Anopheles mosquito

Harbach, Ralph E., 2007, The Culicidae (Diptera): a review of taxonomy, classification and phylogeny *, Zootaxa 1668, pp. 591-638 : 605

Mosquito fossils and the antiquity of Culicidae

Fossil records can provide insights into anatomical diversification, historical biogeography and the antiquity of taxa, but they are too incomplete to document precisely the divergence and ages of taxonomic groups. In the case of mosquitoes, the fossil record is so poor that it is not possible to establish the actual ages of the family and extant taxa. Edwards (1923) surmised that “The origin and phylogenetic history of the Culicidae must go back to well into the Mesozoic Era; and, from the small size and fragile nature of the insects, it is probably too much to hope that we can ever obtain much direct palaeontological evidence on these matters”.

Poinar et al. (2000) provided a list and critical evaluation of mosquito fossils. A number of extinct species have been assigned to Culicidae since the beginning of binomial nomenclature, but only 15 can be placed in the family with confidence (Poinar et al., 2000; Zavortink & Poinar, 2000; Borkent & Grimaldi, 2004). Thirteen of these species are from the Tertiary, including species of Aedes , Culex , Mansonia and two non-extant genera, and two are from the Cretaceous. The discovery of the two cretaceous species confirms Edwards’ (1923) view that the evolution of Culicidae must extend into the Mesozoic. The oldest fossil, Burmaculex antiquus Borkent & Grimaldi, is embedded in Burmese amber from the mid-Cretaceous (90–100 Mya). This species bears several plesiomorphic features, including a short proboscis, which suggest it is a stem-group mosquito that is intermediate between extant mosquitoes and other midges. In fact, the phylogenetic analysis of morphological data conducted by Borkent & Grimaldi (2004) indicates that Burmaculex is the sister group of all other fossil and modern mosquitoes. The second oldest fossil, Paleoculicis minutus Poinar et al. , is entombed in Canadian amber from the Late Cretaceous (76.5–79.5 Mya). Morphological features indicate that Paleoculicis shares a closer affinity with culicine than anopheline mosquitoes, which suggests that this ancestral lineage is younger than the lineage that gave rise to subfamily Anophelinae . Anopheles ( Nyssorhynchus ?) dominicanus Zavortink & Poinar and An. (?) rottensis Statz are the only fossil anopheline mosquitoes. The former is contained in Dominican amber from the mid-Tertiary (15–45 Mya) and the latter is from the Late Oligocene of Germany (approximately 25 Mya). If the Anophelinae are indeed basal to all other Culicidae , it would appear from available fossil evidence that extant groups of Culicidae may have evolved in the Cenozoic Era.

Considering the impact of mosquitoes on human health, it is not surprising that phylogenetic studies of these insects have only dealt with relationships within the four major groups that contain the majority of medically important species. These include subfamily Anophelinae and tribes Aedini , Culicini and Sabethini of subfamily Culicinae . As the following discussions will show, the phylogenies of these groups are far from being resolved and their classifications are not entirely natural.