Figure 4
From: Evolution of the vertebrate skeleton: morphology, embryology, and development
Evolution of the endoskeleton. Phylogenetic framework was adopted from [59]. Asterisks indicate paraphyletic groups. (A) Endoskeleton composed purely of cartilage. (B) Endoskeleton with perichondral ossification. (C) Endoskeleton with peri- and endochondral ossifications.