Fig. 1

Phylogeny of sepsid species with evolutionary history of gains and losses. The current phylogeny of Sepsidae supports one gain of the appendage and multiple losses. The species sampled for histoblast analysis represent one primary gain and three independent losses of the abdominal appendage as well as Orygma luctuosum, a sister group to the remaining sepsid species which lacks abdominal appendages. The pattern of gains and losses was inferred from a phylogeny with more taxa [18]