Genus Psorophora Robineau-Desvoidy, 1827

Type species: 

Psorophora ciliata (Fabricius, 1794); original combination: Culex ciliata. [Mitchell (1906) introduced subfamily Psorophorinae for this genus.]

Classification: 

Subfamily Culicinae, tribe Aedini. Genus Psorophora includes 49 species divided into three subgenera: Grabhamia (16 species), Janthinosoma (23 species) and Psorophora (10 species). Genus abbreviation – Ps.

Characteristics: 

The adults of Psorophora are small to very large mosquitoes that are distinguished from the adults of other genera in the New World by the presence of both prespiracular setae and postspiracular setae. Larvae have a well-developed ventral brush (seta 4-X) with a row of precratal setae attached to a complete saddle, or extending to the middle of segment X if the saddle is incomplete. The latter condition occurs in many aedine species, however the combination of an incomplete saddle and a strongly swollen siphon will distinguish Psorophora. See Aedini.

The following 18 characters diagnosed Psorophora in the phylogenetic study of Reinert et al. (2009), including three unique characters that are indicated by an asterisk (*). ADULTS – Maxillary palpus of males with palpomeres 4 and 5 up-turned; prescutellar area with median and posterior scales; prespiracular setae present. FEMALE GENITALIA – *Tergum VIII and *sternum VIII mostly membranous with heavily sclerotised, lateral rod-shaped structures; tergum IX with setae distally and on much of median area; postgenital lobe with ratio of ventral width at distal 0.20 to cercus width at mid-length ≤ 0.65; upper vaginal sclerite absent; insula tongue-like. MALE GENITALIA – Claspette with ≥ 3 moderately long, stout, bluntly pointed, spiculose setae. EGGS – *Outer chorion with spiny appearance, outer chorionic cells with elongate anteriorly inclined tubercles. LARVAE – Comb plate present; seta 1-S short, ≤ 0.40 width of siphon; seta 6-S noticeably longer than distal width of siphon; ventral brush (seta 4-X) on grid with transverse bars. PUPAE – Seta 3-II longer than seta 6-II; seta 5-V shorter than following tergum; seta 6-VII inserted anterior to seta 9-VII.

Phylogenetic relationships: 

Psorophora was recovered as the sister of all other Aedini in the phylogenetic studies of Reinert et al. (2004, 2006, 2008, 2009) based on morphological data of all life stages, and also in the maximum likelihood phylogeny of Soghigian et al. (2017) based on seven molecular markers. Liria & Navarro (2014) conducted a phylogenetic analysis of relationships for 29 of the 48 recognised species (only 45 indicated in the published article) of Psorophora based on 66 morphological characters from the adult, larval and pupal stages under equal weighting. The analysis weakly supported the monophyly of the genus and strongly supported the monophyly of subgenera Grabhamia and Psorophora. However, in the strict consensus tree of 11 most parsimonious trees, subgenus Janthinosoma was not recovered as monophyletic due to the ambiguous position of Ps. (Jan.) cyanescens, and within the three subgenera, the relationships among the respective included species were poorly resolved. The relationships and conclusions discussed in the paper should be regarded as provisional due to dubious choice of characters, problematic character coding and questionable homologies. Psorophora fell outside of tribe Aedini in an improbable sister relationship with Mansonia in the phylogeny of Wilkerson et al. (2015), probably due to equal weighting of the data set of Reinert et al. (2009).

Bionomics and disease relations: 

Psorophora are called flood-water mosquitoes because females lay their eggs on damp or dry mud and debris in fields and wooded plains where they may withstand long periods (months or years) of desiccation and hatch when the habitat is inundated by rain or flood waters. Larvae of subgenus Psorophora are predacious. The adults are diurnal and the females of many species avidly bite humans.

Several species of Psorophora are vectors of arboviruses. Ilheus virus is transmitted by Ps. ferox and Venezuelan equine encephalitis virus by Ps. ferox and Ps. confinnis. See subgenera Grabhamia, Janthinosoma and Psorophora for viruses isolated from other species of Psorophora.

Distribution: 

Species of Psorophora are associated with flood-water pools in the tropics and warmer temperate regions of North and South America. Most species occur in the southern temperate and tropical countries.

Principal references: 

Lane, 1953 (Neotropical Region,bionomics, keys, taxonomy, distributions); Forattini, 1965 (Neotropical Region); Cova-García et al., 1966 (Venezuela); Belkin et al., 1970 (Jamaica, keys, taxonomy, bionomics, distributions); Wood et al., 1979 (Canada, keys, taxonomy, biology, distribution); Darsie & Ward, 1981, 2005 ( North America, keys); Clark-Gil & Darsie, 1983 (Guatemala, keys); Darsie, 1985 (Argentina, keys); Reinert, 2000 (female genitalia); Reinert et al., 2004, 2006, 2008, 2009 (morphology, phylogeny); Liria & Navarro, 2014 (morphology, phylogenetic relationships); Wilkerson et al., 2015 (phylogeny); Soghigian et al., 2017 (phylogenetic relationships).

Subgenera: 
Nomina dubia

goeldii (Giles, 1904)
marmorata (Philippi, 1865)
perterrens (Walker, 1856)

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith