The late Barremian ecosystem of Las Hoyas sustained by fishes and shrimps as inferred from coprofabrics

Las Hoyas, a locality of the La Huerguina Formation in the southwestern Iberia Basin (Cuenca province,
Spain), is a well-known late Barremian Konservat-Lagerstatte € highly rich in coprolites that have a wide variety of morphologies. Thin sections of twenty specimens were prepared from seven coprolite morphotypes. All of the examined coprolites exhibit a microcrystalline calcium phosphate groundmass lacking recrystallization and containing fine inclusions. Three different coprofabrics have been characterized and reflect the diet and digestive processes of the animal producers. The fish scale coprofabric is formed by ganoine scales likely attributed to Semionotiformes; the decapod cuticle coprofabric includes exoskeletal fragments which might be assigned to Atydae shrimps and Astacidae crayfish prey. A combination of decapod cuticles and fish scales can occasionally occur in the same coprolite. The third coprofabric contains few or no inclusions, and likely denotes the presence of coprolite producers with very efficient digestive systems. The exceptional preservation of the Las Hoyas coprolites reveals the trophic importance of small crustaceans with thin and delicate exoskeletons, a food resource that is not usually evident in coprolites. The number of coprofabrics relative to the number of possible fecal producers is low, and may reflect taphonomic biases. Nevertheless, the coprofabric contents demonstrate that decapods and fishes were important food resources in this Barremian ecosystem.