The MN System: Regional or Continental?

In this paper we apply disjunct distribution ordination (DDO) to a large set of Miocene to Pleistocene mammal localities from western Eurasia. This multivariate method creates a sequence of taxonomic first and last appearance events that minimizes the number of age-range overlaps. Our aim is to compare the event sequence with the existing Eurasian MN system of mammalian biochronology. Our results show that: 1) the sequence and the MN system ordination of localities are highly correlated; 2) a combined data set of western and eastern localities performs better in this regard than either data set separately; 3) most disagreements between the methods involve faunal lists of inadequate length. These results confirm that the current MN system is robust and suggest that it can be usefully extended to encompass all of Eurasia. Specifically, we expect Eurasian mammal biochronology to be refined through the use of algorithmic techniques such as DDO, which are likely to provide objectivity and quantification without generating unpredictable results.