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Phylogenetic relationships in the genus Psorophora Robineau-Desvoidy (Diptera: Culicidae), based on morphological characters

Abstract:

Phylogenetic relationships in the genus Psorophora were examined based on a cladistic analysis of 66 morphological characters (fourth instar larvae, pupae, males and females) of 29 species available from the 45 species reported in the genus, representing the three subgenera. The ingroup species were: five Psorophora (10 spp total, 50%), seven Grabhamia (15 spp total, 47%) and twelve Janthinosoma (20 spp total, 60%). Two Culicini genera (Culex and Toxorhynchites), two Aedini genera (Aedes and Haemagogus), and one Mansoniini (Mansonia) were used as outgroups and sister groups respectively. A parsimony analysis using TNT resulted in 11 trees, each with 164 steps (CI= 0.66 and RI= 0.83). The analysis indicated that Aedini (Haemagogus, Aedes and Psorophora), is monophyletic group that includes Mansonia titillans (Mansoniini), suggesting natural inclusion of the Mansoniini tribe into Aedini. The genus Psorophora is monophyletic, supported by 3 synapomorphies: larvae with presence of trident-like scales in segment VIII; female with tergo and sternum VIII with rod-like structure and male genitalia with few teeth on the sternite process on segment X. The current subgeneric classification was validated by our results. The clades representing the subgenera Psorophora, Grabhamia and Janthinosoma were supported by four, three and two synapomorphies respectively. However, within Grabhamia and Janthinosoma, internal polytomies were observed leaving the internal evolutionary relationships unresolved.