|Daughter taxa: (blue => in age window 0-800Ma)|
Distinguishing features: Holococcoliths with tube, open distally and subdivided internally by vertical septae
Farinacci & Howe catalog pages: septate [no catalog entry yet]
Morphology remarks: Coccospheres monomorphic, coccoliths are open tubes with internal septae (walls), extending down to proximal surface. The tube wall shows hexagonal fabric and the crystallites have radial c-axes (birefringent in plan view in LM). The fabric of the septae is not obviously different but they are non-birefringent in plan view in LM and so the calcite crystallites must have vertical c-axes.
This is a distnictive ultrastructure and although most species have been placen in Syracolithus it is quite different tothe other species tradtionally placed in Syracolithus).
Evolution & Phylogeny: Young et al. (2003) predicted that holococcolihs with this structure would proved to be closely related, and so produced by the Calcidiscaceae. However, Frada et al. (2009) showed that some of them were produced by the Pontosphaeraceae, and so this holococcolih structure has almost certainly evolved at least twice.
Biology & life-cycles: Produced in the haploid phase of Calcidiscaeae (Calcidicus leptoprus ssp. quadriperforatus) and Pontosphaeraceae (
See also: septate ;Search data:
|Tags||LITHS: flaring distally, hollow,|
|Metrics||Lith size: 1.8->4µm; |
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): at base of Ypresian Stage (0% up, 56Ma, in Ypresian stage). Data source: Total of range of species in this database
Plot of occurrence data:
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