Nature study finds early tetrapods could barely turn their heads, using sturgeon as a living analogue
15 October 2026
A study in Nature has modelled how much the earliest four-limbed land animals could move their necks.
Because the fossil animals had an axial column dominated by soft tissue rather than fused bone, the team ran material tests on the axial columns of sturgeon, a living fish with a similarly configured notochord-dominated column.
The model found the soft-tissue-dominated column was surprisingly rigid even though it lacks co-ossified vertebral components.
Most stem tetrapods could move their heads less than 6 degrees laterally and less than 3 degrees dorsally, and could not rotate them at all.
Neck mobility did not change as the gap between head and shoulder widened from Eusthenopteron to more crownward stem tetrapods, so the authors argue that forelimb-driven locomotion, not a need to turn the head, explains that separation.
In plain words
Stem tetrapod Stem tetrapod — An early four-limbed animal on the line leading to modern land vertebrates, but outside the living groups.
Notochord Notochord — A flexible rod of tissue that supports the body along its length before a bony backbone forms.