Appendix 2—table 1. Extant newt and squamate specimens used for muscle mass estimation and for logging centrum proportions along the tail.

Specimen numbers have hyperlinks to MorphoSource specimen pages with associated scans and 3D models.

Specimen no.	Taxon	Sex	Type	Purpose
FMNH 84926	Triturus cristatus	Male	Wet	Caudal centrum ratios, muscle mass estimation
FMNH 57512	Intellagama lesueurii	Male	Wet	Muscle mass estimation
FMNH 22389	Intellagama lesueurii	Male	Skeleton	Caudal centrum ratios, muscle mass estimation
KU 314941	Hydrosaurus amboinensis	Unknown; low neural spines (female/ immature male)	Wet	Caudal centrum ratios
FMNH 52698	Hydrosaurus pustulatus	Male	Wet	Muscle mass estimation
FMNH 236131	Hydrosaurus pustulatus	Unknown; low neural spines (female/ immature male)	Skeleton	Muscle mass estimation
FMNH 112993	Basiliscus plumifrons	Male	Wet	Muscle mass estimation
FMNH 257162	Basiliscus plumifrons	Male	Skeleton	Additional high-resolution visualization
UMMZ 121461	Basiliscus basiliscus	Male	Wet	Caudal centrum ratios
UF 41558	Amblyrhynchus cristatus	Unknown	Wet	Caudal centrum ratios
FMNH 22042	Amblyrhynchus cristatus	Unknown;?male (tallest caudal neural spines in FMNH collection)	Skeleton	Muscle mass estimation
UF 21461	Alligator mississippiensis	Unknown; juvenile	Wet	X-ray image of caudal centra in tail; caudal centrum ratios