Protoceratops dinosaurs used their large skull frills to court potential mates

Protoceratops dinosaurs used their giant skull frills to court potential mates – and not as protective as previously thought, a new study reveals.

Researchers at the Museum of Natural History in London say they have studied the largest complete set of 3D data ever for a single type of dinosaur.

The team analyzed 3D scans of Protoceratops skulls to find out more about the evolution of the creature’s complex neck frills.

About the size of a large sheep, Protoceratops were a very common species that would have inhabited the Gobi desert of present-day Mongolia, somewhere between 74 million and 70 million years ago.

Protoceratops is a member of the Ceratopsian group of mushroom dinosaurs, which includes the most famous and much larger three-horned Triceratops.

The experts concluded that Protoceratops developed the frills as a result of sexual selection – when members of the opposite sex favor certain traits in animals, so over time they can become more complex.

Today, we see the results of sexual selection in the amazing feathers of paradise birds and the extensively expanded mandibles of the stag beetle.

Researchers had wanted to see if sexual selection could explain the evolution of frills of protoceratops.

‘Many fossil animals have unusual structures and features that are rarely seen in living animals today,’ said Dr Andrew Knapp, a postgraduate researcher at the Museum of Natural History.

‘Protoceratops didn’t have horns at all but they still had a big frill.’

Several theories have previously been proposed to reveal these neck frills.

‘Some have said that they were used for protection, others that they played a part in cooling the large strawberries, or that they allowed individuals to identify different members of their own species,’ said Dr. Knapp.

For their study, researchers 3D-scanned a total of 30 skulls of Protoceratops, ranging in size from tiny day hatchlings to fully grown adults, giving it a full-grown sequence of the species.

This allowed them to compare not only how different parts of the skull changed, but also how the skull changed in shape as the animal grew.

From this, it was possible to see if there were any signs that the shapes of the frills were the result of sexual selection.

In living creatures, some traits exhibit a specific growth pattern, called allometry.

When the allometry is positive – because they show a much greater rate of change in growth compared to other markers on the animals – it is always a sexually selected feature, such as deer antlers.

When looking at Protoceratops frills, researchers found that the growth patterns matched this, revealing that the frills seemed to be sexually selected.

Natural History Museum experts also found that the frills were able to evolve and adapt independently – also as a sign of sexual selection.

Sex selection can help explain traits that may not help the animal survive but instead prefer the other species, so it will survive through the evolutionary cycle.

This often leads to differences in the appearance of males and females of the same sex – a condition known as sexual dimorphism, and something that still exists in today’s species.

‘Sexual selection is a little more complicated than it is the most successful male trait,’ said Dr Knapp.

‘While there are several examples in live animals where females usually select males based on the size of their tail feathers or their calls, it is often observed that males do the same. something with women too.

Today, both males and females have the rocky auklet, a bird species, with impressive feathers curling from the top of the heads that each species uses to mark their health.

‘So, while a feather plug is a sexually selected sexual attraction, that has not led to sexual degradation,’ Dr Knapp said.

Similarly, evidence from the Protoceratops fossils suggested that sexual selection appeared to be in action, but apparent sexual dimorphism did not appear.

‘There were almost certainly differences between males and females but there are often differences in body size, so males will be larger than females or vice versa,’ said Dr Knapp.

‘It could also be through something else like colouration, which is not conserved in fossils. ‘

The team agreed that a selection of dinosaurs like Ceratopsians seemed to be the result of sexual selection.

Despite this, there is no way to definitively prove that individuals of extinct species with specific traits that were attractive to the other species were more successful and had more offspring.

They therefore concluded that the frills were the result of the broader ‘socio-sexual selection’ – a term that includes other social behaviors associated with such complex decorations, such as the protection of food or land. .

Dr. Knapp was previously the lead author of the 2016 study of the unique properties of Protoceratops, which authors said could be used to attract the attention of the opposite species.

According to Dr Knapp, this new research, published today in the journal Proceedings B, builds on the previous study ‘in a number of ways’.

‘First, we look at three-dimensional shape rather than the simpler sequential measurements used in the previous paper – this will allow us to grow its analysis in more detail,’ he told MailOnline.

Second, we use our analyzes across the entire skull rather than focusing on one area.

By doing this we can ensure that the effects we see in the frill are not spread over other areas of the skull.

‘Finally, we have included more samples in our study than in the previous study so that we can be more certain of the results.’