What Is the Integrated Taxonomic Information System (ITIS) and How Do You Use It?
ITIS (Integrated Taxonomic Information System, itis.gov) is a publicly accessible taxonomic database that assembles scientific names and their taxonomic relationships for species worldwide, covering all seven kingdoms of life: Archaea, Bacteria, Protozoa, Chromista, Fungi, Plantae, and Animalia. Use it when you need an authoritative reference for a scientific name, its classification hierarchy, or a stable identifier (TSN) to link taxonomic data across systems. ITIS is maintained by 11 active MOU partners and is an Associate Participant of GBIF, as well as a contributor to the Catalogue of Life and ChecklistBank.
What ITIS Provides
The core value of ITIS is not just a list of names but the relationships between them. Each record ties a taxon to its position in a classification hierarchy, so you can move from a species up through genus, family, order, and beyond.
| Element | What it gives you |
|---|---|
| Scientific names | Authoritative names across all seven kingdoms |
| Common names | Vernacular names associated with taxa |
| Taxonomic relationships | Parent/child hierarchy linking a taxon to its classification |
| TSN | A Taxonomic Serial Number, a stable numeric identifier for a taxon |
| Coverage | Plants, animals, fungi, and microbes of North America and the world |
The site reports large and actively updated datasets. As of the figures shown on the homepage, the monthly export lists over 1,000,000 scientific names (any rank, any usage) and more than 167,000 common names, with new and edited names loaded continuously.
What Is a TSN and Why It Matters
A TSN (Taxonomic Serial Number) is a unique, stable number assigned to a taxon in ITIS. Because scientific names can change with new research, and because the same organism may be known by different names in different sources, a TSN gives you a fixed reference point. If you are building a database, linking biodiversity records, or citing a taxon, the TSN lets other systems resolve exactly which entity you mean, even if the name is later revised.
How to Search ITIS
ITIS offers a quick search on the homepage and an Advanced Search and Report tool.
Quick search
- Choose what you are searching on: Any Name or TSN, Common Name, Scientific Name, or TSN.
- Optionally narrow by kingdom: Animal, Plant, Fungal, Bacteria, Protozoa, Chromista, or Archaea.
- Set the match type: exactly, for containing, starting with, or ending with.
- Enter your term and run the search.
Note that the search functionality requires JavaScript. If results do not appear, enable JavaScript or use a JavaScript-enabled browser, or go directly to Advanced Search and Report.
Advanced Search and Report
Use this when you need more control than the quick search allows, for example combining name criteria with rank or kingdom filters, or when you want to generate a report rather than a simple result list.
Working with Results: Reports and Comparisons
Beyond a single lookup, ITIS provides tools for viewing and reconciling taxonomic data:
- Taxonomic Classification Report — shows a taxon's full position in the hierarchy.
- Hierarchical Report — displays the classification as a structured tree.
- Compare Names — helps you check how names relate, useful when you suspect two names refer to the same or different taxa.
- Web Services — programmatic access, including ITIS Web Services, ITIS Solr Web Services (with examples), and a guide to developing a client, for pulling ITIS data into your own application.
Getting the Full Dataset
If you need bulk data rather than individual lookups, ITIS offers a full database download with instructions and database files, plus a download in TWB format. This is the practical route when you want to integrate ITIS taxonomy into a local system rather than query it one name at a time. You can also become a data partner or contribute taxonomic work through the Taxonomic Workbench.
Citing and Linking to ITIS
ITIS provides guidance on how to cite it and how to link to its pages, so your references remain traceable. If you are publishing research or building a resource that depends on ITIS data, follow the citation format the site specifies rather than paraphrasing it.
When a Search Returns Nothing or Names Don't Match
If your query fails or a name seems inconsistent, check these in order:
- Spelling — scientific names are exact; a single wrong letter can return no result.
- Match type — "exactly" is strict; try "containing" or "starting with" if you are unsure of the full string.
- Author/name form — the name as you have it may include an author citation that the search field does not expect.
- Synonyms — the name you have may be a synonym or a name no longer in use; the Compare Names tool and the classification report can help you trace the accepted name.
- Kingdom filter — an over-narrow kingdom selection can hide a valid result.
ITIS is a reference for names and classification, not a source of ecological, geographic, or conservation data. Treat it as the naming and hierarchy layer that other biodiversity information can be indexed and connected against.