Dung, diet, and the paleoenvironment of the extinct shrub-ox (Euceratherium collinum) on the C.....IntroductionStudy areaShrub-ox dung and dietDung morphologySkeletal differences due to dietDung and dietDung morphometricsDiscussion and conclusions: the natural history of Euceratherium collinumAcknowledgmentsReferencesDung, diet, and the paleoenvironment of the extinct shrub-ox(Euceratherium collinum) on the Colorado Plateau, USAManny Kropfa,⁎, Jim I. Meada,c, R. Scott Andersona,baLaboratory of Quaternary Paleontology, Quaternary Sciences Program, Northern Arizona University, Flagstaff, AZ 86011, USAbCenter for Environmental Sciences and Education, and Quaternary Sciences Program, Northern Arizona University, Flagstaff, AZ 86011, USAcDepartment of Geology, Northern Arizona University, Flagstaff, AZ 86011, USAReceived 17 May 2006Available online 7 November 2006AbstractFossil remains of Euceratherium collinum (extinct shrub-ox) have been found throughout North America, including the Grand Canyon. Recentfinds from the Escalante River Basin in southern Utah further extend the animal's range into the heart of the Colorado Plateau. E. collinum teethand a metapodial condyle (foot bone) have been recovered in association with large distinctively shaped dung pellets, a morphology similar to a‘Hershey's Kiss’ (HK), from a late Pleistocene dung layer in Bechan Cave. HK dung pellets have also been recovered from other alcoves in theEscalante River Basin including Willow and Fortymile canyons. Detailed analyses of the HK pellets confirmed them to be E. collinum andindicate a browser-type diet dominated (>95%) by trees and shrubs: Artemisia tridentata (big sagebrush), Acacia sp. (acacia), Quercus (oak), andChrysothamnus (rabbit brush). The retrieval of spring and fall pollen suggests E. collinum was a year-round resident in the Escalante River Basin.© 2006 University of Washington. All rights reserved.Keywords: Pleistocene; Dung; Bechan Cave; Escalante River Basin; Euceratherium; Paleoenvironment; Microhistology; PollenIntroductionThe shrub-ox, Euceratherium collinum (Artiodactyla, Rumi-nantia, Bovidae, Ovibovini), along with several related taxa,represent a little studied and poorly understood group of extinctNorth American ovibovids (Frick, 1937; Scott, 1962; Martinand Wright, 1967; Nelson and Neas, 1980; Harris, 1985). Eu-ceratherium is the earliest known ovibovid to enter NorthAmerica, appearing in the early Irvingtonian Land MammalAge of the Pleistocen e, possibly 1.1 Ma (Kurtén and Anderson,1980). The morphology of the animal and its relationship toother bovids is inferred from a moderate amount of skeletalmaterial found in two caves, including the type locality innorthern California (Sincl air and Furlong, 1904; Furlong, 1905;Sinclair, 1905). Radiocarbon dates taken on dung pellets,having a distinctive shape resembling a ‘Hershey's Kiss’ (HK)and assumed by Mead and Agenbroad (1992) to belong toEuceratherium, indicate extinction as late as 11,50014CyrBP.However, the rational for the identification of the dung has notbeen presented until now.One of the most remarkable finds in the American Southwesthas been the preservation of dung remains from Pleistoceneanimals such as Mammuthus (mammoth; Mead et al., 1986a),Nothrotheriops (ground sloth; Martin et al., 1961), and variouspellet-producing artiodactyls, including Oreamnos harringtoni(Harrington's mountain goat; Mead et al., 1986c) in dry caves(Davis et al., 1984; Mead et al., 1984; Agenbroad et al., 1989;Mead a nd Agenbroad, 1992; Mead et al., 2003). Largedistinctively shaped dung pellets (HK pellets), with an averagecylindrical diameter of 14.5 mm and length of 19.3 mm, taperedon one end only, with a flat to concave shape on the opposite end(giving them their distinctive ‘Hershey's Kiss’ morphology), arelocated in numerous alcoves and caves within the EscalanteRiver Basin, southern Colorado Plate au (Table 1; Mead andAgenbroad, 1992). The purpose of this study is to characterizeand identify the HK dung pellets, previously assumed to belongto Euceratherium collinum, and to describe the diet fromextracted microhistological remains and pollen preserved in thepellets. This study permits a better understanding of the naturalhistory of an extinct and enigmatic herbivore.Quaternary Research 67 (2007) 143 – 151www.elsevier.com/locate/yqres⁎Corresponding author. 780 South 9th Avenue, Tucson, AZ 85701, USA.E-mail address: [email protected] (M. Kropf).0033-5894/$ - see front matter © 2006 University of Washington. All rights reserved.doi:10.1016/j.yqres.2006.10.002HK pell ets are represented in six alcoves on the ColoradoPlateau (Table 1; Fig. 1). Excavations completed in the early1980s at Bechan Cave first revealed the presence of a stratum,up to 40 cm thick (>300 m3), contai ning dung (predominantlyMammuthus) and skeletal remains of Pleistocene mammalsdating between 14,700 and 11,00014CyrBP(Mead et al.,1986a). The HK dung pellets were found in loose associationwith E. collinum skeletal remains (a dentary second molar(M2) and a metapodial condyle; Kropf, 2005).Surveys conducted in Fortymile Canyon and Willow Gulchin the middle to late 1980s recovered HK pellets, similar inmorphology and size to those found in Bechan Cave (Mead andAgenbroad, 1992). HK pellet samples were collected from theloosely compacted flat surface sediments within alcoves andfrom sloping erosional deposits. Table 1 presents the alcovescontaining these distinctive dung pellets. HK dung pellets weredated directly and by stratigraphic association by Mead andAgenbroad (1992).Study areaThe Escalante River Basin, located in southern Utah at thecenter of the Colorado Plateau, contains countless deeplyentrenched canyo ns formed predomi nantl y in th e NavajoSandstone. The formation has numerous alcoves and cavesthat provide a unique arid habitat for the preservation of latePleistocene deposits containing the dry-preserved remains ofplant macrofossils, pollen, dung, and skeletal material (Agenb-road et al., 1989).Climate in the Escalante River Basin today is semiarid withseasonal rains and a mean annual temperature of 10–12°C.Vegetation communities in the Escalante River Basin includedesert scrub along slick rock areas, riparian vegetation alongpermanent stream beds, hanging gardens near seeps, sagebrushalong the dry sandy areas just above the stream beds, and a xericlandscape dominated by an open pinyon–juniper woodlandabove the canyon walls (