Redescription of Culex (Culex) brethesi Dyar, 1919 (Diptera: Culicidae)
Author
Rossi
Author
C, Gustavo
text
Zootaxa
2006
1312
25
35
journal article
10.5281/zenodo.173889
d7f89276-d913-477c-9f9b-11e1175c949f
11755326
173889
Culex
(
Culex
)
brethesi
Dyar, 1919
Previous usage:
Culex lynchii
Bréthès, 1912
, female;
Bréthès, 1916
, male (not female);
Bachmann & Casal, 1962
, male, larva, pupa; in part of
Bram, 1967
.
Culex
(
Culex
)
brethesi
of
Dyar, 1928
, male, female.
Culex
(
Culex
)
inflictus
in part of
Lane, 1953
.
FEMALE: (Range of branches based on 8 reared females). Head: integument dark brown. Vertex and occiput with narrow, curved decumbent pearly scales medially, broader and whitish laterally and denser, forked scales black. Clypeus dark brown, bare. Proboscis longer than forefemur, darkscaled but scales on underside paler from near base to distal 0.2. Maxillary palpus 0.17 length of proboscis, palpomere 3 darkscaled. Antenna subequal to proboscis in length, pedicel brown. Thorax: scutal integument dark brown, setae dark. Scutal scales small, fine, golden, somewhat larger on scutal fossa and supraalar areas. Scutellar integument moderate brown. Scutellar setae strong, long, 8 on mid lobe and 6 each in lateral lobe. Scutellar scales same as scutal fossal scales. Paratergite bare. Antepronotum: light brown, 8–10 large setae, 2–5 small setae and few scales. Pleural integument whitish. Pleural setae dark, numbers as follows: 12 (9–15) proepisternal, 2–4 prealar, 2 upper mesokatepisternal, 2–5 lower mesokatepisternal, 1 prominent lower mesepimeral, 9–12 upper mesepimeral. Pleural scales in whitish patches on lower and upper mesokatepisternal and small patch before upper mesepimeral setae. Without prealar and postspiracular scales. Legs: coxae and trochanters with scales on lateral surface. Femora darkscaled except for line of light scales on anterior surface from base to near apex; tibiae darkscaled with white scales at apex and base; tarsi darkscaled. Wings: darkscaled, costa with pale scales from base to level of humeral crossvein. Halter: stem light, apex and knob darkscaled. Abdomen: terga mainly blackscaled; tergum I setose, without scales; terga II, VIII with traces of basal white bands, with posterolateral triangular patch of white scales extending basally, these spots united to inconspicuous basal pale bands when present. Sternum II with white scales, III to VIII with dark scales and median and posterior patches of white scales.
MALE:
Holotype
male mounted on a microscope slide with a female, labeled: "
Culex Lynchii
Brethes
" (handwritten in ink) and “Holotipo
Culex
(
Culex
)
brethesi
364,
Dyar, 1919
; 1966 Casal” (handwritten in pencil). On the other side: “
Holotypus
” and “Dipt. 62” on separate labels. This information appears in
Belkin
et al
. (1968)
. The
holotype
is deposited in the Buenos Aires Museum (
Fig. 2
a, b, c). Head: as described for female except for sexual differences. Proboscis darkscaled except from base to apex ventrally. Maxillary palpus exceeding length of proboscis by length of two distal palpomeres; bases of palpomeres 3, 4 and 5 and apices of 3 and 5 with spot of white scales, and 4 with small line apically. Abdomen: terga with traces of narrow basal white bands, basolateral spots distinct. Genitalia (Fig. 1): Ninth tergal lobes small, each with 9–19 setae in 2 or 3 irregular rows (Fig. 3 d). Gonocoxite (Fig. 1 a, b,
Fig. 2
c) normal, with 1016 strongly developed ventrolateral setae. Subapical lobe undivided, gonostylus stout, curved and narrowed distally, with 2 small slender setae near apex of concave surface. Gonostylar claw short, troughlike. Subapical lobe of gonostylus prominent, undivided, setae
a–c
and
g
in row on apex, setae
f
and
h
at level of
g
on mesal and lateral sides of lobe respectively, setae
a
rodlike and pointed,
b
and
c
with hooked apices,
g
foliform, asymmetrical,
f
short, and
h
slightly curved distally. Phallosome (Fig. 1 c, d, e, Fig. 3 c): lateral plate small with 13 small teeth, small lateral lobe flat, continuous with base of thumblike dorsal process. Ventral arm straight dorsomesad, dorsal surface somewhat convex, longer than teeth, dorsal arm Vshaped medially. Paraproct with long, curved basal lateral arm and conspicuous ventral acetabulum, with lobelike appearance near paraproct crown, crown dark with numerous needlelike spicules, basal lateral arm with 2–5 cercal setae. Seta
f
of the
holotype
is very short. In 10 of
36 male
genitalia examined, seta
f
was minute (
Fig. 2
c), in 14 other it was represented by one alveolus and in another 12 it was not visible.
PUPA: Placement and character of setae as in Fig. 3, range and modal number of branches in Table 1.
Cephalothorax
: Lightly tanned, metanotum and legs darker, setae 1,2 9CT usually triple, 3,512CT usually with 4 branches, 10CT usually with 9 branches (4–11), 11CT usually double (90%) (2,3).
Trumpet
: tanned, almost cylindrical, index 5.50 (4.18–6.43) tracheoid area darker, about 0.3 from base.
Abdomen
: lightly tanned, posterior area of tergum I and anterior margin of other terga darker, particularly terga IIVII; length about 3.3 mm. Seta
1I
with 6–8 primary branches,
1II
with 9–20 branches,
1III
usually 6 branches, setae
2I
,
10IV
,
11V
,VII and
7VII
usually single (90%).
Genital lobe
: lightly tanned in both sexes, length 0.20 mm in female, 0.39 mm in male.
Paddle
: lightly tanned, midrib distinct except at apex; 2 setae present 1Pa larger, single or double with distinct alveolus, 2Pa shorter, single, without distinct alveolus. The positions of these setae relative to each other are quite variable.
TABLE 1.
Number of branches for pupal setae of
Culex
(
Culex
)
brethesi
Dyar
a.
| Seta Number |
CT |
I |
II |
III |
IV |
V |
VI |
VII |
VIII |
IX |
P |
| 0 1 |
24 (3) |
68 (7)b |
1 410 (8) |
1 920 (17) |
1 48 (7) |
1 27 (6) |
1 37 (4) |
1 16 (3) |
1 |
1 |
1,2 (1) |
| 2 |
24 (3) |
15 (1) 90% |
1 |
1 |
1 |
1 |
1 |
1 |
|
|
1 |
| 3 |
37 (4) |
13 (2) 80% |
2 |
1,2 (2) |
26 (3) |
2 |
13 (2) |
2,3 (3) 90% |
|
|
|
| 4 |
27 (3) |
13 (2) |
17 (4) |
26 (4) |
14 (3) |
27 (3) |
1,2 (2) |
27 (2) 80% |
14 (2) |
|
|
| 5 |
26 (4) |
17 (6) |
46 (4) |
28 (6) |
27 (3) |
2 |
15 (2) |
26 (2) 80% |
|
|
|
| 6 |
24 (2) |
1 |
1 |
26 (4) |
36 (3) |
26 (5) |
28 (5) |
2,3 (3) |
|
|
|
| 7 |
24 (2) |
1,2 (1) |
1,2 (1) |
14 (3) |
17 (3) |
17 (1) |
1 |
1,2 (1) 90% |
|
|
|
| 8 |
37 (6) |
|
|
16 (1) |
1,2 (2) |
14 (2) |
1,2 (1) |
14 (3) |
|
|
|
| 9 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
26(4) |
618 (8) |
|
|
| 10 |
411 (9) |
|
|
1,2 (2) |
1,2 (1) 90% |
1 |
1 |
1 |
|
|
|
| 11 |
1,2 (2) 90% |
1 |
|
1 |
1 |
1,2 (1) |
1 |
1,2 (1) |
|
|
|
| 12 |
27(4) |
|
|
|
|
|
|
|
|
|
|
| 13 |
|
|
|
|
|
|
|
|
|
|
|
| 14 |
|
|
|
1 |
1 |
1 |
1 |
1 |
1 |
|
|
a Based on counts from
10 specimens
. b Number of primary branches Mode in parenthesis.
LARVA: Placement and character of setae as in
Fig 4
, range and modal number of branches in Table 2.
Head
: lightly tanned, darker areas of antennal prominence, compound eye and dorsal apotome. Collar moderately developed along lateralia, tanned. Dorsomentum with 5–7 teeth on either side of median tooth. Seta 1C slender, 2C absent, 3,4C single, 57C strongly developed, 5C usually 5 branched (3–7), 6C usually triple (3–6), 7C with 5–10 branches.
Antenna
: length 0.64–0.74 mm, range 0.66 mm. lightly tanned, darker distally; seta 1A with 18–28 (mode 21) aciculate branches.
Thorax
: integument hyaline, covered with tiny spicules (near 5 µm), tubercles of all large setae tanned, tubercles of setae 912P, M with moderately large spine. Setae 13, 6P single, 4,7P double, 8P usually with 14 branches, 11P with 3–5 branches. Seta 1M usually with 1–5 branches, larger than 3M; 3M usually single. Setae 1,2T of similar length.
Abdomen
: integument hyaline, spiculation present but finer than on thorax, more evident on segment VIII. Tubercles of setae
6I
,VI,
7I
and 1
3
VIII moderately tanned. Seta
1II
VI double,
1I
with 5–11 branches.
Segment VIII
: comb with 34–44 scales arranged in 3 or 4 irregular rows, scales normally fringed on sides and apex. Seta
1VIII
with 7–9 branches,
3VIII
with 8–12 branches,
5VIII
with 3–7 branches.
Siphon
: tanned; pecten on basal 0.3 of siphon, with 11–17 large scales each with 13 basal denticles; index 3.79–4.91, mean 4.35. Seta 1S in six pairs, 1aS inserted near most distal pecten spine, 1eS out of line.
Segment X
: saddle complete, tanned, with distinct spicules on posterolateral end; length 0.44–0.50 mm, range 0.46 mm. Seta
1X
usually double (2,3),
2X
usually double (2,3), ventral brush (seta
4X
) with 6 pairs of setae.
Male genitalia structures of
Culex brethesi
. a, b: Gonocoxite; c: Lateral plate in dorsal
view; d: Lateral plate in ventral view; e: Lateral plate of the
holotype
of
Cx. brethesi
.
FIGURE 2.
Holotype of
Culex brethesi
: a: Microscope slide bearing the holotype (the lower specimen); b: Genitalia; c: Detail of the gonocoxite.
Pupa of
Culex brethesi
. a): Cephalothorax, CT; b): Metathorax and abdomen, left side = dorsal, right side = ventral; and male genitalia structures of
Cx. brethesi
; c): Lateral plate of genitalia; d): Ninth tergum of genitalia.
FIGURE 4.
Larva of
Cx. brethesi
,
a): Thorax and abdominal segments IVI; left side = dorsal, right side = ventral; b): Head; left side = dorsal, right side = ventral. Pecten (PS); comb scale (CS); c): Abdominal segments VIIX, side view.
Material examined
:
Culex brethesi
:
40 ♂
,
41 ♂
G, 30 Ψ, 45 Pe, 8 P, 25 Le, 9 L, as follows:
Argentina
: Buenos Aires Province, San Isidro
1 ♂
holotype
Bréthès leg.
MACN
; Zarate
3X1998
,
12 ♂
,
12 ♂
G, 5 Ψ, 8 Pe, 2 L, 13 Le, Spinelli leg.; same locality Route
9 km
109
3III2004
,
1 ♂
,
1 ♂
G, 5 Ψ, 6 Pe, 4 Le Rossi leg.; Tandil, Airport,
13X2001
1 ♂
,
1 ♂
G, G. Marti leg.; Brandzen, Route
215 km
, 25,
22
III1989,
1
♂,
1 ♂
G, G a r c ίaRossi leg.; La Plata, City Bell,
27IX1987
,
7 ♂
,
7 ♂
G, 2 Pe, 1 Le, Rossi leg.; La Plata, Romero, April, 1996, 3 Ψ, 2 Pe, 6 Le;
24V1996
, 1 Pe, 2 L, 2 Le; Jun., 1996,
1
♂,
1♂
G, 1 Pe, 1 Le;
17VIII2001
,
1 ♂
,
1 ♂
G, 1 Pe, 1 Le;
26VIII2001
,
2 ♂
,
2 ♂
G, 2 Pe, 1 L, 4 Le, all J. J. Garcia leg.; idem,
2 ♂
,
2♂
G, 3 Ψ, 5 Pe, 5 Le,
6VII2005
; idem,
2 ♂
,
2 ♂
G, 6 Ψ, 12 Pe, 9 Le, 2 L,
28IV2005
, all V. Micieli leg.; Ensenada, Punta Lara, Boca Cerrada,
25IX1989
,
4 ♂
,
4 ♂
G, 4 Ψ, 3 Pe, 2 L, CamposMaciá leg. Entre Rίos Province, Chajari, Camping Drewars,
1 ♂
G, 1 Ψ, 1 Pe, R. Ronderos leg.; Corrientes Province, Villa Olivari,
16VIII 1995
, with
CDC
light trap,
2 ♂
,
2 ♂
G, Rossi leg.; Posadas, Misiones Province,
3 ♂
,
3 ♂
G, 3 Pe, Rossi leg. All specimens are deposited in the La Plata Museum.
Comments
: The positions of the paddle setae are variable, as shown in Fig.3b.
Tanaka (2004)
made a similar observation for species of
Culex
from
Japan
. Tanaka designed the longer seta with an alveolus as seta 1Pd and the shorter one without a visible alveolus as seta 2Pd. In this work these setae are designated setae 1Pa and 2Pa, respectively, in accordance with more recent workers.
Distribution
:
Culex brethesi
is known from the provinces of Buenos Aires, Cordoba, Mendoza, Misiones, Santa Fe and Santiago del Estero, all confirmed by dissection of male genitalia (
Bachmann & Casal, 1962
), Entre Rios Province (
Rossi, 1995
), Corrientes Province (
Rossi
et al
., 2002
), and Misiones Province (this report). Other records of this species not based on dissected male genitalia are dubious.
Systematics
:
Culex brethesi
larvae were collected in ponds or pools with or without grass. In some specimens were collected in association with larvae of
Cx. dolosus
and
Cx. maxi
Dyar, 1928
. The presence of pale scales at the base of the costa in adults of
Cx
.
brethesi
is a characteristic of several species in South
America
, including
Cx. apicinus
Phillipi, 1865
,
Cx. fernandezi
Casal
, Garcίa & Cavallieri, 1966,
Cx. lahillei
Bachman & Casal, 1962
,
Cx. maxi
and
Cx. paramaxi
Duret, 1968
. The characteristics that separate
Cx
.
brethesi
from these species include: tarsi and abdominal segments with white bands in
Cx
.
maxi
; abdominal terga with white bands in
Cx
.
fernandezi
; postspiracular scales in
Cx
.
lahillei
; scutum with pattern of pale scales in
Cx
.
apicinus
; and
Cx
.
paramaxi
is known only in the
type
locality. The male is distinguished by the genitalia. The reduction of the mesosome is similar to
Cx
.
acharistus
Root, 1927
, but this species has seta
f
hooked. The majority of pupae of the species of
Culex
(
Culex
)
are extremely similar and very difficult to differentiate. The fourthinstars larva of
Cx. brethesi
is very similar to
Cx
.
dolosus
(
s.l
) and
Cx
.
eduardoi
Casal & Garcia. It
is possible to distinguish
Cx
.
dolosus
by the larger spicules and smaller length of the saddle, and
Cx
.
eduardoi
by the larger siphonal index, larger number of comb scales and absence of spicules in abdominal segments I–VI.
TABLE 2.
Number of branches for setae of the fouthinstar larvae of
Culex
(
Culex
)
brethesi
Dyar.
a
Head Thorax Abdominal segments
| Seta Number |
C |
P |
M |
T |
I |
II |
III |
IV |
V |
VI |
VII |
VIII |
X |
| 0 |
|
48 (8) |
|
|
|
1 |
1 |
1 |
1 |
1 |
1 |
1 |
|
| 1 |
1 |
1 |
15 (4) |
35 (4) |
511 (7) |
46 (4) |
46 (4) |
35 (4) |
3,4 (4) |
24 (4) |
4,5 (5) |
79 (8) |
2,3 (2) |
| 2 |
|
1 |
2,3 (2) |
1,2 (1) |
1,2 (1) |
1,2 (1) |
1,2 (1) |
1 |
1 |
1 |
1,2 (1) |
1 |
2,3 (2) |
| 3 |
|
1 |
1 |
47 (4) |
2,3 (2) |
1,2 (2) |
13 (1) |
1,2 (1) |
1 |
13 (1) |
1,2 (1) |
812 (9) |
1 |
| 4 |
1 |
2 |
24 (2) |
36 (4) |
913 (11) |
49 (7) |
13 (1) |
13 (2) |
47 (5) |
35 (4) |
1,2 (1) |
37 (7) |
5,6 (6) |
| 5 |
38 (7) |
1 |
14 (1) |
1,2 (1) |
25 (3) |
24 (3) |
25 (3) |
35 (3) |
2,3 (3) |
24 (3) |
24 (4) |
|
|
| 6 |
36 (3) |
1 |
1 |
1,2 (1) |
3 |
3 |
2 |
2 |
2 |
2 |
> 16 |
|
|
| 7 |
(7) |
2 |
1 |
69 (9) |
2 |
49 (5) |
310 (8) |
69 (7) |
512 (10) |
1 |
1 |
Siphon |
| 8 |
26 (4) |
2 |
58 (5) |
48 (5) |
|
1 |
1,2 (1) |
1,2 (1) |
2 |
13 (2) |
58 (8) |
1aS 48 (6) |
| 9 |
38 (6) |
1 |
36 (4) |
47 (5) |
2 |
1 |
1,2 (1) |
1 |
1,2 (2) |
1 |
35 (4) |
1bS 38 (6) |
| 10 |
2,3 (2) |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1cS 59 (6) |
| 11 |
(2) |
35 (3) |
24 (3) |
15 (4) |
49 (5) |
25 (3) |
1,2 (2) |
13 (1) |
13 (2) |
15 (4) |
1,2 (2) |
1dS 59 (6) |
| 12 |
35 (3) |
1 |
1 |
1 |
13 (1) |
14 (3) |
13 (1) |
13 (2) |
13 (1) |
1 |
13 (1) |
1eS 35(4) |
| 13 |
2,3 (3) |
|
> 11 |
48 (5) |
13 (2) |
> 30 |
35 (4) |
4,5 (4) |
46 (4) |
> 50 |
35 (3) |
1fS 35 (4) |
| 14 |
1,2 (1) |
1 |
|
|
|
1 |
1 |
1 |
1 |
1 |
1 |
| 15 |
27 (5) |
|
|
|
|
|
|
|
|
|
|
| 16 |
|
|
|
|
|
|
|
|
|
|
|
| 17 |
|
|
|
|
|
|
|
|
|
|
|
|
|
a Based on counts from
10 specimens
. Mode in parenthesis.