Figure 4

Osteohistology of Tamarro insperatus gen. et sp. nov. based on the osteohistological sample from the metatarsal II (MCD-7073). Full petrographic transverse thin section from the proximal mid-shaft of the Mt II (A). Detail of the cortex showing the predominance of primary lamellar and fibrolamellar bone tissues. Black arrows indicate the location of a LAG. White arrow shows the location of the reversal line (B). Outer cortex under transferred and polarized light displaying the distinctive arrangement of the bone tissues (C). Magnification of the inner cortex showing the infilling of primary cancellous spaces with lamellar bone (D). Osteohistological transition (white dashed lines) between the compact coarse cancellous bone of the inner cortex and the laminar fibrolamellar of the outer cortex (E). Type tissue map of areas representing different tissue types are colour coded for quantitative analyses (F). cccb compact coarse cancellous bone; el endosteal lamina; lcb lamellar cancellous bone; lfl laminar fibrolamellar; pvc primary vascular canal. Scale bar: 2 cm (A), 0.5 mm (B), 1 cm (C), and 0.2 mm (D,E).