Understanding locomotion in trilobites by means of three-dimensional models

Trilobites were one of the first animals on Earth to leave their imprints on the sea floor. Such imprints represent behavioral traces related to feeding or protection, in both cases implying different types of locomotion. Modeling how trilobites moved is essential to understand their evolutionary history and ecological impact on marine substrates. Herein, locomotion in trilobites is approached by means of three-dimensional models, which yielded two main gait types. These two gaits reflect basic behaviors: burrowing and walking. This model reveals that trilobites could change their gait and consequently increase rapidly their speed varying the amplitude of the metachronal wave, a change independent from their biological structure. Fast increases in speed enhanced the protection of trilobites against predators and sudden environmental crises. The trilobite body pattern constrained their gaits, controlled by the distance between the pair of legs and between legs in a same segment.

Automated summary

Trilobites, one of the earliest creatures to leave traces on the sea floor, exhibit different locomotion behaviors related to feeding and protection. By using three-dimensional models, researchers have identified two main gait types in trilobites, namely burrowing and walking, which are independent of their biological structure. The ability to change their gait and increase speed by altering the amplitude of the metachronal wave allowed trilobites to better defend against predators and adapt to sudden environmental changes. The constraints on their gaits were determined by the distance between leg pairs and legs within the same segment.