Methods and evidence boundaries
This site generates readable HTML from versioned sources at build time, preserving claims, citations, review status and limitations. This edition includes an age-selectable lightweight map. Full terrain, additional layers, data queries and local SQL belong to the full application.
Known limits
- Occurrence files are bounded, non-random PBDB API-prefix samples with unknown selection probability; they are not exhaustive or statistically representative exports.
- The six CAO2024 geometry layers are nearest-frame model reconstructions with disclosed layer-specific sampling, not direct observations or a continuously interpolated paleogeographic movie; five separate point datasets retain 44,175 upstream observations or constraints, including raw-only records outside the 0-1,800 Ma model range. Neither is assumed to be co-registered with PBDB paleocoordinates, and no layer supplies elevation, bathymetry or terrain relief.
- The atlas-wide hierarchy is a navigation ontology, not a phylogenetic hypothesis; the separate Perissodactyla hypothesis has no time-scaled branch lengths.
- First and last appearances are sampling-dependent observations, not exact origination or extinction dates.
- Observed density and missing records cannot be interpreted as biological richness or absence without sampling controls.