''Calpionellites darderi'' is an extinct

planktonic Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...

eukaryote Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

and an important index fossil for the

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eight ...

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 139.8 ± 3.0 Ma and 132.9 ± 2.0 Ma (million years ago). The Valanginian Stage succeeds the Berriasian Stage of the Lower Cretaceou ...

. 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 ''Calpionellites'' is an extinct genus of single celled eukaryotes.''Calpionellites''

genus.

References

Index fossils Spirotrichea Fossil taxa described in 1934 {{Cretaceous-life-stub