Contrasting Dispersal Histories Shape Distinct Evolutionary Trajectories Between Malesian and Pantropical <i>Talipariti</i> (Malvaceae)

ABSTRACT The complex tectonic history of Malesia makes it a critical region for understanding the origins of tropical biodiversity, yet the drivers of plant diversification and range expansion across this region remain poorly resolved. Talipariti (Malvaceae) provides a unique system to test those drivers across Malesia since the Miocene. We aim to test whether species distributions were shaped primarily by stochastic long‐distance dispersal (LDD) or by stepping‐stone dispersal associated with tectonic collisions, by comparing two Talipariti lineages with contrasting geographic ranges: a pantropical sea hibiscus group and an endemic Papuan group. We constructed a phylogenomic framework using genome‐wide nuclear loci and plastome data, estimated divergence times, and applied quantitative biogeographical modelling to compare alternative dispersal scenarios, explicitly testing the contribution of founder‐event speciation and incorporating time‐stratified palaeogeographical information. Talipariti originated within Malesia ca. 20 Ma. A vicariance event along Lydekker's Line separated the Papuan group to the east from the remaining lineages to the west at ca. 8 Ma, and subsequently, the sea hibiscus group underwent rapid radiation from ca. 1.4 Ma. Biogeographical models reveal a pronounced dichotomy: the sea hibiscus group is best explained by unconstrained models incorporating founder‐event speciation, whereas the Papuan group is best supported by time‐stratified distance‐dependent models without a significant contribution of founder events. Pantropical distributions in the sea hibiscus group arose primarily through effective LDD events, whereas the Papuan group distribution expanded via stepping‐stone dispersal associated with Miocene Sunda‐Sahul island connectivity. These findings demonstrate that the evolutionary fate of plant lineages is not determined by geological history alone, but by the interaction between geological history and lineage‐specific dispersal abilities, revealing Wallace's and Lydekker's Lines as permeable filters rather than absolute barriers. Through biogeographical model comparison, this study provides a quantitative framework for understanding how geological history and dispersal processes jointly shape plant diversification across Malesia.