Using GIS to study palaeobiogeographic and macroevolutionary patterns in soft-bodied Cambrian arthropods

Soft-bodied Cambrian arthropods from Burgess Shale-type deposits are some of the most famous and extensively studied fossil invertebrates, but global species-level assessments of their biogeographic patterns have not previously been explored quantitatively. Here we use a newly developed occurrence database, in conjunction with Geographic Information Systems (GIS) analysis and PaleoGIS—which allows fossil locality positions to be viewed in the context of Cambrian palaeogeography—to quantitatively reconstruct geographic distribution patterns of primarily soft-bodied arthropod species. Further, we compare these patterns with those of co-occurring trilobite taxa. Soft-bodied Cambrian arthropods show both statistically larger geographic ranges and greater stratigraphic longevities than co-occurring trilobites. Many of the most widely distributed soft-bodied arthropods were likely capable of swimming, and this may in part explain their extensive distributions.