A new species group in Megaselia, the lucifrons group, with description of a new species (Diptera, Phoridae)

Abstract

With 1,400 described species, Megaselia is one of the most species-rich genera in the animal kingdom, and at the same time one of the least studied. An important obstacle to taxonomic progress is the lack of knowledge concerning the phylogenetic structure within the genus. Classification of Megaselia at the level of subgenus is incomplete although Schmitz addressed several groups of species in a series of monographs published from 1956 to 1981. Another problem is the lack of molecular phylogenetic analyses to support morphology-based conclusions. As a contribution towards addressing these problems, we here circumscribe a previously unrecognized monophyletic lineage of Megaselia consisting of species similar to Megaselia lucifrons. We base this taxonomic decision on morphological study of an extensive phorid material from Sweden, complemented by molecular analyses of select exemplars using two markers (COI and 28S). We name the clade the lucifrons species group, and show that it contains three distinct species. Our results also demonstrate that Megaselia subnitida Lundbeck, 1920, previously treated as a synonym of Megaselia lucifrons Schmitz, 1918, is a separate species, and we remove it from synonymy. The third species in the group was previously unknown; we describe it here as Megaselia albalucifrons sp. n.

Completing Linnaeus’s inventory of the Swedish insect fauna: Only 5,000 species left?

“…DNA barcoding tends to be consistent with traditional morphology-based taxonomy when sufficient resources have gone into the latter [50][51][52][53]. Barcoding of critical Swedish Diptera taxa (Phoridae, Cecidomyiidae, Chironomidae, and Mycetophilidae) have revealed 0-20% cryptic diversity [36,54,55] but similar results have been obtained for parasitic Hymenoptera [56]. If anything, it seems likely that systematic and large-scale DNA barcoding will show that our current estimates for Swedish insect groups are conservative both for Diptera and Hymenoptera.…”

“…In the Phoridae, the low coverage may be partly due to the small fraction (6%) of the material processed; in other cases, like the Symphyta (30% of the material processed), it appears instead that it is due to the inefficiency of Malaise traps in collecting these groups. DNA barcoding indicates that the accumulation curve for Phoridae is too steep because aberrant male-genitalia variants are sometimes misclassified by taxonomists as representing separate species [36]; this is likely to partly explain the poor performance of species richness estimators for this group.…”

The scuttle flies (Diptera: Phoridae) of Iran with the description of Mahabadphora aesthesphora as a new genus and species

“…We were able to include only 71 paratypes in our molecular experiments as the type specimens were archived in UCMZ and ICHMM collections after identity verifications. The mithocondorial COI and nuclear 28S / AK markers were preferred to other targets because they have been proved to be informative for species-level and genus-level analyses, as indicated in a large number of resources regarding evolutionary associations in insects [e.g., 37 – 40 , 44 , 46 , 119 , 120 ].…”

“…Combinations of mitochondrial and nuclear genes have been engaged to assess the monophyly of Anevrina Lioy, 1864 and Dohrniphora Dahl, 1898 genera in distinct studies [ 44 , 45 ]. The COI and 28S rRNA markers have been utilized to organize Megaselia , the most species-rich genus of scuttle flies, at the subgenus level [ 46 ]. The mito-nuclear markers of COI / wingless genes have also been utilized to discriminate body size biotypes as well as cryptic species of Pseudacteon Coquillett, 1907 [ 47 , 48 ].…”

Scuttling towards monophyly: phylogeny of the mega‐diverse genus Megaselia (Diptera: Phoridae)

“…Most of the core Megaselia species groups herein are being formally described for the first time, but several have been described and discussed in the literature before, to varying degrees. Some are well documented, such as the troublesome pulicaria complex (Disney, 1989b, 1999) and the lucifrons group (Häggqvist, Ulefors, & Ronquist, 2015; Hardy & Beyer, 1964). The humeralis group of this analysis overlaps significantly with the previously revised Megaselia giraudii/densior species complexes and the ‘ pygmaea complex’ (both phenetic assemblages), but neither group characterization holds for the entire humeralis group; more study is needed to delimit that clade morphologically (Disney, 1988; Buck & Disney, 2001).…”