Figure 6. Phylogenetic hypothesis presented in this study plotted on a geological timescale (Gradstein, Ogg & Smith, 2004), with relevant clade names (Table 1) labelled. Selected synapomorphies highlighting some nodes are shown. Brachiosauridae: quadratojugal with triangular ventral prong (shown here in Europasaurus), twisted maxillary teeth (shown here in Giraffatitan), bevelled distal end of metatarsal IV (shown here in Sonorasaurus). Somphospondyli: somphospondylus vertebral pneumaticity, consisting of subcentimetre and submillimetre cells and walls, respectively, that permeate the vertebra (shown here in Saruoposeidon). Euhelopodidae: cervical vertebrae with bifid neural spines, pendant cervical ribs, a thick, vertically orientated epipophyseal–prezygapophyseal lamina, a 'kinked' intrapostzygapophyseal lamina (shown here in Erketu). Titanosauria: plate-like ischium (shown here in Andesaurus). Also shown here are a short ischium (a synapomorphy of Sauroposeidon plus more derived somphospondyls) and a raised tubercle on the lateral ischium (a titanosauriform synapomorphy).