Diagrams showing the histological structure of long bones of four sauropodomorphs: Riojasaurus, Lessemsaurus, Tuebingosaurus and Volkheimeria. The phylogenetic relationships are based on the total evidence phylogenetic analyses from iteration 2.1. The white arrows point to lines of arrested growth (LAG) that correspond to a momentary but complete cessation of growth. The red arrow points to an annulus corresponding to periods of slow growth. The histological samples of Riojasaurus, Lessemsaurus and Volkheimeria, were redrawn from the pictures published in Apaldetti et al. (2018, fig. 2b), and the histological sample of Tuebingosaurus was redrawn from the photographs published in Klein (2004, fig.3E), interpreted there as a fully grown Plateosaurus.