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TDWG Ontology

TDWG has created a series of RDF and OWL ontology documents with associated documentation. The ontologies described by these documents are known in aggregate as the "TDWG Ontology". These ontologies are no longer under development and the documents are archived in this repository.

Although none of the TDWG ontologies ever became TDWG Standards, some are in use in the wild. It is not recommended that new projects use them without tracking their current status here and on the issue list at


The TDWG ontologies were intended to facilitate understanding and exchange of biodiversity data. Their original home was at For a detailed history of the ontology see Section 2.4 of the Report of the TDWG Vocabulary Management Task Group (VoMaG); Permanent URL:

Components of the TDWG Ontology still in use

The following individual ontologies do not have well-known alternatives and appear to be in use by at least one provider:

These ontologies are likely to remain in their current form until they are replaced by new TDWG Standards. Changes in the statuses of these ontologies will be reported on this page.

The Collection, CollectionType, and Institution ontologies are based on the stalled Natural Collections Description (NCD) draft TDWG standard Recommendation 2.10 of the VoMaG report recommends evaluation of the status of the draft NCD standard, but as of 2015-07-01 no action has been taken on this recommendation.

The TaxonConcept, TaxonName, and TaxonRank ontologies are based on the ratified Taxonomic Concept Transfer Schema (TCS) Current (2005) TDWG Standard Recommendation 2.11 of the VoMaG report recommends examination of the status of these three ontologies with the possibility of replacing them upon the creation of a new TCS standard based on current Linked Data/Semantic Web best practices. As of 2015-07-01 no action has been taken on this recommendation.

Deprecated components of the TDWG Ontology

The following parts of the ontology were never widely used and have been deprecated:

See the recommended replacements page for recommended alternatives to some of these deprecated portions of the ontology. As of 2015-07-01, the recommended replacement list is a stub and a work in progress.

Details of modifications made to the TDWG ontologies based on the VoMaG Report

Section 2.6.1 of the VoMaG report) contains a series of recommendations regarding the fate of the various TDWG ontologies. Those recommendations have been implemented and are summarized as follows:

  1. Clarify that documents having the extension .owl (TaxonConcept.owl, TaxonName.owl, and TaxonRank.owl) are not the authoritative documents by indicating in their RDF that they are deprecated and replaced by the corresponding documents having the extension .rdf (TaxonConcept.rdf, TaxonName.rdf, and TaxonRank.rdf). (Recommendation 2.4)

  2. Remove the XML stylesheet references from all documents. (See the text of Recommendation 2.5 for the rationale for this change.)

  3. Deprecate individual ontologies that do not appear to be in use and which may have well-known alternatives (listed above). Increment the version of each deprecated ontology by 0.1 and update the dcterms:modified value. (Recommendations 2.7 and 2.8)

  4. Document recommended replacements for deprecated ontologies and indicate the replacements in RDF using the property dcterms:isReplacedBy. Note: this is a work in progress in consultation with the TDWG RDF/OWL Task Group. (Recommendation 2.8)

  5. Remove rdfs:subClassOf relationships that link classes of the non-deprecated ontologies to deprecated external ontologies. Increment the version of each modified ontology by 0.1 and update the dcterms:modified value. (Recommendation 2.7 and 2.9)


TDWG Ontology







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