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

Abstract

The genus Megaselia Rondani (Diptera: Phoridae) is one of the largest in the animal kingdom, with nearly 1700 described species and many remaining to be discovered. Work on this group is notoriously challenging due to the extreme species diversity, poor knowledge of higher‐level relationships and lack of molecular data. In this paper, we present the largest study to date of Megaselia relationships based on molecular data from one nuclear (28S rDNA) and three mitochondrial (ND1, COI and 16S) markers for 175 Nordic specimens representing 145 species of Megaselia, plus outgroups. Based on phylogenetic analyses of these data, we propose 22 informal Megaselia species groups, all of which match well‐supported terminal clades. Relationships among these groups, and between them and several isolated species, remain largely uncertain. Of the 22, 20 species groups fall into a moderately well‐supported monophyletic clade of ‘core Megaselia’. Two species groups, the spinigera and ruficornis groups, fall outside of core Megaselia, as does the single representative of Myriophora, a genus that is included in Megaselia by some specialists. Here, we explore the morphology of these molecular species groups to aid future studies, and we discuss the implications of our findings for the generic circumscription of Megaselia. Hopefully, our results can aid further characterization of subgroups within the enormous Megaselia radiation and among its closest relatives, thus facilitating future work on this challenging but fascinating group of small flies.

Large-scale Integrative Taxonomy (LIT): resolving the data conundrum for dark taxa

“…Our 18 000 specimens in 365 species were collected across a range of 1 500 km in the temperate zone using 36 trapping points. We only worked on a single family which is dominated by one genus (Megaselia: 80% of species) that has undergone a recent, rapid radiation generating many closely related species (Hartop et al 2021). We therefore expected our dataset to be highly susceptible to complications with additional geographic sampling.…”

Fly Pollination of Kettle Trap Flowers of Riocreuxia torulosa (Ceropegieae-Anisotominae): A Generalized System of Floral Deception

“…Though R. torulosa shares pollinating dipteran genera with Ceropegia ( Figure 3 ) and other plants, the Diptera species might differ among the plants. Comparisons are challenging because many dipteran taxa in the Afrotropics, particularly in super-diverse Megaselia , Forcipomyia, Bradysia , Corynoptera , and Pseudolycoriella , are difficult to identify to species level [ 39 , 40 , 41 ]. The lack of updated taxonomical literature and the vast number of undescribed species hamper proper identification of individuals in these genera [ 41 ], and often only morphospecies can be determined, as was the case in this and other studies.…”

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

“…Later, a new species (the lucifrons) group in Megaselia was introduced, using two COI and 28S molecular markers [ 46 ]. Recently, 22 informal species groups have been proposed for this species-rich genus based on nuclear ( 28S rDNA ) and mitochondrial ( ND1 , COI , and 16S ) markers [ 130 ]. The topology obtained for Megaselia sequences in this study, in agreement with other studies, represents a monophyletic lineage for this challenging genus [ 46 , 130 ].…”

“…Recently, 22 informal species groups have been proposed for this species-rich genus based on nuclear ( 28S rDNA ) and mitochondrial ( ND1 , COI , and 16S ) markers [ 130 ]. The topology obtained for Megaselia sequences in this study, in agreement with other studies, represents a monophyletic lineage for this challenging genus [ 46 , 130 ]. Genome-scale phylogenetics is necessary to infer true monophyly and radiation of Megaselia species.…”