Fig. 2

Abdominal view of adult flies of the sampled species. Species that posess the appendage are in green and species without appendages in red with independent losses indicated by number. Primary gain of the appendage (a, f, i-n) results in a modified sternite, joint and bristles as compared to the ancestral state (o). The current phylogeny supports three independent losses of the appendage (L1 = b-e, L2 = g, L3 = h). The degree of sternite modification and size of the appendages are highly variable between species. T. biloba and T. putris (k, l) posses extensive sternite modification and long appendage brushes relative to other species. Loss of the appendage also results in the loss of the modified sternite which returns to the ancestral state. Scale bars indicate 1 mm