Jurassic paleosurfaces with fecal mounds reveal the last supper of arenicolid worms.

ABSTRACT: Exceptional paleosurfaces preserving fecal casting mounds occur in the Upper Jurassic Lastres Formation of Spain. As in modern shorelines, these biogenic structures are associated with straight to sinuous-crested ripples showing the interplay of biological and physical processes in a low-energy marine environment. These trace fossils display characteristics, distribution, and densities like those of modern arenicolid populations (approximately 35 specimens per m²). Under close examination, these fecal casting mounds are morphologically undistinguishable from those produced by recent arenicolids (e.g. Arenicola marina, Abarenicola pacifica), providing evidence of the presence of these polychaetes in the Late Jurassic. As their modern counterparts, fossil arenicolids very likely m

SUBMITTER: Mangano MG 

PROVIDER: S-EPMC10771522 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature