Fig. 10

Distribution and evolution of different developmental pathways in Pycnogonida. The shown cladograms have been simplified from [96] and [97]. On the right, the different developmental types are indicated by schematic drawings of their hatching stages and a color code. The gray area in each drawing indicates the post-ovigeral body region from which the walking leg segments develop. The developmental pathways have been mapped on the cladograms according to their color code. Note that in the case of Ascorhynchidae and Eurycydidae developmental type 1 has been inferred based on hatching protonymphon larva only, since no descriptions of subsequent postembryonic development exist. Taxa names with white background indicate that no developmental data are available. In both shown scenarios, developmental type 1 (green) has been given preference during the reconstruction of the single nodes whenever it is found in one of the two sister groups in question (therefore also the reconstruction of type 1 as an ancestral feature in scenario two). Accordingly, only the controversial grouping of paraphyletic callipallenids with respect to nymphonids results in developmental type 5 as their ancestral developmental pathway