Figure 9. Calibrated phylogeny of diplodocoid sauropods. Cross-hatched bars indicate Gondwanan affinities, hollow bars indicate Laurasian. Grey bars indicate 'old world' (Europe/Africa), white bars indicate 'new world' (North/South America). Temporal boundaries based on Gradstein, Ogg & Smith (2004). Palaeogeographical reconstructions below phylogeny illustrate continental connectivity at three key time intervals: the Middle Jurassic (170 Mya), likely time of origin for Diplodocoidea; the Late Jurassic (150 Mya), interval of greatest diversity within Flagellicaudata; and Early Cretaceous (120 Mya), interval of greatest rebbachisaurid diversity. Reconstructions based on Blakey (2006).