The article discusses how measuring biodiversity using species richness may not capture the full diversity of species in an area. Instead, considering the evolutionary relationships between species, known as phylogenetic diversity, can provide a more comprehensive view of biodiversity. The researchers compared species richness and phylogenetic diversity of mammals in nine sanctuaries and found that these measures are not always the same. Some areas with few species may actually have a high diversity of evolutionary relationships, and vice versa. To better understand and protect biodiversity, it is important to consider both species richness and phylogenetic diversity.