Culex apicinus Philippi, 1865.
Subfamily Culicinae, genus Culex. Subgenus Phalangomyia is monobasic. Subgenus abbreviation – Pha.
ADULTS – Dark brown mosquitoes; first flagellomere of antenna with scales on inner side; maxillary palpus of females dark brown with pale scales; comprised of 3 palpomeres, maxillary palpus of males with 5 palpomeres; proboscis longer than forefemur, with dorsal and ventral pale scaling; scutum with narrow pale scales, except on bare lines between acrostichal and dorsocentral setae; wing with a patch of pale scales near middle of veins M2 and M3; legs dark-scaled except femora pale-scaled ventrally, forefemur longer than foretarsomere 1, foretarsomere 1 as long as combined length of foretarsomeres 2–5; terga II–VII dark-scaled with broad basal pale bands. FEMALE GENITALIA – Cerci distinctly longer than postgenital lobe, 1.6–1.7 times longer; upper vaginal lip and upper vaginal sclerite strongly sclerotized; insula with patch of prominent rigid setae (not in lateral rows). MALE GENITALIA – Posterior margin of tergum VIII deeply emarginate; tergum IX lobes small, widely separated, each bearing a row of slender flexible setae; gonocoxite modified, with apical cluster of 8–20 long flexible setae, nearly as long as gonostylus, basoventral margin with cluster of shorter flexible setae, subapical lobe not developed, setae highly modified and spread over mesal area from near base to near apex, middle of dorsomesal margin with a protrusion bearing setae a, b and c, foliform seta g (seta h of Laurito & Almirón, 2013) borne near base of gonostylus, homologies of other setae not apparent; gonostylus slightly tapered and strongly curved, apex abruptly upturned with conical subapical gonostylar claw projecting in opposite direction, giving the apex a bifurcate appearance; phallosome broad, with sclerotized opisthophallic bridge (dorsal aedeagal bridge of Harbach & Knight, 1980), lateral plate (opisthophallic sclerite) stout, about as long as aedeagal sclerite, dorsal arm short, slightly shorter than lateral arm, lateral arm with series of laterally directed denticles on caudal margin, ventral arm not distinctly differentiated from denticles of lateral arm; proctiger modified, paraproct strongly produced basolaterally into a blunt dorsally directed basolateral arm, crown with large patch of short spine-like spicules. LARVAE – Head, siphon and saddle strongly sclerotized; antenna shorter than head, seta 1-A inserted about 0.75 from base; seta 16-C absent; seta 8-P inserted directly anterior to slightly anteromesal to pleural setal group 9–12-P; seta 7-I,II about same length, both longer than 7-III but much shorter than 6-I,II; elements of siphonal seta 1-S (a–e) in approximated posterior rows, distal element (1e-S) slightly out of line (more lateral); siphon relatively short, stout, tapered, index ≤ 3.5. PUPAE – Seta 5-IV–VI equally long, about twice length of following tergum; seta 8-II sometimes present; seta 13-III–VI (at least alveolus) usually present; seta 1-IX absent; surface of paddle minutely spiculate; seta 2-Pa present. See genus Culex.
The evolutionary relationships of Phalangomyia are uncertain. Culex apicinus was recovered in a sister relationship with Cx. tramazayguesi, the type species of the monobasic Neotropical subgenus Allimanta, in the morphology-based phylogenetic study of Harbach et al. (2012). This is noteworthy because the two species share morphological features with Old World taxa, e.g. the presence of a sclerotized opisthophallic bridge, and were recovered in a basal relationship to a large clade that consisted of, with the one exception, exclusively New World generic-level taxa. This is also interesting because Allimanta was recovered in association with Old World taxa in the morphology-based phylogenetic analyses of Mallampalli (1995) and St John (2007). Culex apicinus was recovered as the sister of Cx. scheuberi in the morphology-based phylogenetic study of species of subgenus Culex conducted by Laurito & Almirón (2013); however, the relationship is unlikely because data were only available for features of the male genitalia of Cx. scheuberi, the homologies of certain structures appear to be faulty (e.g. see the incorrect identification of seta g noted above) and the study was limited to species of Culex (Culex). In a subsequent morphology-based study of the subgenus Culex conducted by Harbach et al. (2017), phylogenetic analyses largely failed to resolve relationships among the species and informal groups of the subgenus, including the Apicinus Group of Harbach (2011). The authors noted, in agreement with Laurito & Almirón (2013), that Cx. apicinus was “a unique lineage that may require subgeneric rank”. In the recent study of the Neotropical subgenera of Culex conducted by González et al. (2023), Cx. apicinus and the Atacama form of the species were recovered in a strongly supported sister relationship with Cx. amazonensis of the subgenus Aedinus based on a Bayesian and Maximum Likelihood analysis of a data set consisting of sequences for two nuclear protein-coding genes, carbamoyl-phosphate synthetase 2 (CAD) and hunchback (HB), and the mitochondrial cytochrome c oxidase subunit I (COI) gene.
The immature stages can be found throughout the year in temporary to permanent collections of water, including ditches, rock holes, rock pools, river pools and stream margins. Culex apicinus larvae have also been found in water tanks and swimming pools (Rossi et al., 2008). Females are not known to bite humans and probably feed on domestic animals and livestock. The species is apparently of no medical importance to humans.
Argentina, Bolivia, Chile and Peru.
Rossi et al., 2008 (Cx. apicinus, description, bionomics, distribution); Harbach et al., 2012 (Cx. apicinus, morphology, phylogenetic relationships); Laurito & Almirón, 2013 (Cx. apicinus, morphology, phylogenetic relationships of species of subgenus Culex in Argentina); Harbach et al., 2017 (Cx. apicinus, morphology, taxonomy, phylogenetic relationships); González et al., 2023 (subgeneric status, molecular phylogeny of the Neotropical subgenera of Culex).
apicinus Philippi, 1865