Table 1.

Crocodylomorph specimens used for morphometric and RoM analyses. Vertebral count is the total number of thoracic and lumbar vertebrae; figures in parentheses represent number of thoracic vertebrae (first) and lumbar (second) in taxa that have distinct thoracic and lumbar regions. Column length is summed centrum length (CL), and intervertebral (IV) space was measured from joints used to estimate RoM, excluding lumbosacral joint. Voxel size (v.s.) is the same in all dimensions. ‘Average number of mesh faces’ refers to the STL files exported from Mimics. IV space in Steneosaurus is not applicable (n.a.) because it is disarticulated and we did not model joints. Institutional abbreviations: American Museum of Natural History, New York (AMNH), Natural History Museum, London (NHMUK), Royal Veterinary College, London (RVC), Stony Brook University, New York (SBU).

taxon	type	source	scan		vertebral count	column length and range of CL (cm)	scan parameters	avg. no. mesh faces	IV space (cm) and as % of CL
Terrestrisuchus gracilis	fossil	NHMUK PV R 7562	μCT	NHMUK	(15a (10a,5)	unknown (0.99–1.03)	190 kVp, 200 μA, v.s. 0.06 mm	61K	0.04 (4%)
Protosuchus richardsoni	fossil	AMNH 3024	CT	SBU	15 (10,5)	13.8 (0.88–1.31)	140 kVp, 300 mA, v.s. 0.39 mm	23K	0.12–0.17 (12.5%)
Pelagosaurus typus	fossil	NHMUK PV OR 32598	μCT	NHMUK	15 (10,5)	31.7 (1.73–2.29)	200–210 kVp, 200–220 μA, v.s. 0.08 mm	145K	0.07–0.12 (9%)
Metriorhynchus superciliosus	fossil	NHMUK R 2054	CT	RVC	17	66.3 (3.14–4.14)	100 kVp, 200 mA, v.s. 0.36 mm	76K	0.42–0.63 (13.4%)
Steneosaurus leedsi	fossil	NHMUK R 3806	CT	RVC	13	62.7 (5.02–5.47)	100 kVp, 200 mA, v.s. 0.32 mm	89K	n.a.
Crocodylus niloticus	frozen; recent	La Ferme aux Crocodiles	CT	RVC	15 (10,5)	52.7 (1.64–1.94)	120 kVp, 100 mA, v.s. 0.41 mm	57K	0.48–0.59 (19%)

^aThoracic vertebral number for Terrestrisuchus is reconstructed based on related taxa [8].