Placoid scales in bioluminescent sharks: Scaling their evolution using morphology and elemental composition
Elasmobranchs are characterised by the presence of placoid scales on their skin.These scales, structurally homologous to gnathostome teeth, are thought to have various ecological functions related to drag reduction, predator defense or abrasion reduction.Some scales, particularly those present in the ventral area, are also thought to be functionall