standards.md

@@ -33,6 +33,7 @@
 | Taxon | `dwc` | Darwin Core | http://rs.tdwg.org/dwc/terms/ | [VOWL](http://visualdataweb.de/webvowl/#iri=https://raw.githubusercontent.com/tdwg/dwc/master/rdf/dwcterms.rdf) |  | [Doc](http://rs.tdwg.org/dwc/terms/guides/rdf/) |
 | Taxon | `tc` | Taxon Concept | http://rs.tdwg.org/ontology/voc/TaxonConcept# | [VOWL](http://visualdataweb.de/webvowl/#iri=https://raw.githubusercontent.com/tdwg/ontology/master/ontology/voc/TaxonConcept.rdf) |  | [Doc](https://github.com/tdwg/rdf/blob/master/TCSBasedTaxon.md) |
 | Taxon | `tn`| Taxon Name | http://rs.tdwg.org/ontology/voc/TaxonName# | [VOWL](http://visualdataweb.de/webvowl/#iri=https://raw.githubusercontent.com/tdwg/ontology/master/ontology/voc/TaxonName.rdf) |  | [Doc](https://github.com/tdwg/rdf/blob/master/TCSBasedTaxon.md) |
+| Taxon | `tr`| Tax Rank | http://purl.obolibrary.org/obo/taxrank.owl# | [VOWL](http://visualdataweb.de/webvowl/#iri=http://visualdataweb.de/webvowl/#iri=http://purl.obolibrary.org/obo/taxrank.owl) |  | [Doc](https://github.com/tdwg/rdf/blob/master/TCSBasedTaxon.md) |
 | Gene | `obi` | Ontology for Biomedical Investigations | http://purl.obolibrary.org/obo/obi# |  | [LOV](http://lov.okfn.org/dataset/lov/vocabs/obo) | [Doc](https://bioportal.bioontology.org/ontologies/OBI/) |
 | Gene | `so` | Sequence Ontology | http://purl.obolibrary.org/obo/so# | [VOWL](http://visualdataweb.de/webvowl/#iri=https://raw.githubusercontent.com/obi-ontology/obi/v2017-02-22/obi_core.owl) |  | [Doc](http://www.sequenceontology.org) |
 | Gene | `go` | Gene Ontology | http://purl.obolibrary.org/obo/go# |  |  | [Doc](http://geneontology.org/) |