Figure 6

Phylogenetic character distributions that would support developmental bias. (A) Convergence – If certain characters appear repeatedly in a phylogeny despite the obvious absence of exogenous selective causes, this may suggest an evolution biased by development. A possible example are the horizontal bar patterns evolved in parallel in Lake Tanganyika and Lake Malawi cichlids (indicated by black hashmarks), for which similar developmental mechanisms might be used. (B) Phylogenetic inertia (or constraints) – If characters show significant resistance against evolutionary change despite substantial environmental heterogeneity, then at least part of these constraints may be developmentally induced. Different species-rich tribes of East African cichlids show a relatively conservative number of spines of the dorsal fin (Ectodini: 12–15 with the exception of Enantiopus having 16–19; Lamprologini: 17–24, indicated by red hashmarks) and of the anal fin (Ectodini and most other cichlids: 3; Lamprologini: 4 or more [98], indicated by grey and black hashmarks) despite having evolved manifold body shapes.