Yizhousaurus sunae (Zhang et al. 2018) was an Early Jurassic basal sauropod, basal to Diplodocus and kin. Note the kinked manual digit 1 and the robust dorsal vertebrae.

Diplodocus carnegii (Marsh 1878; Late Jurassic; 25-32 m long), was a long-necked, long-tailed saurpod able to rise to a bipedal stance, but traveled quadrupedally. The whip tail tip was likely for defense and to balance the long neck. Note the distally elongated chevrons at mid-tail. These were likely set on the ground creating a tripodal stance with the neck elevated.

Rapetosaurus krausei (Curry, Rogers & Forster, 2001) is a Late Cretaceous titanosaur sauropod that is known from several bits and pieces from 3 adults, plus the majority of a juvenile specimen (Fig. 1). Adult lengths are estimated up to 15 m. Rapetosaurus has a much larger pubis for no better reason than to help support its guts when bipedal.

Samientosaurus musacchioi (Martinez et al 2016, est 12m long, MDT-PV 2, Late Cretaceous, 95mya) is a South American titanosaur known chiefly from the largely complete skull.

Titanosaur embryo (Kundrát et al 2020, MCR-PVPH-263, Late Cretaceous, 80myya) is an embryo sauropod preserving the left half of the skull in 3D. Here it nests with Samientosaurus (above). The purported stereoscopic vision is reduced when the frontal is moved closer to the parasagittal plane. The overbite is notable.

Curry Rogers K and Forster CA 2001. The last of the dinosaur titans: a new sauropod from Madagascar. Nature. 412: 530–534. doi:10.1038/35087566

Kundrát M et al (6 co-authors) 2020. Specialized craniofacial anatomy of a titanosaurian embryo from Argentina. Current Biology 30:4263–4269.

Marsh OC 1878. Principal characters of American Jurassic dinosaurs. Part I. American Journal of Science. 3: 411–416.

Martínez RDF, et al (7 co-authors) 2016. A Basal Lithostrotian Titanosaur (Dinosauria: Sauropoda) with a Complete Skull: Implications for the Evolution and Paleobiology of Titanosauria. PLOS ONE. 11 (4): e0151661.

Zhang Q-N, You H-K, Wang T and Chatterjee S 2018. A new sauropodiform dinosaur with a ‘sauropodan’ skull from the Lower Jurassic Lufeng Formation of Yunnan Province, China. Nature.com/scientificreports 8:13464 | DOI:10.1038/s41598-018-31874-9

wiki/Diplodocus
wiki/Rapetosaurus
wiki/Yizhousaurus
wiki/Sarmientosaurus