Psorophora discrucians (Walker, 1856); original combination: Culex discrucians.
Subfamily Culicinae, genus Psorophora. Subgenus Janthinosoma includes 23 species. Subgenus abbreviation – Jan.
Species of subgenus Janthinosoma are characterised and distinguished from species of subgenera Grabhamia and Psorophora by the following combinations of characters. Characters that diagnose Janthinosoma in the phylogenetic analyses of Reinert et al. (2009), based on features observed in Ps. cyanescens and Ps. ferox, are indicated by an asterisk (*).
ADULTS – Small to medium-sized mosquitoes; proboscis, legs and abdominal terga with dark violet metallic scaling, proboscis entirely dark-scaled; scutum with scales between acrostichal and dorsocentral setae and between prescutellar and supraalar setae; *lower proepisternal scales present; wing entirely dark-scaled or with few inconspicuous pale scales on costa and subcosta (*costal scales all dark); *anteprocoxal scales present; apices of femora without erect scales, hindfemur without subapical ring of pale scales, tibiae uniformly dark-scaled with violet to purple reflections (*hindtibia with only dark scales), tarsomeres l–3 of all legs without basal pale markings (*hindtarsomere 1 and *hindtarsomere 1 without basal pale scales), hindtarsomeres 4 and/or 5 and sometimes 3 with conspicuous white markings in most species; ungues of all legs with 1 tooth; tip of abdomen with tapering sharply pointed appearance. MALE GENITALIA – Claspette with 1 short simple and 2 large twisted foliform setae on apex; aedeagus conical or cylindrical, without lateral spine. LARVAE – Head and lateral palatal brushes normal, antenna extending well beyond anterior margin of head capsule; pecten reduced, usually fewer than 10 pecten spines. PUPAE – Trumpet long; *seta 7-CT ≥ 6.0 length of seta 6-CT; seta 10-CT usually with more than 5 branches; *seta 11-CT branched; *seta 3-II branched; seta 5-II inserted anterior to seta 3-II, usually with more than 5 branches; posterolateral angle of abdominal segment IV with conspicuous spines; paddle without contrasting pigmentation near external buttress and apex. See genus Psorophora.
Subgenus Janthinosoma was the sister of subgenus Psorophora, and this pair was the sister of subgenus Grabhamia, in the phylogeny of Aedini recovered in the phylogenetic study of Reinert et al. (2009) based on morphological data of all life stages. Liria & Navarro (2014) explored relationships within genus Psorophora using 66 characters from the adult, larval and pupal stages coded for 12 species of subgenus Janthinosoma, five of subgenus Psorophora and seven of subgenus Grabhamia. Subgenus Janthinosoma was not recovered as monophyletic in their strict consensus tree of 11 most parsimonious trees due to the ambiguous position of Ps. (Jan.) cyanescens, and the relationships of species of the subgenus included in the study were poorly resolved. Contrary to the findings of Reinert et al., Janthinosoma was recovered as the sister of Grabhamia + Psorophora in the maximum likelihood phylogeny of Soghigian et al. (2017) based on seven molecular markers.
The immature stages of species of subgenus Janthinosoma are seldom collected because they are found in primarily shaded habitats in flooded woodland areas that are often inaccessible. Females of some species readily attack and feed on humans who enter their haunts.
Ilheus and Venezuelan equine encephalitis viruses are transmitted by Ps. ferox. West Nile virus, as well as Cache, Kairi, Mayaro, Oriboca, St Louis and Una viruses, have also been isolated from this species. Other species of the subgenus that have tested positive for viruses include Ps. albipes (Ilheus and Una viruses) and Ps. lutzii (Guama and Ilheus viruses).
Most species of subgenus Janthinosoma have distributions in the Neotropical Region, in countries from Mexico in Central America to northern Argentina and Uruguay in South American. Two species, Ps. longipalpus and Ps. mexicana, are only recorded from Mexico and the United States, Ps. johnstonii is widely distributed in the Caribbean and occurs in the extreme south of Florida, and Ps. cyanescens and Ps. ferox have distributions that extend from Argentina and Uruguay northward into the United States, with the latter species reaching southern Canada.
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); Harrison et al., 2008 (United States, descriptions, key to females); Liria & Navarro, 2014 (morphology, phylogenetic relationships); Soghigian et al., 2017 (phylogenetic relationships).
albigenu (Lutz, 1908) (in Peryassú, 1908)
albipes (Theobald, 1907)
amazonica Cerqueira, 1960
champerico (Dyar & Knab, 1906)
circumflava Cerqueira, 1943
cyanescens (Coquillett, 1902)
discrucians (Walker, 1856)
ferox (von Humboldt, 1819)
fiebrigi Edwards, 1922
forceps Cerqueira, 1939
horrida (Dyar & Knab, 1908)
johnstonii (Grabham, 1905)
lanei Shannon & Cerqueira, 1943
longipalpus Randolph & O'Neill, 1944 (in Division of Medical Entomology, Bureau of Laboratories, 1944)
lutzii (Theobald, 1901)
mathesoni Belkin & Heinemann, 1975
melanota Cerqueira, 1943
mexicana (Bellardi, 1859)
pilosa Duret, 1971
pseudoalbipes Duret, 1971
pseudomelanota Barata & Cotrim, 1971
totonaci Lassmann, 1951
varipes (Coquillett, 1904)