This is the fourth in a series of articles presenting the theoretical background for reconstructing dinosaurs in all scientific details, focusing on the body of Amargasaurus cazaui. Following the Extant Phylogenetic Bracket method, the musculature of the neck, pectoral girdle, forelimbs, hindlimbs and tail are reconstructed using comparative anatomy of extant archosaurs, primarily Alligator mississippiensis and Crocodylus porosus. The posture of the skeleton is critically evaluated against competing gait hypotheses, and a walking stance with the right forelimb and left hindfoot bearing the weight is adopted. The elongated neural spines of the neck are reconstructed with a sail blending smoothly with the rest of the body. For a full-scale physical reconstruction, the bones are formed from welded steel wire rods assembled on a steel armature, with iron reinforced concrete columns and beams providing structural support. Muscles are built up using wire mesh and plaster guided by metal templates, and the skin is finished with rolling stamps producing polygonal scale rosettes. The completed model is a scientifically informed, full-scale representation of Amargasaurus, ready for exhibition. This work aims to promote understanding of past life on earth and to motivate interaction with the art of paleontology.
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