Common genera

Distinguishing features:
Parent taxon (Holococcoliths): Coccoliths formed of minute (ca 0.1µm) rhombohedral micro-crystals. Often a life-cycle stage with heterococcolith counterpart(s).
This taxon: The four most commonly recorded genera

Daughter taxa (time control age-window is: 0-800Ma)					Granddaughter taxa
				Calculites Holococcoliths with a proximal plate of four blocks; ridged and pitted distal surface; and short, narrow, hollow spines. Entire coccolith bright in xpl in plan view	Calculites favosus Calculites anfractus Calculites axosuturalis Calculites obscurus Calculites ovalis Calculites rosalyniae Calculites additus Calculites karaiensis Calculites cenomanicus Calculites cyclops Calculites juliae Calculites maghredaswampensis Calculites paulus Calculites percernis Calculites proscissus Calculites turonicus Calculites sarstedtensis Calculites suturus Calculites sp.
				Lucianorhabdus Holococcoliths with a proximal plate of four blocks and tall, hollow spines, which are often ridged or pitted and may be bulbous or curved.	Lucianorhabdus cayeuxii Lucianorhabdus arcuatus Lucianorhabdus compactus Lucianorhabdus inflatus Lucianorhabdus maleformis Lucianorhabdus quadrifidus Lucianorhabdus salomonii Lucianorhabdus boudagherfadeliae Lucianorhabdus tabernus Lucianorhabdus turris Lucianorhabdus arborius Lucianorhabdus cubiterminalis Lucianorhabdus phlaskus Lucianorhabdus lageniformis Lucianorhabdus windii Lucianorhabdus sp.
				Orastrum Holococcoliths with narrow rim surrounding a central-area formed of 1-4 blocks. Typically non-cavate with no spine. Rim bright and central plate dark	Orastrum asarotum Orastrum campanensis Orastrum porosuturalis Orastrum perspicuum Orastrum robinsonii Orastrum colligatum Orastrum schollei Orastrum sp.
				Owenia Holococcoliths with a narrow rim and a central structure comprising two or four blocks which typically incorporate a distal bridge-shaped structure which may extend into a spine; the blocks may be perforate.	Owenia dispar Owenia hillii Owenia partitum Owenia sp.

Taxonomy:

Farinacci & Howe catalog pages:

Distinguishing features:
Parent taxon (Holococcoliths): Coccoliths formed of minute (ca 0.1µm) rhombohedral micro-crystals. Often a life-cycle stage with heterococcolith counterpart(s).
This taxon: The four most commonly recorded genera

Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Late Valanginian Substage (132.60-135.70Ma, base in Valanginian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:

• Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
• Triangles indicate an event for which a precise placement has been suggested
• Neptune data: this is a higher taxon page so Neptune data is not plotted. For the customisable plot option go to a genus page Parent: Holococcoliths

Common genera compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-10-2024 Taxon Search: Advanced Search Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=10268 Go to Archive.is to create a permanent copy of this page - citation notes