Fig. 1. Simplified archosaur phylogeny illustrating the taxa investigated in this and previous clumped isotope studies.

Extant ectotherms are blue; extant endotherms are orange. Maiasaura represents the major dinosaurian subclade Ornithischia, which is traditionally thought to represent the sister taxon to a Theropoda + Sauropoda clade as shown in (14) but in some recent phylogenies is placed as sister to Theropoda (13). Asterisk indicates taxonomic uncertainty for the Romanian eggshell sample, which may derive from a titanosaur sauropod (either the dwarf taxa Magyarosaurus or Paludititan or a larger titanosaurian) or the dwarf hadrosauroid Telmatosaurus (39).