Helicosphaera HOL dalmaticus type


Classification: Coccolithophores -> Holococcoliths -> flat-topped -> Helicosphaera HOL -> Helicosphaera HOL dalmaticus type
Sister taxa: H. HOL catilliferus type, H. HOL confusus type, H. HOL dalmaticus type, H. HOL ponticuliferus type,

Distinguishing features: Liths with open centre spanned by broad central mound from which 4-6 irregular ridges radiate defining pores.


Taxonomy:

Citation: Helicosphaera HOL dalmaticus type informal
Rank: Form
Basionym: Syracosphaera dalmatica Kamptner 1927
Synonyms:
Notes & discussion: Nomenclature here follows Young & Bown (2014)

Farinacci & Howe catalog pages: Syracosphaera dalmatica *

Distinguishing features: Liths with open centre spanned by broad central mound from which 4-6 irregular ridges radiate defining pores.


Morphology remarks: Outer part of disk similar to S. catilliferus, inner part appears to be open, but spanned by the central mound with 4-6 irregular ridges radiating from this to define pores. Distinct central opening on proximal side, and it is likely that beneath the central mound a cavity extends to the proximal surface. Differentiation of this taxon from confusus is discussed at length in Kleijne 1991.

Size: Liths 2-3 µm long; disk 6-7 crystallites high

Biology & life-cycles: Possible combination coccosphere with H. wallichii HET was observed by Young & Geisen 2002, and a rather more likely combination coccosphere with H. pavimentum HET observed by Triantaphyllou et al. 2016. 
A further combination cocccosphere of H. pavimentum and S. dalmaticus is shown here, from the research collection of Dr. Jasna Arapov (Inst Oceanography & Fisheries, Croatia). This strongly supports the life-cycle association of the two species, so the taxonomy now needs to be revised. [my interpretation - JRY 2019]

Search data:
TagsLITHS: holococcolith, H: disk-like, RIM: H: base flangeless, H: tube (Holos), CA: H: distal-cover, H: distal-cover-flat, H: fabric-rhomboid, pores, PROCESS: conical,
CSPH: spherical, monomorphic, V-UNITS: none, R-UNITS: all, DETAILS: 1ou,
MetricsLith size: 2.4->3.3µm; Coccosphere size: 10->12µm; Liths per sphere: 45->100
Sources: morphom data from Yang & Wei (2003), Cros & Fortuño (2002) & Kleijne 1991
The morphological data given here can be used on the advanced search page. See also these notes

See also: Helicosphaera wallichii ;Helicosphaera pavimentum ;

Geological Range:
Last occurrence (top): Extant Data source: present in the plankton (Young et al. 2003)
First occurrence (base): within Quaternary Period (0.00-2.59Ma, base in Gelasian stage). Data source: [JRY rough estimate]

Plot of occurrence data:

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

    References:

    Kamptner, E., (1927). Beitrag zur Kenntnis adriatischer Coccolithophoriden. Archiv für Protistenkunde, 58: 173-184.GS

    Kleijne, A., (1991). Holococcolithophorids from the Indian Ocean, Red Sea, Mediterranean Sea and North Atlantic Ocean. Marine Micropaleontology, 17: 1-76.GS

    Loeblich, A.R. & Tappan, H., (1963). Type fixation and validation of certain calcareous nannoplankton genera. Proceedings of the Biological Society of Washington, 76: 191-198.GS

    Okada, H. & McIntyre, A., (1977). Modern coccolithophores of the Pacific and North Atlantic Oceans. Micropaleontology, 23(1): 1-55.GS

    Triantaphyllou, M.; Karatsolis, B.; Dimiza, M.D.; Malinverno, E.; Cerino, F.; Psarra, S.; Jordan, R.W. & Young, J.R., (2016). Coccolithophore combination coccospheres from the NE Mediterranean Sea: new evidence and taxonomic revisions. Micropaleontology, 61(6): 457-472.GS

    Winter, A.; Reiss, Z. & Luz, B., (1979). Distribution of living coccolithophore assemblages in the Gulf of Elat ('Aqaba). Marine Micropaleontology, 4: 197-223.GS

    Young, J.R. & Bown, P.R., (2014). Some emendments to calcareous nannoplankton taxonomy. Journal of Nannoplankton Research, 33(1): 39-46.GS

    Young, J.R. & Geisen, M., (2002). Xenospheres – associations of coccoliths resembling coccospheres. Journal of Nannoplankton Research, 24(1): 27-35.GS


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    Helicosphaera HOL dalmaticus type compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 24-2-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=665 Go to Archive.is to create a permanent copy of this page - citation notes



    Comments (1)

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    Ines Galovic (Zagreb, Croatia)

    This is also characteristic Paratethyan species for mid-Miocen (Badenian) of Slovenia, Croatia and Romania (our article).

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