Marty1, L. and Cavin L. (2005) A “baby”-sauropod trackway from the Late Jurassic Courtedoux Dinosaur Tracksite Excavations, Canton Jura, Northern Switzerland 1st Meeting of the EAVP Natural History Museum Basel

In 2002, the “Section de paléontologie” discovered and excavated a new dinosaur tracksite at Courtedoux on the future course of the “Transjurane“ highway. Intertidal to supratidal calcareous laminites of the Reuchenette Formation (Upper Kimmeridgian) contain at least 6 track-bearing levels in a total thickness of nearly 1 m. In 2002, the main track level has been excavated on a surface of about 650 m 2 , revealing 2 trackways of theropods and 17 trackways of sauropods (Marty et al., submitted b). The latter belong to the ichnogenus Parabrontopodus (Lockley et al., 1994) being the first clear evidence in central Europe and the youngest well-dated evidence for this ichnogenus worldwide.

The size range for the sauropod pes prints is between 34.4 and 46.8 cm length and between 27.0 and 35.7 width, which are the smallest known sauropod tracks in the Jurassic so far (Marty et al., submitted a). However, on an overlying level, about 2 m of a narrow gauge (interpedes distance/internal trackway width being about 13 cm) sauropod trackway segment has been excavated, exhibiting evidence for even smaller sauropods.

The mean pes print length is about 20 cm and theme an width about 13.5 cm. The gleno-acetabular distance is about 0.8 m and according to the formula of Thulborn (1990: 252) a hip height of about 1.2 m results (hip height = 5.9 pes length). Such small sauropod tracks are only known from the Cretaceous Jindong Formation of South Korea (Lim et al., 1994) and Lockley (1994) attributes them to very young (post-hatchling) individuals in their first year of growth. The Courtedoux tracksite thus reveals the first ichnological evidence for Jurassic “baby”- sauropods.

The Courtedoux “Sur Combe Ronde” tracksite is a geotope or geosite of international importance and it will be protected over an area of approximately 1500 m 2 underneath an especially constructed highway-bridge. The site has the potential for development into one of the most important sauropod tracksites and it offers plenty of possibilities for future excavations and research, but also for public viewing and installation of an educational, tourist and interpretative center

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