''Calpionellites darderi'' is an extinct planktonic

eukaryote The eukaryotes ( ) constitute the Domain (biology), domain of Eukaryota or Eukarya, organisms whose Cell (biology), cells have a membrane-bound cell nucleus, nucleus. All animals, plants, Fungus, fungi, seaweeds, and many unicellular organisms ...

and an important index fossil for the Lower Cretaceous stratigraphy. The first appearance of ''C. darderi'' marks the beginning of the

Valanginian In the geologic timescale, the Valanginian is an age or stage of the Early or Lower Cretaceous. It spans between 137.05 ± 0.2 Ma and 132.6 ± 0.2 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretac ...

. It also defines the base of the "Calpionellid Zone E". The species was first described by Colom in 1934 and is part of the Calpionellites genus.

References

Index fossils Spirotrichea Ciliate species Fossil taxa described in 1934 {{Paleo-stub