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This chapter addresses the sauropod growth rates from the perspectives of bone histology, long bone growth, and developmental mass. It provides an overview of the evidence from living and fossil vertebrate taxa relevant to qualitative interpretations of sauropod bone tissue. A case study for Apatosaurus that incorporates all methods discussed in the text is then reported. Bone histology offers an exceptional tool for studying bone growth in dinosaurs at the microscopic level. The growth rates of dinosaurs depended on the size of the taxon of interest: the larger the dinosaur, the more rapid the overall body growth rate. Amprino's Rule suggests that laminar tissue in sauropods grew at the same basic range of rates that occurs in extant mammals and birds. Application of developmental mass extrapolation (DME) and longevity estimates provide quantified measures of growth rates for all stages of whole-body growth, including the exponential stage.

This chapter addresses some of the questions and issues associated with the “four signals” of bone histology, with the aim of actuating further research. It discusses how knowledge in skeletochronology, linear and mass growth rates, and timing of the reproductive maturity of extinct tetrapods can be applied to life-history reconstructions.

This chapter discusses the advantages and disadvantages of various types of growth measurements including mass, length, time, and osteohistological texture. It explains the intensity of measurement, and how sampling intensity can limit the types of questions addressed by growth data but can also clarify longstanding misconceptions such as “indeterminate” growth. The chapter reviews the mathematical description of growth data using models, as well as how a single model is selected from a set of plausible models, and provides examples using growth models and bone histology to show that analyses of relative growth can be equally informative as analyses of absolute growth. It concludes with recommendations for the standardization of paleobiological growth analyses.

This chapter discusses the “four signals” of bone histology: ontogeny, phylogeny, mechanics, and environment. These “signals” help us to make sense of the kinds of variation seen in the bone tissues of extinct tetrapods. They have been shown empirically to be reliable guides to the interpretation of the most basic question in the paleohistology of bone: Why is this tissue formed the way it is, and why does it differ from the tissue of this other animal? Along with some calibration methods based on teeth in many mammalian groups, bone histology forms the basis of skeletochronology, the only currently available universal line of evidence that provides an absolute age on the skeletons of extinct vertebrates.