Nannotax3 - ntax_cenozoic - Hymenomonadaceae Nannotax3 - ntax_cenozoic - Hymenomonadaceae


Classification: ntax_cenozoic -> Coccolithales -> Hymenomonadaceae
Sister taxa: Coccolithaceae, Calcidiscaceae ⟩⟨ Hymenomonadaceae, Pleurochrysidaceae

Daughter taxa (time control age-window is: 0-800Ma)Granddaughter taxa
Coccoliths with serated distal margin
Hymenomonas coronata
Hymenomonas globosa
Hymenomonas lacuna
Hymenomonas roseola
Hymenomonas krejcigrafii
Hymenomonas sp.

Murolith coccoliths with simple rim, partially calcified specimens show beaded ultrastructure.
Jomonlithus littoralis
Jomonlithus sp.

Coccoliths with well-developed basal flange and sometimes with distal flange
Ochrosphaera neapolitana
Ochrosphaera sp.


Citation: Hymenomonadaceae Senn, 1900
taxonomic rank: Family

Distinguishing features:
Parent taxon (Coccolithales): 2N: Mostly placolith heterococcoliths with V-unit forming the distal shield; R-unit the proximal shield. Non-motile
N: Form holococcoliths formed of single block, or non-calcifying

This taxon: 2N: cells motile, bearing muroliths with open central-area; proximal and distal flanges variably developed. Coccosphere large, monomorphic with many small coccoliths. Neritic. N: non-calcifying.

Farinacci & Howe catalog pages: Hymenomonadaceae


Coccoliths are goblet-shaped muroliths with open central-area (tremaliths). At the base of the coccoliths there is usually a well-developed proximal flange. At the top of the coccoliths there may be a narrow distal flange or the wall may flare. The coccoliths appear to be entirely formed of a single cycle of <20 crystal-units. In Ochrosphaera, crystal-units have steeply inclined oblique orientations (JRY unpubl obs.).
They differ from Pleurochrysidaceae by the absence of a second cycle of units.
See also Manton & Peterfi (1969), Braarud (1954).

Ecology & Biogeography

Litoral and freshwater

Biology & life-cycles
Diploid phase produces heterococcoliths, motile, haploid phase non-calcifying - see Fresnel (1994), Fresnel & Probert (2005),

Phylogenetic relations
Affinity of this family is not obvious from coccolith morphology, but molecular genetics, the life-cycle and cytological characters strongly indicate affinity with the Pleurochrysidaceae.

Search data:
Lith size: 0.8->2.5µm;
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 Miocene Epoch (5.33-23.03Ma, base in Aquitanian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:


Braarud, T. (1954). Coccolith morphology and taxonomic position of Hymenomonas roseola Stein and Syracosphaera carterae Braarud & Fagerland. Nytt Magasin for Botanikk. 3: 1-4. gs

Fresnel, J. & Probert, I. (2005). The ultrastructure and life cycle of the coastal coccolithophorid Ochrosphaera neapolitana (Prymnesiophyceae). European Journal of Phycology. 40(1): 105-122. gs

Fresnel, J. (1994). A heteromorphic life cycle in two coastal coccolithophorids, Hymenomonas lacuna and Hymenomonas coronata (Prymnesiophyceae). Canadian Journal of Botany. 72: 1455-1462. gs

Manton, I. & Peterfi, L. S. (1969). Observations on the fine structure of coccoliths, scales and protoplast of freshwater coccolithophorid Hymenomonas roseola Stein, with supplementary observations on the protoplast of Cricosphaera carterae. Proceedings of the Royal Society of London. 172: 1-15. gs

Senn, G. (1900). Chrysomonadineae. In, Engler, A. & Prantl, K. (eds) Die natürlichen Pflanzenfamilien. Engelmann, Leipzig 151-167. gs


Hymenomonadaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 23-6-2024

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