Nannotax3 - ntax_cenozoic - Hymenomonas lacuna

Hymenomonas lacuna

Classification: ntax_cenozoic -> Coccolithales -> Hymenomonadaceae -> Hymenomonas -> Hymenomonas lacuna
Sister taxa: H. coronata, H. globosa, H. lacuna, H. roseola, H. krejcigrafii, H. sp.

JRYSEM-225-40a.JPG
Young_etal_2003_hymenomonas_lacuna.JPG
Pienaar 1976 H lacuna f1.JPG
Pienaar 1976 H lacuna f2.JPG
Meier_etal_2014JNR_3-6.jpg
Pienaar 1976 H lacuna pl1A.JPG
Pienaar 1976 H lacuna pl1B.JPG
Pienaar 1976 H lacuna pl1C.JPG
Pienaar 1976 H lacuna pl1D.JPG
Pienaar 1976 H lacuna pl1E.JPG
Pienaar 1976 H lacuna pl1F.JPG
Pienaar 1976 H lacuna pl2A.JPG
Pienaar 1976 H lacuna pl2B.JPG
Pienaar 1976 H lacuna pl2C.JPG

Taxonomy:

Citation: Hymenomonas lacuna Pienaar, 1976

Rank: Species

Synonyms:

H. roseola var. marina Lefort 1975 - invalid (according to Pienaar 1976).

Taxonomic discussion: This has been regarded as a discrete species from H. globosa but it is extremely similar and close examination of the evidence suggests it is probably a junior synonym [my interpretation - JRY 2018] since:

The coccoliths from the two species are virtually identical - both in reference cultures and in the descriptions of Pienaar 1976 vs Gayral & Fresnel 1976.
The scales are identical (round body scales and elliptical baseplate scales).
The cells are identical (& cultures are typically dominated by non-motile coccolith-bearing cells with a few motile cells).
Pienaar (1976) does not discuss H. globosa so probably was not aware of it.
Both papers regard H. roseola var. marina Lefort 1975 as an (invalid) synonym.

It was, however, reported in Young et al (2003) that H. lacuna forms higher coccoliths than H. globosa, based on culture observations of I. Probert.

Distinguishing features: Coccoliths similar to H. globosa but higher and tube better developed (tube ca 0.8µm high)

Farinacci & Howe catalog pages: Hymenomonas lacuna

Size: Cells 25-30µm

Cultures: strains of this species are maintained in culture, for details see Roscoff culture collection.

Search data:

Tags	LITHS: murolith, elliptical, CA: vacant, CSPH: equant, monomorphic,
Metrics	Lith size: 1->2µm; Segments: 14->15; Coccosphere size: 15->30µm; Data source notes: RCC

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: present in the plankton (Young et al. 2003)
First occurrence (base): within No known fossil record modern (0.00-0.00Ma, base in "Holocene" stage). Data source: [JRY rough estimate]

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
(NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Hymenomonas

References:

Gayral, P. & Fresnel, J. (1976). Nouvelles observations sur deux Coccolithophoracées marines: Cricosphaera roscoffensis (P. Dangeard) comb. nov. et Hymenomonas globosa (F. Magne) comb nov. Phycologia. 15(339-355): -. gs

Lefort, F. (1975). Etude du quelques Coccolithophoracees marines rapportees aux genres Hymenomonas et Ochros_phaera. 15, 213-229. Cahiers de Biologie Marine. 1975(213-229): -. gs

Meier, K. J. S., Kinkel, H. & Young, J. R. (2014b). A note on calcareous nannoplankton from the Kieler Förde (Baltic Sea). Journal of Nannoplankton Research. 33(1): 29-37. gs V O

Pienaar, R. N. (1976). The microanatomy of Hymenomonas lacuna sp. nov. (Haptophyceae). Journal of the Marine Biological Association of the United Kingdom. 56: 1-11. gs

Young, J. R., Geisen, M., Cros, L., Kleijne, A., Probert, I. & Ostergaard, J. B. (2003). A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research, Special Issue. 1: 1-132. gs V O

Hymenomonas lacuna compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 4-3-2021

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=750 Go to Archive.is to create a permanent copy of this page - citation notes

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