New ichnological data from the lower Paleozoic of the Central Pyrenees: presence of <em>Arthrophycus brongniartii</em> (Harlan, 1832) in the Upper Ordovician Cava Formation

Abstract

The ichnogenus Arthrophycus, characteristic of Ordovician-Silurian sedimentary rocks, is described by the first time in the Pyrenees. This ichnogenus is located in fine-grained sandstones of the upper part of the Cava Formation, on the Upper Ordovician rocks of the southern slope of the la Rabassa Dome, close to the Andorra-Spain border. Studied samples exhibit characteristics of the ichnogenus Arthrophycus Hall, 1852, and in particular to the ichnospecies A. brongniartii (=A. linearis) (Harlan, 1832). Bioturbation structures are well preserved, and diagnostic features of the ichnosubspecies A. brongniartii protrusiva (Seilacher, 2000) can be observed. These data confirm the Ordovician age of the study section, otherwise well-established on the basis of its abundant fossil content.