First Occurrence of Tetrapod Footprints from Westphalian Strata of the Sidi Kassem Basin, Central Morocco

Abstract

The Sidi Kassem Basin is the only limnic basin of Westphalian age in Morocco. It is built up of 1,250 m of alluvio-fluvial to lacustrine deposits that have so far yielded plant fossils and invertebrate remains only. Recent exploration for fossil tetrapod footprints in floodplain-deposits of the basin revealed a moderately diverse vertebrate ichnofauna composed of tracks assigned to cf. Batrachichnus Woodworth, 1900; cf. Hylopus Dawson, 1882; Dimetropus Romer and Price, 1940; and Notalacerta Butts, 1891. The tracks can be referred to temnospondyl, anamniote reptiliomorph, non-therapsid synapsid (pelycosaur), and captorhinomorph trackmakers. The described ichnoassemblage is important in at least three aspects: (1) It suggests an Early to mid-Pennsylvanian age for the footprint-bearing strata of the study area. (2) It is the oldest association of tetrapod footprints from Africa. (3) It is the first evidence of the relatively rare ichnogenera cf. Hylopus and Notalacerta outside of North America and Europe. Judged from the variety of tetrapod tracks and previously collected floral remains, the Sidi Kassem Basin must have represented a well-established continental ecosystem during Pennsylvanian time. Further exploration for trace and body fossils of Palaeozoic vertebrates in this basin may be important for the reconstruction of early tetrapod evolution.

Keywords:

• Vertebrate ichnology
• Early tetrapods
• Biostratigraphy
• Palaeoecology
• Late Carboniferous
• NW Africa

ACKNOWLEDGMENTS

Bill DiMichele is acknowledged for supporting identification of plant fossils from the Sidi Kassem Basin. We thank Spencer G. Lucas, Hendrik Klein and Murray Gingras for constructive reviews. We also wish to thank Mr. Adnane Habib (UCD EL Jadida) who assisted with digital mapping.

FUNDING

This research was supported by a grant from the German Science Foundation (DFG SCHN 408/17-1). A. Lagnaoui participated in fieldwork by financial support of the German Academic Exchange Service.