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First report on dinosaur tracks from the Burro Canyon Formation, San Juan County, Utah, USA : evidence of a diverse, hitherto unknown Lower Cretaceous dinosaur fauna

Milàn J., Chiappe L. M., Loope D. B., Kirkland J. I., Lockley M. G.

Annales Societatis Geologorum Poloniae

2015

Vol. 85, No. 3

515--525

The newly discovered White Mesa tracksite in the Burro Canyon Formation represents a snapshot of a diverse, Lower Cretaceous dinosaur fauna from south-eastern Utah. The tracks were found at a construction site where the sandstone had been bulldozed and broken up. All tracks were found as deep, well-preserved natural casts on the underside of the sandstone slabs. Individual theropod tracks are 19–57 cm in length; one peculiar track shows evidence of a possible pathological swelling in the middle of digit III and an apparently didactyl track is tentatively assigned to a dromaeosaurid. Individual sauropod tracks are found with pes lengths of 36–72 cm, and interestingly, three distinct shapes of manus tracks, ranging from wide banana shaped to rounded and hoof-like. Ornithopods are represented with individual tracks 18–37 cm in length; a sin gle track can possibly be attributed to the thyreophoran ichnogenus Deltapodus. Zircon U-Pb dating places the track-bearing layer in the Barremian, contemporary to the lower Yellow Cat Member of the Cedar Mountain Formation, which has a similar faunal composition based on both tracks and body fossils. This new track-fauna demonstrates the existence of a diverse dinosaurian assemblage in the lower part of the Burro Canyon Formation, which hitherto is not known to yield skeletalre mains.

Correlation of the Barremian belemnite successions of northwest Europe and the Ulyanovsk - Saratov area (Russian Platform)

Baraboshkin E. J., Mutterlose J.

Acta Geologica Polonica

2004

Vol. 54, no. 4

499-510

The marine sedimentary successions of Barremian age yield, both in northwest Europe and on the Russian Platform, diverse and abundant belemnite faunas. These include the genera Praeoxyteuthis, Aulacoteuthis and Oxyteuthis and are attributed to the boreal belemnite family Oxyteuthididae. The Oxyteuthididae are endemic to northwest Europe (northern Germany, northeast England, North Sea) and the Russian Platform, where they evolved in isolation. They possibly derived from the belemnite genus Acroteuthis in Late Hauterivian time. Phylogenetically they are interpreted as the latest off shoot of the Belemnitina, which became extinct in the Early Aptian. Since ammonites are extremely rare on the Russian Platform oxyteuthid belemnites have been used to establish a biozonation scheme with seven belemnite zones (from bottom to top):Praeoxyteuthis hibolitiformis Zone (Early Barremian), Praeoxyteuthis jasikofiana Zone (Early Barremian), Praeoxyteuthis pugio Zone (earliest Barremian), Aulacoteuth is descendens Zone (late Early Barremian), Oxyteuthis brunsvicensis Zone (early Late Barremian), Oxyteuthis germanica Zone (Late Barremian), and Oxyteuthis lahuseni Zone (latest Barremian/Aptian). Apart from the O. lahuseni Zone this zonation can be correlated to the well established belemnite scheme of northwest Europe, allowing a detailed correlation of the Barremian of both areas.