Herrero & Farke, Hadrosaurid Dinosaur Skin Impressions PalArch’s Journal of Vertebrate Palaeontology, 7(2) (2010) © PalArch Foundation 1 HADROSAURID DINOSAUR SKIN IMPRESSIONS FROM THE UPPER CRETACEOUS KAIPAROWITS FORMATION OF SOUTHERN UTAH, USA Lucia Herrero* & Andrew A. Farke** * The Webb Schools, 1175 West Baseline Road, Claremont, CA 91711 USA lucyherrero@yahoo.com ** Raymond M. Alf Museum of Paleontology, 1175 West Baseline Road, Claremont, CA 91711 USA afarke@webb.org Lucia Herrero & Andrew A. Farke. 2010. Hadrosaurid Dinosaur Skin Impression from the Upper Cretaceous Kaiparowits Formation of Southern Utah, USA. – Palarch’s Jour- nal of Vertebrate Palaeontology 7(2) (2010), 1-7. ISSN 1567-2158. 7 pages + 1 igure. Keywords: skin impressions, hadrosaur, Kaiparowits Formation AbstrAct Skin impressions from hadrosaurid dinosaurs are relatively common inds throughout the Cretaceous Western Interior of North America. A recently discovered specimen from the late Campanian-aged Kaiparowits Formation of southern Utah is typical for hadro- saurs, with randomly arranged polygonal tubercles averaging around 4 mm in length and 3 mm in width. Based on the associated bones, these impressions likely originated on the thorax of the animal. In contrast with most previously published inds, the skin is not preserved in perfect articulation with the skeleton. This suggests a taphonomic mode in which the skeleton and soft tissues were partially disarticulated prior to burial. Introduction The hadrosaurs, or ‘duck-billed’ dinosaurs, pres- ent one of the best-known records of fossil skin impressions for any dinosaur group. These im- pressions range from small patches to entire ‘mummies,’ allowing conident reconstruction of virtually the entire body’s surface texture (e.g. Lull & Wright, 1942). To date, skin impressions have been described and igured for lambeo- saurine and hadrosaurine hadrosaurids from throughout the Upper Cretaceous of western North America, including the Almond Forma- tion of Wyoming (Gates & Farke, 2009), Dino- saur Park Formation of Alberta (Lambe, 1902; 1914a,b; Brown, 1916; Parks, 1920), Hell Creek Formation of Montana (Horner, 1984; Wideman & Lofgren, 2001), North Dakota (Manning et al.,