A revision of Afrotropical Chyromyidae (excluding Gymnochiromyia Hendel) (Diptera: Schizophora), with the recognition of two subfamilies and the description of new genera
Author
Ebejer, Martin J.
text
African Invertebrates
2009
2009-12-31
50
2
321
321
http://www.bioone.org/doi/abs/10.5733/afin.050.0208
journal article
10.5733/afin.050.0208
2305-2562
7910603
Oroschyromya dubia
(
Lamb, 1914
)
,
comb. n.
Figs 16
,
17
Chiromyia dubia
:
Lamb 1914: 353
.
Lamb wrote that he had
11 specimens
, four of which were males. I examined these specimens and found them to be all females belonging to two species. The
holotype
has the abdomen missing, but otherwise has all the characters agreeing with the remaining series.
One
other of the
five specimens
at the
Natural History Museum in London
is a dissected female and it agrees with the figure given in this article (
Fig. 17
).
Another
specimen (
BMNH
) and three more (
CUMZ
) belong to a species of
Gymnochiromyia
.
They
have a thorax with chaetotaxy typical of that genus: the
mtn
is a clear yellow; the
tg
are uniformly dark chocolate brown and completely shiny, only the membrane separating one
tg
from the other is pale yellow; the
prscut acrs
are particularly strong. I am unable to assign this species with confidence to any of the recently described species from
southern Africa
(Ebejer 2008
b
), so until more material, including males, becomes available, it remains unnamed. I labelled each of the
four specimens
as ‘
Gymnochiromyia
female, sp. indet
.’.
Diagnosis:An orange-yellow species with large hypopygium having vertically elongate
ep
. In spite of weak
pra
and
pa
setae suggesting this might be a
Notiochyromya
, the long
surs
, conical
prg
and accesssory ventral
hyp
plate properly place this within
Oroschyromya
. The female postabdomen also shows strong affinities with this genus. So far, it is the only species in the genus known from a relatively lowland habitat.
Redescription:
Male
.
Head
: All yellow except for black
oc
triangle;
fr
narrow, at widest point less than half width of head; strongly narrowed anteriorly: at level of antennae 0.4 width that at level of anterior
oc
and 0.3 width of one eye viewed in front. Gena: only a little narrower in front than behind; in profile, below middle of eye, about 0.6 height of eye; pale yellow and pale-haired;
ocp
in profile narrowly visible behind eye; with short postocular setulae in one irregular row, the top 4 developed into short dark setae; isolated lower postgenal seta long. Mouthparts small, all yellow; setulae of buccal margin moderately developed. Face poorly sclerotized and small, hardly visible.Antenna yellow, second segment with short dark seta dorsally; third segment round, finely pubescent: hairs short, only those on lower margin as long as diameter of arista at base; arista dark almost throughout and completely bare. Chaetotaxy: 3
orb
, all markedly reclinate, the anterior also slightly inclinate, middle and posterior
orb
closer together than middle is to first;
pvt
short and crossed; 1
vti
and 1
vte
strong; ocellars almost as long as hind
orb
, proclinate and divergent; about 8 short setulae across middle of
fr
and about 6 on each
orb
plate. All setae dark brown, setulae yellow.
Thorax
: In profile, anterior margin of scutum rectangular; scutum,
scut
,
mtn
and all pleura yellow and without defined pattern, paler on pleura. Chaetotaxy: 1
pprn
and another about half its size, 1
posthu
, 2
ntpl
, 1
pra
and 1
sa
(both short), 1
pa
, 1
post ia
, 1
dc
with another half its size or less, in front of it, scutal setulae in 6–8 irregular rows at level of transverse suture between
dc
lines, 4 slightly stronger
prscut
setulae in a transverse row between
dc
, and 2 more on each side between
dc
and
pa
; subapical and basal
scut
as usual, 1 anepisternal and 1 katepisternal, all setae dark brown, only on pleura yellow.
Fig. 16.
Oroschyromya dubia
(Lamb)
, ơ: (a) head, lateral; (b)
st
5, ventral; (c) hypopygium, lateral; (d)
ej apd
, dorsal; (e)
distiph
, lateral. Scale bars = 0.3 mm in Fig. 16a and 0.2 mm in Figs 16b–e.
Fig. 17.
Oroschyromya dubia
(Lamb)
, ^postabdomen, lateral (a) and ventral (b). Scale bar = 0.15 mm.
Wing: Hyaline, veins pale brown; distance between R
2+3
and R
4+5
about 0.8 that between R
4+5
and M
1+2
; distance between crossveins from 0.8 length of apical section of vein Cu or about equal to it. Haltere pale yellow.
Legs: Not modified except for slightly thicker femora; fine setulae scattered on all pairs of legs, in addition to longer setae on fore femur; mid tibial apicoventral seta absent; claws and pulvilli normal.
Abdomen
: Entirely yellow; pale setae, about half to two thirds length of
tg
.
Postabdomen:
ep
yellow and distinctly elongated from top to bottom,
cerc
also elongated and densely setulose;
surs
long and narrow;
hyp
basally with large distal section that fuses with
ep
and small accessory plate;
ph apd
long and narrow;
ej apd
moderately developed, narrow in profile;
prg
large, sclerotized and conical with strong setae on anterior surface;
psg
small and narrow.
Female
.
Scutum with 4 pale brown stripes: 2 along midline reaching about half way to
scut
, and one on each side of these between
dc
and
ia
lines reaching just beyond wing base; setae and setulae darker and stronger; otherwise as male. Postabdomen: elongate lateral sclerites of
tg
7 of distinctive shape due to irregular margins, these sclerites partly overlapping
st
8; setae on
st
8 short;
hypr
sclerotized,
cerc
small oval.
Length
: ơ body
1.5 mm
, wing
1.5 mm
; ^body
1.6 mm
, wing
1.6 mm
.
Type material examined:
SEYCHELLES
: ^(
holotype
) ‘Mahé 08-9, Seychelles Exp. /
Prof. J.S. Gardiner’
(
BMNH
); 6^(
paratypes
) same data (3 BMNH, 3
CUMZ
)
.
Other material examined:
MAURITIUS
: 3ơ
1^Wolmar
,
1–2 km
S,
21.v.2000
,
J.W. Ismay
, coast roadside (
OXUM
); 1ơ 1^same data (
NMWC
)
.
Distribution:
Mauritius
,
Seychelles
.