This chapter reports the current view of sauropod phylogeny and shows that sauropods were successful in terms of their geographic and temporal distributions, biomass, morphological complexity, and diversity at both higher and lower levels. It reviews the difficulties in tracing two major parts of the sauropod phylogeny. The main topological disagreement among early cladistic analyses of Sauropoda centered on the relationships of broad- and narrow-crowned sauropods. Additionally, the evolutionary events diagnosing several major sauropod clades (Sauropoda, Eusauropoda, Neosauropoda, Diplodocoidea, Macronaria) are described. The chapter outlines the major specializations relating to herbivory, neck elongation, and locomotion for each of five major sauropod clades. The stratigraphic distribution of the first representatives of Sauropoda and of their sister-taxon Prosauropoda implies a 10 million to 15-million year missing lineage during which the score of features diagnosing sauropods evolved. Despite advances in understanding of the group, substantial gaps in the knowledge of sauropod history still exist.
Keywords: sauropod phylogeny; sauropod evolution; Sauropoda; Eusauropoda; Neosauropoda; Diplodocoidea; Macronaria; herbivory; neck elongation; locomotion
Chapter. 16471 words. Illustrated.
Subjects: Evolutionary Biology
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