Arthrotardigrada Echiniscoidea Thermozodia Apochela Parachela · solid rings are pictures, credited on hover; dashed rings are drawn from the order's body plan ·
fossil map DNA graph photo · the number after a group is its species count · greyed names are doubtful (nomen dubium or inquirendum)
How this is built
- Data
- Every name, rank and authority from the 45th edition of Degma & Guidetti's world checklist (2026, CC BY 4.0). Pictures at the tips: openly licensed photos (Wikimedia Commons, iNaturalist, museum type slides published through GBIF) and panels cropped from CC BY and CC BY-NC figures in papers. Line drawings: our redrawings of public-domain plates and CC BY or CC BY-NC figures.
- Built with
build_species.pyparses the checklist PDF intotree.json.treeviz.jsdraws it as a zoomable radial tree on a canvas with d3, plus the line-up and list views.build_tips.pycrops each picture into a square without stretching and records its credit;trace_drawings.pyskeletonises each plate and redraws it at one line width, so every drawing shares one style. Genera with no open picture get a body-plan sketch drawn from their order.- Checked
- By hand: the parse reproduces the checklist's own totals of families and genera, and the one-species difference from its stated total traces to a genus header. Every picture carries its licence and source. Not tested against data.
- Limits
- The tree follows the checklist's classification, not a DNA tree (that is the DNA tree page); distance from the centre shows rank, not time. Only drawings traced from openly licensed sources appear here.
- More
- How the whole project is built
Fossils
Four named tardigrade fossils, all crown-group animals preserved in amber, and older Cambrian forms that may sit on the stem below them. Each entry was checked against its paper; the pages say how much of each we read.
- Paradoryphoribius chronocaribbeus Mapalo, Robin, Boudinot, Ortega-Hernández & Barden, 2021
- Beorn leggi Cooper, 1964
- Aerobius dactylus Mapalo, Wolfe & Ortega-Hernández, 2024
- Milnesium swolenskyi Bertolani & Grimaldi, 2000
- Orsten tardigrade (unnamed)
- Aysheaia pedunculata Walcott preprint
How this is built
- Data
- The four fossils the checklist marks, plus two Cambrian forms outside it. Ages, places and specimens come from the describing papers: Cooper 1964, Mapalo et al. 2021 and 2024, and Mapalo & Ortega-Hernández's 2026 preprint for Aysheaia.
- Built with
- A hand-checked list in
build_species.py, each entry with the passage it rests on. The build stops if a named fossil is not marked as a fossil in the checklist. The timeline is drawn as SVG on a logarithmic time axis. - Checked
- Each entry was read against its papers: the 2021 and 2024 papers in full, Cooper 1964 in part. Three older works (Bertolani & Grimaldi 2000 and the two Orsten papers) are not yet read, so their facts rest on the later papers that cite them. Not tested against data.
- Limits
- The Cambrian ages are our approximate placements, since the papers give the epoch, not a figure. The placement of Aysheaia comes from a preprint and has not been peer reviewed.
- More
- How the whole project is built
Where tardigrades have been recorded
How this is built
- Data
- Tardigrade occurrence records from GBIF through its API (date and terms in the sources below). The map uses only records released under CC0 or CC BY, with coordinates and no geospatial issue flag. World outline: Natural Earth.
- Built with
build_species.pymatches each checklist name to the GBIF backbone, fetches up to 900 open, georeferenced records per species, rounds them to 0.1° and thins them to at most 6,000 places, drawn as one SVG.- Checked
- Only exact matches to accepted species count, so no species borrows the records of a synonym or a near-miss spelling. Not tested against data.
- Limits
- Records are as their publishers identified them, and older tardigrade identifications are often uncertain. CC BY-NC records are counted but not mapped. Very well-recorded species contribute at most 900 records.
- More
- How the whole project is built
How it was made
We read the checklist's PDF character by character. It marks this edition's deletions with strikethrough and its changes with a yellow background, so we dropped struck-out text, flagged the highlighted names as new or changed, and took bold names as their genus's type species. The parse reproduces the checklist's own totals (35 families, 168 genera), and finds 1,550 species entries where its introduction states 1,549: one genus header counts 49 species above 50 listed names. Doubtful names (nomina dubia and inquirenda, 141 of them) are kept and marked, as the checklist keeps them.
Each species name was matched exactly to the GBIF backbone for its records, and to our genome, sequencing-run and literature collections. Paper counts are by exact name match in titles and abstracts, so older names and genus-only mentions are missed.
Sources: classification and authorities from Degma & Guidetti 2026, Actual checklist of Tardigrada species, 45th edition (CC BY 4.0), which asks users also to cite Guidetti & Bertolani 2005 (Zootaxa 845: 1–46) and Degma & Guidetti 2007 (Zootaxa 1579: 41–53). Records: GBIF.org, accessed 2026-09-20 through the GBIF API; each record belongs to the dataset that published it. The map shows only records released under CC0 or CC BY, with coordinates and no geospatial issue flag. Sequences: NCBI. Literature: OpenAlex. Photos: Wikimedia Commons and iNaturalist, CC0 or CC BY only, credited on each page. World outline: Natural Earth (public domain) via the world-atlas package.