Catalogue of Organisms: The Bolivinitids

The Cretaceous was a interval of serious innovation within the evolution of Foraminifera with a variety of distinct new lineages making their look throughout this era. Amongst these, showing within the latter a part of the Cretaceous, had been the primary members of the fashionable household Bolivinitidae.

Bolivinita costifera, from the Smithsonian Nationwide Museum of Pure Historical past.

The Bolivinitidae are free-living benthic forams with a calcareous, hyaline (glassy) check. The general form of the check is elongate with chambers organized in biserial coils (that’s, there are two chambers per loop). The terminal aperture is often loop-shaped with a surrounding lip. Contained in the chamber, a tooth plate (an internal protrusion of the check) runs from the aperture to the opening of the earlier chamber and will protrude by the aperture (Revets 1996).

Representatives of the Bolivinitidae are present in a variety of depths, from the shallow waters of the ocean to the bathyal zone. They could be among the many most plentiful forams in areas of low oxygen concentrations and are generally related to sustained natural matter enter (Erdem & Schönfeld 2017). In different phrases, these are muck-lovers. People rising in low oxygen situations have a tendency to point out much less pronounced floor sculpture on the check than these the place the oxygen ranges are increased. Conversely, people at deeper ranges are usually bigger general than these in shallower waters (Brun et al. 1984). As such, bolivinitids have obtained their fair proportion of consideration as potential indicators of modifications in environmental situation over time.

REFERENCES

Brun, L., M. A. Chierici & M. Meijer. 1984. Evolution and morphological variations of the principal species of Bolivinitidae within the Tertiary of the Gulf of Guinea. Géologie Méditerranéenne 11 (1): 13–57.

Erdem, Z., & J. Schönfeld. 2017. Pleistocene to Holocene benthic foraminiferal assemblages from the Peruvian continental margin. Palaeontologica Electronica 20.2.35A: 1–32.

Revets, S. A. 1996. The generic revision of the Bolivinitidae Cushman, 1927. Cushman Basis for Foraminiferal Analysis Particular Publication 34: 1–55.