Trilobites used trident-like horns to fight over mates like stags

trident weapon on head wallicerops Fossils Suggest Animals First Dueled In Sexual Warfare At Least 400 Million Years Ago

To Riley Black

The trident-like horns on the heads of some trilobites were probably used for fighting over mates. This postulated behavior is the oldest confirmed example of sexual struggle in the fossil record.

Alan Gishrich of Bloomsburg University in Pennsylvania said, “The unusual structures of organisms are crying out for functional explanations.

Previously, paleontologists suggested that the teeth were on top walliserops, Trilobites, which lived about 400 million years ago, may have been used as a defense against the ancient nautilus, which was hungry for these marine invertebrates. Processes can grow over 25 mm in length, which is roughly the size of the rest of the animal.

But Gishlick and his colleague Richard Forty at London’s Natural History Museum came to a different conclusion after studying the rare specimen. wallicerops Uses 4 tines instead of 3.

It was a size comparable to other adult insects, so it was a tetrapod trilobite that protruded into a gishric wallicerops, indicating that the species had an expected longevity. This seemed like evidence against the trident being a defensive weapon. This is because defensive structural abnormalities may have made trilobites more vulnerable.

The structures used in competition for mates are less critical to survival. “We know that structural malformations associated with sexual selection are highly tolerant, because malformations only affect mating,” he says.

The researchers looked for more evidence in modern Japanese beetles (Tripoxylus dichotomas), which has a similar structure protruding from the head. Male beetles often have variations and anomalies in the shape of their horns, as they are used in courtship competition with other males rather than as defense against predators.

This is also true of deer and wild sheep, whose horns are less about pushing back predators and more about confronting each other.

Although it is difficult to identify the sex of fossil trilobites, wallicerops And the beetle led Gishrik and Forty to suspect the one with the trident. wallicerops was a man.

“It is amazing that such complex behaviors emerged so early in the evolutionary process and have persisted to the present day,” said Jean Vannier of the University of Lyon, France.

“Better understanding of past lives and being able to test hypotheses as rigorously as possible is essential to understanding the evolution of form and function,” says Gishrich.