A new genus and species within the tribe Earomyiini (Diptera, Lonchaeidae)
Author
Macgowan, Iain
text
Zootaxa
2017
4216
3
201
224
journal article
37361
10.5281/zenodo.231764
56021fb5-820d-4ae5-bdb1-ce4420f10aa3
1175-5326
231764
0EF8190D-313C-403F-A99E-50CB172D4BA2
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.
FIGURE 1.
Fulgenta apicalis
sp. nov.
, adult male.
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)
.
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.
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, t9 = tergite 9. t10 = tergite 10.
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.