Data from: Quantifying morphological change during an evolutionary radiation of Devonian trilobites

The fossil record provides an important source of data on adaptive radiations, and indeed some of the earliest theoretical insights on the nature of these radiations were made by paleontologists. Here we focus on the diverse Devonian Metacryphaeus group calmoniid trilobites, known from the Malvinokaffric Realm; these have been considered a classic example of an adaptive radiation preserved in the fossil record. A geometric morphometric analysis is used in conjunction with phylogenetic and biogeographic patterns and data on speciation rates. Patterns of morphological change are quantified using ancestral character state reconstruction during speciation events in order to assess the role ecological and geographical factors may have played in mediating this radiation. No significant differences were found between the amount of morphological change that occurred during speciation events when ancestors and descendents were in the same area as opposed to when they occupied different areas. Further, the magnitude of morphological divergence did not change through time or with cladogenetic rank. These patterns, in conjunction with the fact that the radiation occurs in a geographically heterogeneous region subjected to repeated episodes of sea-level rise and fall, suggests that at the macroevolutionary scale this radiation may have been motivated more by phenomena that facilitated geographic isolation than by competition.