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Imagine that Labradors and golden retrievers died out a million years ago, leaving only fossilized skeletons behind. Without the help of DNA, how could we determine that a fossil Labrador, a fossil retriever and a modern Chihuahua all belong to the same species, Canis lupus familiaris? And could we look at the wide variety of dogs today to gain clues about lost diversity in the past?
A new study shows how scientists can use animals' physical features -- also known as morphology -- to make connections between a modern species and its fossilized relatives, even if they look strikingly different. Scientists often use color, sexual differences, soft tissues, signs of age and DNA to analyze variation within modern species. But these can be missing in fossil specimens. The researchers relied on a technique known as geometric morphometrics, a way of quantifying an object's shape, to test whether shape is a reliable way to tease out the subtle relationships between species, subspecies and individuals of the same species that just look different from each other.Image credit: Natasha Vitek/Florida Museum
