to which period did these fossils date back to?
Early Cretaceous period.
Acamptonectes
Acamptonectes (meaning "rigid swimmer") is an extinct genus of ophthalmosaurid ichthyosaur that lived between 134 and 132 million years ago during the Early Cretaceous.
what is acamptonectes? It is an extinct genus of ophthalmosaurid ichthyosaur. what did they eat? Fish and squid. where were their fossils discovered? England and Germany.
wiki:19746916
Acamptonectes [SEP] Introduction
Acamptonectes (meaning "rigid swimmer") is an extinct genus of ophthalmosaurid ichthyosaur that lived between 134 and 132 million years ago during the Early Cretaceous. Known from fossil deposits in England and Germany, the genus currently contains the single species A. densus, which was first described in 2012. Its discovery was important in the research of ichthyosaurs, as being one of the first known ophthalmosaurines from the Early Cretaceous, it provided evidence that no mass extinction of ichthyosaurs occurred during the Jurasic-Cretaceous boundary as previously understood. Nevertheless, "Acamptonectes" remains one of only eight genera of ichthyosaurs known during the Cretaceous. In life, "Acamptonectes" was probably a generalist predator.