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:
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
Farinacci & Howe catalog pages: Acanthoica + * , Anacanthoica *
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.
LITHS: planolith, elliptical, circular, CA: ca_disjunct, grill, process, CSPH: equant, CFC, AAC, |
Lith size: 1->4µm; Coccosphere size: 6->12µm; |
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:
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 References:
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Acanthoica compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-2-2025
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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