Figure 2.

The CIP is dominated by more frequent and older colonizations compared with other regions. (a–c) The cumulative number of colonizations across the Cenozoic, in 5 million-year time bins. (a) In reconstructions without fossil constraints, the CIP was colonized by more lineages than any other region until approximately 5 Ma, when it was surpassed by the CP. (b) Reconstructions with fossil constraints yield similar results. (c) Compared with warm oceans, there are fewer colonizations into freshwater and the cold oceans. (d–f) The proportion of living species in the region descended from colonizations that occurred during or prior to each time-bin. (d) Without fossil constraints, a greater proportion of species in the CIP are descended from older colonizations overall, compared with other warm marine regions. (e) With fossil constraints, the oldest colonizations (greater than 34 Ma) contribute more to Atlantic richness than other regions, but the Atlantic is ultimately dominated by more recent colonizations (approximately last 20 Ma). The CIP is still dominated by relatively older colonizations approximately over the last 30 million years. (f) A high proportion of living freshwater richness comes from older colonizations (greater than 34 Ma). Dashed lines indicate the start of the Oligocene (34 Ma) and Pliocene (5.3 Ma).