The simplest explanation for this is that the axolotl lineage alone lost the ability to metamorphose, while others retained it.
对此最简单的解释是,只有蝾螈谱系失去了变形的能力,而其他族系则保留了这种能力。
3
From a detailed analysis of the salamanders' family tree, however, it is clear that the other lineages evolved from an ancestor that itself had lost the ability to metamorphose.