A new species of spider fly in the genus Sabroskya Schlinger from Malawi, with a key to Acrocerinae world genera (Diptera, Acroceridae)
Author
Winterton, Shaun L.
Author
Gillung, Jessica P.
text
ZooKeys
2012
171
1
15
http://dx.doi.org/10.3897/zookeys.171.2137
journal article
http://dx.doi.org/10.3897/zookeys.171.2137
1313-2970-171-1
Sabroskya Schlinger
Type species.
Sabroskya ogcodoides
Schlinger 1960
: 479 by original designation.
Diagnosis.
Body length: 6.0-7.0 mm. Body shape not arched. Head width slightly narrower than thorax; sub-spherical; postocular ridge and occiput rounded; three ocelli; posterior margin of eye rounded; eye pilose (dense); eyes contiguous above antennal base; antennae located adjacent to mouthparts; palpus present or absent; proboscis length less than head length, with sparse setal pile; flagellum stylate, apex with relatively large terminal seta; postpronotal lobes not enlarged or contiguous medially; antenotum expanded, collar-like behind head; subscutellum relatively enlarged; tibial spines absent; pulvilli present; wing hyaline or slightly smoky infuscate, markings absent; costa ending near wing apex; costal margin straight; humeral crossvein absent; R1 very slightly inflated at pterostigma; R2+3 present or absent; veins R4 and R5 present as single vein R4+5; radial veins straight, complete to wing margin; crossvein 2r-m present between M1 and R4+5, bisecting cell r4+5, cell formed by 2r-m narrow elongate; medial vein compliment: M1, M2 and M3 present (M3 fused with CuA1), medial veins may or
may
not reach wing margin; discal cell closed completely; cell m3 absent; CuA2 fused to A1 before wing margin, petiolate; wing microtrichia absent; anal lobe well developed; alula well developed; abdominal tergites smooth, rounded; abdomen rounded, inflated, slightly wider than thorax.
Comments.
Sabroskya
is a highly specialized
Acrocerinae
spider fly genus morphologically similar to
Meruia
,
Ogcodes
,
Glaesoncodes
and
Pterodontia
. These five genera all have stylate antennae located on the lower side of the head adjacent to the often reduced or absent mouthparts. Other acrocerine genera related to this clade include
Turbopsebius
,
Opsebius
,
Villalus
,
Acrocera
and
Sphaerops
, all of which have a wing venation lacking cell m3. The Baltic amber genus
Glaesoncodes
is unique among this acrocerine clade as the wing retains remnants of cell m3, with spur veins present in cell d+m3 (
Hennig 1968
); similar remnants of m3 can also be found in more distantly related
Turbopsebius
. This provides important insights into the evolution of acrocerid wing venation, suggesting rampant reduction in number of cells and veins through loss or fusion, and can be found in derived clades in all three extant subfamilies (
Winterton et al. 2007
;
Gillung and Winterton 2011
).
In
Pterodontia
,
Sabroskya
and
Ogcodes
the costal margin has a membranous rim or flange between R1 and wing apex (Figs 2-3). This character still needs to be confirmed in
Meruia
, but appears to be likely a synapomorphy for the group. The putative sister genus to
Sabroskya
is
Meruia
, and both have similar wing venation comprising well defined and complete discal and basal r4+5 wing cells. These cells are absent in
Ogcodes
and are fused to form a single cell in
Pterodontia
.
Sabroskya
can be immediately identified from other acrocerine genera by the presence of a cervical collar, antennae located adjacent to mouthparts, R4+5 straight, cell m3 absent and discal and basal r4+5 cells separate and closed.
Schlinger (1960a)
described the antennal flagellum of
Sabroskya
as stylate without a terminal seta, and with a large subterminal seta on the lateral surface of the flagellum. Detailed examination of the topotype series of
Sabroskya ogcodoides
(
Schlinger 1960b
) shows a similar condition as found in both
Sabroskya schlingeri
sp. n. and
Sabroskya palpalis
, with the flagellum actually having large terminal setae present (Fig. 3C) (see also
Grimaldi (1995
: fig. 5)). Only in
Sabroskya palpalis
are palpi present while in
Sabroskya ogcodoides
and
Sabroskya schlingeri
sp. n., the palpi are absent.
Included species.
Sabroskya ogcodoides
Schlinger, 1960;
Sabroskya palpalis
Barraclough, 1984;
Sabroskya schlingeri
sp. n.
Key to species of
Sabroskya
..
(Females are unknown for
Sabroskya palpalis
and
Sabroskya schlingeri
sp. n.)
|
Sabroskya palpalis
|
| Fig. 3C |
|
2
+3 Fig. 3BFigs 36
|
Sabroskya schlingeri
.
|
| 2+3 Fig. 3AFigs 710 |
Sabroskya ogcodoides
0
|