A lizard tail trapped in a piece of amber just 18 millimetres long has given researchers the clearest fossil evidence yet that lizards were deliberately shedding their tails to escape predators 99 million years ago. The study, led by Tel Aviv University, appears in the journal Palaeontologia Electronica.
The amber comes from northern Myanmar and dates to the mid-Cretaceous period, when dinosaurs still roamed. Inside it sits a detached tail with its skin and muscle tissue preserved. The researchers say it is the best-preserved direct fossil evidence of a voluntarily dropped tail, a defence known as autotomy.
The key evidence sits at the break point. X-ray micro-computed tomography revealed a wedge-shaped arrangement of muscle tissue there, matching the muscle contractions living lizards make when they drop a tail on purpose. That pattern, plus a clean break with none of the crushing typical of accidental injury, convinced the team the tail was shed deliberately rather than torn off.
PhD candidate Dolev Fabrikant led the study with his supervisor, Dr Leonidas-Romanos Davranoglou, working with researchers from the National and Kapodistrian University of Athens and Israel’s Volcani Institute. The tail belonged to a relative of modern monitor lizards or lacertids. Earlier fossils had hinted at tail shedding through fracture planes in vertebrae, but the researchers say those features only showed an animal could shed its tail, not that it did.
Source: Phys.org
