Detecting sexual selection in the fossil record is not impossible, according to scientists writing in Trends in Ecology and Evolution this month, co-authored by Dr Darren Naish of the University of Southampton.
The term “sexual selection” refers to the evolutionary pressures that relate to a species’ ability to repel rivals, meet mates and pass on genes. We can observe these processes happening in living animals but how do palaeontologists know that sexual selection operated in fossil ones?
Historically, palaeontologists have thought it challenging, even impossible, to recognise sexual selection in extinct animals. Many fossil animals have elaborate crests, horns, frills and other structures that look like they were used in sexual display but it can be difficult to distinguish these structures from those that might play a role in feeding behaviour, escaping predators, controlling body temperature and so on.
However in their review, the scientists argue that clues in the fossil record can indeed be used to infer sexual selection.