A review of Afrotropical Acnephalum Macquart, 1838, including the reinstatement of Sporadothrix Hermann, 1907 and descriptions of two new genera (Diptera: Asilidae: Stenopogoninae)
Author
Londt, Jason G. H.
text
African Invertebrates
2010
2010-12-31
51
2
431
431
http://www.bioone.org/doi/abs/10.5733/afin.051.0212
journal article
10.5733/afin.051.0212
2305-2562
7913777
ADE55AE3-E55C-46CE-865D-1101B9875869
Afroholopogon futilis
(
Wulp, 1899
)
comb. n.
Figs 2
,
52–54
Acnephalum futile
:
Wulp 1899: 87
(pl. II, fig. 11 wing venation);
Kertesz 1909: 88
(catalogue);
Engel 1929:
277;
Hull 1962: 192
; Oldroyd 1981: 359 (catalogue);
Lehr 1988: 232
(catalogue).
On receipt of the
type
material it was immediately apparent that
futilis
should not have been described in
Acnephalum
as the specimens fail to display the diagnostic characteristics of the genus. Indeed, it is doubtful that any researcher has consulted the
types
since their original description. The species is fully congeneric with
Afroholopogon
and is therefore unhesitatingly transferred to that genus.
Redescription (Format follows that of Londt (2005). Based on
lectotype
(
Fig. 2
). Condition: Excellent; right antenna broken off beyond pedicel.):
Head
: Antenna: Dark redbrown, fine silver pruinose, white setose; segmental formula 1.0:1.1:3.3:0.3:1.3. Face black, entirely silver pruinose, mystax white, extending to antennal sockets, with vertical asetose strip medially. Face width:head width ratio 1.0:4.4. Frons and vertex black, frons apruinose except for silver lateral areas and a central spot. Vertex apruinose, fine white setose. Occiput dark redbrown to black, entirely silver pruinose, white setose. Proboscis and palpi dark red-brown, white setose.
Thorax
: Mesonotum black, silver pruinose except for extensive apruinose spots and stripes, setae short, white (absent on some apruinose areas). Setation:
ac
– short white setulae;
dc
– short white;
npl
– 2 pale yellow-white;
spal
– absent;
pal
– 1 white. Scutellum black, entirely apruinose, disc asetose, margin with 7, white, medially directed, quite short apical macrosetae arranged in a single row. Pleura black, extensively silver pruinose, white setose. Wing 3.6×
1.5 mm
, transparent, membrane entirely microtrichose, basal angle of cell r
4
19°. Haltere with pale yellow knob and light brown stalk. Legs:
cx
dark red-brown, silver pruinose, white setose; trochanters dark red-brown;
fem
red-brown with brown-orange distal end, pale yellow and white setose;
tib
orange-brown, pale yellowish setose (few black ventrodistally);
tar
orange-brown, pale yellowish (dorsally) and dark red-brown (ventrally) setose.
Abdomen
: Terga dark red-brown, shiny apruinose except for silver areas posterolaterally (that extend medially to almost centre of tergum, but not along posterior margin), white setose. Sterna dark red-brown. silver pruinose, short white setose. Genitalia (
Figs 52– 54
): Hypopygium unrotated;
epand
(in dorsal view) quite short (about as long as
proc
), shallowly incised to form short distolateral lobes;
goncx
externally distally bilobed and projecting (in lateral view) to a level beyond that reached by
epand
;
hypd
(laterally) of moderate length (longer than external lobe of
goncx
) and (ventrally) broadly rounded distally.
Variation:
Paralectotype
slightly smaller (wing
3.4 mm
long), otherwise similar to
lectotype
.
Lectotype
:
♂
SOUTH YEMEN
:
lectotype
, ‘S. W. Arabia, /
Aden
. [
12°46'N
:
45°01'E
] / Capt. Feb. 13.95 / & pres. 1899 by / J. W. Yerbury’ glued to ‘A. / capt. in / cop. with / B.’, ‘Type. / v.d.Wulp,
Trans. Ent. Soc
., / 1899, page 87, / pl. ii, fig.11.’, ‘
Acnephalum
/
futile
n. s.’, ‘1899 / 7704’, ‘4’, ‘Type Dip: 154 1/2 /
Acnephalum
/
futile
/ v.d. Wulp / Hope Dept. Oxford’ (OXUM).
Paralectotype
:
♀
SOUTH YEMEN
: ‘S. W. Arabia, /
Aden
. / Capt. Feb. 13.95 / & pres. 1899 by / J. W. Yerbury’ glued to ‘B. / capt. in / cop. with / A.’, ‘Type. / v.d.Wulp,
Trans. Ent. Soc
., / 1899, page 87, / pl. ii, fig. 11.’, ‘
Acnephalum
/
futile
n. s.’, ‘1899 / 7703’, ‘Type Dip: 154 2/2 /
Acnephalum
/
futile
/ v.d. Wulp / Hope Dept. Oxford’ (OXUM).
Lectotype
designation:Wulp described the species on ‘a pair in coitu, from Aden’.As he did not designate a
holotype
, the specimens are considered
syntypes
.For reasons of taxonomic stability I hereby designate the male as
lectotype
and the female as
paralectotype
. Distribution, phenology and biology: The species is only known from the type locality. Specimens were collected in February. Nothing is known of its biology.
Similar species:
Wulp (1899)
stated that
futile
was ‘closely allied to
Dasypogon
(
Acnephalum
)
andrenoides
’, a comment echoed by
Engel (1929)
. The similarity is, however, minimal and it is surprising that Engel did not suspect a misallocation.
Afroholopogon
was fully revised by
Londt
(2005), who gave an historical account together with redescriptions and descriptions of 17 species, most of which are
southern African. Using Londt’s
key to species reveals that
futilis
keys out at the end of the key together with three other species –
dasys
Londt
, 2005,
pardosoros
Londt
, 2005 and
uranopia
Londt
, 2005.
Two
of these are known only from
South Africa
(
pardosoros
from the
Tierberg Nature Reserve
, and
uranopia
from the
Graaff-Reinet area
) while
dasys
is known from
three specimens
from
Eritrea
,
Oman
, and the
Yemenese island
of Abd al Kuri. Besides the characters provided in the key below there are obvious differences to be observed in male genital form
.
A. futilis
can easily be incorporated into Londt’s (2005) key by making the following small modifications to the final couplets:
15 Mesonotal pruinescence entirely gold; apical scutellar setal number>40 .............. ....................................................................................................
dasys
Londt, 2005 – Mesonotal pruinescence silver (
uranopia
female has silver laterally and gold medially); apical scutellar setal number <30............................................................16 16 Eye anteromedially flattened, especially in male; male with facial area occupied by mystax shiny apruinose; scutellum with
c
. 20 apical macrosetae....................... ..............................................................................................
uranopia
Londt, 2005
– Eye not anteromedially flattened; male with facial area occupied by mystax entirely silver pruinose ......................................................................................................17
17 Face broarder in relation to head (1:<5); supra-alar macrosetae absent; scutellum with <10 apical macrosetae; wing with basal angle of r
4
<20°; known only from
South Yemen
............................................................................
futilis
(
Wulp, 1899
)
– Face narrower in relation to head (1:>5); 1 supra-alar macroseta present; scutellum with>20 apical macrosetae; wing with basal angle of r
4
>25°; known only from
South Africa
.....................................................................
pardosoros
Londt, 2005