Applied Biostratigraphy

• considered by Armstrong and Brasier (2005) to be related to the ciliated (possessing tiny fronds which beat in waves used for locomotion and food-gathering) Tintinnids which are in turn considered to be protozoa (animals)
• hyaline calcareous wall (true tintinnids have organic walls), generally flask shaped
• seldom recorded as loose specimens as they are very fragile – they are normally observed in thin-section
• geologic range: Late Tithonian (latest Jurassic) – Early Valanginian (Early Cretaceous)
• biostratigraphically significant in the Early Cretaceous and Late Jurassic but with very few practicing specialists however relatively low numbers of species ensure that general microfossil workers can usually identify them

A calpionellid. These enigmatic organisms occur commonly around the Jurassic-Cretaceous boundary but in very few other time intervals.