title: The oldest known communal latrines provide evidence of gregarism in Triassic megaherbivores.
abstract: Defecation in communal latrines is a common behaviour of extant mammals widely distributed among megaherbivores. This behaviour has key social functions with important biological and ecological implications. Herbivore communal latrines are only documented among mammals and their fossil record is exceptionally restricted to the late Cenozoic. Here we report the discovery of several massive coprolite associations in the Middle-Late Triassic of the Chañares Formation, Argentina, which represent fossil communal latrines based on a high areal density, small areal extension and taphonomic attributes. Several lines of evidence (size, morphology, abundance and coprofabrics) and their association with kannemeyeriiform dicynodonts indicate that these large synapsids produced the communal latrines and had a gregarious behaviour comparable to that of extant megaherbivores. This is the first evidence of megaherbivore communal latrines in non-mammal vertebrates, indicating that this mammal-type behaviour was present in distant relatives of mammals, and predates its previous oldest record by 220 Mya.
authors.affiliation: 1] Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) [2] Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR). Entre Ríos y Mendoza s/n., 5301, Anillaco, La Rioja, Argentina.
authors.forename: Lucas E
authors.initials: LE
authors.lastname: Fiorelli
authors.forename: Martín D
authors.initials: MD
authors.lastname: Ezcurra
authors.forename: E Martín
authors.initials: EM
authors.lastname: Hechenleitner
authors.forename: Eloisa
authors.initials: E
authors.lastname: Argañaraz
authors.forename: Jeremías R A
authors.initials: JR
authors.lastname: Taborda
authors.forename: M Jimena
authors.initials: MJ
authors.lastname: Trotteyn
authors.forename: M Belén
authors.initials: MB
authors.lastname: von Baczko
authors.forename: Julia B
authors.initials: JB
authors.lastname: Desojo
mesh_terms: D000818:Animals; D003710:Demography; D005580:Fossils; D060434:Herbivory / Q000502:physiology*; D008322:Mammals; D010163:Paleontology; D012919:Social Behavior; D014038:Toilet Facilities