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Nannotax3 - ntax_main - Acanthoica Nannotax3 - ntax_main - Acanthoica

Acanthoica

Classification: ntax_main -> Syracosphaerales -> Rhabdosphaeraceae -> Acanthoica
Sister taxa: Acanthoica, Algirosphaera, Blackites, Cyrtosphaera, Discosphaera, Palusphaera, Rhabdosphaera, Solisphaera

Daughter taxa (time control age-window is: 0-800Ma)
				Acanthoica quattrospina Body coccoliths sub-circular, (1.5-2.5 µm), with slits between radial cycle elements, lamellar cycle makes low cone. Long spines on polar coccoliths (one or both ends).
				Acanthoica acanthifera Like A. quattrospina but lamellar cycle forms hollow protrusion.
				Acanthoica acanthos Like A. quattrospina but lacking spine coccoliths, and rim broader
				Acanthoica biscayensis Like A. quattrospina but liths larger (2.5-3 µm), oblong, no gaps between radial cycle elements.
				Acanthoica janchenii Like A. quattrospina, but with no gaps between radial cycle elements.
				Acanthoica maxima Like A. quattrospina but liths larger (3.5-4 µm), elongate oblong, with large gaps between radial cycle elements
				Acanthoica sp A
				fossil species
				Acanthoica backmanii Small (2-3µm), broadly elliptical body coccoliths with well-developed rim, radial-lath and lamellar cycles. Lamellar cycle forms very low domed protrusion or elongate spine.
				Acanthoica cohenii Coccoliths irregularly elliptical; single well-developed radial lath cycle and discrete central protrusion formed numerous very small elements.
				Acanthoica laffittei Circular to broadly elliptical; rim broad; two concentric lath cycles; low central protrusion
				Acanthoica sp. Specimens which cannot be assigned to established species

Taxonomy:

Citation: Acanthoica Lohmann 1903

Taxonomic rank: genus

Type species: Acanthoica quattrospina Lohmann 1903

Taxonomic discussion:

Although many extant species have been described the only one which is regularly recorded is Acanthoica quattrospina and none of the others are unambiguously established. Several species were described by early workers based on the number of apical coccoliths with elongate spines (e.g. A. monospina). Kleijne (1992) synonymised most of these on the grounds that apical spines were often lost and instead used body-coccolith morphology as the prime criterion to separate species.

Synonyms:

The genera Cyrtosphaera and Anacanthoica are separated in the plankton on coccosphere charaterisitics, in the fossil record all specimens would be included in Acanthoica

Acanthoica * Lohmann 1903 [x]
Anacanthoica * Deflandre 1952 [synonym according to Young & Bown (2014)]

Variants:

Distinguishing features:
Parent taxon (Rhabdosphaeraceae): BCs planoliths with radial lath cycle and highly-variable axial structures. Often polymorphic and/or varimorphic
This taxon: Body coccoliths with well-developed radial lath cycle, low mound in centre; coccospheres polymorphic, usually some coccoliths with well-developed spines

Morphology:

Coccosphere polymorphic with characteristic set of apical and antapical spines shown by all species, though some individual specimens may depart from standard pattern. The following coccolith types occur:
1. Body coccoliths; well-developed radial cycle, usually with openings; lamellar cycle forms low solid cone or hollow protrusion.
2. Four circum flagellar coccoliths, with spine formed by lamellar cycles. Three with short spines, one with a long spine.
3. Two antapical coccoliths; with very long spines, the basal disk folded with a broad rim but no radial lath cycle.

Search data:

LITHS: planolith, circular, elliptical, CA: ca_disjunct, grill, process,
CSPH: equant, AAC, CFC,

Lith size: 1->4µm; Coccosphere size: 6->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 ranges of the species in this database
First occurrence (base): within NP19-20 zone (34.44-36.97Ma, base in Priabonian 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.
See also: customisable plot Parent: Rhabdosphaeraceae

References:

Dunkley Jones, T., Bown, P. R. & Pearson, P. (2009). Exceptionally well preserved upper Eocene to lower Oligocene calcareous nannofossils (Prymnesiophycidae) from the Pande Formation (Kilwa Group), Tanzania. Journal of Systematic Palaeontology. 7(4): 359-411. gs

Kleijne, A. (1992). Extant Rhabdosphaeraceae (coccolithophorids, class Prymnesiophyceae) from the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic Ocean. Scripta Geologica. 100: 1-63. gs

Lohmann, H. (1902). Die Coccolithophoridae, eine Monographie der Coccolithen bildenden Flagellaten, zugleich ein Beitrag zur Kenntnis des Mittelmeerauftriebs. Archiv für Protistenkunde. 1: 89-165. gs O

Young, J. R. & Bown, P. R. (2014). Some emendments to calcareous nannoplankton taxonomy. Journal of Nannoplankton Research. 33(1): 39-46. gs

Acanthoica compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 20-7-2026

Taxon Search:

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=4 Go to Archive.is to create a permanent copy of this page - citation notes

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