A titanosaurid megatracksite from the Maastrichtian of Catalonia (Spain)

Jean Le Loeuff* and Albert Martinez-Rius**

*Musée des Dinosaures, I 1260 Espéraza, France
**Geoleg Consultor. c/ Enamorats,132, 2-1, 08026 Barcelona, Spain

Abstract

The Fumanya tracksite, 20 kms north of Berga in Catalonia (eastern Pyrenees), is the first known locality which shows titanosaurid footprints. It is the largest known sauropod trackway site from the Late Cretaceous in Europe. Thousands of footprints are organized in tens of trackways on a main track level which can be followed for several kilometers. A preliminary study indicates that titanosaurids had four pes claws. Most of the animals apparently walked alone. A few twinned trackways indicate that some titanosaurids moved together. The monospecific nature of the prints suggests some kind of gregarious habits for titanosaurids.

INTRODUCTION

The Fumanya tracksite is situated in the eastern part of the Serra d’Ensija, 20 kms north of Berga, in the eastern Pyrenees (fig.1). The trackways outcrop on the steeply tilted layers of an ancient lignite quarry (Carbones de Berga). This outcrop is located in the lower part of the continental Garumnian facies. The lignites are of Maastrichtian-Paleocene age, and the K-T boundary is probably located in the Vallcebre limestones (Feist & Colombo,1983; Masriera Ullastre,1983). The structure of the area consists of E-W trending folds related to the Pedraforca thrust sheet emplacement (Vergés & Martinez,1988).

The working face of the quarry consists of a detritic limestone which commonly yields plant remains; this limestone is also the main track level. The next beds consist of sands and lignite, with dark clay and limestone. Shell accumulation indicate a lagunar paleoenvironment. Above this estuarine formation are red marls of typical Garumnian facies, which possibly include the Cretaceous-Tertiary boundary. The estuarine facies of Fumanya have yielded a very few dinosaur bone fragments and eggshells.
The site was discovered by L. Viladrich in 1985 (see Viladrich,1986), and has been recently referred in the 1:25.000 geological map of Catalunya (Martinez,1991). Detailed track mapping of the site began in 1995 and is far from complete, so that only preliminary results will be presented here.

Fig.1: Location of the Fumanya tracksite (square)

Fig.1: Location of the Fumanya tracksite (square)

DESCRIPTION OF THE SITE

The Fumanya quarry tracksite is mainly born by a very large slab of limestone which, fortunately, constitutes the working face of this lignite exploitation. This main level directed N20° can be studied for several kms and shows thousands of footprints.

The most interesting place is in the southern part of the quarry, where a vast 500 meters long and nearly 100 meters high wall exposes dinosaur footprints. We have only begun the mapping of the northern portion of this place, i.e. an 8000 square meters slab, showing at least four different trackways (fig. 2). Presently, all the tracks (consisting of manus and pes impressions) can be assigned to sauropod dinosaurs, and more precisely to titanosaurids (the only group of sauropods which was present in the Late Cretaceous in Europe; cf. Le Loeuff,1993). To map this vertical exposure, we disposed ropes from the top of the hill to make a grid with a 10 m mesh; then pictures were taken to prepare the map of the site.

The longest of these trackways (more than 50 meters long) is composed of 38 pes prints and 14 manus prints. A few well-preserved footprints show four claws impressions (the strongest is the internal clawprint). This is an interesting detail because this part of titanosaurid anatomy was presently unknown (Powell,1992). Mean pes stride is about 2.5 m; following Thulborn’s (1990) estimations, the track maker was 3.5 to 4 m high at the acetabulum and its total length was about 20 m.

To the south of the main trackway, two parallel trackways can be traced for 10 m (one of them is displaced by a normal fault). Along with the monospecific nature of the site, they could suggest some kind of social behaviour (two titanosaurids were walking side by side). One can also notice than no tail mark was discovered at Fumanya, which confirms than titanosaurids walked with their tail held erect above the ground.

Fig. 2 : Map of the northern part of the main slab (scale bar:1 meter)

Fig. 2 : Map of the northern part of the main slab (scale bar:1 meter)

CONCLUSIONS

The Fumanya tracksite is the largest Late Cretaceous tracksite ever found in the world, and the first locality showing indisputable titanosaur footprints. This preliminary study allows us to widen to this poorly known family observations made for other sauropod groups: they walked slowly with their tail held erect above the ground (which was suggested by osteology) and they were possibly gregarious. This site confirms the abundance of titanosaurids in the Late Cretaceous of Southern Europe (Le Loeuff,1993). Precise mapping of the whole site has been undertaken in 1996 and its results will be reported later.

An European program is being elaborated with the Generalitat of Catalonia to study the Fumanya Quarry. New footprint levels will be excavated and consolidated in the near future, allowing a precise study of this remarkable site, which makes possible a frst palaeoichnological study of titanosaurids.

Acknowledgments : We thank M Jordi Garcia, director of the Parc Natural de Cadi-Moitxerro and M. Jesus Orespo, director of the Carbones de Berga, who authorized our work in Fumanya. We also thank Alain Le Loeuff, Lionel Cavin, Christel Souillat, Anne Schulp, Wouter Brokx who participated to the field work in Fumanya and Dr. Eric Buffetaut for helpful comments and improvements of the text.

REFERENCES

Feist, M. & Colombo, F.1983. La limité Crétacé-Tertiaire dans le NE de I’Espagne du point de vue des charophytes. Géologie Méditerranéenne,10, 303-326.
Le Loeuff, J.1993. European Titanosaurids. Revue de Paléobiologie, Vol. spéc. 7,105-117.
Masriera, A. & Ullastre, J.1983. Essai de synthése stratigraphique des couches continentales de la fm du Crétacé des Pyrénées catalanes. Géologie Méditerranéenne,10, 283-290.
Martinez, A.1991. Mapa geologic de Catalunya a escala 1:25.000 (full 254-2-2, Gosol). Servei Geologic de Catalunya. (Unpublished). Barcelona.
Powell, J.E.1992. Osteologia de Saltasaurus loricatus (Sauropoda-Titanosauridae) del Cretacico Superior del Noroeste argentino. In : Sanz, J.L. & Buscalioni, A.D. (Eds) – Los dinosaurios y su entorno biotico. Instituto Juan de Valdes, Serie Actas Academicas, 4,165-230.
Thulborn, T.1990. Dinosaur tracks. Chapman and Hall,1-410.
Vergés, J. & Martinez, A.1988. Corte compensado del Pirineo oriental: geometria de las cuencas de antepais y edades de empazamiento de los mantos de corrimiento. Acta Geologica Hispanica, 23, 95-106.
Viladrich, L.1986. Les petjades fossils del Coll de Fumanya. L’Erol,18. Berga.


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