The teeth of freshwater crayfish are covered by an enamel-like coating similar to that of mammals, discovers a study published in Nature Communications this week. The similarity with mammalian enamel may be a unique example of convergent evolution between vertebrates and crustaceans.
The compositional makeup of skeletons and teeth in invertebrates and vertebrates is generally very different. Barbara Aichmayer and co-workers perform a detailed investigation of the material composition and properties of freshwater crayfish mandibles, and show that they are covered by a hard and water-resistant layer of apatite similar to mammalian enamel. Given the genetic distance between vertebrates and invertebrates, this finding suggests an unusual case of convergent evolution.