Fig. 6

Bone histology of the right tibia of Quilmesaurus curriei MPCA-PV-100. The letters in the inset boxes indicate the position of the detailed pictures in the figure. A, B Complete section of the element. Note the presence of a distinct layer of highly vascularized fibrolamellar bone. The opacity of the medullary cavity and most of the bone tissue has been digitally reduced for better contrast. C General view of the cortex showing cortical bone formed by parallel fibered bone, interrupted by lines of arrested growth (white arrowheads), and fibrolamellar bone. Note that the cortex is broken in the boundary between these two different types of bone tissues (asterisk). D-F General views of the fibrolamellar bone. Detailed view of the fibrolamellar bone. Abbreviations: flb, fibrolamellar bone; pfb, parallel fibered bone; po, primary osteon; wfb, woven fibered bone