Dinosaurs through time

Dots are fossil sites, not where an animal could live. A genus lived wherever conditions suited it; we only know the places its fossils survived and were found. North America, Europe and China have been searched far more than Africa, South America or Antarctica, so empty land often means "not yet searched", not "nothing lived here".

Rocks are dated to a window, not a year. A dot shows whenever the moment you choose falls inside the age window of the rock it came from. Hollow dots come from rocks dated to a window wider than 5 million years, so that animal may have lived somewhat earlier or later. Two genera appearing at the same moment means their fossils come from rocks of overlapping age.

Continents then, or today. "Continents then" shows the land and seas reconstructed by the PALEOMAP project for the nearest available time (maps every 5 to 15 million years), with each fossil site moved to where it lay when its rocks formed, using the same plate model. These are scientific reconstructions: positions can be out by hundreds of kilometres, and other models place things differently. "Today" shows present-day continents, with each site where it is now.

Seas at their highest. The ancient coastlines show each stage's seas at their greatest extent. Many dinosaurs lived on low coastal plains, so some sites sit just offshore, in the pale blue shallow seas.

Coverage. The map shows the 464 genera Omnisaura covers so far, out of the 1,572 the Paleobiology Database recognises, and uses the same fossil records Omnisaura calculates each genus's age from.