Both salamanders and lizards can regrow lost tails, with varying success. Researchers studied tail regeneration abilities between the two critters and found that neural stem cells in the spinal cord determine the outcome. According to the study published August 13 in PNAS, neural stem cells from lizards are limited in their regeneration capacity, while those from salamanders can form a variety of cell types—even when transplanted into a lizard’s tail stump.
A.X. Sun et al., “Differences in neural stem cell identity and differentiation capacity drive divergent regenerative outcomes in lizards and salamanders,” PNAS, doi:10.1073/pnas.1803780115, 2018.