How large was the Pararhabdodon?
Pararhabdodon
Pararhabdodon most likely was a bipedal-quadrupedal herbivore, in the neighborhood of 6m (19.7ft) long, fully grown. The dorsal and sacral neural spines were elongate, so the animal would have had a tall back, like other hadrosaurids. Because the material is sparse, more specific conclusions cannot be reached.[1]
Bruhathkayosaurus
By comparison, the titanosaur "Argentinosaurus" is estimated to have reached in length, and to have weighed 80–100 tons. Another huge titanosaurid, "Paralititan", was probably long, and weighed 59–80 tons. All of these sauropods are known only from partial or fragmentary remains, so the size estimates are uncertain. Length is calculated by comparing existing bones to the bones of similar dinosaurs, which are known from more complete skeletons and scaling them up isometrically. However, such extrapolation can never be more than an educated guess and the length of the tail, in particular, is often hard to judge. Determining mass is even more difficult, because little evidence of soft tissues survives in the fossil record. In addition, isometric scaling is based on the assumption that body proportions remain the same, which is not necessarily the case. In particular, the proportions of the titanosaurs are not well known, due to a limited number of relatively complete specimens.