New species of Culex (Culiciomyia) (Diptera: Culicidae) from Talangaye Forest in Cameroon and descriptions and identification keys for males of the Afrotropical species of the subgenus
Author
Cornel, Anthony John
0000-0003-2735-8232
Mosquito Control Research Laboratory, Department of Entomology and Nematology and Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology, University of California at Davis. 9240 South Riverbend Avenue, Parlier, CA 93648. USA. Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang. PO Box 067, Dschang, Cameroon. & ajcornel @ ucanr. edu; https: // orcid. org / 0000 - 0003 - 2735 - 8232
ajcornel@ucanr.edu
Author
Mayi, Marie Paul Audrey
0000-0001-9892-7012
mayimariepaulaudrey @ yahoo. com; https: // orcid. org / 0000 - 0001 - 9892 - 7012
mayimariepaulaudrey@yahoo.com
Author
Kowo, Cyril
0000-0002-1880-1733
Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon. & kowoCyril @ gmail. com; https: // orcid. org / 0000 - 0002 - 1880 - 1733
yril@gmail.com
Author
Foncha, David
0000-0002-5476-1978
Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
Author
Andongma, Esack
Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
Author
Anong, Damian Nota
Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
Author
Elad, Mirabel
Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon.
Author
Djomo, Charlene
Higher Institute of Environmental Science, PO Box 35460, Yaounde, Cameroon.
Author
Tchuinkam, Timoleon
Author
Brisco, Katherine K.
Mosquito Control Research Laboratory, Department of Entomology and Nematology and Vector Genetics Laboratory, Department of Pathology, Microbiology and Immunology, University of California at Davis. 9240 South Riverbend Avenue, Parlier, CA 93648. USA. Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang. PO Box 067, Dschang, Cameroon.
Author
Sehgal, Ravinder
0000-0002-5255-4641
Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA. sehgal @ sfsu. edu, https: // orcid. org / 0000 - 0002 - 5255 - 4641
text
Zootaxa
2020
2020-10-02
4858
4
451
506
journal article
8293
10.11646/zootaxa.4858.4.1
2b22dadf-f467-49c8-be34-1362152a881b
1175-5326
4412583
2EBB5900-13F8-488A-8BE1-969BCCF5605B
Culex
(
Culiciomyia
)
nebulosus
Theobald, 1901
Male.
A small brown to greyish mosquito with no obvious distinguishing features. Integument of thoracic pleura generally not uniform in colour, with mesanepimeron, metepisternum and coxae whitish and antepronotum, proepisternum, postspiracular and subspiracular areas, mesokatepisternum and mesomeron light to dark brown. Scutal integument light brown. Wing
2.70 mm
. Proboscis
1.87 mm
. Forefemur
1.60 mm
.
Head:
Row of broad white decumbent scales along eye margin (
Fig. 25A,B,E
), pale narrow decumbent scales numerous on vertex (
Fig. 25A,B,E
), erect scales numerous, pale brown except for white to very light brown apices, broad white scales along eye margin tend to be more numerous towards sides of head and form a more distinct lateral patch (
Fig. 25A,E
). Maxillary palpus slightly longer than proboscis, palpomeres 4 and 5 bearing setae, palpomere 4 shorter than palpomere 5 (ratio 0.45–0.33), palpal comb scales described by
Edwards (1941)
as “the proximal part of this comb formed of scales shaped like spear-heads, the distal part of more close-set scales which are also broader and have fine recurved points” (
Fig. 25C
), 3 or 4 most basal of proximal set of 7 or 8 (rarely 9) with longer points, significant gap between proximal and distal sets, distal set with 9–10 scales more closely spaced, proximal scales often darker than distal set of scales (
Fig. 25C
); we prefer to describe distal scales as spatulate or oblanceolate with recurved fine points (aristate apices), proximal 3 or 4 scales of proximal set as lanceolate and other distal scales as narrowly ovate with aristate apices and cuneate bases. Antenna and proboscis similar to those of other
Culiciomyia
.
Thorax:
Variation in colour of thoracic integument may be dependent on age of mosquito or environmental conditions, such as larval diet, habitat or perhaps degree of exposure to UV light. Scutal and pleural integument light brown (in most specimens) to greyish (in some) creates some confusion about general colouring of this species (
Fig. 25A,D
). Scutum covered with short brown to shiny translucent setae, narrow white scales on scutellar lobes. Colour of thoracic pleural integument highly variable and mostly non-uniform. Mesanepimeron, metepisternum and coxae whitish, integument of antepronotum, proepisternum, postspiracular and subspiracular areas, mesokatepisternum and mesomeron light to dark brown; middle region of metepisternum light brown in some specimens, which gives pleura a more uniform brown appearance, but in others pleura appear more greyish, thus more closely fitting
Edwards (1941
“greyish mesonotum”); pleura devoid of scales except for small patch among setae on upper mesokatepisternum and occasionally a row along posterior margin of lower mesokatepisternum, scales absent on mesepimeron in majority of specimens but a few have 1 or 2 below mesepimeral seta; setae present in following regions: antepronotum, a row of 6 on posterior margin of postpronotum, 3 on proepisternum, prealar knob, all coxae, a few on upper and lower posterior margin of mesokatepisternum, and
1 in
lower mesepimeral area. Capitellum of halter darker than pedicel.
Wings:
Scales all dark.
Legs:
Coloured similar to those of other
Culiciomyia
, except
Cx. cambournaci
.
Abdomen:
Terga uniformly brown with paler small lateral spots in a few specimens; sterna light brown to beige.
Genitalia:
Lobes of tergum IX each with 5–9 (mostly 6, rarely 9) setae along upper margin (
Fig. 27A
). Description below includes details that were not mentioned in
Edwards (1941)
. Gonocoxites moderately broad with distinct patch of gold ventrolateral setae, mostly confined to middle 0.33 of gonocoxite, patch of 3 to 4 setae wide with each seta about 0.66 length of gonocoxite (
Fig. 26A,B
); dorsal surface of gonocoxite with few setae, each about same length as gonocoxite, distinct apical dorsal lobe bearing 4–7 setae (mostly 4), 3 rod-like setae (
a–c
) with 1 placed slightly more ventrally than other 2 and rod-like setae not necessarily as close together as described by
Edwards (1941)
, with tip of seta
a
slightly shorter and sharper apically than
b
and
c
,
b
and
c
slightly hooked apically and
b
noticeably darker than
a
and
c
(
Fig. 26B
), a consistently short seta present below or next to
a;
1 very broad slightly striated foliform seta (
g
) and shorter narrower foliform seta (
f
) half as broad as
g
; a stout striated seta (
e
) between bases of
f
and
g
slightly longer than
f
and
g
and 4 setae of which 2 (
d
1
–d
2
) longer and slightly broader than other 2. Gonostylus bent in middle with a large membranous flange dorsally, a single subapical seta and 1–5 (mostly 3 or 4) setae pre-dorsally positioned in proximity where gonostylus bends downwards (
Fig. 26A
), tip of gonostylus bent upwards into a hook and with a small broad foliform seta. Aedeagus broadened basally with distinct tooth at base of each lateral plate (
Fig. 27A,B
); from dorsal aspect lateral plate smooth and rounded apically, resembling what
Edwards (1941)
described as being “finger like processes”, however, from ventral and lateral aspects lateral plate clearly toothed along one margin and apex ends sharply, resembling the description provided for
Cx. nebulosus
by
Hamon & Lambrecht (1959)
, who described the lateral plate as sharp and having strong lateral teeth. Paraproct with typical dense crown of spicules and 3 or 4 small subapical setae (
Fig. 27A
).
Additional notes:
None of the
Cx. nebulosus
males from the Talangaye Forest have white scaling on the propleuron (proepisternum) and there was always only one lower mesepimeral (mesanepimeral) seta with no accompanying short setae, which precludes them from identification as
Cx
.
pseudocinereus
, which according to
Edwards (1941)
occurs more in eastern and southern Africa. Males of
Cx. nebulosus
,
Cx. furlongi
,
Cx. cinereus
,
Cx. lanzaroi
and
Cx. muspratti
have similar external features. The genitalia of
Cx. cinereus
are most easily distinguished from the genitalia of the other three species by the dense patch of delicate setae at the base of the subapical lobe, and
Cx. cinereus
also has no gap between the proximal and distal sets of palpal comb scales.
Hamon & Lambrecht (1959)
noted that the apices of the lateral plates of
Cx. nebulosus
are sharp whereas they are rounded in
Cx. muspratti
. In our opinion, the apices of the lateral plates of
Cx. nebulosus
appear rounded depending on the angle of the slide mount, we caution relying on using this feature to distinguish these two species.
Culex nebulosus
and
Cx. muspratti
have a strong basal tooth at the base of the lateral plate, whereas this is absent in
Cx. furlongi
.
The only character that likely separates
Cx. nebulosus
from
Cx. muspratti
is the number of narrower accessory appendages on the subapical lobe of the gonocoxite, with three in
Cx. muspratti
and two in
Cx. nebulosus
.
Van Someren (1954)
reported the presence of three short “narrow leaflets (
d–f
), which sometimes appear as “stout setae”, but did not mention or figure them as having barbs. The most distal palpal comb scales in
Cx. furlongi
end in fine short straight points whereas in
Cx. nebulosus
,
Cx. lanzaroi
and
Cx. muspratti
they are longer, strongly recurved and shaped much like the top bill of a hawk’s beak. Flat scales on the upper mesokatepisternum and the scales on the mesepimeron are easily rubbed off, and when present, these scales are often translucent and can be easily overlooked. The larvae of
Cx. muspratti
and
Cx. lanzaroi
are unknown. The larva of
Cx. nebulosus
is quite different from the larvae of
Cx. furlongi
and
Cx. cinereus
(
Hopkins 1952
;
van Someren 1954
). The only noticeable difference in the larvae of the latter two species is that the comb is composed of scales in
Cx. cinereus
and spine-like scales in
Cx. furlongi
(
van Someren 1954
)
.
Specimens examined:
The following males were reared from egg rafts laid in bamboo pots. Field accession numbers
CAM 47
e
1a 2/VII/2017
,
CAM 47
e1b
2/VII/2016
,
CAM 47
e1c
2/VII/2016
,
CAM 60
c.2
16/VII/2016
,
CAM 113
ca
7/
V/2017,
CAM 113
cb
7/
V/2017,
CAM 230
c
1a 10/XI/2017
,
CAM 230
c1b
10/XI/2017
and
CAM 230
c1c
10/ XI/2017
. One male examined was reared from a pupa collected in a rain-filled coconut husk lying on the ground. Field accession number
CAM 196
f3
16/VII/2017
.The other males examined from the Talangaye Forest were collected by sweep netting through vegetation on the forest floor. Field accession numbers
CAM 50
b.1
16/VII/2016
,
CAM 50
c.2
16/VII/2016
,
CAM 62
h
18/VII/2016
,
CAM
62g
28/VII/2016
,
CAM 62
d
29/VII/2016
,
CAM 86
ra
9/ XI/2016
,
CAM 132
ya
31/I/2017
,
CAM 132
yb
31/I/2017
,
CAM 132
yd
31/I/2017
,
CAM 132
ye
31/I/2017
,
CAM 132
yh
31/I/2017
,
CAM 132
yi
31/I/2017
,
CAM 132
yk
31/I/2017
,
CAM 132
o1d
1/II/2017
,
CAM 132
b
1a 2/II/2017
,
CAM 132
b1b
2/II/2017
,
CAM 132
ka
5/II/2017
,
CAM 132
kd
5/II/2017
,
CAM 132
ke
5/II/2017
,
CAM
132kg
5/II 2017
,
CAM 132
kh
5/II/2017
,
CAM 132
kj
5/II/2017
,
CAM 132
kk
5/II/2017
,
CAM 132
oa
6/II/2017
,
CAM 132
oc
6/II/2017
,
CAM 132
oe
6/II/2017
,
CAM 132
of
6/II/2017
,
CAM 132
og
6/II/2017
,
CAM 132
ga
7/II/2017
,
CAM 132
gc
7/II/2017
,
CAM 132
gf
7/II/2017
,
CAM 132
gi
7/II/2017
,
CAM 132
gk
7/II/2017
,
CAM 163
f
27/IV/2017
,
CAM 163
ca
28/IV/2017
,
CAM 163
cb
28/IV/2017
,
CAM 163
ia
1/
V/2017,
CAM 163
ib
1/
V/2017,
CAM 163
ga
2/
V/2017,
CAM 163
gb
2/
V/2017,
CAM 163
sb
2/
V/2017,
CAM 163
sc
2/
V/2017,
CAM 163
fb
5/
V/2017,
CAM 163
la
10/
V/2017, CAM
163lb
10/V/2017
,
CAM 163
la
26/
V/2017,
CAM 202
j
5/VII/2017
,
CAM 202
fb
6/VII/2017
,
CAM 202
la
8/VII/2017
,
CAM
202lb
8/VII/2017
,
CAM 202
na
9/VII/2017
,
CAM 202
nb
9/VII/2017
,
CAM 202
nc
9/VII/2017
,
CAM 202
ne
9/VII/2017
,
CAM 202
nf
9/VII/2017
,
CAM
202ng
9/VII/2017
,
CAM 202
ni
9/VII/2017
,
CAM 202
sb
10/VII/2017
,
CAM 202
rc
12/VII/2017
,
CAM 202
rd
12/VII/2017
,
CAM 202
re
12/VII/2017
,
CAM 202
rf
12/VII/2017
,
CAM 202
qb
13/VII/2017
,
CAM 202
qd
13/VII/2017
,
CAM 202
jb
14/VII/2017
,
CAM 202
jc
14/ VII/2017
,
CAM 202
jd
14/VII/2017
,
CAM 202
je
14/VII/2017
,
CAM 202
hb
16/VII/2017
,
CAM 202
c
17/VII/2017
,
CAM 202
tc
19/VII/2017
,
CAM 202
o
20/VII/2017
and
CAM 202
na
21/VII/2017
.
For
comparative purposes, we also examined males in the collection of the
National Health Laboratory Services Museum in Johannesburg
,
South Africa
.
These
were from: (i)
Gwaliweni Forest
,
Kwazulu Natal
,
South Africa
.
Cx. nebulosus
—
1 male
. Collected and identified by
Jim Muspratt
, 1957; (ii)
Port Shepstone
,
Kwazulu Natal
,
South Africa
.
Cx. nebulosus
—
1 male
.
Field
accession number
T154
.
No
other collection information on the label; (iii)
Livingstone
,
Zambia
.
Cx. nebulosus
var.
pseudocinereus
—
1 male
. Collected in 1945.
No
other collection information on the label; (iv)
Tete District
,
Kwazulu Natal
,
South Africa
.
Cx. nebulosus
var.
pseudocinereus
—
1 male
. Collected and identified by
Jim Muspratt
, 1955; (v)
Skukuza
,
South Africa
.
Cx. nebulosus
var.
pseudocinereus
—
1 male
. Collected and identified by
Leo Braack
,
22/III/1991
. Man-biting
.
FIGURE 25.
External features of
Culex nebulosus
.
(A, D) Dorsolateral views of the head and scutum; (B,E) dorsal views of the head; (C) lateral view of the palpal comb scales (100x).
FIGURE 26.
Gonocoxite of
Culex nebulosus
.
(A) Drawn depiction; (B) image (100x).
FIGURE 27.
Lateral plate-aedeagal sclerite and paraproct of
Culex nebulosus
.
(A) Drawn depiction; (B) image (400x).
Other
specimens previously collected by one of us (
AJC
) in
Cameroon
were also examined.
These
were from: (i)
Ikange
,
Cameroon
(
4.12000º N
;
9.44944º E
).
Cx. nebulosus
—
2 males
. Collected and identified by
AJC
, 2011. Reared from a larva found in a collecting cup on the side of a rubber tree; field accession number
CAM 12.32
.1
6/IX/2011
.
Reared
from larva in road-side pool; field accession number
CAM 12.34
.1
8/IX/2011
; (ii)
Beau
,
Cameroon
(
4.15333° N
;
9.25333° E
).
Cx. nebulosus
—
2 males
. Collected and identified by
AJC
, 2011. Reared from a larva found in a bucket of water; field accession number
CAM 12.22
.1
3/IX/2011
.
Reared
from larva collected in a concrete water reservoir; field accession number
CAM 12.37
b
10/IX/2011
; (iii)
Niete
,
Cameroon
(
2.72617º N
;
10.07096º E
).
Cx. nebulosus
—
1 male
. Collected and identified by
AJC
, 2013. Reared from larval collection in a banana leaf axil; field accession number
CAM 12.58
.16
6/IX/2013
.