The genus Sphegina Meigen (Diptera, Syrphidae) in a biodiversity hotspot: the thirty-six sympatric species in Kambaiti, Myanmar
Author
Hippa, Heikki
Author
Steenis, Jeroen Van
Author
Mutin, Valeri A.
text
Zootaxa
2015
3954
1
1
67
journal article
10.11646/zootaxa.3954.1.1
44878647-9450-4895-ad32-d1fc79eb30ea
1175-5326
288397
AA3DB71F-AD9A-4205-889B-FB212E367A37
Sphegina (Asiosphegina) achaeta
sp. n.
Figs 37
A–E
MALE.
Body length 7.0 mm, wing length
5.9 mm
.
Head.
Face strongly concave, weakly projected anteroventrally; frontal prominence weakly developed (similar to Fig. 1F). Width of vertex at anterior ocellus:width of head 1:4.5, depth of occipital concavity ca. 1/5 of the width of an eye in dorsal view. Width of face:width of head 1:4.3. Face dark brown, pale pollinose. Gena shiny brown. Frons and vertex black, densely pale pollinose; lunula shiny brownish; the pile short, erect and pale. Occiput dull black. Eye with an area of enlarged facets at anterior margin alongside face. Antenna brown; basoflagellomere semicircular; arista pilose.
Thorax.
Colour black, pale pollinose; scutum with short, adpressed reddish pile; scutellum semicircular, the pile similar to posterior part of scutum, a pair of convergent long pale setae at apical margin.
Wing.
Hyaline, stigma brownish.
Legs.
Proleg mainly yellow; femur yellow with wide, near 1/2 of femur length, apical brownish annulus; apical 1/2 of tibia diffusely brownish; tarsus yellowish, tarsomeres 4 and 5 lost in the single specimen. Mesoleg lost. Metaleg: coxa brown; trochanter brown, simple; femur brown with basal 1/4 yellow; tibia without apico-ventral tooth, brown with the basal 1/4 and an annulus on apical 1/2 yellow; tarsus dark brown.
Abdomen.
Length ratio of tergites I, II,
III and IV 1
:3.0:2.0:1.9. Tergites shiny black, tergite III with a yellow fascia on the anterior 1/2, the pile of tergites adpressed and pale, becoming longer towards the lateral margin; tergite I laterally with vertical row of 5 long, thin, pale setae which are only weakly differentiated from the other lateral vestiture; sternite IV (
Fig. 37
B) with a lobelike part posteriorly on the left side, brown, the pile pale; sternites VI–VIII simple, black, the pile pale.
Genitalia,
Figs 37
A, C–E. Note that the surstyli and the superior lobes are nearly symmetrical.
FEMALE.
Unknown.
Type
material.
HOLOTYPE
. ♂, N.E.
Burma
, Kambaiti,
7000 ft
,
14.v.1934
, R.
Malaise
(
SMNH
).
Etymology.
The name is derived and Latinized from Greek words
a
, without, and
chaite
, long hair, referring to the lack of strong setae laterally on tergite I.
Discussion.
In
Sphegina achaeta
the transverse postero-lateral row of 4–5 setae on abdominal tergite I differs from other species having this structure by having the setae weak, not much deviating from the other vestiture and in that the row is almost transverse, scarcely oblique. In its general appearance
S. achaeta
resembles
S. adusta
,
S. atricolor
and
S. furva
but is not especially similar to any of them and is easily distinguished by the characters given in the key. The male genitalia recall
S. pollex
and
S. culex
, especially in the superior lobe which posteriorly is widened both dorsally and ventrally.
S. achaeta
differs by having the posterodorsal corner acute. The surstylus of
S. achaeta
differs from both by having it much broader, from
S. pollex
also by lacking a subbasal dorsal thumb-like lobe.
S. achaeta
is similar to
S. japonica
Shiraki & Edashige, 1953
by the chaetotaxy of tergite I but differs by normal metatibia (in
S. japonica
apically strongly carinate), asymmetrical sternite IV (in
S. japonica
symmetrical), and the normal-sized apically rounded cerci (in
S. japonica
very large and triangular).