The basal archosaur
(crocs + dinos) Saltopus (von Huene 1910; Late Triassic; ~210 mya, ±60 cm long; Figs. 1–3) poorly preserves bones, but also preserves some scaly skin.
Saltopus nests well within
the Crocodylomorpha and, along with Scleromochlus (Fig. 1), present examples of basal archosaur skin and scales. Even more basal, Gracilisuchus (Fig. 1) had dorsal scutes derived from ancestors going back to the Early Triassic Euparkeria.
Gracilisuchus and basal dinosaurs
had only two sacral vertebrae, but basal bipedal crocs, like Scleromochlus, double that number. Benton and Walker 2011 traced two sacrals in a latex cast of the sacral area, but each sacral was twice as long as proximal dorsals and causals. Here four sacrals are tentatively identified in the latex peel, all about as long as proximal non-sacral vertebrae.
can be scaly, or naked with feathers, or a combination of the two. Dinosaur scales may be different than croc or lizard scales in that at least some dinosaur scales, like those on the metatarsus of theropods appear to be derived from former feathers.
Benton MJ and Walker AD 2011. Saltopus, a dinosauriform from the Upper Triassic of Scotland. Earth and Environmental Science Transactions of the Royal Society of Edinburgh: 101 (Special Issue 3-4):285-299. DOI:10.1017/S1755691011020081
von Huene FR 1910. Ein primitiver Dinosaurier aus der mittleren Trias von Elgin. Geol. Pal. Abh. n. s., 8:315-322.