range of variation in the development of the cerci and surstyli. Species such as F. complexa have relatively small cerci and relatively well developed setulose surstyli. ( Figs. 14–16 ) whereas in F. apicalis the cerci are very large, long and laminate and the surstyli are reduced to simple rods bearing only a few long setulae ( Figs. 6–8 ). The latter is presumed to be the more derived condition. The surstyli normally play an important part in gripping the female during copulation, with the surstyli being greatly reduced in Fulgenta it would appear that this gripping function is performed by the large laminate cerci acting against the posterior surface of the epandrium, this would explain why the posterior margin of the epandrium is rounded often with an expanded medial lobe which in some species bears numerous small spicules.

The exact placing of Fulgenta within the Earomyiini is not entirely clear at present, the orientation of the male terminalia and the broad t 9 may be regarded as more basal features whilst the reduction of the surstyli and the large cerci may be seen as being more derived. DNA analysis will be required to confirm the relation between Fulgenta and the other genera in the tribe.

As a result of the findings in this paper the genus Lamprolonchaea, Bezzi now contains 18 species with the greatest species diversity being found in the Australasian-Oceania region. The genus still contains Afrotropical representatives with one described species L. smaradgi being widely distributed and at least another two undescribed species being present.

Figures

FIGURES 2 – 3. Ventral view of abdomen showing the orientation of the male terminalia (sternites removed). 2. Fulgenta excisa sp. nov. 3. Lamprolonchaea smaragdi (Walker, 1849).

FIGURES 4 – 5. Fulgenta species, male terminalia. 4. F. excisa sp. nov. lateral view with half of epandrium removed to show medial structures. 5. F. saegeri sp. nov., male terminalia, posterior view. Abbreviations: C = Cerci, Ep = epandrium, HA = hypandrial apodeme, Hypand = hypandrium, Ilobe = medial lobe of epandrium, Ph = phallus, Preg = pregonite, Pgt = postgonite, Sur = Surstylus, t 9 = tergite 9. t 10 = tergite 10.

FIGURES 14 – 18. Fulgenta complexa sp. nov. 14. Epandrium and associated structures, posterior view. 15. Same, lateral view. 16. Epandrium, internal view showing surstylus and associated structures. 17. Phallus, lateral view. 18. Same, ventral view.

FIGURES 6 – 9. Fulgenta apicalis sp. nov. 6. Epandrium and associated structures, posterior view. 7. Same, lateral view. 8. Epandrium, internal view, showing surstylus and associated structures. 9. Phallus, lateral view.