Table 1.

Summary of main macroecological principles investigated in dinosaur palaeontology with key taxonomic, regional and temporal examples from the literature.

macroecological principles	description	case studies
Allen’s rule	in homeothermic animals living in cold environments, a reduced ratio of body surface area to volume helps them retain heat more efficiently (shorter and stouter appendices).	Late Campanian–Early Maastrichtian Hadrosauridae in North America [28].
Bergmann’s rule	homeothermic animals in colder climates are typically larger than those in warmer regions, which helps them conserve heat more effectively.	Late Campanian–Early Maastrichtian Troodontidae [29]; Ornithischia and Theropoda in the Campanian–Maastrichtian of North America [12].
Damuth’s law	inverse relationship between body size and population density: as the size of a species increases, the number of individuals living in a given area decreases.	Maastrichtian of North America, Tyrannosaurus rex [30].
ecological release	population growth and increased diversification result from the relaxation of environmental limiting factors, such as competition, which allows for expansion into new niches and ecomorphological space.	Late Triassic Dinosauria versus non-dinosaur tetrapods (global) [31–34].
island rule (Foster’s rule)	animals isolated on islands often experience changes in body size, with smaller species tending to become larger (gigantism) and larger species tending to become smaller (dwarfism).	Europasaurus, Kimmeridgian (Europe) [35]; titanosaurs in Europe [36,37] and South America [38]; Tethyshadros insularis, Campanian of Europe [39,40].
latitudinal biodiversity gradient (LBG)	species richness peaks in the tropics and declines progressively toward the poles.	Jurassic–Cretaceous Dinosauria (global) [41,42].
thermogeochromic egg variation (TEV)	in birds from cold habitats, especially those with nests exposed to direct sunlight (and coinciding with high latitudes), eggshells are darker to enhance heat absorption; eggshells tend to be lighter (e.g. light blue and green) in the tropics.	modern examples [43], with future potential for investigation in the dinosaur fossil record [44,45].
species–area relationship (SAR)	species richness increases in proportion to the available area, with larger areas supporting greater biodiversity.	Maastrichtian Dinosauria (global) [46].