An article published in the journal “Frontiers in Ecology and Evolution” describes a research on mesosaurs, the most ancient reptiles whose adaptation to aquatic life is known. A team of researchers carried out an accurate analysis of a number of fossils concluding that the bones of adults have similarities with those of land-dwelling animals and this suggests that they were semi-aquatic while their juveniles were aquatic. It’s a result obtained by examining fossils of specimens of various ages, a type of study that can reveal changes that occur with the growth of an individual of a species.