The oldest known communal latrines provide evidence of gregarism in Triassic megaherbivores

FIORELLI, L. E.; EZCURRA, M. D.; HECHENLEITNER, E. M.; ARGAÑARAZ, E.; TABORDA, J. R. A.; TROTTEYN, M. J.; BACZKO, M. B.; DESOJO, J. B.

SCIENTIFIC REPORTS

Nature Publishing Group

Año: 2013 vol. 3

2045-2322

Defecation in communal latrines is a common behaviour of extant mammals widely distributed amongmegaherbivores. This behaviour has key social functions with important biological and ecologicalimplications. Herbivore communal latrines are only documented among mammals and their fossilrecord is exceptionally restricted to the late Cenozoic. Here we report the discovery of several massivecoprolite associations in the Middle-Late Triassic of the Chan?ares Formation, Argentina, whichrepresent fossil communal latrines based on a high areal density, small areal extension and taphonomicattributes. Several lines of evidence (size, morphology, abundance and coprofabrics) and theirassociation with kannemeyeriiform dicynodonts indicate that these large synapsids produced thecommunal latrines and had a gregarious behaviour comparable to that of extant megaherbivores. This isthe first evidence of megaherbivore communal latrines in non-mammal vertebrates, indicating that thismammal-type behaviour was present in distant relatives of mammals, and predates its previous oldestrecord by 220 Mya.