A 2013 study describes paddle-limbed forms of Mosasauroidea as about 4–15 metres long. The Natural History Museum presents differing length estimates for Mosasaurus hoffmannii, the largest of the five Mosasaurus species it discusses: 17–18 metres in some estimates, compared with 11–12 metres in others.
In the mosasaur specimens examined in one study, every sclerotic ring had an eccentric opening and small bony plates with a slightly convex outer surface.
Approved version OWNER-REVIEW-20261028T180251014 · last approved 28 October 2026
As Mosasauroidea transitioned from terrestrial ancestors to forms highly adapted to ocean life, their internal bone architecture changed profoundly. Microanatomical trends in the bones of the subfamily Mosasaurinae support evolutionary convergence with cetaceans in the transition from coastal to open-ocean life.
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Based on the type of bone tissue in the limb bones of mosasaurs in the subfamily Mosasaurinae, their growth rates and basal metabolic rates are inferred to have been intermediate between those of the extant Dermochelys turtle and the rates proposed for plesiosaurs and ichthyosaurs.
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