It is unlikely that dinosaur frills and horns evolved as a way for different species to recognize one another, according to a study published in the Proceedings of the Royal Society B.
This finding — which comes from researchers at Queen Mary University of London — challenges classic assumptions that certain species in the same location can evolve specific features to help themselves stand out and avoid problems like hybridization.
The team made their discovery by examining diversity patterns in the ornamentation of 46 ceratopsian species. Though they expected to find differences based on where animals lived, they found the species that lived together were the same as those that lived separately.
As there is no discrepancy, it shows the ancient reptiles did not evolve their frills or horns as a means of recognition. While scientists are not sure why the traits came about, the new finding adds credence to the idea that they were a means of sexual selection.
Researchers also found that ornamental traits seemed to evolve at a much faster rate than other ones. As such structures are costly to grow and maintain, this finding similarly points to a strong selective pressure.
The fossil record is a great way to study evolution because it enables scientists to see patterns over extremely long periods of time. However, in some cases, it can be quite difficult to determine why certain features evolved in the way that they did.
The new study helps narrow down why frills and horns evolved in ceratopsian species, and scientists think the information could be used to look at other animals as well. Though more research needs to be done before researchers can say sexual selection is the reason for horn development, it is likely the two are linked.
Researchers plan to continue their research by taking an in-depth look at the fossil record in order to see if they can track down other examples of sexual selection.