The biogeographic distribution of organisms has continuously changed through Earth’s

history as plate tectonics changed the configurations of land masses, ocean basins, and climate

zones. Yet, methods to investigate this dynamic through geologic time are limited. Here,

network analysis is used to explore and to visualize the biogeographic history of brachiopods

through the entire Triassic period. Many previously recognized biogeographic provinces are

found, and in addition, the stratigraphic ranges of these provinces were identified. Provinces

in the Tethys Ocean show the lowest degree of connectedness, which can be linked to higher

evolutionary rates in this tropical ocean basin and possibly also to higher habitat heterogeneity.

Stratigraphically, the Tethyan provinces are separated largely along the boundaries of

the Early, Middle, and Late Triassic. This suggests that the events resulting in faunal changes

among the index fossils used to define these sub-periods also affected the brachiopods. However,

through the ~50 m.y. of the Triassic period, geographic proximity played a greater role

in producing faunal similarity than proximity in geologic age. Thus network analysis is a

viable tool to better understand the dynamic evolution of biogeography through geologic time.