An adult salamander
Unknown author<span style="display: none;">Unknown author</span>
CC BY 2.5
<i>Regenerating Lost Muscle: Msx1 to the Rescue.</i> PLoS Biol 2/8/2004: e266. <a rel="nofollow" class="external free" href="https://dx.doi.org/10.1371/journal.pbio.0020266">https://dx.doi.org/10.1371/journal.pbio.0020266</a>