Distinguishing features: Coccoliths elliptical with moderately high walls and no inner structure, dimorphic with low and high liths. Perforate wall fabric. FRESHWATER
Farinacci & Howe catalog pages: Hymenomonas prenanti + * , ,
Morphology remarks: Described by Lecal (1965) as having structure intermediate between heterococcoliths and holococcoliths. However, re-examintion of her published TEMs in light of modrn knowledge of the range of crystallite fabrics shown by holococcoliths fdoes not support this.
These holococcoliths are similar to Calcicasphaera but do correspond to any of the species described by Kleijne 1991. They are higher and less blocky than H. blokii and clearly different from the other two species.
Ecology & Biogeography: Freshwater - described from a stream in SW France
Biology & life-cycles: This is the only holococcolith we know of decribed from freshwater so it possible that it is the alternate life-cycle phase of the realtively well-known heterococcolith H. roseola.
|Tags||LITHS: holococcolith, elliptical, RIM: H: tube (Holos), CA: vacant, |
CSPH: not known, monomorphic, V-UNITS: none, R-UNITS: all, rim,
|Metrics||Lith size: 0->0µm; |
See also: Hymenomonas roseola - possible alternate life-cycle phase.;
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 stage). Data source: Total of range of species in this database
Plot of occurrence data:
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