Credits
We built the models, conversions and viewers. The measurements they rest on belong to the people who made them, listed below, and every model credits its sources.
Data
| Source | Used for | Licence |
|---|---|---|
| Gross V, Müller M, Hehn L, Ferstl S, Allner S, Dierolf M, Achterhold K, Mayer G, Pfeiffer F (2019). X-ray imaging of a water bear offers a new look at tardigrade internal anatomy. Zoological Letters 5:14. doi:10.1186/s40851-019-0130-6; data on figshare | The whole-body and head nano-CT scans, organ labels and published volumes: the glass tardigrade, the cut face, the Minecraft builds and the stone X-ray | CC BY 4.0 |
| Anderson EM, Houck SG, Conklin CL, Tucci KL, Rodas JD, Mori KE, Armstrong LJ, Illingworth VB, Lo TW, Woods IG (2024). Comparative analysis of tardigrade locomotion across life stage, species, and disulfiram treatment. PLOS ONE. doi:10.1371/journal.pone.0310738; code and data github.com/enwudz/gait | Step events for all eight legs, the sample walking video, and group means for adults, juveniles, Ramazzottius and disulfiram | Paper CC BY 4.0; repository has no licence stated |
| Gabriel WN, McNuff R, Patel SK, Gregory TR, Jeck WR, Jones CD, Goldstein B (2007). The tardigrade Hypsibius dujardini, a new model for studying the evolution of development. Developmental Biology 312:545–559. doi:10.1016/j.ydbio.2007.09.055 | Embryo stage timings and cell counts; the egg size for the scale spheres (about 60 µm, p. 548) | Facts cited; no figures reproduced |
| Heikes KL, Game M, Smith FW, Goldstein B (2023). The embryonic origin of primordial germ cells in the tardigrade Hypsibius exemplaris. Developmental Biology. doi:10.1016/j.ydbio.2023.02.008 | The germline precursors and their timing in the embryo | Facts cited |
| Quiroga-Artigas G, Moriel-Carretero M (2024). Storage cell proliferation during somatic growth establishes that tardigrades are not eutelic organisms. Biology Open. doi:10.1242/bio.060299 | Storage cell counts in hatchlings and adults; hatchling cell count in the embryo | CC BY 4.0 |
| Martin C, Gross V, Hering L, Tepper B, Jahn H, de Sena Oliveira I, Stevenson PA, Mayer G (2017). The nervous and visual systems of onychophorans and tardigrades. J Comp Physiol A. doi:10.1007/s00359-017-1186-4 | Scale spheres: neuron cell body size, and a locust neuron large enough to hold the whole tardigrade brain | Facts cited |
| Mayer G, Kauschke S, Rüdiger J, Stevenson PA (2013). Neural markers reveal a one-segmented head in tardigrades (water bears). PLOS ONE 8:e59090. doi:10.1371/journal.pone.0059090 | Scale sphere: trunk ganglion size | CC BY 4.0 |
| Gross V, Mayer G (2019). Cellular morphology of leg musculature in the water bear Hypsibius exemplaris (Tardigrada) unravels serial homologies. Royal Society Open Science 6:191159. doi:10.1098/rsos.191159; label fields on Dryad | Every leg muscle (M1–M14 in legs I–IV), their names and serial homologies: the muscles in the glass tardigrade | Paper CC BY 4.0; data CC0 |
| Yoshida Y et al. (2017). Comparative genomics of the tardigrades Hypsibius dujardini and Ramazzottius varieornatus. PLOS Biology 15:e2002266. doi:10.1371/journal.pbio.2002266 | The nHd_3.1 genome and proteome, developmental RNA-seq: genomics pages | CC BY 4.0; data public (NCBI) |
| Levin M et al. (2016). The mid-developmental transition and the evolution of animal body plans. Nature 531:637–641. doi:10.1038/nature16994 | Hourly embryo transcriptome (GBZR01), mapped onto the genome | Data public (NCBI) |
| Hoencamp C et al. (2021). 3D genomics across the tree of life reveals condensin II as a determinant of architecture type. Science 372:984–989. doi:10.1126/science.abe2218 | The condensin question checked on the genomics page | Facts cited |
| van Hooff JJE, Raas MWD, Tromer EC, Eme L (2025). Repeated duplications and losses shaped SMC complex evolution from archaeal ancestors to modern eukaryotes. Cell Reports 44:115855. doi:10.1016/j.celrep.2025.115855 | Found the two Ramazzottius CAP-H2 genes first; their profiles and sequences (GitHub jolienvanhooff/SMCevolution) checked against ours | Facts cited |
| Ramazzotti G, Maucci W (1983). Il Phylum Tardigrada, 3rd ed. Memorie dell'Istituto Italiano di Idrobiologia 41; English translation by C. W. Beasley (1995), The Phylum Tardigrada. | History (Eichhorn, Corti, the 1859 commission), Rahm's heat and cold experiments, and older physiology, paraphrased with page numbers | Facts cited |
| Brixi G et al. (2025). Genome modeling and design across all domains of life with Evo 2 (bioRxiv), and its training set OpenGenome2 on Hugging Face (arcinstitute/opengenome2) | Which tardigrade sequence Evo 2 was trained on | Data public |
What we made
Organ names for the unnamed labels (matched to published volumes), the traced body surface, the registration of the head scan onto the whole body, the leg rig, the Minecraft builds and stone palette, the landscape, block textures, videos and viewers. Anything marked "probable" or "unidentified" in the viewers is our call, not the original authors'.
You can share the videos, stills and Minecraft schematics with credit to the data sources above and a link to this site.
Pictures and drawings on the species tree
Every picture on the species tree is credited in its card, with its licence and a link to its source. The photos come from museum type-slide collections (Natural History Museum of Denmark, Te Papa, Smithsonian), Wikimedia Commons, iNaturalist observers (CC BY and CC BY-NC) and openly licensed figures in papers. The line drawings are our own redrawings, traced into one style from public-domain plates (Doyère 1840, Richters, Murray, Thulin) and from figures in CC BY papers; each card says which drawing it was traced from. Taxonomy follows Degma & Guidetti's world checklist (CC BY 4.0).
Software
three.js (MIT) for 3D in the browser; scikit-image, SciPy, trimesh and fast-simplification for meshes; FFmpeg for video.
Something wrong?
If you produced any of this data and want something changed or credited differently, email meow@meow-meow.io.
Figures from papers, and removal on request
The figure library shows figures from open-access papers with their full captions, the authors' credit and the licence each paper states. A few papers are under no-derivatives licences (shown unmodified), a few state no licence, and some figures reprint panels from other sources, credited as their captions do. If you are an author or rights holder and would like a figure taken down or credited differently, email meow@meow-meow.io and we will act on it promptly.
How this is built
- Data
- The licence each source states for itself: the article's own licence record, the data deposit's (Dryad, figshare, GitHub), or each photo's and record's licence on Wikimedia Commons, iNaturalist and GBIF.
- Built with
- We keep this page by hand for the main data behind the models. The generated pages carry their own credits: the species pages, the tree's picture cards and the figure library show each photo's, figure's and record's credit and licence beside it, taken from the files that
build_species.py,build_tips.pyandbuild_gallery.pywrite with the pictures. - Checked
- By hand, against each source's licence statement; figure licences are also cross-checked against PMC's own record. Not tested against data.
- Limits
- This page lists the main sources. Every paper we read is a source in the graph, and each page names its own sources.
- More
- How the whole project is built