Unraveling the origins, dispersal patterns, and evolutionary trajectory of marmots through integrated fossil and molecular evidence

Abstract

Marmota represents a genus of relatively large‐bodied, fossorial rodents widely distributed across grassland and alpine meadow ecosystems in the Northern Hemisphere. This study integrates paleontological data with molecular phylogenetics from extant species to reconstruct the spatiotemporal dynamics of Marmota distribution, elucidating its origins, biogeographic dispersal patterns, phylogenetic relationships, and species divergence times. Results indicate that the genus likely originated in North America, with the earliest fossil occurrences dated to ~16.3 million years ago (Mya). The radiation of extant Marmota commenced approximately 6.09 Mya, marked by elevated speciation rates during the Late Miocene and Pliocene. Throughout the late Miocene to the early Pleistocene, the extinction rate was maintained at a relatively stable level. At around 1 Mya, both the speciation rate and the extinction rate increased synchronously, leading to a slight increase in the net diversification rate. These shifts in net diversification rate showed strong correlations with global environmental transformations, particularly the expansion of grasslands since the Late Miocene and climatic oscillations associated with the Last Glacial Maximum. Within the context of contemporary anthropogenic climate warming, Marmota species face significant survival challenges, with certain taxa potentially at risk of extinction due to maladaptation to rapidly altering environments.