Description of the female of Syrittosyrphus opacea Hull, 1944 (Diptera, Syrphidae, Eristalinae) with additional notes on the genus
Author
Ssymank, Axel
https://orcid.org/0000-0002-8285-5429
Federal Agency for Nature conservation (BfN, II 2.2), Konstantinstrasse 110, 53179 Bonn, Germany
ssymanka@bfn.de
Author
Jordaens, Kurt
Royal Museum for Central Africa, Invertebrates Section, Leuvensesteenweg 13, B- 3080 Tervuren, Belgium
text
African Invertebrates
2021
2021-04-23
62
1
339
353
http://dx.doi.org/10.3897/AfrInvertebr.62.61504
journal article
http://dx.doi.org/10.3897/AfrInvertebr.62.61504
2305-2562-1-339
230C8E00FB984059B04ED95090D3B399
130A24C69F5156D0A32BE498458F3FDE
Genus
Syrittosyrphus Hull
Syrittosyrphus
Hull, 1944: 203. Type species:
Syrittosyrphus opacea
Hull, 1944, (by monotypy).
Syrittosyrphus opacea
Hull-
Smith and Vockeroth (1980)
: 508;
Dirickx (1998)
: 137;
Whittington (1998)
, 39: 193;
Whittington (2003)
, 10: 603.
Differential diagnosis.
The genus differs from any other genus of hoverflies in the following combination of characters: scutellum with deep rim and fringe of pile ventrally, metasternum pilose, coxae with long pile, all sternites with long pile, wing cell
r1
widely open, wing vein
R4+5
deeply sinuate, stigmal cross-vein present, petiole of anal cell long.
Examined material.
Syrittosyrphus opacea
Hull
:
Holotype
(Fig.
1
), male,
"Holo-//type"
"Cape Province://Somerset East,//
November 1930
" "
S. Africa.
//
R.E. Turner.
//Brit. Mus.//1930-593." "
Holotype
//
Syrittosyrphus
//
Syrittosyrphus opacea
//Hull" [red label, handwritten] [
32.72°S
,
25.58°E
; coordinates taken from Gazetteer and therefore approximate] [NHMUK].
Figure 1.
Syrittosyrphus opacea
Hull, 1944
A
dorsolateral view of the male
holotype
B
labels.
Other material.
South Africa
•
1 ♂
;
Cathedral Peak Area
,
KwaZulu-Natal
;
28°57'S
,
29°12'E
;
16 Dec 1977
;
J.G.H. Londt
leg.; NMSA-Dip 53518 (NMSA)
•
1 ♀
;
Nkandla Forest Reserve
,
KwaZulu-Natal
;
28°42'36"S
,
31°8'29"E
;
12 Jun 2003
;
A.J. Armstrong
leg.; NMSA-Dip 65136 (NMSA)
•
1 ♀
;
Royal Natal National Park
,
KwaZulu-Natal
;
28°41'S
,
28°39'E
;
I.1971
;
H. Townes
leg.; NMSA-Dip 51877 (NMSA)
•
1 ♀
;
Hlatikulu Mountain
,
Monks Trail Bush
edge,
KwaZulu-Natal
;
28°13'S
,
30°01'E
;
17 Mar 1997
;
J.G.H. Londt
leg.; NMSA-Dip 015878 (NMSA)
•
1 ♀
;
Forest Glens, N
.
Drakensberg
,
Limpopo Province
;
23.96951°S
,
29.91860°E
;
Dec 2001
;
J. Swaye
leg.; NMSA-Dip 015879 (NMSA)
•
1 ♀
;
10 km
E of Bedford
, on
Adelaide-Bedford Road
, roadside
Karoo
bush,
Eastern Cape
;
32.6667S
,
26.2833E
(
Gazetteer
); [date unknown];
D. Barraclough
&
C. Barraclough
leg.; NMSA-Dip 049495 (NMSA)
•
1 ♀
;
Royal Natal National Park
,
Day Visitor Car Park
,
KwaZulu-Natal
;
28°41'25.4"S
,
28°56'53.9"E
;
1410 m
a.s.l.
;
4 Dec 2012
;
A. Ssymank
leg.; (ASPC)
•
1 ♂
;
Karkloof Nature Reserve
,
KwaZulu-Natal
;
29°17'54.53"S
,
30°18'21"E
;
13 Nov 2018
,
K. Jordaens
; KMMA AB59880784; DNA voucher 1179A01 (KMMA) • not studied, but cited in
Horn (2004)
:
1 ♂
from
Forest Glens
,
northern Drakensberg
,
Limpopo Province
; (WBPC)
.
Zimbabwe
•
1 ♀
;
Vumba
;
12 Mar 1964
;
D. Cookson
leg.; NMSA-Dip 32362 (NMSA)
•
1 ♂
; N
Vumba
;
6 Feb 1966
;
D. Cookson
leg.; NMSA-Dip 32374 (NMSA)
.
Re-description male.
(Figs
2A
,
3A
,
4A, C, D
: all from NMSA-Dip 53518).
Body
length: 15.0 mm (n = 1); wing length: 11.4 mm (n = 1).
Head
[Figs
1
and
4A
; see also fig. 6G and H, p.15 in
Hippa (1990)
]: Eyes holoptic; eye contiguity shorter than length of ocellar triangle. Face yellow with median Y-shaped brown non-trichose band, yellow parts densely pale pollinose; pale setose. Gena ochre with brownish-black band from oral margin to eye margin. Clypeus subquadrate, broad, dark brown, greyish microtrichose. Lunule brownish-orange. Frons above antennae dark brown shining, non-pollinose, inflated, with a small central round depression. Frontal triangle brownish to black setose on anterior inferior part, with pale setae dorsally, non-pollinose, except narrowly along eye margin. Ocellar triangle equilateral, ocelli reddish, bare. Occiput pale greyish microtrichose; pale setose. Antennae with scapes and pedicel brownish, non-pollinose; postpedicel twice as long as wide, yellowish, densely greyish pollinose; arista yellow, bare, about 2-2.5 times as long as postpedicel.
Figure 2.
Syrittosyrphus opacea
Hull, 1944
A
dorsal view male
B
dorsal view female.
Figure 3.
Syrittosyrphus opacea
Hull, 1944
A
lateral view male
B
lateral view female.
Thorax
(Figs
1
,
2A
and
3A
): Dark brown to black, scutum yellow pollinose along margins and suture and in anterior part, also along median line, leaving large brownish-black non-pollinose areas with blackish setae. Scutellum yellow, width to length ratio 2.5:1, with premarginal sulcus, long yellow densely setose (setae ca. 1/3-1/2 length of scutellum); subscutellar fringe well developed with dense long yellow setae of ca. 0.45 mm. Pleurae brownish, mostly densely grey pollinose; postpronotum with a small pronounced non-pollinose bulge leading into an elevated rim of the scutum, with yellow and a few black setae intermixed; anterior anepisternum, posterior part of proepimeron and anterior part or posterior anepisternum bare; proepisternum, posterior part of anepisternum and anterior anepimeron with long yellow setae; katepisternum with posteriodorsal tuft of long setae and ventrally setose; meron, metepimeron, katepimeron, katatergite, posterior anepimeron, except for some short microsetae, bare; metasternum densely long yellow setose. Ampulla yellow. Plumula yellowish. Thoracic spiracles with whitish to ochre vestiture.
Legs
[Figs
1
,
2A
,
3A
and
4C
: see also fig. 6E and F, p. 16 in
Hippa (1990)
]: reddish-brown, tibia with basal 1/3 to 1/2 yellow. Mesofemur posteriorly grey pollinose, anteriorly with a broad median pollinose band; short adpressed yellowish setae; tarsae ventrally with short stout black setulae. Mesotibia abruptly broadened in apical 1/4. Mesofemur posterolateral with a row of longer whitish setae (length ca. 1/2 diameter of mesofemur). Mesotibia slightly dilated apically with apicoventrally a short comb of short black stout setulae and a small pointed tooth on the opposite side. Metacoxa (Fig.
4C
) with two black spurs of ca. 1 mm long. Metafemur with posterolateral row of longer whitish setae (length ca. 1/3 of diameter of metafemur); ventrobasally with a low ridge carrying a black comb of short stout black setulae; apicoventrally with a depression that carries a ridge with a row of black stout setae on the anterior side. Metatibia yellow, apical 2/3 brownish; dilated towards apex, apical half carinate posteriorly; anteriorly with an oblique depression at 1/4 from apex.
Figure 4.
Syrittosyrphus opacea
Hull, 1944
A
head male, frontal view
B
head female, frontal view
C
metaleg male, posterior view
D
right wing male.
Wing
(Figs
1
,
4D
): hyaline, along anterior margin yellowish with darkened patches below pterostigma extending to cross-vein
r-m
, wing tip slightly darkened. Anal cell very long. Cell
r1
widely open, in apical half widened and close to wing margin suddenly narrowed, ending at wing margin. Vein
R4+5
with a deep oblique sinuate loop into cell
r4+5
. Spurious vein well developed, as thick as other veins, extending into cell
r4+5
. Anal cell microtrichose with basal area bare. Basal half of wing up to cross-vein
r-m
with sparse microtrichia, with bare areas along veins; apical 1/3 of wing (including entire cell
r4+5
) densely microtrichose. Calypters white with an orange-brown margin, long yellow-white pilose. Halteres yellow-brown.
Abdomen
(Figs
1
,
2A
,
3A
): long and conical; setae from tergites I to IV mostly yellowish short and adpressed, only on lateral margins longer yellow setae. Tergite I yellow to ochre, densely greyish pollinose with the exception of a narrow non-pollinose posterior margin. Tergite II with large orange maculae, with lateral, anterior and posterior margins brownish to black; slightly darkened along median line; mostly non-pollinose. Tergite III narrowly yellow along anterior margin, otherwise dark brown; with sparse, but distinct yellowish to grey pollinosity, pollinosity more dense along median line and towards posterior margin. Tergite IV brownish-black, only anterior part of median line greyish pollinose. On tergites II-IV, the dark coloured parts have short blackish setulae. Hypopygium with brownish-black long setae. Sternite I brownish, densely grey pollinose. Sternite II yellow with black median line; only along anterior margin whitish pollinose. Sternite III anterior and posterior margin yellow, with central broad brownish-black fascia, uniform, but weak pollinose. Sternites I-III with very long dense setae of ca. 2 mm length. Sternite IV brownish-black, distinctly greyish pollinose laterally, with long setae that form a dense comb along lateral margin, leaving a median non-pollinose, almost bare, area of approx. 1/4 to 1/3 of sternal width.
Genitalia
[Fig.
5A, B
; see also fig. 6A and B, p. 15 in
Hippa (1990)
]: Epandrium with surstylus dorsally from halfway strongly curved downwards, pointed, ventrally with subtriangular expansion, dorsally and ventrally long yellow-brown pilose. Hypandrium very large and ventrally broadly expanded; aedeagus with a ventral sharp tooth. Cerci broad, club-shaped; on posterior and ventral side long yellow-brown pilose.
Figure 5.
Male genitalia of
Syrittosyrphus opacea
Hull, 1944
A
ventral view
B
lateral view. Abbreviations: cerc, cercus; ep, epandrium; hyp, hypandrium; v, ventral tooth of the aedeagus.
Figure 6.
Female genitalia of
Syrittosyrphus opacea
Hull, 1944
A
dorsal view
B
ventral view
C
lateral view. Abbreviations: ap, apodeme of epiproct; cerc, cercus; ep, epiproct; hyp, hypoproct; ll, lateral lobe to the epiproct; mem, membranous area between epiproct and cerci; st8, sternite 8; st9, sternite 9; tg8, tergite 8.
Description female.
Figs
2B
,
3B
,
4B
(specimen NMSA-Dip 65136) and 6 (ASPC).
Body
length: 14.0 mm (n = 1); wing length: 11.4 mm (n = 1)
Similar to male, except for distinct sexual dimorphism. Frons with a broad greyish pollinose band with grey setae (Fig.
4B
). Ocellar triangle and upper part of frons brownish-black, non-pollinose, brownish to black setose (Fig.
2B
). Legs (Figs
2B
and
3B
): protibia less broadened in apical third. Mesoleg without black setal comb on tip of tibia. Metaleg: coxa without long spur; femur with very low ventral bump, with some stout black setae; basoventral patch of black setae missing; no long pale setae posterolaterally. Abdomen (Figs
2B
,
3B
): Tergite V black, non-pollinose, black setose, but shorter than in male. Sternites with long pale setae much shorter and less dense than in male (1.5 mm on sternite II, 0.65 mm on sternite V); sternite III + IV with scattered longer setae only; sternite V with only a few longer setae. Genitalia (Fig.
6
) compact, tergite 7 approx. 1.5
x
as broad as long, tergite 8 approx. as long as broad, posteriorly rounded, without lateral apodemes, with very long evenly distributed long yellow-brown pile; epiproct broad, with two rounded anterior areas and with a single basal area with two triangular large apodemes, with a granulated small lateral lobe to the epiproct; sternite 8 large, with an unusual ventral modification, ventrally concave; sternite 9 with conspicuous pigmentation at apical margin; cerci rounded, semi-circular, apical end gently curved inwards, long yellow-brown pilose.
Distribution.
South Africa (
Hull 1944
; this study), Zimbabwe (
Whittington 1998
) (Fig.
7
).
Figure 7.
Distribution of
Syrittosyrphus opacea
Hull, 1944 in South Africa and Zimbabwe. Red dots: distribution records; green dot: type locality.