Tetrapod terrestrialisation: a weight-bearing potential already present in the humerus of the stem-tetrapod fishEusthenopteron foordi

• DOI: 10.1101/2024.02.09.579723
• Publication Date: 2024-02-12T20:15:23Z
• Authors: François Clarac; Alexis Cornille; Sifra Bijl; Sophie Sanchez
• Keywords: Tetrapod (structure)

Abstract Our study shows that the von Mises stress, induced by external load on humerus of Eusthenopteron, dissipates through cortex, trabeculae and muscles pectoral appendage involved in elevation protraction. As Eusthenopteron’s microanatomy is similar to Devonian tetrapods, we expect them share same process dissipation energy absorption 1) cortical stress distribution; 2) longitudinal trabecular conduction. FE simulations hypothetical terrestrial conditions demonstrate this type microanatomical architecture could withstand weight Tiktaalik proportionally size Eusthenopteron standing posture. This tubular arrangement, including marrow processes originally long-bone elongation, would have acquired a key secondary biomechanical function increase resistance strength cancellous bone compressive load. an exaptation, specific may played major role tetrapod land exploration about 400 million years ago.