It appears that the number of currently recognized mammal species in the world increased from 5,416 to 6,495 species in the past 13 years! These are the findings of the Mammal Diversity Database (MDD), a digital, publically accessible, and updateable list of all mammalian species. The Mammal Diversity Database is home base for tracking the latest taxonomic changes to species and higher groups of mammals. Here we are curating new research and its taxonomic implications in real time — with the goal of promoting rigorous study of mammal biodiversity worldwide.
Species are a fundamental unit of study in mammalogy. Yet species limits are subject to change with improved understanding of geographic distributions, field behaviors, and genetic relationships, among other advances. These changes are recorded in a vast taxonomic literature of monographs, books, and periodicals, many of which are difficult to access. As a consequence, a unified tabulation of changes to species and higher taxa has become essential to mammalogical research and conservation efforts in mammalogy. Where better to keep this tabulation than on the internet. Lists in books (e.g. Wilson and Reeder’s Mammal Species of the World ) are outdated the day they are published. The intention of the MDD is to be a community resource for compiling and disseminating published changes to mammalian taxonomy in real time, rather than as a subjective arbiter for the relative strength of revisionary evidence, and hence defer to the peer-reviewed literature for such debates.
A scientific article about the changes in mammalian taxonomy that have occurred over the last 13 years and evaluate the distribution of species diversity and new species descriptions across both geography and time can be found here: Journal of Mammalogy, Volume 99, Issue 1
And this is the link to the database: Mammal Diversity Database.