What shall we do with the melanogaster species group?
Authors: Artyom Kopp 1; Bernard Kim 3; Amir Yassin 2
Affiliations: 1) University California, Davis; 2) CNRS Laboratoire Evolution, Génomes, Comportement et Ecologie; 3) Stanford University
Keywords: g. phylogenetics; m. webtools and databases
The genus Drosophila contains many hundreds of species that can be reared in the laboratory. This feature, along with the prominence of D. melanogaster as an experimental model system, has contributed to the widespread use of Drosophila as a model for molecular evolution, evo-devo, and comparative genomics. Ever since the 1930s, it has been recognized that classifying Drosophila species in a scheme reflecting their relatedness as well as their degree of divergence was fundamental for comparative studies. Therefore, the taxonomic rank of species groups was introduced and gained wide usage in Drosophila research. Of the nearly 60 species groups, the melanogaster group was initially created for 7-14 species since much of the diversity of Australasian and Afrotropical regions was unknown at that time. Over time, this group came to encompass ~200 species, far exceeding the typical size of other groups, and was subdivided into 10 subgroups. Recent phylogenetic studies revealed that those subgroups intermingle with several other species groups; thus, maintaining a monophyletic melanogaster group would require expanding its size and diversity even further. Some authors suggested upgrading the earliest branching ananassae (27 spp.) and montium (94 spp.) subgroups to species-group level, redefining the boundaries of the melanogaster group to a more reasonably sized clade. This solution simplifies the discussion of evolution within each lineage, as was done for example by subdividing the newly created montium species group into 7 new subgroups and 13 species complexes. On the other hand, this approach breaks with a huge body of comparative literature that includes ananassae and montium species as members of the melanogaster group. The aim of this poster is to discuss the taxonomic complexity of the melanogaster species group and to present through a balanced debate the benefits and disadvantages of different solutions. We also show that the ananassae subgroup/group is not monophyletic as currently defined, requiring additional taxonomic revisions.