Among the most important differences is the availability in some instances of what Sokal and Camin (1965) have called chronistic information, which refers to the times of events in phylogeny, such as times of cladogenesis, chronological sequences of populations, and geologic ranges of taxa. Obtaining even as much chronistic information as neontologists customarily have, such as precise contemporaneity of populations, may be impossible if the area of study is widespread. […]
Source: wiktionary