First Upper Cretaceous dinosaur track assemblage from Jordan (Middle East) ? preliminary results
Dinosaur tracks from Jordan (Middle East) have only been briefly reported in geological overview
papers and books. We present here the first description and documentation of Jordanian dinosaur tracks based on
a new tracksite from the south-central part of the country. The track-bearing strata belong to marginal marine (tidal
flat) deposits of the Na?ur Formation (Upper Cretaceous, Cenomanian). This unit largely consists of well-bedded
limestones, dolomites and marls that contain abundant marine invertebrate fossils such as bivalves, ammonites and
foraminifers. The dinosaur ichnofauna occurs on four different levels and comprises abundant theropod tracks and
trackways as well as isolated sauropod and ornithopod tracks. Theropod trackways consist of two different morphotypes.
Morphotype 1 is tridactyl (26 cm pes length) and with a broad, but short metatarsal area and resembles
the ichnogenus Picunichnus from the Lower Cretaceous (Albian) of Argentina. Morphotype 2 (36 cm pes length)
has extensive and narrow metatarsal impressions continuously occurring along regularly-spaced trackways. This
suggests either a plantigrade movement of the trackmaker or reflects preservational factors. By their overall-shape
with thin digits, Morphotype 2 resembles described penetrative tracks suggesting a strong influence of the substrate.
Sauropod tracks are relatively small (40 cm pes length) and show low heteropody with a kidney-shaped
manus imprint, pointing to a Sauropodichnus-like form. The single ornithopod pes track (18 cm in length) is
similar to material described as Ornithopodichnus from the Lower Cretaceous of Korea. Due to the incomplete
material of sauropod and ornithopod prints, no concrete assignment is given to this material and further study is
needed. The presence of dinosaur tracks proves a temporary subaerial exposure of the surface whereas the main
part of the Na?ur Formation is dominated by subaqueous activity of marine faunas.