Poricalyptra


Classification: ntax_cenozoic -> Holococcoliths -> flat-topped -> Poricalyptra
Sister taxa: Calyptrosphaera -flat, Helicosphaera HOL, Poricalyptra, S. mediterranea HOL type, Zygosphaera

Daughter taxa (time control age-window is: 0-800Ma)
Poricalyptra aurisinae
4 transvere pores in distal surface, tube openings large, quadrate.
Usually 2 concentric rings of crystallites around margin
Poricalyptra isselii
4-7 irregular pores in distal surface, tube openings irregular, well separated.
1 concentric ring of crystallites around margin
Poricalyptra magnaghii
Distal surface has hexagonal mesh fabric, but no large openings.
3 concentric rings of crystallites around margin
Syracosphaera gaarderae HOL
2 irregular pores in distal surface.
1 concentric ring of crystallites around margin
Poricalyptra sp.
Specimens which cannot be assigned to established species

Taxonomy:

Citation: Poricalyptra Kleijne, 1991
Rank: Genus
Type species: Poricalyptra aurisinae (Kamptner 1941) Kleijne, 1991
Taxonomic discussion: The four species are separated by the patterns of pores in the body coccoliths, but the separation is consistent - coccospheres bearing more than one type have not been reported nor do intermediate morphotypes seem to occur. The number of rings of crystallites seems to vary between species. The central ridge is similar in all four species, it is formed of a single row of crystallites, usually does not reach the edges of the coccolith and is often oblique  [my observations - JRY 2018].

Distinguishing features: Dimorphic - liths cavate
BCs flat topped with large openings in tube and variable openings in distal surface; tiered wall fabric; low transverse ridge.
CFCs helladoliths - ridge of BCs is extended into prominent leaf, no openings in tube.

Farinacci & Howe catalog pages: Poricalyptra *


Size: Liths 2-2.5 µm long.

Search data:
TagsLITHS: holococcolith, elliptical,
CSPH: elongated, CFC, CROSS-POLARS: V-prominent, R-prominent,
MetricsLith size: 1.7->2.6µm; Coccosphere size: 7->12µm;
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): at top of No known fossil record modern (100% up, 0Ma, in "Holocene" stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Kleijne, A. (1991). Holococcolithophorids from the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic Ocean. Marine Micropaleontology. 17: 1-76. gs


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Poricalyptra compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-2-2021

Taxon Search:
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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1106 Go to Archive.is to create a permanent copy of this page - citation notes



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