Mammal Diversity Database synonym table

Synonymy and nomenclatural table from the Mammal Diversity Database (MDD), covering all names applicable to species- and subspecies-level mammal taxa within Class Mammalia. Designed to align with the online nomenclature database Hesperomys (https://hesperomys.com).

Usage

mdd_synonyms

Format

A tibble with 44 variables in the MDD v2.4 release, with source column names normalized to snake_case during data import. Variables and their original naming equivalents:

mdd_syn_id: (MDD_syn_ID) Unique MDD synonym identification number assigned to each synonym, starting from 100000001 and incrementing as new synonyms are added.
mdd_species: (MDD_species) Genus and specific epithet of the accepted species to which this synonym is assigned, with a space between the two elements; listed as "genus incertae_sedis" or "incertae_sedis incertae_sedis" for nomina dubia, nomina inquirenda, and names based on composite or hybrid type material.
mdd_species_id: (MDD_species_id) Identification number of the accepted species as listed in mdd_checklist (the MDD_Current sheet).
hesp_id: (Hesp_id) Identification number of the matching entry in the Hesperomys nomenclature database (https://hesperomys.com), used to link and synchronise data between MDD and Hesperomys.
mdd_root_name: (MDD_root_name) Specific epithet used as the root to form a valid taxon name; spelling is adjusted to match generic gender when the epithet is an adjective, or Latinised when originally written in non-Latin characters.
mdd_author: (MDD_author) Author surname(s) of the original description, following the same formatting conventions as authority_species_author in mdd_checklist: all authors on the author line are included; Oxford comma before the last name when three or more authors are present; an "in" statement is added when the work appears in a volume with different editors; shared surnames are disambiguated by initials or full middle names; Chinese, Korean, and Indochinese names are written with surname first and hyphens removed.
mdd_year: (MDD_year) Year of the original description as given in the original publication.
mdd_authority_parentheses: (MDD_authority_parentheses) Parenthesis flag: 0 = no parentheses; 1 = authority in parentheses (indicating the species was originally described under a different genus).
mdd_nomenclature_status: (MDD_nomenclature_status) Nomenclatural status of the name under the ICZN Code; indicates whether the name is available, a spelling variant, a name combination, or unavailable (with the specific reason given); see Nomenclature_Taxonomy_Metadata in the MDD spreadsheet for full value definitions.
mdd_validity: (MDD_validity) Taxonomic status of the name under the ICZN Code and primary literature; indicates whether the name is a valid species or subspecies, or is a nomen dubium, nomen inquirendum, or based on composite or hybrid type material; see Nomenclature_Taxonomy_Metadata for full value definitions.
mdd_original_combination: (MDD_original_combination) Name combination exactly as it appears in the original description; all parts of the scientific name are written in full even if abbreviated in the source.
mdd_original_rank: (MDD_original_rank) Taxonomic rank at which the name was first described; one of "species", "subspecies", "form", "variety", "infrasubspecific", "unranked", "synonym", or "other".
mdd_authority_citation: (MDD_authority_citation) Full APA citation of the original description, including specific month and day of publication when known; populated only when the MDD team has verified the citation by obtaining a PDF or physical copy.
mdd_unchecked_authority_citation: (MDD_unchecked_authority_citation) Unverified original description citation in non-standardised format, often abbreviated from regional or global taxonomic compendia; set to NA once mdd_authority_citation is filled.
mdd_sourced_unverified_citations: (MDD_sourced_unverified_citations) Same as mdd_unchecked_authority_citation but includes the sources from which the citation was obtained; retained as an internal reference for the MDD team.
mdd_citation_group: (MDD_citation_group) Journal name or city of publication (for books) of the original description; used internally by the MDD team when locating citation materials.
mdd_citation_kind: (MDD_citation_kind) Whether the MDD team holds a physical, electronic, or no copy of the original description; used internally by the MDD team.
mdd_authority_page: (MDD_authority_page) Page number where the scientific name first appears in the original description; special cases (footnotes, unnumbered pages, figures, plates) are noted in parentheses.
mdd_authority_link: (MDD_authority_link) URL to an online copy of the original description; older publications link to the Biodiversity Heritage Library or other archives; newer publications use a DOI.
mdd_authority_page_link: (MDD_authority_page_link) URL to the exact first page where the name appears in an online copy; primarily applicable to records in the Biodiversity Heritage Library, HathiTrust, Gallica, or the Internet Archive.
mdd_unchecked_authority_page_link: (MDD_unchecked_authority_page_link) Candidate page links identified programmatically from the Biodiversity Heritage Library but not yet manually verified for inclusion of the name; multiple links separated by |.
mdd_old_type_locality: (MDD_old_type_locality) Type locality as it appeared in the MDD synonym sheet before harmonisation with Hesperomys; retained for internal reference only — not for general use.
mdd_original_type_locality: (MDD_original_type_locality) Verbatim type locality transcribed from the original description and verified by the MDD team; blank when a type locality is not applicable.
mdd_unchecked_type_locality: (MDD_unchecked_type_locality) Verbatim type locality from non-original sources, with source attribution appended; multiple entries from different sources separated by |; blank when not applicable.
mdd_emended_type_locality: (MDD_emended_type_locality) Verbatim emended type locality from sources making a restriction, emendation, or declaration, followed by the reference; currently empty — reserved for future curation; blank when not applicable.
mdd_type_latitude: (MDD_type_latitude) Latitude of the type locality in decimal degrees; georeferenced from the original description or via web search / GeoLocate; blank when not applicable.
mdd_type_longitude: (MDD_type_longitude) Longitude of the type locality in decimal degrees; sourced as for mdd_type_latitude; blank when not applicable.
mdd_type_country: (MDD_type_country) Modern country containing the type locality; see Distribution_List in the MDD spreadsheet for the full list of country names used; blank when not applicable.
mdd_type_subregion: (MDD_type_subregion) First-level subnational unit containing the type locality (state, province, territory, or island group for larger countries); blank when not applicable.
mdd_type_subregion2: (MDD_type_subregion2) Second-level subnational unit within mdd_type_subregion; primarily US counties and individual islands within archipelagoes; blank when not applicable.
mdd_holotype: (MDD_holotype) Museum catalogue number(s) of the type series (holotype, syntypes, lectotype, or neotype); multiple syntypes are comma-separated; blank when type material has not been verified.
mdd_type_kind: (MDD_type_kind) Category of type specimen listed in mdd_holotype: one of "holotype", "syntypes", "lectotype", "neotype", or "nonexistent" (confirmed absence of type material); blank when existence of type material has not been verified.
mdd_type_specimen_link: (MDD_type_specimen_link) URL(s) to type material records in external museum collection databases.
mdd_order: (MDD_order) Taxonomic order; "incertae_sedis" when not assigned to an order.
mdd_family: (MDD_family) Taxonomic family; "incertae_sedis" when not assigned to a family.
mdd_genus: (MDD_genus) Taxonomic genus; "incertae_sedis" when not assigned to a genus.
mdd_specific_epithet: (MDD_specificEpithet) Specific epithet of the accepted species; "incertae_sedis" when not assigned to a species.
mdd_subspecific_epithet: (MDD_subspecificEpithet) Subspecific epithet of the accepted subspecies; blank when no subspecies are recognised within the species. Note: this field currently contains a tentative, unvetted subspecies list — assignments are incomplete and subject to revision.
mdd_variant_of: (MDD_variant_of) For spelling variants and name combinations, the name they are a variant of, given with its original name combination, authority, and MDD synonym ID.
mdd_senior_homonym: (MDD_senior_homonym) For preoccupied names (primary or secondary homonymy), the senior homonym that preoccupies the name, given with its original name combination, authority, and MDD synonym ID.
mdd_name_usages: (MDD_name_usages) Later citations using the exact spelling of the name as given in mdd_original_combination; each citation is abbreviated to authors, year, and page number.
mdd_comments: (MDD_comments) Free-text comments on the nomenclature or taxonomy of the name.

Source

Mammal Diversity Database release archive (https://www.mammaldiversity.org). Field definitions are derived from the META_v2.4.csv file and the column-level annotations in the Species_Syn_Current sheet of the official MDD spreadsheet.

Details

This table covers every name — valid, synonymised, or otherwise — that has been applied to a species- or subspecies-level mammal taxon and is recognised by the MDD. It serves as the primary nomenclatural backbone for the checklist in mdd_checklist and is designed to interoperate with the Hesperomys database (https://hesperomys.com) via hesp_id.

Column names have been normalised from the original mixed-case convention (MDD_syn_ID, MDD_specificEpithet, etc.) to snake_case during data import; the original names are shown in parentheses in each \item above for cross-reference with the upstream spreadsheet.

Citation verification follows a two-tier structure: mdd_authority_citation holds APA-formatted, MDD-verified citations, while mdd_unchecked_authority_citation holds unverified or abbreviated citations from secondary sources and is set to NA once the verified field is populated.

Several fields are retained for internal MDD team reference and should not be used for analysis: mdd_old_type_locality, mdd_sourced_unverified_citations, mdd_citation_group, and mdd_citation_kind. The mdd_emended_type_locality and mdd_subspecific_epithet fields are present but not yet fully curated.