Palaeobiological implications of the bone microstructure of South American traversodontids (Therapsida: Cynodontia)

CHINSAMY-TURAN, A.; ABDALA, F.

SOUTH AFRICAN JOURNAL OF SCIENCE

ACAD SCIENCE SOUTH AFRICA A S S AF

Lugar: Johannesburg; Año: 2008 vol. 104 p. 225 - 230

0038-2353

We document the bone microstructure of traversodontids from Argentina and Brazil and make detailed comparisons of the bone microstructure of these cynodonts with that of other traversodontids, nonmammaliaform therapsids (including cynodonts), and Mesozoic mammalian taxa. Our analysis provides information on traversodontid ontogenetic age, growth patterns and life-style adaptations. The osteohistological data derived from the current study, as well as data on other nonmammaliaform cynodonts, provide an understanding of the evolution of life-history patterns among the therapsids. We show that many of the nonmammaliaform cynodonts (including some traversodontids) formed bone atrapid rates but retained flexible developmental growth patterns. In addition, although we observe a trend of increasingly rapid osteogenesis among the traversodontids, our findings do not discern a particular bone tissue type as a synapomorphy of the clade. This reinforces earlier hypotheses that the microscopic structure of bone is influenced by several intrinsic and extrinsic factors, and is not constrained by phylogeny alone.