Journal of Iberian Geology 41 (1) 2015: 71-81 http://dx.doi.org/10.5209/rev_JIGE.2015.v41.n1.48656 www.ucm.es /info/estratig/journal.htm ISSN (print): 1698-6180. ISSN (online): 1886-7995 Presence of diminutive hadrosaurids (Dinosauria: Ornithopoda) in the Maastrichtian of the south-central Pyrenees (Spain) J. Company1*, P. Cruzado-Caballero2, 3, J.I. Canudo3 1Departamento de Ingeniería del Terreno, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain. 2Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro, Isidro Lobo y Belgrano, 8332 General Roca, Río Negro, Argentina. 3Grupo Aragosaurus-IUCA, Departamento de Ciencias de la Tierra, Facultad de Ciencias, Universidad de Zaragoza. c/ Pedro Cerbuna 12, 50009 Zaragoza, Spain. e-mail addresses:
[email protected] (J.C., *corresponding autor);
[email protected] (P.C.C.);
[email protected] (J.I.C.) Received: 8 January 2014 / Accepted: 18 December 2014 / Available online: 20 March 2015 Abstract In recent years a rich and diverse fauna of hadrosaurid dinosaurs has been described in the Upper Cretaceous of the Pyrenees. Recent fieldwork carried out in the upper Maastrichtian levels of the Tremp Formation, in the south-central Pyrenees (province of Huesca, north- eastern Spain), has allowed us to recover diminutive fossil bones referable to hadrosaurid dinosaurs. To date, small-sized specimens had not been reported in the area. The remains consist of small vertebrae and fragmentary long bones found in a relatively small area, so it is assumed that they probably belong to individuals of a single population. A morphological examination and a histological study reveal that they represent specimens of advanced ontogenetic stage and allow the identification of an undescribed taxon of small-bodied hadrosaurids.