Morphology And Phylogeny

The family Drosophilidae is divided into a number of genera, subgenera, species groups, and species subgroups; this system gives each species a "taxonomic address" that loosely defines relationships within the family. For example, D. melanogaster is placed in the genus Drosophila, subgenus Sophophora, and melanogaster species group and subgroup (Fig. 2). D. melanogaster is a typical drosophilid and possesses a number of the characteristics, such as red eyes and plumose arista, that delineate this family. Along with the other taxa in the melanogaster and obscura species groups, D. melanogaster bears a single sex comb on its first tarsal segment. These are 7 to 12 thickened setae (hairs), which are closely set in a row, or comb. The number and position of the setae diagnose D. melanogaster from all but the most closely related species.

Within the Afrotropical melanogaster species subgroup, D. melanogaster is most closely related to the triad of species containing D. simulans, D. sechellia, and D. mauritiana, the common ancestor of which is thought to have diverged between 2 and 3 mya. D. simulans, a closely related species that is also cosmopolitan, can be differentiated only by examining the characters of the male genitalia, namely the number of prensisetae and the shape of the epandrial lobes.

+ -12 other subgroups

8 species

D. erecta, D. melanogaster, D. mauritiana,

D. teissieri, D. yakuba

FIGURE 2 Placement of D. melanogaster within the family Drosophilidae. [Modified after Powell, J. R. (1997). "Progress and Prospects in Evolutionary Biology. The Drosophila Model." Oxford University Press, New York.]

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