Culex (Culex) articularis Philippi
Creators: name: Laurito, Magdalena
name: Almirón, Walter Ricardo
name: Rossi, Gustavo Carlos
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Culicidae
Culex
Culex articularis

description: Culex (Culex) articularis Philippi
Culex articularis Philippi, 1865: 596 (A). Type locality: Casa Pangue, Llanquihue, Chile (USNM). Stone et al. 1959. Dyar 1928: 358 (M*, F). Lane 1951: 334 (syn. of archegus Dyar). Lane 1953: 362 (M*, F). Forattini 1965: 145 (M*). Bram 1967: 23 (M*, L*; syn., neotype designation).
PUPA (Fig. 4): Placement and character of setae as figured; number of branches in Table 3. Cephalothorax (Fig. 4 a): integument yellowish, homogeneously colored; distal half of maxillary palpus and median keel slightly tan, metanotum yellowish to tan. Trumpet conical to cylindrical, uniformly tanned, length 0.56–0.67 mm, width 0.12– 0.17 mm, index 3.94–4.67. Abdomen (Fig. 4 b): length 2.74–3.62 mm; integument yellowish, medio-apical and basal area of each segment slightly tan. Seta 1-I fanlike with 20–35 aciculate branches. Setae 9-II,IV,VII longer (more than double) than 9-I,III,V,VI. Genital lobe: tan, smooth in both sexes, males: length 0.25–0.40 mm, wrinkled ventrally; female: length 0.17 mm. Paddle: length 0.87–0.92 mm, width 0.69–0.80 mm; index 1.24–1.29; yellowish, smooth, midrib thick and strong, as long as paddle. Seta 2-Pa stronger than 1-Pa.
a = not found, alveolus without seta.
LARVA (fourth-instar) (Figs. 5, 6): Placement and character of setae as in Fig. 5; range and modal number of branches in Table 4. Head (Fig. 5 a): wider (1.40 mm) than long (1.06 mm), oval, heavily tanned, distal half of lateralia lighter. Hypostomal suture extends to collar. Collar narrow, brown. Dorsomentum brown (Fig. 5 b), teeth pointed, not sharp, with 7 or 8 teeth on each side of median tooth. Maxilla (Fig. 6): 6- Mx single, 1.53 longer than 14-C. Setae 0,2-C single, in dorsal position, setae 1,3,4-C also single, setae 5–7-C fanlike with aciculate branches, 15-C generally triple, 16,17-C absent. Antenna: length 0.56–0.62 mm (0.58 mm), tanned; basal ring darker. Spicules uniformly distributed, shorter and more evident on distal third. Seta 1-A fanlike with 20–26 aciculate branches, inserted 0.39–0.46 mm (0.41 mm) from base. Thorax (Fig. 5 c): integument hyaline, apparently glabrous, minute spicules 2.5–5.0 µm or shorter, exceptionally up to 10 µm. Tubercles of large dorsal setae tanned, tubercles of setae 9–12-M,T with 2 strong, sclerotized denticles, lateral to seta 12-M and/or 10-T, or with a crown of 5–7 sclerotized denticles. Setae 1–8,12-P aciculate, seta 4-P 0.70 length of 1-P. Seta 1-M quadruple in general, length 0.26–0.34 mm (0.29 mm). Seta 1-T 0.11–0.13 mm (0.12 mm) long, setae 7,9,10-T with aciculate branches. Abdomen (Fig. 5 c): integument hyaline, coverd by minute spicules 2,5–5.0 µm. Setae: 6-I–VI; 7-I; 12-V; 1-VII and 1,3,5-VIII aciculate. Segment VIII (Fig. 5 d): with more and longer spicules (7.5–10 µm) than the other segments. Comb with 40–50 scales arranged in 4 rows, fringed apically and/or marginally. Siphon: length 1.41–1.55 mm (1.50 mm), width 0.31–0.35 (0.32 mm), index 4.03–5.21 (4.68). Uniformly tanned, including acus, basal margin darker. Pecten on basal 0.23 with 10–14 spines, with 2 or 3 basal denticles. Seta 1-S in 5 pairs distal to pecten, seta 1d-S not in line with the others. Length of seta 1a-S 0.87 width of siphon. Setae 2,6,9-S single. Segment X: saddle complete, length 0.35–0.40 mm (0.37 mm), tanned, basal margin, dorsal and middle of posterior margin slightly darker. Segment covered with spicules that are more evident on posterior margin. Siphon/saddle index 3.87–4.43 (4.05). Seta 4-X in 6 pairs. Anal papillae slender, tapering toward apex, ventral pair lightly shorter than the dorsal pair.
Material examined. 3Pe, 6Le, as follow: ARGENTINA, Río Negro Province, Estancia El Rincón spring of Valcheta stream (40º 59´26.7´´ S – 66° 40´37.3´´ O), 05-XII-2006, Donato coll.
Distribution. Culex articularis is known from Chile, Argentina, Ecuador and Perú (Walter Reed Biosystematics Unit 2001). In Argentina it is recorded from the provinces of Neuquén, Río Negro (Campos & Maciá 1998) and Chubut (Rossi & Vezzani, unpublished data).
Bionomics. Larvae of Cx. articularis were collected in Río Negro Province, at 620 m. a.s.l. with dry and cold climate. The environment is a fertile lowland that feeds the most important spring of Valcheta stream (near El Rincón farm). The stream has abundant coastal vegetation of the genus Cortadeira. Culex articularis was found associated with amphipods of the genus Hyalella.
Seta Head Thorax Abdominal segments
no. H P M T I II III IV V VI VII VIII X 0 1 9−13 (11) - - - 1 1 1 1 1 1 - - 40−50 20−26(21)
? = not counted.
Taxonomy. Larvae of Cx. articularis are very similar to several species of the subgenus, including Cx. eduardoi Casal & García, Cx. brethesi Dyar, Cx. dolosus Lynch Arribálzaga, Cx. cuyanus Duret, Cx. archegus Dyar, Cx. carcinoxenus de Oliveira Castro and Cx. foliaceus Lane. The characters that distinguish Cx. articularis from these species are: pecten spines with one subapical denticle, longer antenna and saddle and higher siphon index in Cx. eduardoi; setae 0,2-C absent, seta 1-VIII with 7−9 branches and longer saddle in Cx. brethesi; conspicuous spicules (10−15 µm) covering the thorax and seta 3-P double in Cx. dolosus; setae 16,17-C present and one denticle in pecten spines in Cx. cuyanus; seta 1-S with 5 and 4-X with 4 elements, respectively, in Cx. archegus; Cx. carcinoxenus only inhabits crab holes; and siphon index higher than 5 and seta 1-S with 4 elements in Cx. foliaceus. Furthermore, the last three species are not recorded from Argentina.
Discussion. The fourth-instar larva of Cx. ameliae is distinguishable from other Cx. (Cux.) by the conspicuously longer seta 4-M, and the pupa by the nearly perfectly cylindrical trumpet.
The dorsal position of setae 0,2-C and the medial and separated location of setae 1,2-T relative to the other dorsal setae of the same segment easily distinguish the fourth-instar larva of Cx. articularis from other species of the subgenus. The pupa is very similar to other species of Cx. (Cux.), but differs in trumpet shape, which varies between conical and cylindrical, and having seta 2-Pa stronger than 1-Pa.
description: Published as part of Laurito, Magdalena, Almirón, Walter Ricardo & Rossi, Gustavo Carlos, 2011, Description of the immature stages of Culex (Culex) ameliae Casal and Culex (Culex) articularis Philippi (Diptera: Culicidae), pp. 58-68 in Zootaxa 2778 on pages 63-65, DOI: 10.5281/zenodo.202653