Psorophora (Grabhamia) paulli Paterson & Shannon

Stein, Marina, Rossi, Gustavo Carlos & Almirón, Walter Ricardo, 2013, Description of male, pupa and larva of Psorophora (Grabhamia) paulli and redescription of the female (Diptera: Culicidae), Zootaxa 3686 (3), pp. 389-395 : 390-393

Psorophora (Grabhamia) paulli Paterson & Shannon

Psorophora paulli Paterson & Shannon, 1927: 4 ,9 (F). Type locality: Tres Pozos, Salta, Argentina (I.N.M). Lane 1953: 768 (F). Guedes et al. 1965: 18 (F*). Casal in Belkin et al. 1968: 13 (lectotype designation).

FEMALE: Small mosquito. General colour dark brown. Head: Occiput covered with narrow silver decumbent scales; forked scales broad and pale. Antenna same length as proboscis. Pedicel with silver scales on mesal side. Proboscis slightly longer than forefemur, mainly dark with small white scales scattered on whole length except, at apex. Maxillarypalpus 0.16 length of proboscis, with black scales. Thorax: Scutal integument dark brown, covered with thin dark brown scales and narrow silver scales laterally, extending mesad on scutum. Acrostichal and dorsocentral setae light brown. Pleura with broad white scales forming groups on mesokatepisternum, mesanepimeron and paratergite. Pleural setae light brown: 9–12(10) proepisternal, 10–16(14) prealar, 6–10 and 2–4 upper and lower mesanepimeral respectively, 4–6(6) and 3–6(5) upper and lower mesokatepisternal and 1 or 2 and 4 or 5 pre- and postspiracular respectively. Scutellum with silver scales confined to lobes, large setae on mid (13) and lateral lobes 8 total. Wing: Whitish and dark scales on most veins. White scale-spots before bifurcation of R2+3, on R4+5, apically on R2+3, R 2 and R3, at base of M1+2, R3+4 and CuA, and middle of CuA and 1A. Halter : Integument white, capitellum covered with white scales. Legs: Integument dark brown, coxae with white scales. Femora black-scaled anteriorly, posteriorly white-scaled, and pre-apically with white-scaled band. Femur-tibial joints white-scaled. Tibiae dark scaled. Joints of tarsomeres with small rings of white scales. Ungues of all legs simple. Abdomen: Integument dark brown. Terga with black scales and triangular spots that join to form an apical band of white scales. Tergum VII with scattered white scales. Sterna with white scales, black scales on lateral margins of some sterna.

MALE: Like female except for following sexual differences. Genitalia ( Fig. 1 c): Tergum IX sclerotized, lobes separated by central concavity, each lobe with 6 conspicuous setae. Gonocoxite cylindrical, 2.5 times longer than basal width, minutely spiculate, long, strong setae on dorsal surface, shorter and thinner setae ventrally. Apex of gonocoxite expanded. Gonostylus narrow, widened in middle, round basally, enlarged reticulate surface at middle, slender at apex, 0.60 of gonocoxite length, with 2 setae on inner side. Gonostylar claw gently curved and pointed. Claspette: Not divided, narrow, apex with 7 flattened setae with blunt tips and small distal spicules. Proctiger: Narrow, toothed. Cercus with 4 setae. Aedeagus: Cylindrical, moderately broad at base with large basal opening.

PUPA ( Fig. 1 a, b): Insertions and character of setae as figured; range and modal number of branches in Table 1 . Cephalothorax: Integument light brown. Trumpet cylindrical, lightly tanned; length 0.40–0.45 mm (mean 0.42 mm), width 0.10–0.16 mm (mean 0.13 mm), index 3.33–4.00; pinna ~0.37 length of trumpet; tracheoid area ~0.60 length of trumpet. Abdomen: Lightly tanned, similar to cephalothorax, with darker median longitudinal strip. Setae 1-IV-VII usually double. Genital lobe: Tanned in both sexes, length 0.22–0.23 mm (mean 0.23 mm) in female, 0.30 mm in male. Paddle: Ovoid, hyaline, buttress darker, length 0.65–0.70 mm (mean 0.68 mm), width 0.43–0.52 mm (mean 0.47 mm), paddle index 0.66–0.74, midrib evident, except apically, length 0.50–0.55 mm (mean 0.53 mm). Seta 1-Pa usually single, seta 2-Pa 0.50 length of 1-Pa.

LARVA (fourth-instar) ( Fig. 2 ): Placement and character of setae as figured; range and modal number of branches in Table 2. Head: Wider than long, width 1.12–1.22 mm (mean 1.18 mm), length 0.68–0.75 mm (mean 0.70 mm). Integument lightly tanned. Dorsomentum triangular, with 9–10 (9) dark teeth on each side of median tooth. Setae 1,3-C single; seta 2-C absent; seta 3-C, 0.10 length of 1-C; seta 4-C very small, with 3–6(4) branches, inserted posterior to setae 5,6-C; setae 5,6-C single, aciculate; seta 7-C with 3,4(3) branches; setae 8,9-C similar in length, 8-C with 1,2(2) branches, seta 9-C with 2,3(2) branches; seta 11-C with 2–4(3) branches; seta 15-C with 8,9(9) branches; setae 10,13,14-C single, seta 12-C with 3,4(4) branches. Antenna: Length 0.74–0.85 mm (mean 0.79 mm), slightly Sshaped, spiculose, darkly tanned. Seta 1-A with 6–8(6) aciculate branches, inserted before mid-length of antenna; setae 2,3-A broad, inserted on apical third of antenna. Thorax: Integument hyaline, smooth. Tubercles of setae 9–12- M,T with small rounded apical denticles. Seta 0-P with 2–4(3) branches; setae 1–4-P single; seta 5-P single or double; setae 1,6,7-P aciculate, 6,7-P each on sclerotized tubercle, seta 6-P single, seta 7-P double; seta 8-P triple; setae 9–12- P single, inserted on common tubercle; seta 14-P single. Setae 1–3-M single, small; seta 4-M single or double, small; seta 5-M single, strong; seta 6-M with 4,5(4) branches; seta 7-M single; seta 8-M with 5 branches; seta 9-M with 3– 5(5) branches; setae 10,12-M single; seta 11-M double; seta 13-M with 6,7(7) branches; seta 14-M with 4,5(5) branches. Setae 1,2,4,5,6-T single; seta 3-T double; seta 7-T with 5–7(7) aciculate branches; seta 8-T with 7–9(7) branches; seta 9,11,12-T single; seta 10-T with 3,4(3) branches; setae 11,12-T similar to 11,12-M; seta 13-T single. Abdomen: Integument hyaline, smooth. Tubercles of setae 6,7-I,II evenly colored light brown. Seta 0-II–V single; seta 1-I with 3–5(5) branches, seta 1-II–V,VII,VIII single, seta 1-III–V longer than corresponding segment, seta 1-VI triple; seta 6-I with 5,6(6) branches, seta 6-II with 2,3(3) branches, seta 6-III with 2,3(2) branches, seta 6-IV,V double; seta 7-I with 3,4(4) branches, seta 7-II –IV-V triple, seta 7-III with 2,3(3) branches, seta 7-VI single. Segment VII with short setae, only seta 1-VII stout, long. Segment VIII: Comb with 6,7(6) spine-like scales of same size in a row on sclerotized plate; apical spine 4 times longer than lateral spicules. Seta 5-VIII twice length of segment X, broad. Segment X: Saddle complete, brown, with minute spicules on posterolateral margins. Setae 1,3-X single, 1-X <0.5 length of segment X; 2-X triple; seta 4-X with 3 precratal setae and 4 setae on grid.. Anal papillae 4.3 times longer than segment X, each with conspicuous tracheae. Siphon: Brown, length 0.65–0.70 mm (mean 0.66 mm), width at base 0.25–0.28 mm (mean 0.26 mm), index 2.50. Pecten on basal 0.30, with 4–6(5) spines, length of spines 125–150 µm, sometimes with 1,2 basal denticles. Seta 1-S with 6–9(6) aciculate branches; seta 2-S curved, strong, length 125 µm, similar to apical diameter of siphon.

†Seta 1-I has 6–10 main branches and more than 60 secondary branches. *: uncontable.

Material examined. Argentina, Chaco: Monte Alto (27º 26’ S, 58º 55’ W), 3F, 1M, 1MG, 4Le, 4Pe collected 21-III-2002 and 2F, 2Pe, 2Le collected 23-X-2003, Stein & Willener coll.

Distribution. This species is known from Argentina and Bolivia ( Knight & Stone 1977). In Argentina, it is known from the following provinces: Chaco, Corrientes, Formosa, Jujuy, Salta, Santa Fe and Santiago del Estero ( Mitchell & Darsie 1985; Campos & Maciá 1998; Ludueña Almeida et al. 2004).

Bionomics. Immature stages were collected from shallow, temporary, ground pools with clear or turbid water, with or without emergent grasses and full exposure to sun light. They were found in association with larvae of Ochlerotatus albifasciatus (Macquart) , Ps. ciliata Fabricius , Ps. cingulata (Fabricius) , Ps. cyanescens (Coquillett) , Ps. pallescens Edwards and Ps. varinervis Edwards.

Taxonomy. The antennal shape and positions of setae 2 and 3-A of Ps paulli are similar to those of Ps. varinervis and Ps. discolor (Coquillett) . Psorophora paulli can be distinguished from these two species by the following characters: seta 1-X single less 0.5 length of segment X, anal papillae 4.3 times as long as segment X, seta 5-VIII strong and long, comb with 6 spines on sclerotized plate, seta 1-C long and straight and seta 2-S sometimes hook-like. In Ps. discolor seta 1-X is single, longer than segment X, anal papillae approximately three times as long as segment X, comb similar to that of Ps. paulli , seta 1-C long and very curved, similar to an inverted U, and seta 2-S curved. In Ps. varinervis , seta 1-X is double, anal papillae approximately twice as long as segment X, seta 5-VIII multibranched and comb with 6 separated spines ( Carpenter & La Casse 1955; Rossi et al. 2008). The pupa of Ps. paulli is similar to the pupa of Ps. varinervis but can be distinguished by having setae 6,7-I nearly the same length whereas seta 7-I is shorter than seta 6-I in Ps. varinervis . The pupa of Ps. discolor may be distinguished from the pupae of Ps. paulli and Ps. varinervis by the extremely long paddle seta, which is generally more than 0.25 the length of the paddle ( Barr & Barr 1969) (in Ps. paulli and Ps. varinervis it is less than 0.17 the length of the paddle). Seta 12-CT is long and double and seta 5-I is generally long and single in Ps. paulli ; seta 12-CT is short and single, and seta 5-I is short and multiple in Ps. varinervis ( Rossi et al. 2008) . The male genitalia of Ps. paulli are similar to the genitalia of other species of subgenus Grabhamia , but the claspette differs in having seven flattened setae with blunt tips and small distal spicules, the three internal setae have distal spicules and the three external setae have minute striation in Ps. varinervis . The gonostylus is narrow, quadrangular basally and has an enlarged median reticulated area in Ps. discolor whereas in Ps. paulli it is round basally and in Ps. varinervis it is slightly expanded at mid-length. Each ninth tergal lobe has six setae in Ps. paulli and 12–14 in Ps. varinervis ( Rossi et al. 2008) . The adults of Ps. paulli are small, which allows this species to be separated from other species of Psorophora . The general coloration is dark, similar to Ps. confinnis (Lynch Arribalzaga) , but Ps. paulli can be separated from Ps. confinnis by the presence of white-scaled spots on the wings and the absent of basal pale-scaled bands on hindtarsomere 1 (Darsie 1985). Psorophora varinervis and Ps. discolor are generally pale with dark-scaled spots on the wings. The wings of Ps. varinervis have a single dark spot on the base of vein R4 +5 whereas the distribution of pale and dark scales in Ps. discolor is similar to that of Ps. paulli . The species can be separates by the preponderance of pale scales on veins 1A and CuA in Ps. discolor (pale scales are located in a median strip or at the base of the wing in Ps. paulli ). Pale scales occur on the middle of veins M1+2 and R3+ 4 in Ps. discolor whereas in Ps. paulli they extend to the apex of vein M1+2 and are absent from vein R3+4.

Figures

FIGURE 1. Pupa and male genitalia of Psorophora paulli. a: Cephalothorax; b: metanotum and abdomen; c: gonocoxopodite and phallosome; d: tergum IX. A = antenna; Ae = aedeagus; BP = basal piece; CT = cephalothorax; Cl = claspette; Dap = dorsal apotome; Gc = gonocoxite; GC = gonostylar claw; Gl = genital lobe; Gs = gonostylus; MK = median keel; MPlp = maxillary palpus; Mtn = metanotum; Pa = paddle; Par = paramere; Ppr = paraproct; T = trumpet; I – VIII = abdominal segments.

FIGURE 2. Larva of Psorophora paulli. a: Head; b: thorax and abdominal segments I – VI; c: abdominal segments VII, X and siphon. A = antenna; C = cranium; CS = comb scale; Dm = dorsomentum; M = mesothorax; P = prothorax; PS = pecten spines; S = siphon; T = metathorax; I – VIII, X = abdominal segments.

Tables

TABLE 1. Range (mode) of branches for setae of the pupa of Psorophora (Grabhamia) paulli (n = 6). CT: cephalothorax; Pa: paddle.

Seta no. CT	Abdominal segments						Pa
	I II III	IV	V	VI	VII	VIII
0 -	- 1 1	1	1	1	1	1	-
1 2	† 3-6(4) 2-5(4)	2	2	1-4(2)	1-3(2)	-	1
2 2	1,2(1) 1 1	1	1	1	1	-	1
3 2	1-4(1) 1 1	3-5(5)	2-5(5)	1	1-3(1)	-	-
4 2,3(2)	* 4,5(4) 2-5(5)	1-3(2)	1-5	1-4(4)	1,2(1)	1	-
5 4,3(3)	1-3(1) 3-5(4) 3-5(5)	2	2	2	1-3(2)	-	-
6 1-4(4)	1-3(1) 1 1,2(1)	1,2(1)	1	1	4-6(5)	-	-
7 1-5(2)	1-3(1) 3 2,3(3)	2,3(2)	1-4(1)	1	1,2(1)	-	-
8 2,3(2)	- - 1,2(2)	1,2(1)	1-3(1)	2,3(2)	3-7(3)	-	-
9 1,2(1)	1 1 1	1	1	1	3	3-6(4)	-
10 5	- - 1	1	1	1	1	-	-
11 1	- - 1	1	1	2-4(3)	1-3(1)	-	-
12 2,3(2)	- - -	-	-	-	-	-	-
13 -	- - -	-	-	-	-	-	-
14 -	- - 1	1	1	1	1	1	-