A new study has countered previous theories that dinosaurs developed horns and other similar ornaments in order to stand apart from each other as separate species, instead suggesting that these features might have been used for a totally different purpose altogether.
As earlier research had suggested that dinosaurs sharing the same habitat developed frills, horns, and other similar features to be recognizable to each other, and to avoid the possibility of unhealthy or infertile offspring due to hybridization, researchers from Queen Mary University in London analyzed the horns of close to 50 ceratopsian species to look for notable differences. In their paper, which was published in the Proceedings of the Royal Society B, the researchers noted that there were no significant diversity between the species that lived in the same area and those that didn't.
With the old theories seemingly debunked by the new study, the researchers believe that dinosaurs developed horns and other forms of armored features for the purpose of socio-sexual selection, or to determine if another animal is sexually compatible. Study lead author Andrew Knapp, a PhD candidate from Queen Mary University's School of Biological and Chemical Sciences, explained to BBC News that this is similar to how peacocks use their tail feathers to attract potential partners.As BBC News further explained, the theory that dinosaur horns and frills originated to differentiate between species and prevent interspecies mating did not hold up because only "subtle indications" are necessary for such things to happen, and because features separating one species from the other are not as drastically different as the ones that characterize a male or a female of the species. Furthermore, Phys.org also noted that the new research came after a separate paper from Queen Mary researchers, which suggested that the ceratopsian species Protoceratops' evolution might have been linked to sexual selection.
Although the researchers primarily focused on ceratopsians in their new paper, they believe there's a chance that this could also apply to other prehistoric creatures, as fossil records could allow for a better look at how evolution had over a substantial period of time, as opposed to tracking evolution in present-day living creatures. And with today's computer models suggesting that sexual selection is capable of promoting "rapid speciation, adaptation, and extinction," such simulations could have important implications with regards to the conservation and preservation of threatened or endangered species.
"If sexual selection is indeed the driver of ornament evolution in ceratopsians, as we are increasingly confident it is, demonstrating it through different lines of evidence can provide a crucial window into tracing its effects over potentially huge timescales," Knapp explained in a statement.
For future studies, Knapp and his colleagues hope to find definitive evidence that socio-sexual selection was indeed the reason why dinosaurs grew horns and other ornaments. As for the old theory of species recognition, he told BBC News that even living creatures don't show too many signs of such characteristics, as there might be a "more innate understanding" that allows large herds of animals to recognize each other.