Late Cenozoic micromammal biochronology of northwestern Africa

• This is the first biochronological synthesis on fossil North African small mammals.
• Ten main biozones were identified, four of which being divided into sub-biozones.
• Geologic and climatic events have highly influenced migrations and local evolution.
• Future discoveries will easily find their place in this updated framework.

This synthesis aims to integrate former, recent and unpublished data on fossil micromammals (Rodentia, Erinaceomorpha, Soricomorpha, Chiroptera) from Moroccan, Algerian and Tunisian archeological and paleontological sites. An updated biochronology of these taxa is established from the middle Miocene to the Holocene. Ten main biozones are defined: they are characterized by specific faunal assemblages, whose evolution and migrations were influenced by geologic and climatic events throughout the studied period. During the Miocene, Myocricetodontinae were dominant. This period was followed by a progressive diversification among Murinae, Gerbillinae, and Crocidurinae from the Plio-Pleistocene onwards, along with sporadic occurrences of European, Asian and sub-Saharan taxa, before a decrease in small mammal diversity at the beginning of the late Pleistocene, while modern faunas stabilized. Overall, the new biochronology matches well with the former ones. However, some slight discrepancies emerge, notably because the former biochronologies were based on more sporadic data and often did not consider the whole small mammal faunas. The present work represents the first complete biochronological synthesis of North African small faunas for the whole late Cenozoic, which should be useful for paleontologists and archeologists in providing an up-to-date framework into which future discoveries will easily find their place.