Chirothere Footprint Sites from the Otter Sandstone Formation (Middle Triassic, late Anisian) of Devon,United Kingdom

Abstract

Three chirothere footprint sites are documented from the Middle Triassic (Anisian) fluvial Otter Sandstone Formation of Sidmouth, Devon, UK. One site, on the foreshore below Peak Hill, has revealed numerous tracks, including a probable manus imprint, which are recorded here. Another site, also beneath Peak Hill, has produced a single probable manus track from a higher horizon. The third site, on the foreshore below Salcombe Hill Cliff, has yielded a small number of pes tracks similar to those from Peak Hill. The footprints at all sites are interpreted as belonging to a large Chirotherium ichnospecies, perhaps C. barthii Kaup. Unusually, the tracks are preserved in mudstone, often in convex epirelief, and are inferred to have been generated subaqueously. The apparent restriction of the footprints to the higher part of the Otter Sandstone Formation supports other evidence, such as a greater abundance of vertebrate skeletal material, subhorizontal rather than vertical rhizocretions, and a greater frequency of lacustrine facies, for a less arid climate and higher water table than lower in the sequence.

Keywords:

• Chirotheriid
• Chirotherium
• Isochirotherium
• Rauisuchian
• Otter Sandstone Formation
• Triassic

ACKNOWLEDGMENTS

We wish to thank Ian West (Romsey), Ramues Gallois (Exeter), Mike King (Finland), Mike Benton (University of Bristol), and Richard Edmonds (Earth Science Manager, Dorset and East Devon Coast World Heritage site) for helpful comments and other assistance. We are also grateful to Hendrik Klein (Saurierwelt Paläontologisches Museum, Germany) and Spencer G. Lucas (New Mexico Museum of Natural History) for valuable feedback on the submitted manuscript.