Fig. 4 in Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms

Fig. 4. Tyrannosaur growth and ecology. (A) Histological section of a T. rex dorsal rib, showing growth lines whose counts are used to reveal age and longevity. (B) Growth curves for North American tyrannosaurids derived from growth line counts and body size estimations for individuals showing how size changes with age. No sampled tyrannosaurid adults were more than 30 years old, and accelerated rather than prolonged development was the key to the great size of T. rex (8). (C) survivorship curve for Albertosaurus sarcophagus. This tyrannosaur exhibited high neonate mortality, then few deaths after age two, and then increased mortality at mid-life (8).