Phylogenetics and temporal diversification of the earliest true flies (Insecta: Diptera) based on multiple nuclear genes

Abstract

Relationships among families of the lower Diptera (formerly suborder 'Nematocera') have been exceptionally difficult to resolve. Multiple hypotheses based on morphology have been proposed to identify the earliest lineages of flies and place the phylogenetic origin of the higher flies (Brachycera), but convincing support is limited. Here we resolve relationships among the major groups of lower Diptera using sequence data from four nuclear markers, including both ribosomal (28S rDNA) and protein-coding (CAD, TPI and PGD) genes. Our results support both novel and traditional arrangements. Most unexpectedly, the small, highly-specialized family Deuterophlebiidae appears to be sister to all remaining Diptera. Other results include the resolution of the traditional infra-orders Culicomorpha (including a novel superfamily Simulioidea ¼ Thaumaleidae þ Simuliidae), Tipulomorpha (Tipulidae sensu lato þ Trichoceridae) and Bibionomorpha sensu lato. We find support for a limited Psychodomorpha (Blephariceridae, Tanyderidae and Psychodidae) and Ptychopteromorpha (Ptychopteridae), whereas the placement of several enigmatic families (Nymphomyiidae, Axymyiidae and Perissommatidae) remains ambiguous. According to genetic data, the infra-order Bibionomorpha is sister to the Brachycera. Much of the phylogenetic signal for major lineages was found in the 28S rDNA gene, whereas protein-coding genes performed variably at different levels. In addition to elucidating relationships, we also estimate the age of major lower dipteran clades, based on molecular divergence time estimates using relaxed-clock Bayesian methods and fossil calibration points.

Episodic radiations in the fly tree of life

“…These fly families include very few species, all of which have extreme morphological adaptations in both larval and adult stages for living in fast-flowing water. These morphological specializations have previously obscured their evolutionary relationships, although a recent molecular analysis hypothesizes the early divergence that we confirm here (11,12). The remaining lower Diptera is composed of the infraorders Tipulomorpha (crane flies), Culicomorpha (mosquitoes), Psychodomorpha (sand flies), and Bibionomorpha (march flies and gall midges) (11) (Fig.…”

“…From numerous studies, we established a list of 457 putatively informative morphological characters to cover the anatomical diversity of Diptera. Team consultation reduced this to 371 external and internal morphological characters for larvae (93), pupae (11), and adults (267, including 55 head, 54 wing, 31 female genitalia, and 49 male genitalia). We scored 42 tier 1 dipteran taxa and 5 holometabolous outgroup taxa.…”

Ovary ecdysteroidogenic hormone activates egg maturation in the mosquito, Georgecraigius atropalpus, after adult eclosion or a blood meal

“…Mosquitoes (Diptera: Culicidae) form a monophyletic assemblage that is currently divided into two subfamilies (Anophelinae and Culicinae), 44 genera and >3500 species (Harbach and Kitching, 1998;Harbach, 2007;Bertone et al, 2008;Reidenbach et al, 2009). Typically, adult mosquitoes obtain nutrients for survival and reproduction from three sources (Clements, 1992;Foster, 1995): (1) teneral reserves from larval feeding on the microbiota and detritus in water, (2) nectar or other plant juices for energy, and (3) blood taken only by females for egg production.…”

Nannotanyderinae: a new subfamily of Tanyderidae (Diptera)

“…This group also includes extinct families such as Grauvogeliidae (Lower/ Middle Triassic), Kuperwoodidae (Upper Triassic), Hennigmatidae (Lower Jurassic to Lower Cretaceous) and Nadipteridae (Lower/Middle Triassic to Lower Jurassic) (Krzemiński and Krzemińska, 2003;Shcherbakov et al, 1995). Recent phylogenetic studies based primarily on molecular data have found that Trichoceridae, Tipulidae, Nymphomyiidae, Deuterophlebiidae, Ptychopteridae and Blephariceridae are also among the most ancient lineages of the order (Bertone et al, 2008;Wiegmann et al, 2011). To date no phylogenetic study of Tanyderidae is existing, and its relationships within the family remain poorly understood; however, continued study of both fossil and extant species is likely to help in reconstructing the phylogeny.…”