Mammal Diversity Database

Accurate taxonomy is central to the study of biological diversity, as it provides the needed evolutionary framework for taxon sampling and interpreting results. While the number of recognized species in the class Mammalia has increased through time, tabulation of those increases has relied on the sporadic release of revisionary compendia like the Mammal Species of the World (MSW) series. Here, we present the Mammal Diversity Database (MDD), a digital, publicly accessible, and updateable list of all mammalian species, now available online: https://mammaldiversity.org. The MDD will continue to be updated as manuscripts describing new species and higher taxonomic changes are released. Starting from the baseline of the 3rd edition of MSW (MSW3), we performed a review of taxonomic changes published since 2004 and digitally linked species names to their original descriptions and subsequent revisionary articles in an interactive, hierarchical database. The MDD provides the mammalogical community with an updateable online database of taxonomic changes, joining digital efforts already established for amphibians (AmphibiaWeb, AMNH’s Amphibian Species of the World), birds (e.g., Avibase, IOC World Bird List, HBW Alive), non-avian reptiles (The Reptile Database), and fish (e.g., FishBase, Catalog of Fishes). Development for this work is funded primarily by the American Society of Mammalogists (ASM; 2017-present), with logistical and planning support provided related grants at different time points (2025-present: NIH R35 to Upham; 2021-2023: NIH R21 to Upham, Reeder, Sterner, Sen; 2017-2019: NSF Vertlife Terrestrial grant). The ASM Biodiversity Committee compiles and maintains the MDD, curating regular releases that are downloadable in comma-delimited format. Downstream goals include expanded hosting of ecological, trait, and taxonomic data. Overall, this initiative aims to promote the ASM’s role as a leader in high quality research on mammalian biology. A new section on Subjective Decisions has been added to the MDD About page for use in summarizing opinion-based decisions of the MDD team that depart from the most recently published peer-reviewed article on a given taxon. Some of these decisions are made in collaboration with the Global Bat Taxonomy Working Group of the IUCN SSC Bat Specialist Group to promote harmonization between the MDD and batnames.org. Future subjective decisions will also be authored by the MDD Taxonomic Subcommittees that we are assembling in early 2026. VERSIONS Version 2.5 (28 Jul 2026). This is an incremental release that documents 6,904 total species, of which 113 are recently extinct (same as previous version) and 6,791 are extant (17 domestic extant, 6,774 wild extant). There are 228 species flagged for further review (same as last version). The Cell-by-Cell Tracked Differerences file ("Diff-AllChanges_v2.4-v2.5.csv") lists 6,617 changes to cells in the matrix that occurred between v2.4 and v2.5 as arranged by category, column, new value, and old value. This detailed tracking complements the Summary Tracked Differences file ("Diff_v2.4-v2.5.csv"), which documents 79 taxonomic changes made since MDD v2.4. Differences include... for species: 38 new species recognized (27 de novo, 11 split), 1 de-extinction (Tous ayamaruensis, species originally named as a subfossil and now known as a living animal and moved to a new genus), 6 synonymizations (lumps), and 5 species name changes; for genera: 4 new genera recognized (de novo: Apnoctomys, Tous; split: Dactylonax, Dasyphractus), 1 genus lump (Dorcopsulus lumped into Dorcopsis), and 7 genus-level name changes; for families: 2 new families recognized (split: Euphractidae and Tolypeutidae split from Chlamyphoridae); and for other ranks recognized: 3 new tribes, 3 new subfamilies, 7 new subgenera, 1 new superfamily, and 1 new suborder. In total, there was a net increase of 33 species, 3 genera, and 2 families of recognized extant or recently extinct mammals since MDD v2.4. Version 2.4 (2 Jan 2026). This is an incremental release that documents 6,871 total species, of which 113 are recently extinct (same as previous version) and 6,758 are extant (17 domestic extant, 6,741 wild extant). There are 228 species flagged for further review (+4 from last version). The Cell-by-Cell Tracked Differerences file ("Diff-AllChanges_v2.3-v2.4.csv") lists 5,377 changes to cells in the matrix that occurred between v2.3 and v2.4 as arranged by category, column, new value, and old value. This detailed tracking complements the Summary Tracked Differences file ("Diff_v2.3-v2.4.csv"), which documents 73 taxonomic changes made since MDD v2.3. Differences include 45 new species recognized (22 de novo, 23 split), 9 synonymizations (lumps), 1 species name change, 1 species removed, 1 new genus (Andinocervus), 6 genera with name changes and 2 genera lumped, as well as 6 species with genus name changes, 6 subgenera changes, and 2 tribes changed. In total, there was a net increase of 35 species and -1 genera of recognized extant or recently extinct mammals since MDD v2.3. Version 2.3 (1 Sep 2025). This is an incremental release that documents 6,836 total species, of which 113 are recently extinct (+1 from previous version: Galea tixiensis, found to have gone extinct in the past 500 years) and 6,723 are extant (17 domestic extant, 6,705 wild extant). There are 224 species flagged for further review. The Cell-by-Cell Tracked Differerences file ("Diff-AllChanges_v2.2-v2.3.csv") lists 1,325 changes to cells in the matrix that occurred between v2.2 and v2.3 as arranged by column, new value, and old value. This detailed tracking complements the Summary Tracked Differences file ("Diff_v2.2-v2.3.csv"), which documents 65 taxonomic changes made since MDD v2.2. Differences include 27 new species recognized (16 de novo, 11 split), 7 synonymizations (lumps), 4 genera newly added (Nagasorex, Breviforamen, Incanomys, Aethalodelphis) and 2 genera lumped (Sagmatias--changed to Aethalodelphis; and Maxomys--all species transferred to Crunomys), as well as 27 species with genus name changes and 3 tribes added. The typeVoucher field is now filled for 6,189 accepted species, with corresponding typeKind categorizations for all those (e.g., holotype, lectotype, neotype, syntype). Hyperlinks to those type specimens are available in typeVoucherURIs for 3,682 species. Links to authority species citations in the authoritySpeciesLink field are now available for 6,442 species. In total, there was a net increase of 21 species and 2 genera of recognized extant or recently extinct mammals since MDD v2.2. Note also that the 1500th species of bat was also recognized in MDD v2.3 -- Pipistrellus etula described by Torrent et al. (2025) -- see press release by Bat Conservational International (forthcoming). Version 2.2 (13 Jun 2025). This is an incremental release that documents 6,815 total species, of which 112 are recently extinct (identical to previous version) and 6,703 are extant (17 domestic extant, 6,686 wild extant). There are still 223 species flagged for further review. The Cell-by-Cell Tracked Differerences file ("Diff-AllChanges_v2.1-v2.2.csv") lists 6,638 changes to cells in the matrix that occurred between v2.1 and v2.2 as arranged by column, new value, and old value. The majority of these changes are to higher taxonomic categories that were a focus of the curation this version (tribe: 533 changes; superorder: 133; superfamily: 1,541; suborder: 1,764; subgenus: 445; subfamily: 415; subclass: 5; specificEpithet: 8; parvorder: 572; infraorder: 287; genus: 20). This detailed tracking complements the Summary Tracked Differences file ("Diff_v2.1-v2.2.csv"), which documents 382 taxonomic changes made since MDD v2.1. Differences include 14 new species recognized (13 de novo, 4 split), 3 synonymizations (lumps), 2 genera split and newly added (Pipistrellus to Alionoctula; Phodopus to Cricetiscus), 20 species with genus name changes, 2 species epithet changes, 340 higher taxonomy changes (as mentioned above), and 107 species with common name changes (spelling or geographic consistency). The typeVoucher field is now filled for 5,948 accepted species, with corresponding typeKind categorizations for all those (e.g., holotype, lectotype, neotype, syntype). Hyperlinks to those type specimens are available in typeVoucherURIs for 3,649 species. Links to authority species citations in the authoritySpeciesLink field are now available for 6,420 species. In total, there was a net increase of 14 species and 2 genera of recognized extant or recently extinct mammals since MDD v2.1. Version 2.1 (6 Apr 2025). This is an incremental release that documents 6,801 total species, of which 112 are recently extinct (compared to 113 previously; Lagostomus crassus was lumped into L. maximus) and 6,689 are extant (17 domestic extant, 6,672 wild extant). There are now 223 species flagged for further review. A new addition to the MDD in v2.1 is the inclusion of a Cell-by-Cell Tracked Differerences file ("Diff-AllChanges_v2.0-v2.1.csv"), which lists 4,683 changes to cells in the matrix that occurred between v2.0 and v2.1 as arranged by column, new value, and old value. This detailed tracking complements the Summary Tracked Differences file ("Diff_v2.0-v2.1.csv"), which documents 215 taxonomic changes made since the MDD v2.0 taxonomic cutoff of 15 Aug 2024. Differences include 57 new species recognized (26 de novo, 31 split), 14 synonymizations (lumps), 1 species removal for unavailable name, 4 genera split and newly added (Afropipistrellus, Casiomys, Megascapheus, Nyctinomus), 20 species with genus name changes, 6 spelling changes, 2 tribe changes, and 114 species with common name changes (spelling or geographic consistency). The typeVoucher field is now filled for 5,918 accepted species, with corresponding typeKind categorizations for all those (e.g., holotype, lectotype, neotype, syntype). Hyperlinks to those type specime