In basal amniotes, the condition is quite different, with the ankle only formed by eight bones. The five distal tarsals are typically unchanged, but usually only a single centrale is preserved. This single remaining centrale, referred to as the "" bone, was either formed by the retention of only the second centrale or the fusion of the first and second. Amniotes are also very different from amphibians in the fact that they possess only two large proximal tarsals. The calcaneum, which contacts the fibula, is almost unanimously considered to be identical to the fibulare. The other proximal tarsal, the astragalus (or talus), is likely a mass formed by the fusion of the intermedium, tibiale, and the fourth (and possible also the third) centrale. Some lepospondyls, such as the reptile-like microsaur "Tuditanus", also may have evolved these modifications.