The neck as key innovation to understand evolvability
A key event in vertebrate evolution was the development of a mobile and functionally distinct neck. However, assessing the macroevolutionary dynamics of the cervical vertebral column across different clades is complex due to the different numbers of bones in the neck (7 cervical vertebrae in most mammals, 10-26 cervical vertebrae in birds, und up to 76 cervical vertebrae in extinct marine reptiles).
Here, I will present the concept of modularity that separates the organism into homologous, semi-autonomous units to provide new insights into the evolution of the neck as key innovation facilitating the adaptive radiation of the extremely diverse four-limbed vertebrates known as tetrapods, such as amphibians, non-avian reptiles, birds, and mammals.