English: Diagram of the vertebrae of different prehistoric tetrapods showing the traditional view of tetrapod evolution through changes in the structure of their vertebrae. The bodies of rhachitomous vertebrae are divided into two parts, the pleurocentrum and intercentrum, with the intercentrum making up most of the vertebra. The pleurocentrum is enlarged in schizomerous tetrapods, fusing with the neural arch to form a solid vertebra in living tetrapods. The dashed line indicates the uncertain placement of lepospondyls. Lepospondyls are not placed as rhachitomes or schizomeres because the origin of their simple vertebrae is uncertain.

• Panderichthys rhombolepis based on Figure 20 of "Description and systematics of panderichthyid fishes with comments on their relationship to tetrapods" by Emilia Vorobyeva and Hans-Peter Schultze (Origins of the Higher Groups of Tetrapods: Controversy and Consensus pp. 68-109).
• Acanthostega gunnari based on Figure 6.10 of Gaining Ground: The Origin and Evolution of Tetrapods by Jennifer A. Clack.
• Eryops megacephalus based on Figure 4 of "The homologies of the labyrinthodont centrum" by A.L. Panchen (Evolution 21 (1): 24-33).
• Stanocephalosaurus pronus based on Figure 1 of "A hemivertebra in a temnospondyl amphibian: the oldest record of scoliosis" by Florian Witzmann (Journal of Vertebrate Paleontology 27 (4): 1043-1046).
• Asaphestera intermedia based on Figure 8 of "The Order Microsauria" by Robert Lynn Carroll and Pamela Gaskill.
• Bystrowiella schumanni based on Figure 3 of "A relict basal tetrapod from Germany: first evidence of a Triassic chroniosuchian outside Russia" by Florian Witzmann, Rainer R. Schoch and Michael W. Maisch (Naturwissenschaften 95 (1): 67-72).
• Archeria crassidisca based on Figure 3 of "The homologies of the labyrinthodont centrum" by A.L. Panchen (Evolution 21 (1): 24-33).
• Seymouria baylorensis based on Figure 2 of "Locomotor features of taxa spanning the origin of amniotes" by Stuart S. Sumida (Amniote Origins: Completing the Transition to Land pp. 353–398).
• Limnoscelis paludis based on Figure 2 of "Locomotor features of taxa spanning the origin of amniotes" by Stuart S. Sumida (Amniote Origins: Completing the Transition to Land pp. 353–398).
• Varanops brevirostris based on Figure 2 of "An Early Permian varanodontine varanopid (Synapsida: Eupelycosauria) from the Richards Spur locality, Oklahoma" by Hillary C. Maddin, David C. Evans, and Robert R. Reisz (Journal of Vertebrate Paleontology 26 (4): 957-966).