Bone microstructure is affected by ontogeny, phylogeny, biomechanics and environments.
These aspects of life history of an extinct animal, especially its growth patterns,
may be assessed as fossil bone generally maintains its histological integrity. Recent
studies on the bone histology of fossil vertebrates from India encompass different
types of temnospondyls and dicynodonts from different Permian and Triassic horizons.
The examined taxa show that they had distinct bone histology and varied growth patterns.
The Early Triassic trematosaurids had an overall fast growth, which contrasts with
that of the Middle and Late Triassic temnospondyl taxa examined. The dicynodonts on
the other hand, were characterized by an overall fast growth with periodic interruptions,
variable growth rates dependent on ontogeny and indeterminate growth strategy. A comparative
study encompassing several neotherapsid genera including the dicynodonts shows signifi
cant evolutionary trends towards determinate growth strategy and reduced developmental