FIG. 4 in Structural, functional, and physiological signals in ichthyosaur vertebral centrum microanatomy and histology

FIG. 4. — Histological features of ichthyosaur vertebral centra: A, B, E, F, Stenopterygius sp. SMNS uncat. longitudinal section; C, Stenopterygius sp. SMNS uncat. longitudinal section; D, Temnodontosaurus sp. SMNS uncat. longitudinal section; A, cartilaginous cells (Cc) and osseous trabeculae in the periphery of the endochondral territory in natural light (NL); articular surface at the bottom; B, illustration of the change of organization/orientation of the trabeculae from the periphery (bottom) to the core of the endochondral territory and limit (L) with the peripheral territory (from bottom to top) in NL; C, inner endochondral bone showing some degree of remodelling in polarized light (PL) with gypsum filter; arrows point to secondary osteons; D, E, unusual parallel fibered bone with platings of parallel-fibered bone in the periosteal territory in PL (D) and additional gypsum filter (E); F, core of a trabeculae of unusual parallel fibered bone showing the large randomly shaped osteocyte lacunae and the elongated cells in the platings of parallelfibered bone in NL. Scale bars: A, D, E, 200 µm; B, C, 500 µm; F, 50 µm.