| The limbs and appendicular musculature of tetrapods are a further elaboration of the non-axial musculature. |
| Evolutionists sought the ancestry of the tetrapods among the lobe-finned fishes. |
| All these taxa are relevant to the history of the conquest of land by vertebrates because they are outside the large clades of extant tetrapods. |
| Before tetrapods existed, vertebrates were all confined to living in aquatic habitats. |
| In other tetrapods, haemal arches do not begin for several vertebrae posterior to the sacrum. |
| The plants, invertebrates, and tetrapods can be thought of as three separate subsystems of the larger terrestrial ecosystem. |
