Static osteogenesis does not precede dynamic osteogenesis in periosteal ossification of Pleurodeles (Caudata, Amphibia) and Pogona (Squamata, Lepidosauria)

Two successive mechanisms have been described in perichondral ossification: (1) in static osteogenesis, mesenchymal cells differentiate into stationary osteoblasts oriented randomly, which differentiate into osteocytes in the same site; (2) in dynamic osteogenesis, mesenchymal cells differentiate into osteoblasts that are all oriented in the same direction and move back as they secrete collagen fibers. This study is aimed at testing the...