Mammal Track Assemblages from the Early Tertiary of China, Peru, Europe and North America

Abstract

Recent discovery of small, tridactyl vertebrate tracks in a remote region of northwestern China has expanded the data set for the interpretation of similar trackways elsewhere in the world. Previously, similar tracks reported found in Peru from the Formation des Couches Rouges, were attributed to ornithopod dinosaurs, and then used to reinterpret the age of the section as Late Cretaceous. Similarly, the Chinese trackways were, prior to this study, assigned to the very broad chronological interval Cretaceous through Oligocene.Comparison with the similar ichnofaunas in North America and Europe where the age of the tracks is well constrained to Paleogene, and where the tracks are attributed to odd-toed ungulates (perissodactyls), necessitates careful analysis of the affinity and age of the Chinese and Peruvian trackways. In all regions the track assemblages are mammalian (i.e., of ungulate affinity). The Northern hemisphere tracks maybe be attributed to perissodactyls, but the South American tracks probably represent native ungulate groups such as the Notungulata and Litopterna, that show convergent foot morphology. Even at the high taxonomic level of odd toed ungulate such broad biostratigraphic (palichnostratigraphic) correlations are useful in providing insights into the geologic and tectonic history of terrestrial successions, where the age and faunas are poorly known.

New paleomagnetic constraints on central Asian kinematics: Displacement along the Altyn Tagh fault and rotation of the Qaidam Basin

“…and Eucypris sp. Lockley et al [1999] reported fossilized tridactyl vertebrate tracks from Tula and placed them within the Paleogene based on correlation with similar tracks from other continents.…”

Mammal and Bird Tracks from the Eocene Puget Group, Northwest Washington, USA

“…Key differences include the larger size of Apoxypus footprints, the relatively short length of the digits, and the spade-shaped to ovate shapes of the sole pads. (Mustoe, 2002); Debecque Formation, Eocene, western Colorado (Lockley et al 1999). different in form.…”

“…A simplified sketch appears in Lockley et al (1999), who mention similar perissodactyl tracks from the Eocene Debecque Formation in western Colorado, Xinjiang Provence, NW China (probably Paleogene), and Formation Couches Rouges, Peru (probably Paleogene). These ichnofossils are not described, and illustrated only as simple outlines (Fig.…”

Extant Lizard Tracks: Variation and Implications for Paleoichnology

“…Exceptions are isolated lacertoid track from Lower Cretaceous of Northeastern Brazil (Leonardi and Santos, 2004), a lizard trackway (Grande, 1984: fig III.5) and a single lizard track (Lockley et al, 1999), both from the Green River Formation (Eocene) of Utah. Those specimens have not been described or figured in any detail, which may reflect relatively little attention paid to fossil lizard tracks.…”