How many mammal species are there now? Updates and trends in taxonomic, nomenclatural, and geographic knowledge

Probably not a substantial claim: may not pass S3 (load-bearing).

A collaboration with Yale University researchers enabled the digitization of geographic range maps as polygon shapefiles for all mammal species, as matched to the taxonomies of MDD v1.2, HMW series, and CMW.

“A further collaboration with Yale University researchers enabled the digitization of geographic range maps as polygon shapefiles for all mammal species, as matched to the taxonomies of MDD v1.2, HMW series, and CMW (see Marsh et al. 2022 and map downloads updated to MDD v1.4 via the “mddmaps” R package; Robles-Fernández 2024).”

• cites Marsh et al. 2022 sourcePartly supported

  The Introduction and Materials and Methods describe digitized range maps harmonized to MDD v1.2, HMW, and CMW and provided as shapefiles; the Biosketch identifies the lead author as based at Yale University. However, Table 1 and the Harmonisation between data sources section state that a few species in each taxonomy lack georeferenced range maps, so the claim that shapefiles were produced for all species is too absolute. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites Robles-Fernández 2024Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

These changes have been controversial within the mammalogical community, and many specialists have subsequently reverted to the taxonomy presented in MSW3.

“These changes have been controversial within the mammalogical community, and many specialists have subsequently reverted to the taxonomy presented in MSW3 (e.g., Holbrook 2013; Gutiérrez and Garbino 2018).”

• cites Holbrook 2013 sourceNot checked — no full text of the source
• cites Gutiérrez and Garbino 2018 sourcePartly supported

  The Introduction and the section on objective criteria describe recent criticism of Groves and Grubb’s ungulate taxonomy and identify several controversial aspects of it. They do not report that many specialists subsequently reverted to the taxonomy in MSW3 (searched: MSW3 and reversion to earlier taxonomy). Our copy provides no page numbers for these passages. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

May combine two claims.

Recognition of these domestic forms as distinct species by the MDD contradicts much of the evolutionary and taxonomic research on these taxa, which has shown that the wild and domestic forms should be considered a single species in most cases.

“Recognition of these domestic forms as distinct species by the MDD contradicts much of the evolutionary and taxonomic research on these taxa, which has shown that the wild and domestic forms should be considered a single species in most cases (e.g., Driscoll et al. 2007; Groenen 2016; Jackson et al. 2019, 2021).”

• cites Driscoll et al. 2007 sourceNot checked — no full text of the source
• cites Groenen 2016 sourcePartly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured
• cites Jackson et al. 2019, 2021Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The recent and rapid net increase in recognized mammal species is comparable to activity in other major clades of life, for example, reptiles: +49% from 1995 to 2024; amphibians: +60% from 1985 to 2024; foraminifera: +21% from 1987 to 2020.

“The recent and rapid net increase in recognized mammal species is comparable to activity in other major clades of life, for example, reptiles: +49% from 1995 to 2024 (Uetz 2016; Uetz et al. 2024); amphibians: +60% from 1985 to 2024 (AmphibiaWeb 2024); foraminifera: +21% from 1987 to 2020 (Hayward et al. 2020).”

• cites Uetz 2016Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Uetz et al. 2024 sourcePartly supported

  Split into 2 atoms — 0 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 1 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured
• cites AmphibiaWeb 2024Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Historically, much of the mammalogical research done in Global South countries was done by researchers from Europe and North America, leading to limited taxonomic research funding and access to museum specimens for Global South researchers.

“Historically, much of the mammalogical research done in Global South countries was done by researchers from Europe and North America, leading to limited taxonomic research funding and access to museum specimens for Global South researchers (Salvador et al. 2022).”

• cites Salvador et al. 2022 sourcePartly supported

  The Discussion’s Geography section says developing countries lack taxonomists, infrastructure, and funding, and the Abstract identifies lack of research funding especially in the Global South. Neither passage establishes that European and North American researchers historically conducted much of the mammalogical research in Global South countries, that this caused the funding gap, or that Global South researchers lack access to museum specimens. Page numbers were not supplied in our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

These shortfalls pose hurdles to zoonotic disease studies and other biomedical research as well as to implementation of species conservation and management plans.

“These shortfalls pose hurdles to zoonotic disease studies and other biomedical research (Upham et al. 2021) as well as to the implementation of species conservation and management plans (Senior et al. 2024).”

• cites Upham et al. 2021 sourceSupported
• cites Senior et al. 2024 sourcePartly supported

  The Abstract (page unavailable) reports that conservation interventions are insufficient or absent for many threatened species, and the Main section calls better documentation a critical first step toward improving conservation practices. This supports a broad link between the shortfalls and conservation action, but the paper does not specifically assess whether they hinder implementation of species conservation or management plans. The biomedical-research portion is attributed to a different citation and is not judged here. (LLM, conf=0.78)

  Experimental — accuracy not yet measured

May combine two claims.

17% to 93% of the genomes of European Myotis bats apparently have introgressive origins, suggesting that many genomic regions can be freely exchanged as long as certain other regions are conserved, protecting the distinctiveness of a given species.

“Consistent with this finding is the observation that 17% to 93% of the genomes of European Myotis bats apparently have introgressive origins (Foley et al. 2024), suggesting that many genomic regions can be freely exchanged as long as certain other regions are conserved, protecting the distinctiveness of a given species.”

• cites Foley et al. 2024 sourcePartly supported

  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Mammals can serve as sentinels of change in threatened ecosystems or key nodes in pathogen-sharing networks.

“This is particularly true for mammals given that they can serve as sentinels of change in threatened ecosystems (Moore 2008; Marneweck et al. 2022) or key nodes in pathogen-sharing networks (Plowright et al. 2021; Venkatesan 2023; Weber et al. 2023).”

• cites Moore 2008 sourceNot checked — no full text of the source
• cites Marneweck et al. 2022 sourceNot checked — no full text of the source
• cites Plowright et al. 2021 sourceSupported

May combine two claims.

Taxonomy and nomenclature are not static; creation of species lists is plagued by gaps in biodiversity knowledge, differing taxonomic opinions, failure to track and digitally integrate changing taxonomies, and inconsistencies in ICZN Code implementation.

“However, as discussed throughout this article, taxonomy and nomenclature are by no means static—the creation of species lists is plagued by gaps in biodiversity knowledge (i.e., the Linnean and Wallacean shortfalls), differing taxonomic opinions, failure to track and digitally integrate those changing taxonomies, and inconsistencies in how the ICZN Code is implemented (Garnett and Christidis 2017;”

• cites Garnett and Christidis 2017 sourceNot checked — no full text of the source
• cites Raposo et al. 2017, 2021Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Franz and Sterner 2018 sourcePartly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured

May combine two claims.

Recognized Giraffa diversity has ranged from 1 to 11 species, but most workers now recognize 4 species based on integrative taxonomic approaches.

“For example, recognized Giraffa diversity has ranged from 1 to 11 species, but most workers now recognize 4 species based on integrative taxonomic approaches (Winter et al. 2018; Petzold and Hassanin 2020; Coimbra et al. 2021; Kargopoulos et al. 2024).”

• cites Winter et al. 2018 sourcePartly supported

  The Introduction and Discussion support a historical one-species classification and this paper’s evidence for four species. But the Introduction says up to eleven *subspecies*, not eleven species; the Discussion mentions proposals of up to eight species. The paper also says the four-species conclusion may not be fully accepted and calls for revision of the IUCN’s one-species classification, so it does not support the claim that most workers now recognize four. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites Petzold and Hassanin 2020 sourcePartly supported

  The Introduction (page unavailable) documents a historical one-species classification and reports that two studies proposed four species. It does not document a range extending to 11 species or say that most workers now recognize four; instead, it describes the four-species proposal as controversial. The Abstract and conservation-management conclusion (pages unavailable) favor three species based on this paper’s analyses. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites Coimbra et al. 2021 sourceNot checked — no full text of the source

May combine two claims.

This practice can overlook finer-scale intraspecific diversity and taxonomically unrecognized species in understudied taxa, resulting in loss of cryptic biodiversity.

“However, this practice can overlook finer-scale intraspecific diversity (Des Roches et al. 2021) and taxonomically unrecognized species in understudied taxa (i.e., “dark extinctions”; Boehm and Cronk 2021), resulting in the loss of cryptic biodiversity (see review by Hending 2025).”

• cites Des Roches et al. 2021 sourceNot checked — no full text of the source
• cites Boehm and Cronk 2021 sourceNot checked — no full text of the source
• cites Hending 2025 sourcePartly supported

  The Introduction (‘Why do many cryptic species remain undetected?’; page unavailable) says morphologically indistinguishable species have historically been overlooked. ‘Cryptic species recognition’ says visually based assessments underestimate biodiversity and can misinform conservation, while ‘Recent taxonomic description’ identifies greater extinction risk for newly recognized species. These passages support the concern behind the citation, but do not establish that overlooking them has resulted in an actual loss of cryptic biodiversity. (LLM, conf=0.83)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

MDD2 governance includes a rewritten website that improves access and scalability.

“a rewritten website that improves access and scalability”

May combine two claims.

The American Society of Mammalogists launched the Mammal Diversity Database (MDD) in 2018, which then recognized ∼20% more mammal species (+1,251 and -172 species) compared to MSW3.

“the American Society of Mammalogists launched the Mammal Diversity Database (MDD) in 2018, which then recognized ∼20% more mammal species (+1,251 and –172 species) compared to the previous authoritative compendium, the Mammal Species of the World, third edition (MSW3; Wilson and Reeder 2005; Burgin et al. 2018).”

• cites Wilson and Reeder 2005Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Burgin et al. 2018 sourceNot checked — no full text of the source

May combine two claims.

Areas of high mammal endemism include Madagascar, Philippines, Andes, East Africa, Himalayas, and Atlantic Forest.

“highlighting areas of high mammal endemism (e.g., Madagascar, Philippines, Andes, East Africa, Himalayas, Atlantic Forest)”

Probably not a substantial claim: may not pass S3 (load-bearing).

MDD2 governance includes the establishment of external taxonomic subcommittees to guide data collection and curation.

“Governance advancements in MDD2 include the establishment of external taxonomic subcommittees to guide data collection and curation”

Probably not a substantial claim: may not pass S3 (load-bearing).

MDD2 governance includes a cross-platform mobile application that provides offline access.

“a cross-platform mobile application that provides offline access”

Probably not a substantial claim: may not pass S3 (load-bearing).

MDD2 governance includes new partnerships to continue linking MDD data to global biodiversity infrastructure.

“and new partnerships to continue linking MDD data to global biodiversity infrastructure”

May combine two claims.

The paper identifies 4 major time periods of change in mammalian taxonomy and nomenclature over the past 267 years: (i) 1758 to 1880 initial monographic description of traditionally charismatic species; (ii) 1881 to 1939 peak of descriptive taxonomy, describing subspecies, and publishing in journals; (iii) 1940 to 1999 shift toward revisionary taxonomy and recognizing polytypic species; and (iv) 2

“identifying 4 major time periods of change in mammalian taxonomy and nomenclature: (i) the initial monographic description of traditionally charismatic species (1758 to 1880); (ii) the peak of descriptive taxonomy, describing subspecies, and publishing in journals (1881 to 1939); (iii) the shift toward revisionary taxonomy and recognizing polytypic species (1940 to 1999); and (iv) the current”

May combine two claims.

The MDD2 taxonomy documents a net increase of 339 (27.6%) genera, 38 (29.5%) families, and 6 (28.6%) orders since C&H1.

“the MDD2 taxonomy documents a net increase of 339 (27.6%) genera, 38 (29.5%) families, and 6 (28.6%) orders since C&H1”

May combine two claims.

Version 1.11 marked the beginning of collaborations between the MDD and Hesperomys and Batnames, leading to many changes in taxonomy (15 de novo; 49 splits; 29 lumps) and nomenclature (e.g., spelling changes to 52 species-rank specific epithets) despite a gap of only 5 mo between MDD v1.10 and v1.11 release dates.

“Version 1.11 is also notable because it marked the beginning of collaborations between the MDD and Hesperomys and Batnames, which involved considerable efforts to reconcile information across the 3 databases, leading to many changes in taxonomy (15 de novo; 49 splits; 29 lumps) and nomenclature (e.g., spelling changes to 52 species-rank specific epithets) despite a gap of only 5 mo between MDD v1.”

May combine two claims.

The MDD2 taxonomy documents a net increase of 123 (10.0%) genera and 14 (8.4%) families since MSW3.

“a net increase of 123 (10.0%) genera and 14 (8.4%) families since MSW3”

Probably not a substantial claim: may not pass S3 (load-bearing).

Subspecies of bats are currently only listed in Batnames.

“(however, subspecies of bats are currently only listed in Batnames)”

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

The representatives of 17 mammal species domesticated by humans during prehistoric times are considered separate species from their ancestors in the MDD; all but 2 of these (Bos primigenius and the unknown ancestor of Camelus dromedarius) are extant.

“The representatives of 17 mammal species that were domesticated by humans during prehistoric times are considered separate species from their ancestors in the MDD, all but 2 of which (Bos primigenius and the unknown ancestor of Camelus dromedarius) are extant.”

Probably not a substantial claim: may not pass S3 (load-bearing).

These data were primarily integrated into MDD2 species-rank synonym data, resulting in expanded coverage of type localities, type specimens, and other nomenclatural data.

“These data were primarily integrated into MDD2 species-rank synonym data, resulting in expanded coverage of type localities, type specimens, and other nomenclatural data detailed below.”

May combine two claims.

Since MDD1, Callitrichidae and Aotidae were recognized as distinct, while Eschrichtiidae was lumped into Balaenopteridae.

“The families Callitrichidae and Aotidae were recognized as distinct, while Eschrichtiidae was lumped into Balaenopteridae since MDD1.”

May combine two claims.

Between MDD1 and MDD2, there were net differences of 37 more genera (1,316 to 1,353) and 1 more family (166 to 167) recognized, with no changes to the 27 orders.

“Between MDD1 and MDD2, there were net differences of 37 more genera (1,316 to 1,353) and 1 more family (166 to 167) recognized, with no changes to the 27 orders.”

May combine two claims.

The highest number of taxonomic changes between 2 MDD versions occurred between versions 1.1 and 1.2, versions 1.9.1 and 1.10, and versions 1.10 and 1.11.

“The highest number of taxonomic changes between 2 MDD versions occurred between versions 1.1 (March 2019) and 1.2 (September 2020), versions 1.9.1 (June 2022) and 1.10 (December 2022), and versions 1.10 and 1.11 (April 2023)”

Probably not a substantial claim: may not pass S3 (load-bearing).

Efforts to coordinate with the ASM Mammal Images Library have aligned taxonomic names and concepts used in the expert-identified images to each new release of the MDD.

“Finally, efforts to coordinate with the ASM Mammal Images Library have aligned taxonomic names and concepts used in the expert-identified images to each new release of the MDD (available for download at https://www.mammalogy.org/image-library).”

May combine two claims.

The 2024-1 IUCN Red List includes 5,983 species, which is 776 fewer (-11.5%) than MDD2.

“the 2024-1 IUCN Red List includes 5,983 species, which is 776 fewer (–11.5%) than MDD2 despite being released the same year.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The synonym list includes available and unavailable names; spelling variants and name combinations; and names associated with currently valid species, subspecies, synonyms, nomina dubia, or species inquirendae.

“The synonym list includes available and unavailable names; spelling variants and name combinations; and names that are associated with currently valid species, subspecies, synonyms, nomina dubia, or species inquirendae.”

May combine two claims.

When comparing MDD1 and MDD2 directly, there were 296 de novo species, 321 split species, 357 lumped species, 11 missing species subsequently added, 6 removed species, 227 generic changes, 17 specific epithet name changes, and 148 spelling changes or corrections.

“there were 296 de novo species, 321 split species, 357 lumped species, 11 missing species that were subsequently added (mostly recently extinct and domestic species), 6 removed species (all either extinct species that did not survive recently enough for inclusion, or names now considered unavailable or nomina dubia), 227 generic changes, 17 specific epithet name changes, and 148 spelling changes”

Probably not a substantial claim: may not pass S3 (load-bearing).

The 18 total releases of the MDD from MDD1 to MDD2 included 15 primary releases and 3 patch releases from August 2017 to August 2024.

“The 18 total releases of the MDD from MDD1 to MDD2 included 15 primary releases (i.e., 1.X and 1.XX releases) and 3 patch releases (i.e., 1.X.X releases) from August 2017 to August 2024”

May combine two claims.

Of the 6,759 valid mammal species in MDD2, 6,629 are wild extant, 113 are extinct, and 17 are domestic.

“6,759 valid mammal species (6,629 wild extant; 113 extinct; 17 domestic)”

May combine two claims.

The 3 most speciose mammal orders are Rodentia (2,747 species; 536 genera; 35 families), Chiroptera (1,485 species; 236 genera; 21 families), and Eulipotyphla (599 species; 61 genera; 5 families).

“The 3 most speciose mammal orders are still Rodentia (2,747 species; 536 genera; 35 families), Chiroptera (1,485 species; 236 genera; 21 families), and Eulipotyphla (599 species; 61 genera; 5 families)”

Probably not a substantial claim: may not pass S3 (load-bearing).

The countries with the highest overall MDD website usage during the 17-month period were the United States (34.3%), Brazil (6.7%), Mexico (6.2%), and China (5.4%).

“The countries with the highest overall usage during this period were the United States (34.3% of users), Brazil (6.7%), Mexico (6.2%), and China (5.4%), which topped the 12 countries with over 500 users and the 50 countries with over 50 users (see Supplementary Data SD11 for complete usage data).”

• AssumptionRests on an assumption: The Google Analytics data accurately reflects the number of unique users and their locations.

May combine two claims.

The countries with the most type localities of valid species described during the 21st century are Brazil (98), Madagascar (78), Indonesia (57), China (53), and Peru (52).

“The countries with the most type localities of valid species described during the 21st century are Brazil (98 names), Madagascar (78), Indonesia (57), China (53), and Peru (52).”

May combine two claims.

Across terrestrial biogeographic realms, the Palearctic has the most available names with type localities in that region (20.5% of total available names), followed by Afrotropical (19.7%), Neotropical (19.4%), Indomalayan (15.4%), Nearctic (10.9%), Australasian (7.4%), Oceanian (0.2%), and Antarctic (<0.1%).

“the Palearctic has the most available names with type localities in that region (20.5% of total available names), followed by the Afrotropical (19.7%), Neotropical (19.4%), Indomalayan (15.4%), Nearctic (10.9%), Australasian (7.4%), Oceanian (0.2%), and Antarctic (<0.1%)”

May combine two claims.

At the continental scale, Asia contains the most recognized mammal species, followed by Africa, South America, North America, Oceania, Europe, and Antarctica.

“Asia contains the most recognized mammal species, followed by Africa, South America, North America, Oceania, Europe, and Antarctica.”

May combine two claims.

Since MSW3, 1,579 more species have been recognized as distinct (23.4% of all currently valid species), including 805 de novo and 774 split species listed in MDD2, while 226 species have been lumped or removed.

“Since MSW3, there have been 1,579 more species recognized as distinct (23.4% of all currently valid species), including 805 de novo and 774 split species listed in MDD2, while 226 species have been lumped or removed”

Probably not a substantial claim: may not pass S3 (load-bearing).

MDD2 provides an online overview of research studies authored by mammalogists worldwide over the past 267 years (1758 to 2024).

“MDD2 provides an online overview of research studies authored by mammalogists worldwide over the past 267 yrs (1758 to 2024), jointly illuminating the latest advances in taxonomic understanding of this charismatic vertebrate clade.”

May combine two claims.

All other mammal families have fewer than 200 species, with 24 families having only 1 extant species.

“All other mammal families have fewer than 200 species, with 24 families having only 1 extant species”

May combine two claims.

The 3 most speciose genera are Crocidura (220 species), Myotis (139 species), and Rhinolophus (114 species), which are also the only mammal genera exceeding 100 extant or recently extinct species.

“The 3 most speciose genera are Crocidura (220 species), Myotis (139 species), and Rhinolophus (114 species), which are also the only mammal genera exceeding 100 extant or recently extinct species”

May combine two claims.

In terms of species density per land area, Indomalaya has the highest density of mammal species, followed by Australasia, Neotropical, Afrotropical, Nearctic, Palearctic, and Oceania.

“Indomalaya has the highest density of mammal species, followed by the realms of Australasia, Neotropical, Afrotropical, Nearctic, Palearctic, and Oceania”

May combine two claims.

Few newly described names from the 21st century have type localities in northern North America, Europe, and northern Asia; most that do are subspecific names or names now regarded as synonyms.

“Few newly described names from the 21st century have type localities in northern North America, Europe, and northern Asia, and most that do are either subspecific names or names now regarded as synonyms.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Global MDD website usage rates rose from an average of ~450 weekly users to ~700 between months 1-10 and 11-17 of tracking.

“Global usage rates rose from an average of ∼450 weekly users to ∼700 between months 1 to 10 and 11 to 17 of tracking.”

• AssumptionRests on an assumption: The Google Analytics data accurately reflects the number of unique users and their locations.

May combine two claims.

MDD2 considers 113 species to be recently extinct and documents the extinction of 25 entire genera and 7 entire families since the year 1500.

“MDD2 considers 113 species to be recently extinct and documents the extinction of 25 entire genera and 7 entire families since the year 1500.”

May combine two claims.

The orders with the largest number of threatened extant species are Primates (335 species; 64.2% of total MDD2 species), Rodentia (313; 11.4%), Chiroptera (217; 14.6%), and Artiodactyla (122; 32.9%).

“The orders with the largest number of threatened extant species are Primates (335 species; 64.2% of total MDD2 species), Rodentia (313; 11.4%), Chiroptera (217; 14.6%), and Artiodactyla (122; 32.9%).”

May combine two claims.

The most speciose mammalian families are Muridae (876 species; 156 genera), Cricetidae (869 species; 162 genera), Vespertilionidae (535 species; 60 genera), Soricidae (488 species; 28 genera), Sciuridae (321 species; 64 genera), Phyllostomidae (231 species; 61 genera), and Pteropodidae (202 species; 46 genera).

“The most speciose mammalian families are Muridae (876 species; 156 genera), Cricetidae (869 species; 162 genera), Vespertilionidae (535 species; 60 genera), Soricidae (488 species; 28 genera), Sciuridae (321 species; 64 genera), Phyllostomidae (231 species; 61 genera), and Pteropodidae (202 species; 46 genera).”

May combine two claims.

These orders are followed by Primates (522 species; 84 genera; 19 families), Artiodactyla (371 species; 138 genera; 23 families), and Carnivora (319 species; 129 genera; 16 families); all other mammal orders have fewer than 200 recognized species.

“These orders are followed by Primates (522 species; 84 genera; 19 families), Artiodactyla (371 species; 138 genera; 23 families), and Carnivora (319 species; 129 genera; 16 families); all other mammal orders have fewer than 200 recognized species.”

Classified as probably not a substantial claim.

The MDD2 dataset allows for novel explorations of how the recognized taxonomy of mammal species and higher taxa has changed through time.

“The MDD2 dataset allows for novel explorations of how the recognized taxonomy of mammal species and higher taxa has changed through time, which is briefly contextualized here.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Over a recent 17-month period, the MDD website was visited by 1,200 to 2,900 users/month for a total of 25,991 unique users located in 170 countries.

“Over a recent 17-mo period, it was visited by 1,200 to 2,900 users/mo for a total of 25,991 unique users that were located in 170 different countries (Google Analytics: 19 May 2023 to 19 October 2024).”

• AssumptionRests on an assumption: The Google Analytics data accurately reflects the number of unique users and their locations.

May combine two claims.

Of the total species recognized in MDD2, 19.2% (1,295 species) are threatened with extinction and 11.5% (773 species) are classified as Data Deficient (DD).

“Of the total species recognized in MDD2, 19.2% (1,295 species) are threatened with extinction (VU, EN, CR, and EW IUCN statuses) and 11.5% (773 species) are classified as Data Deficient (DD).”

May combine two claims.

Tubulidentata is currently the only mammal order with a single living species, since Microbiotheria now includes 2 species.

“Tubulidentata is currently the only mammal order with a single living species, since Microbiotheria now includes 2 species”

May combine two claims.

There are 2 notable single-year spikes in species descriptions associated with single publications: Linnaeus (1758) with 208 names (152 currently valid species) and R. Kerr (1792) with 202 names (27 currently valid species).

“Linnaeus (1758) with 208 names (152 currently valid species) and R. Kerr in Britain (Kerr 1792) with 202 names (27 currently valid species).”

May combine two claims.

The orders with the most species newly recognized since MSW3 are Rodentia (595 species; 21.7% of order total in MDD2), Chiroptera (410; 27.6%), Eulipotyphla (166; 27.7%), and Primates (161; 30.8%).

“The orders with the most species newly recognized since MSW3 are Rodentia (595 species; 21.7% relative to the order total in MDD2), Chiroptera (410; 27.6%), Eulipotyphla (166; 27.7%), and Primates (161; 30.8%).”

May combine two claims.

MDD2 recognizes 2 fewer orders than MSW3 because Soricomorpha and Erinaceomorpha are now lumped into a single order (Eulipotyphla), and Cetacea is now lumped into Artiodactyla.

“MDD2 recognizes 2 fewer orders than MSW3 because Soricomorpha and Erinaceomorpha are now lumped into a single order (Eulipotyphla), and Cetacea is now lumped into Artiodactyla.”

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Linnaeus's Systema Naturae (10th edition) still holds the title of proposing the largest number of currently valid mammal species in a single publication.

“Binomial nomenclature and taxonomy for mammals and other animals starts with C. Linnaeus in Sweden (1758), whose Systema Naturae (10th edition) still holds the title of proposing the largest number of currently valid mammal species in a single publication.”

May combine two claims.

Crocidura exceeded 200 species and Rhinolophus exceeded 100 species as a result of new species recognized since MSW3.

“Crocidura exceeded 200 species and Rhinolophus exceeded 100 species as a result of new species recognized since MSW3.”

Probably not a substantial claim: may not pass S3 (load-bearing).

A large spike in MDD website traffic on 15-17 July 2024 involved 1,326 weekly users.

“A large spike in MDD website traffic on 15 to 17 July 2024 involved 1,326 weekly users, likely stemming from the MDD v1.13 taxonomy release on 13 July 2024.”

• AssumptionRests on an assumption: The Google Analytics data accurately reflects the number of unique users and their locations.

May combine two claims.

The Neotropical realm contains the most newly recognized species since MSW3 (563 total species), followed by Afrotropical (294), Indomalaya (268), Palearctic (265), Australasia (131), Nearctic (114), and Oceania (3).

“the Neotropics also contain the most newly recognized species since MSW3 (563 total species), followed by the realms of Afrotropical (294), Indomalaya (268), Palearctic (265), Australasia (131), Nearctic (114), and Oceania (3).”

Probably not a substantial claim: may not pass S3 (load-bearing).

The curatorial efforts of MDD2, Hesperomys, and Batnames have uncovered extensive information relevant to the history of studying mammal taxa, especially type localities, type specimens, original description citations, and hyperlinks to sources.

“The curatorial efforts of MDD2, Hesperomys, and Batnames have uncovered extensive information relevant to the history of studying mammal taxa—especially type localities, type specimens, original description citations, and hyperlinks to those sources.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Archived versions of the MDD taxonomy on Zenodo garnered 33,208 page views and 17,159 downloads over a 4-year period (September 2020 to October 2024).

“Archived versions of the MDD taxonomy on Zenodo (https://doi.org/10.5281/zenodo.4139722) have garnered 33,208 page views and 17,159 downloads over a 4-yr period (September 2020 to -October 2024).”

May combine two claims.

Over the 20-yr period since MSW3, at least 1 new species has been recognized in 20 out of 27 orders and 98 out of 167 families of mammals.

“Over this same 20-yr period, at least 1 new species has been recognized in 20 out of 27 orders and 98 out of 167 families of mammals”

May combine two claims.

The IUCN version 2024-1 recognizes 1,308 genera and 164 families, which is a net difference of 45 (3.3%) fewer genera and 3 (1.8%) fewer families than MDD2, but recognizes the same 27 orders.

“The IUCN version 2024-1 recognizes 1,308 genera and 164 families, which is a net difference of 45 (3.3%) fewer genera and 3 (1.8%) fewer families than MDD2, but recognizes the same 27 orders.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Species-rank names described during 1758-1880 were often based on illustrations or firsthand accounts of living or recently deceased animals without reference to voucher specimens.

“Species-rank names described during this period were often based on illustrations or firsthand accounts of living or recently deceased animals without reference to voucher specimens, but museum specimens would become the preferred reference material for biological descriptions later in the 19th and early 20th century (i.e., museum-based type material).”

May combine two claims.

Only 8 of 27 orders and 72 of 167 families of mammals are currently "completely evaluated" by the IUCN.

“Only 8 of 27 orders and 72 of 167 families of mammals are currently “completely evaluated” by the IUCN”

May combine two claims.

Mammal research typifies activities of the taxonomic renaissance in 2 ways: increased splitting of existing species through taxonomic revisions (774 species split since MSW3); and proportionately more names described as new species rather than subspecies (83.4% of available names since 2000 are described as new species rather than subspecies, versus 36.1% from 1950 to 1999).

“Mammal research typifies activities of this renaissance in 2 ways: (i) increased splitting of existing species through taxonomic revisions (774 species split since MSW3); and (ii) proportionately more names described as new species rather than subspecies (83.4% of available names since 2000 are described as new species rather than subspecies, versus 36.1% from 1950 to 1999).”

Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

The period 1881-1939 was also characterized by an increasing prevalence in the use of the subspecies rank (replacing forms and varieties).

“This standardization contributed to the rapid increase in mammalian taxonomic activity during the late 19th and early 20th century, which was also characterized by an increasing prevalence in the use of the subspecies rank (replacing forms and varieties).”

May combine two claims.

Species during 1881-1939 were often described based on subtle morphological distinctions, and some traits used for species diagnoses at this time are now known to vary substantially within species relative to environmental factors.

“Additionally, species were often described based on subtle morphological distinctions, and some of the traits used for species diagnoses at this time are now known to vary substantially within species relative to environmental factors (e.g., pelage coloration).”

May combine two claims.

The recognized species richness of Microcebus mouse lemurs rose from 2 to 25 species over 4 decades, and was recently reduced to 19 species after an integrative taxonomic revision.

“Even the recognized species richness of groups such as Microcebus mouse lemurs, which rose from 2 to 25 species over 4 decades (Franz et al. 2020), was recently reduced to 19 species after an integrative taxonomic revision (van Elst et al. 2025—published after the MDD2 cutoff date).”

• cites Franz et al. 2020 sourceNot checked — no full text of the source
• cites van Elst et al. 2025Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Merriam's (1918) treatment of the Brown Bear (Ursus arctos) as ~74 distinct species in North America alone contrasts with the currently defined single Holarctic species.

“A prime example of the frequency with which now-synonymous names were proposed during this period is Merriam’s (1918) treatment of the Brown Bear (Ursus arctos) as ∼74 distinct species in North America alone, as opposed to the currently defined single Holarctic species.”

• cites Merriam’s (1918) sourceNot checked — no full text of the source

May combine two claims.

Mammal-focused expeditions occurred more frequently during 1881-1939, generally associated with colonial exploration, resulting in specimens being sent to museums in Europe and North America (rarely in the country of collection).

“Mammal-focused expeditions also occurred more frequently, generally associated with colonial exploration, resulting in specimens being sent to museums in Europe and North America (rarely in the country of collection; e.g., see Mohammed et al. 2022).”

• cites Mohammed et al. 2022 sourceNot checked — no full text of the source

The quote only partly states this claim.

Researchers during 1881-1939 primarily described mammal species based on relatively few specimens sent to museums from widely separated localities.

“Researchers primarily described mammal species based on relatively few specimens sent to museums from widely separated localities.”

May combine two claims.

C&H1 marks the shift from predominantly lumping species back to predominantly splitting species, as total estimates of extant mammal species richness began increasing thereafter.

“C&H1 marks the shift from predominantly lumping species back to predominantly splitting species, as total estimates of extant mammal species richness began increasing thereafter (Table 1, Fig. 1).”

May combine two claims.

226 species-rank names that were recognized as species in MSW3 have since been synonymized, or about 1 lump for every 6 newly recognized species from 2004 to 2024.

“For example, 226 species-rank names that were recognized as species in MSW3 have since been synonymized, or about 1 lump for every 6 newly recognized species from 2004 to 2024 (considering both de novo and split names).”

May combine two claims.

During 1940-1999, fewer names were being described, and even fewer are now considered valid species (e.g., only 3 currently valid species were described in 1961).

“During this period, fewer names were being described, and even fewer are now considered valid species (e.g., only 3 currently valid species were described in 1961).”

May combine two claims.

There has been a net increase of 123 recognized genera since MSW3, typically to establish generic monophyly, which has also been bidirectional (+178 and -55 genera).

“Similarly, there has been a net increase of 123 recognized genera since MSW3, typically to establish generic monophyly, which has also been bidirectional (+178 and –55 genera).”

Probably not a substantial claim: may not pass S3 (load-bearing).

Prototheria, Metatheria, and Eutheria are retained in the MDD to match the most common use of the names of extant mammals for the time being.

“Prototheria, Metatheria, and Eutheria are retained in the MDD to match the most common use of the names of extant mammals for the time being.”

May combine two claims.

In contrast to the previous period, proportionately more new names described during the mid- to late 20th century were described as subspecies, and many names described earlier as species were joined together into polytypic species with many subspecies.

“In contrast to the previous period, proportionately more new names described during the mid- to late 20th century were described as subspecies, and many names described earlier as species were joined together into polytypic species with many subspecies.”

May combine two claims.

The period 1881-1939 is characterized by the appearance of more seriously cataloged museum type specimens and more precisely defined type localities.

“Thus, this period is further characterized by the appearance of more seriously cataloged museum type specimens and more precisely defined type localities (rather than broadly defined type localities at the country or continent level).”

May combine two claims.

The Annals and Magazine of Natural History published the descriptions of 3,434 available species-rank mammal names from 1841 to 1959, 12.1% of available names in MDD2 (including 990 currently valid species).

“A single journal, the Annals and Magazine of Natural History, published the descriptions of 3,434 available species-rank mammal names from 1841 to 1959, 12.1% of available names in MDD2 (including 990 currently valid species).”

May combine two claims.

Didelphimorphia has both a high degree of potential for cryptic species and extensive recent taxonomic research, with over 50 new species recognized since MSW3 (39.7% of valid Didelphimorphia species in MDD2).

“Didelphimorphia stands out as having both a high degree of potential for cryptic species and extensive recent taxonomic research, with over 50 new species recognized since MSW3 (39.7% of valid Didelphimorphia species in MDD2).”

May combine two claims.

Only around half of newly recognized tropical species are splits, whereas in Nearctic/North America and Palearctic/Europe splits form a higher proportion of new species recognitions since MSW3.

“Only around half of these newly recognized tropical species are splits, as opposed to the Nearctic/North America and Palearctic/Europe where splits form a higher proportion of new species recognitions since MSW3.”

May combine two claims.

The Neotropics and Indomalaya have particularly high proportions of newly recognized species since MSW3, including 9 of the top 10 countries and top 2 continents for new species (South America and Asia).

“The Neotropics and Indomalaya have particularly high proportions of newly recognized species since MSW3, including 9 of the top 10 countries (Figs 2A and 4B) and top 2 continents for new species (South America and Asia; Fig. 2B).”

May combine two claims.

The 2000-2009 decadal total was 315 currently valid species, compared to originally 341 species in Burgin et al. 2018, reduced by synonymizations in MDD2.

“That decadal total compares to 315 during 2000 to 2009 (originally 341 species in Burgin et al. 2018, but reduced by synonymizations in MDD2).”

• cites Burgin et al. 2018 sourceNot checked — no full text of the source

May combine two claims.

For 2010-2019, the expectation was 418 valid de novo species descriptions, but only 369 currently valid species were actually described de novo.

“the expectation for 418 valid de novo species descriptions from 2010 to 2019 compares to only 369 currently valid species that were actually described de novo (i.e., with an authority year during this interval).”

May combine two claims.

Primate species began being split with the publication of Primate Taxonomy (Groves 2001), which initiated a wave of taxonomic revisions that massively increased recognized species richness-176 species (Napier and Napier 1967) versus 376 in MSW3, growing to 522 in MDD2.

“Primates species began being split with the publication of Primate Taxonomy (Groves 2001), which was controversial at the time but initiated a wave of taxonomic revisions that massively increased their recognized species richness—176 species (Napier and Napier 1967) versus 376 in MSW3, growing to 522 in MDD2 (Groves 2014).”

• cites Groves 2001Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Napier and Napier 1967Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Groves 2014 sourceNot checked — no full text of the source

May combine two claims.

Both primates and terrestrial ungulates have been at the center of splitting versus lumping debates due to their inclusion of many traditionally charismatic species threatened with extinction (∼64% of primates and ∼40% of wild ungulates in MDD2 are threatened in the IUCN Red List).

“Both groups have been at the center of splitting versus lumping debates (e.g., Rylands and Mittermeier 2014; Gippoliti et al. 2018) due to their inclusion of many traditionally charismatic species threatened with extinction (∼64% of primates and ∼40% of wild ungulates in MDD2 are threatened in the IUCN Red List).”

• cites Rylands and Mittermeier 2014 sourceNot checked — no full text of the source
• cites Gippoliti et al. 2018 sourceNot checked — no full text of the source

May combine two claims.

The IUCN Red List has assessed the conservation status of 5,983 mammal species as of version 2024-1, which is only 494 species more than were assessed in the 2008 IUCN Red List version (5,489 species).

“The IUCN Red List has assessed the conservation status of 5,983 mammal species as of version 2024-1, which is only 494 species more than were assessed in the 2008 IUCN Red List version (5,489 species; summarized in Schipper et al. 2008).”

• cites Schipper et al. 2008 sourceNot checked — no full text of the source

May combine two claims.

Both groups have received more frequent taxonomic updates in the IUCN than other mammals, with only ∼3% of primates and ∼8% of wild ungulates in MDD2 Not Evaluated by the IUCN.

“Both groups have received more frequent taxonomic updates in the IUCN than other mammals, with only ∼3% of primates and ∼8% of wild ungulates in MDD2 Not Evaluated by the IUCN.”

Probably not a substantial claim: may not pass S4 (based).

Most taxonomic changes incorporated into the MDD have, thus far, closely followed the most recent empirical evidence given in peer-reviewed articles, which each represent the current best hypothesis of species boundaries.

“Most taxonomic changes incorporated into the MDD have, thus far, closely followed the most recent empirical evidence given in peer-reviewed articles, which each represent the current best hypothesis of species boundaries.”

May combine two claims.

The IUCN completed the Global Mammal Assessment in 2008, which made range maps available for ∼95% of the species recognized in MSW3 (5,489 species).

“In 2008, the IUCN completed the landmark Global Mammal Assessment (GMA), which made range maps available for ∼95% of the species recognized in MSW3 (5,489 species; Schipper et al. 2008).”

• cites Schipper et al. 2008 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

By consistently following the most recent evidence from peer-reviewed literature, taxonomy in the MDD is designed to collectively reflect the most up-to-date taxonomic perspective of the global mammalogical community and thereby minimize subjective biases coming from the MDD team.

“By consistently following the most recent evidence from peer-reviewed literature, taxonomy in the MDD is designed to collectively reflect the most up-to-date taxonomic perspective of the global mammalogical community and thereby minimize subjective biases coming from the MDD team.”

Probably not a substantial claim: may not pass S3 (load-bearing).

All currently recognized species on the MDD have been included within at least an order, family, and genus, with intermediary higher and lower ranks assigned when suggested in the literature.

“All currently recognized species on the MDD have been included within at least an order, family, and genus, with intermediary higher and lower ranks assigned when suggested in the literature.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

All distributional listings are generally supported by a confirmed record of the species living there (a museum specimen or photographic evidence), with question marks for suspected but unconfirmed occurrences.

“All distributional listings are generally supported by a confirmed record of the species living there (i.e., a museum specimen or photographic evidence), although if a species is suspected to occur in a region but there is no evidence to confirm its presence a question mark is listed after the region name.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The MDD follows the ICZN Code to inform issues of the nomenclatural availability and spelling of scientific names.

“The MDD follows the ICZN Code to inform issues of the nomenclatural availability and spelling of scientific names”

Classified as probably not a substantial claim.

Recognizing domestic species emphasizes the wild forms as an entity to be separately considered and protected.

“Recognizing domestic species also emphasizes the wild forms as an entity to be separately considered and protected.”

Classified as probably not a substantial claim.

To verify citation and associated nomenclatural data for each name, the MDD team has examined the original descriptions of each name, including the page number where the name or description first occurs and the exact month or day of publication when available.

“To verify citation and associated nomenclatural data for each name, the MDD team has examined the original descriptions of each name, including the page number where the name or description first occurs and the exact month or day of publication when available.”

Classified as probably not a substantial claim.

Nomenclatural availability of each name was determined based on application of the ICZN Code and executive decisions by the ICZN on the protection or rejection of specific names when applicable.

“Nomenclatural availability of each name was determined based on application of the ICZN Code (ICZN 1999) as well as executive decisions made by the ICZN on the protection or rejection of specific names when applicable.”

• cites ICZN 1999Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

The MDD considers 8 terrestrial biogeographic realms as defined by Olson et al. (2001): Nearctic, Neotropical, Palearctic, Afrotropical, Indomalayan, Australasian, Oceanian, and Antarctic.

“The MDD considers 8 terrestrial biogeographic realms, as defined by Olson et al. (2001): Nearctic, Neotropical, Palearctic, Afrotropical, Indomalayan, Australasian, Oceanian, and Antarctic”

• cites Olson et al. (2001) sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

On the current synonym sheet, the MDD has verified and copied the verbatim type locality from the original description text for names with verified citations.

“On the current synonym sheet, the MDD has now verified and copied the verbatim type locality from the original description text for names with verified citations.”

Classified as probably not a substantial claim.

The MDD chooses to recognize these specific domestic forms as distinct species to avoid confusion regarding which forms are being discussed in various political and conservation situations.

“However, the MDD chooses to recognize these specific domestic forms as distinct species to avoid confusion regarding which forms are being discussed in various political and conservation situations.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Citations are considered verified when either a PDF of the cited source is obtained or a member of the MDD team has physically examined the cited source.

“Citations are considered verified when either a PDF of the cited source is obtained or when a member of the MDD team has physically examined the cited source.”

Classified as probably not a substantial claim.

All species believed to have been extant after the year 1500 CE, according to evidence published in the peer-reviewed literature, are included in the MDD.

“All species that are believed to have been extant after the year 1500 CE, according to evidence published in the peer-reviewed literature, are included in the MDD.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Beginning with v1.10 (December 2022), the MDD piloted a protocol for publishing taxonomic opinion "white papers" on Zenodo in collaboration with members of the Global Bat Taxonomy Working Group.

“However, beginning with v1.10 (December 2022), the MDD piloted a protocol for publishing taxonomic opinion “white papers” on Zenodo in collaboration with members of the Global Bat Taxonomy Working Group, which is part of the IUCN SSC Bat Specialist Group and aligned with Batnames.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

In cases where there is insufficient evidence to support a taxonomic change or if multiple conflicting taxonomic arrangements are published in rapid succession, the MDD team provides justifications and citations on the relevant per-species pages, with summaries given on the About page.

“In cases where there is insufficient evidence to support a taxonomic change or if multiple conflicting taxonomic arrangements are published in rapid succession, the MDD team provides justifications and citations on the relevant per-species pages, with summaries given on the About page at https://mammaldiversity.org.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The MDD acknowledges that recognizing these 17 domestic forms as species is a deviation from the species recognition standards outlined in the Taxonomic decision making section and follows the naming conventions for domestic species and their wild ancestors outlined by Gentry et al. (2004).

“Thus, the MDD acknowledges that recognizing these 17 domestic forms as species is a deviation from the species recognition standards outlined in the Taxonomic decision making section above and follows the naming conventions for domestic species and their wild ancestors outlined by Gentry et al. (2004).”

• cites Gentry et al. (2004) sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

MDD2 is a digital compendium of global mammal taxonomic, nomenclatural, and geographic information that is more complete and accessible than prior efforts.

“The Mammal Diversity Database version 2.0 (MDD2) is a digital compendium of global mammal taxonomic, nomenclatural, and geographic information that is more complete and accessible than prior efforts, providing a steppingstone to greater knowledge about mammalian biology.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The 19th century saw significant philosophical advances in evolutionary theory, which drove further advances in the understanding of mammal biodiversity.

“The 19th century also saw significant philosophical advances in evolutionary theory, which drove further advances in the understanding of mammal biodiversity.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The modern terms for the 3 extant mammal clades (Prototheria, Metatheria, Eutheria) were established by T.N. Gill (1872) and T.H. Huxley (1881).

“The modern terms for these 3 extant mammal clades were established by T.N. Gill (1872), who initially proposed Prototheria for monotremes and Eutheria for marsupials and placentals; and T.H. Huxley (1881), who then termed Metatheria for the marsupials (albeit not initially intended as a scientific name), leaving placental mammals in Eutheria.”

• cites T.N. Gill (1872)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites T.H. Huxley (1881)Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Probably not a substantial claim: may not pass S3 (load-bearing).

The release of MDD1 7 years ago marked a shift from decadal printed volumes to semi-annual online versions.

“The release of MDD1 7 yrs ago marked a shift from decadal printed volumes to semi-annual online versions (Burgin et al. 2018).”

• cites Burgin et al. 2018 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

The spike in MDD website traffic on 15-17 July 2024 likely stemmed from the MDD v1.13 taxonomy release on 13 July 2024.

“A large spike in MDD website traffic on 15 to 17 July 2024 involved 1,326 weekly users, likely stemming from the MDD v1.13 taxonomy release on 13 July 2024.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The higher classification of mammals began to take shape with H.M.D. de Blainville, who used reproductive biology and skull and skeletal features to group mammals into distinct subclasses: monotremes, marsupials, and placentals.

“The higher classification of mammals began to take shape with H.M.D. de Blainville, who used reproductive biology and skull and skeletal features to group mammals into distinct subclasses: monotremes (Ornithodelphes), marsupials (Didelphes), and placentals (Monodelphes; de Blainville 1816, 1864).”

• cites de Blainville 1816, 1864Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The lack of structure spurred the need for standardized nomenclatural and taxonomic rules for zoological taxonomy, culminating in the publication of the International Rules of Zoological Nomenclature in 1905.

“The lack of structure spurred the need for standardized nomenclatural and taxonomic rules for zoological taxonomy, which culminated in the publication of the International Rules of Zoological Nomenclature in 1905 (Blanchard et al. 1905) that would eventually develop into the first edition of the ICZN Code (ICZN 1961).”

• cites Blanchard et al. 1905Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites ICZN 1961Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Prior to the 1890s, taxonomic and nomenclatural practices were unstandardized, leading to differential naming systems and confusion regarding a given species proper name.

“Prior to the 1890s, taxonomic and nomenclatural practices were unstandardized, leading to differential naming systems and confusion regarding a given species proper name, especially as many authors knowingly renamed already-named species.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The International Rules of Zoological Nomenclature established fundamental nomenclatural rules still used today, including the principle of priority, the use of physical type material and type localities, and the rule that names must be published according to the ICZN Code to be considered available.

“These documents established fundamental nomenclatural rules that are still used today including the principle of priority for scientific names, the use of physical type material and type localities to define species-rank names, and the rule that names must be published according to the ICZN Code to be considered available.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The publication of The Principles of Classification and a Classification of Mammals (Simpson 1945) is the foundation of modern mammalian ordinal and familial arrangements, based on a more complete consideration of the deep-time evolutionary history of both living and extinct mammals.

“The publication of The Principles of Classification and a Classification of Mammals (Simpson 1945), which is the foundation of modern mammalian ordinal and familial arrangements, is based on a more complete consideration of the deep-time evolutionary history of both living and extinct mammals.”

• cites Simpson 1945Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

Revisionary taxonomy is perhaps the most appropriate characterization of mammal taxonomic change in the modern era, albeit with more frequent splitting than lumping.

“Thus, like the preceding time period discussed above, revisionary taxonomy is perhaps the most appropriate characterization of mammal taxonomic change in this modern era (albeit with more frequent splitting than lumping).”

May combine two claims.

The estimate of ∼11,625 species by 2100 seems more far-fetched given that this trend is likely to level off at some point, but the ∼70% increase over the current MDD2 total would be equivalent to the 1980 to 2024 increase since C&H1 was published.

“The estimate of ∼11,625 species by 2100 seems more far-fetched given that this trend is likely to level off at some point, but the ∼70% increase over the current MDD2 total would be equivalent to the 1980 to 2024 increase since C&H1 was published.”

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

Currently, broadening such conclusions into generalities is likely premature.

“Currently, broadening such conclusions into generalities is likely premature.”

May combine two claims.

If the trend continues, total recognized mammal species richness will increase to ∼7,084 species by 2030 and ∼8,382 species by 2050.

“If this trend continues, we estimate that the total recognized mammal species richness will increase to ∼7,084 species by 2030 and ∼8,382 species by 2050.”

• AssumptionThe authors state this as an assumption: Observed trends in historical species descriptions or species recognition will continue into the future.

Probably not a substantial claim: may not pass S3 (load-bearing).

Modern taxonomic research trends reflect a paradigm shift in how systematists define the species unit.

“Overall, trends in modern taxonomic research appear to reflect a paradigm shift in how systematists define the species unit (reviewed in Padial and De la Riva 2021).”

• cites Padial and De la Riva 2021 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

Relevant estimates of the number of known and unknown species will only be achieved by accounting for the dynamic nature of the taxonomic process itself.

“Lessa et al. (2024) reviewed this problem in detail, concluding that “relevant estimates of the number of known and unknown species will only be achieved by accounting for the dynamic nature of the taxonomic process itself” (p. 1365).”

• cites Lessa et al. 2024 sourceNot checked — no full text of the source

May combine two claims.

Rates of de novo species description are only part of the discovery rates story, with the other major component being rates of species splitting and lumping from revisionary taxonomic efforts.

“Thus, these data reinforce the perspective that rates of de novo species description are only part of the “discovery rates” story (Alroy 2002), with the other major component being rates of species splitting and lumping that result from revisionary taxonomic efforts.”

• cites Alroy 2002 sourceNot checked — no full text of the source

May combine two claims.

These estimates are considerably higher than those given by Burgin et al. (2018) and Reeder et al. (2007), but are nonetheless realistic owing to the combined consideration of species splits, lumps, and de novo descriptions.

“Both of these estimates are considerably higher than those given by Burgin et al. (2018) and Reeder et al. (2007), but are nonetheless realistic owing to the combined consideration of species splits, lumps, and de novo descriptions.”

• cites Burgin et al. 2018 sourceNot checked — no full text of the source
• cites Reeder et al. 2007 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

In 2018, the MDD team estimated that recognized extant and recently extinct mammal richness will increase to 7,409 species by 2050 and to 9,009 by 2100 if observed trends in historical species descriptions were to continue.

“Using this approach in 2018, the MDD team estimated that recognized extant and recently extinct mammal richness will increase to 7,409 species by 2050 and to 9,009 by 2100 if observed trends in historical species descriptions were to continue (Burgin et al. 2018).”

• cites Burgin et al. 2018 sourceNot checked — no full text of the source

• AssumptionThe authors state this as an assumption: Observed trends in historical species descriptions or species recognition will continue into the future.

Probably not a substantial claim: may not pass S2 (checkable).

The digital availability of extracted evidence from taxonomic publications is a key resource needed to make consistent decisions across disparate taxa.

“In either case, the digital availability of extracted evidence from taxonomic publications is a key resource needed to make consistent decisions across disparate taxa.”

Probably not a substantial claim: may not pass S2 (checkable).

Efficient communication and application of biodiversity knowledge between conservation and biodiversity resources requires agreed-upon organismal units that can serve as foundational designations for downstream decisions.

“Efficient communication and application of biodiversity knowledge between conservation and biodiversity resources requires agreed-upon organismal units that can serve as foundational designations for downstream decisions made on those units.”

May combine two claims.

Untracked taxonomic rearrangements risk misallocation of resources, e.g., Sylvilagus mansuetus is listed by IUCN as Critically Endangered but is not recognized in MDD2 due to synonymization with S. bachmani.

“Untracked taxonomic rearrangements also risk the misallocation of resources (e.g., Sylvilagus mansuetus is listed by the IUCN as Critically Endangered, but is not recognized in MDD2 due to synonymization with S. bachmani; Álvarez-Castañeda and Lorenzo 2016).”

• cites Álvarez-Castañeda and Lorenzo 2016 sourceNot checked — no full text of the source

May combine two claims.

Databases such as ITIS and CoL are increasingly critical for national and international processes of biodiversity decision-making, but they still primarily rely on MSW3-based taxonomies and synonymies for mammals.

“Databases such as the Integrated Taxonomic Information System (ITIS 2025) and Catalog of Life (CoL 2025) are increasingly critical for national and international processes of biodiversity decision-making, but they still primarily rely on MSW3-based taxonomies and synonymies for mammals.”

• cites ITIS 2025Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites CoL 2025Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.