Collective behaviour in 480-million-year-old trilobite arthropods from Morocco
|Author(s)||Vannier Jean1, Vidal Muriel2, Marchant Robin3, El Hariri Khadija4, Kouraiss Khaoula4, Pittet Bernard1, El Albani Abderrazak5, Mazurier Arnaud5, Martin Emmanuel1|
|Affiliation(s)||1 : Univ Lyon 1, Univ Lyon, Lab Geol Lyon Terre, CNRS,UMR 5276,ENS Lyon,Planetes,Environm, Batiment Geode,2 Rue Raphael Dubois, F-69622 Villeurbanne, France.
2 : Univ Brest, Lab Geosci Ocean, IUEM UBO, CNRS,UMR 6538, Rue Dumont Urville, F-29280 Plouzane, France.
3 : Univ Lausanne, Musee Cantonal Geol, Batiment Anthropole, CH-1015 Lausanne, Switzerland.
4 : Univ Cadi Ayyad, Dept Sci Terre, Fac Sci & Tech, BP 549, Marrakech 40000, Morocco.
5 : Univ Poitiers, UFR SFA, IC2MP, CNRS,UMR 7285 HydrASA, 5 Rue Albert Turpin,Batiment B8,TSA 51106, F-86073 Poitiers, France.
|Source||Scientific Reports (2045-2322) (Nature Publishing Group), 2019-10 , Vol. 9 , P. 14941 (10p.)|
|WOS© Times Cited||9|
Interactions and coordination between conspecific individuals have produced a remarkable variety of collective behaviours. This co-operation occurs in vertebrate and invertebrate animals and is well expressed in the group flight of birds, fish shoals and highly organized activities of social insects. How individuals interact and why they co-operate to constitute group-level patterns has been extensively studied in extant animals through a variety mechanistic, functional and theoretical approaches. Although collective and social behaviour evolved through natural selection over millions of years, its origin and early history has remained largely unknown. In-situ monospecific linear clusters of trilobite arthropods from the lower Ordovician (ca 480 Ma) of Morocco are interpreted here as resulting either from a collective behaviour triggered by hydrodynamic cues in which mechanical stimulation detected by motion and touch sensors may have played a major role, or from a possible seasonal reproduction behaviour leading to the migration of sexually mature conspecifics to spawning grounds, possibly driven by chemical attraction (e.g. pheromones). This study confirms that collective behaviour has a very ancient origin and probably developed throughout the Cambrian-Ordovician interval, at the same time as the first animal radiation events.