Rochefort-les grattes: An early tithonian dinosaur tracksite from the canton neuchâtel, switzerland

The first vertebrate tracks from the Canton Neuchâtel (Switzerland), discovered at "Les Grattes" (Rochefort, Canton Neuchâtel) are described. The track-bearing level is located within intertidal to supratidal shallow marine limestones and biolaminites of the Jura carbonate platform, that form part of the lower Twannbach Formation (Early Tithonian). So far, several scattered sauropod tracks and one trackway have been identified. Due to particular substrate conditions at the time of track formation and recent weathering, all tracks are rather poorly preserved, shallow, and do not exhibit any anatomical details such as digit and claw impressions. However, the trackway is well defined, has a quadrupedal pattern, a regular configuration with manus tracks located well in front of the precedent pes track, and a narrow gauge. The mean pes length is 32.3 cm and the mean manus width 18.2 cm, suggesting a quite small or juvenile sauropod as the trackmaker. Based on comparisons with other similar trackways from the Late Jurassic of the Swiss Jura Mountains, trackway S1 is tentatively assigned to the ichnotaxon Parabrontopodus. Accordingly, it is amongst the youngest occurrences of Parabrontopodus, and constitutes an important temporal pinpoint, close to the Jurassic-Cretaceous boundary. The Rochefort-Les Grattes tracksite is located much further southwest than other known Early Tithonian tracksites in the Swiss Jura Mountains, and is further evidence for the existence of an Early Tithonian megatracksite. Likewise, this discovery considerably narrows down the spatial gap between the Tithonian tracksites in the Swiss and French Jura Mountains, which is important for the recognition and definition of a Late Jurassic "faunal exchange corridor" for dinosaur and other terrestrial vertebrates from further south (Iberian Massif - Massif Central) and further North (Rhenish Massif - London-Brabant Massif).