Revision of Genus Culex Linnaeus, 1758 from Mon, 2022-05-23 15:26

Belkin (1962) indicated that the affinities of the subgenera of Culex were obscure, but surmised that Lutzia is an ancient derivative that appears to have a strong affinity with subgenus Culex. It is generally assumed that the Melanoconion Group of subgenera, i.e. Aedinus, Anoedioporpa, Belkinomyia, Carrollia, Melanoconion, Micraedes, Microculex and Tinolestes, includes the most derived mosquitoes of the genus (Belkin, 1968; Berlin, 1969; Adames & Galindo, 1973; Sirivanakarn, 1983). Sirivanakarn (1983) noted that Melanoconion shares several anatomical features with the “more primitive” and widespread subgenus Neoculex, suggesting that an offshoot of Neoculex may have given rise to the Melanoconion Group. Valencia (1973) suggested that Carrollia and the closely related Deinocerites and Galindomyia share a similar evolutionary history as derivatives from a primitive stock of subgenus Melanoconion. Miller et al. (1996) used sequence divergence in the ITS1 and ITS2 regions of rDNA to infer relationships between 14 species representing four subgenera of Culex. Neighbour-joining analyses produced a tree (rooted on Melanoconion) that supported the notion that Melanoconion bears a number of resemblances with Neoculex, and Lutzia shares an ancestry with subgenus Culex

Navarro & Liria (2000) conducted a parsimony analysis of 30 characters of larval mouthparts (mandibles and maxillae) to infer the phylogenetic relationships of Deinocerites and seven subgenera of Culex. The phylogeny indicated that Lutzia and Culex formed distinct monophyletic clades, with Lutzia being the more primitive of the two. Although only New World species were included in the analysis, members of the Melanoconion Group formed a distinct monophyletic clade in a sister-group relationship with subgenus Culex. It is interesting to note that this clade included Deinocerites in an unresolved polytomy with Anoedioporpa, Melanoconion and Microculex in a derived position relative to Carrollia.

Vesgueiro et al. (2011) used ITS2 sequences and neighbor-joining to infer the relationships of 17 Neotropical species representing genus Lutzia (1 species) and subgenera Culex (9 species), Microculex (1 species), Melanoconion (5 species) and Phenacomyia (1 species). In a companion study, Demari-Silva et al. (2011) used a 478-bp fragment of the COI gene and Bayesian methodology to assess the relationships of the same 17 species (and a species of subgenus Carrollia). The species of Lutzia was placed among species of genus Culex in both studies. In the neighbor-joining tree of Vesgueiro et al., Lutzia and Phenacomyia were placed in a clade among species of subgenus Culex. In the Bayesian analysis of Demari-Silva et al., Lutzia was recovered as the sister of a clade comprised of subgenera Culex and Phenacomyia. Harbach et al. (2012) explored relationships among taxa of Culicini using 169 morphological characters from 86 exemplar species representing the four genera and 26 subgenera of Culicini, most species groups and subgroups of subgenus Culex and an outgroup of five species from five other tribes. As in previous phylogenetic studies based on morphology (Navarro & Liria, 2000; St John, 2007; Laurito & Almirón, 2013), Lutzia was recovered as a clade separate from Culex. However, genus Culex was not recovered as monophyletic because it included Deinocerites and Galindomyia as derived members of the New World subgenera. With the exception of subgenera Culex, Eumelanomyia and Neoculex, there was strong support for the monophyly of all subgenera. They noted that subgenus Culex would be monophyletic if it did not include the Afrotropical Cx. duttoni, the Neotropical Cx. apicinus and the Australasian Atriceps Group. Based on a series of comparative and data exclusion analyses of the data set of Harbach et al. (2012) and a critical examination of the results of other phylogenetic studies, Kitching et al., (2015) concluded that no morphological or molecular data set analysed in any previously published study has adequate signal to place Lutzia unequivocally with regard to other taxa in Culicini.

Harbach et al. (2016) recently critically analysed a morphological data set comprised of 286 characters of the larval, pupal and adult stages of 150 species of subgenus Culex and an outgroup of 17 species representing genus Lutzia, 11 other subgenera of Culex and tribes Aedini, Culisetini and Sabethini. Unlike the results of previous analyses of morphological data that placed Lutzia outside genus Culex (Harbach et al., 2012; Navarro & Liria, 2000; St John, 2007; Laurito & Almirón, 2013), the more stringent assessment of clade support applied in their study indicated, in agreement with Kitching et al. (2015), that the placement of Lutzia relative to Culex based on morphology is highly equivocal.