The mammalian cervical vertebral column (neck vertebrae) is interesting because most mammals only have seven cervical vertebrae, and variation in this number is linked to severe consequences and high risk of disease. This is despite a wide variety of locomotor behaviors in mammals. Previous research found a similar pattern of integration of the cervical vertebrae among quadrupedal mammals, but integration evolves in response to locomotor changes like those linked to hominin bipedalism. I tested covariation in the cervical vertebrae of three hominoids (Hylobates, Pan, Homo) who engage in upright postures and locomotion and found that these patterns are similar to those of other quadrupedal mammals, indicating covariation is highly conserved. These results suggest that when looking at functional changes in the cervical vertebrae, it’s the cervical vertebral column as a whole, rather than individual elements, that may show a functional signal.
New article in press at Evolution, here.