Nannotax3 - ntax_main - Zygodiscaceae

Nannotax3 - ntax_main - Zygodiscaceae Nannotax3 - ntax_main - Zygodiscaceae

Zygodiscaceae

Classification: ntax_main -> Zygodiscales -> Zygodiscaceae
Sister taxa: Helicosphaeraceae, Pontosphaeraceae, Zygodiscaceae

Daughter taxa (time control age-window is: 0-800Ma)		Granddaughter taxa
	R-units well-developed
	Lophodolithus Modified muroliths with high walls (higher at one end and forming an asymmetric flange) and wide central area usually spanned by a disjunct, complex tranverse bar.	Lophodolithus acutus Lophodolithus luntii Lophodolithus mochlophorus Lophodolithus mytiliformis Lophodolithus nascens Lophodolithus reniformis Lophodolithus rotundus Lophodolithus sp.
	Neochiastozygus Muroliths with well-developed V- and R-units and diagonal or asymmetric cross in central-area.	Neochiastozygus alabamaensis Neochiastozygus denticulatus Neochiastozygus tenansa Neochiastozygus cf. imbriei Neochiastozygus concinnus Neochiastozygus digitosus Neochiastozygus distentus Neochiastozygus modestus Neochiastozygus pusillus Neochiastozygus substrictus Neochiastozygus junctus Neochiastozygus macilentus Neochiastozygus perfectus Neochiastozygus rosenkrantzii Neochiastozygus sp.
	Zygodiscus Muroliths with well-developed V- and R-units and transverse bar in central-area. LM image is dominated by bright, broad R-unit inner cycle; V-unit cycle is narrow.	Zygodiscus adamas Zygodiscus cearae Zygodiscus clausus Zygodiscus herlyni Zygodiscus multiforus Zygodiscus plectopons Zygodiscus segmentatus Zygodiscus sheldoniae Zygodiscus sp.
	Jakubowskia Elliptical murolith with narrow rim and wide vacant central area.	Jakubowskia leoniae Jakubowskia sp.
	R-units vestigial, central structures septa extending through the coccolith
	Chiphragmalithus Muroliths with very high wall (similar to coccolith width) and well-developed central-area cross. V-unit cycle dominates and results in a moderately birefringent unicyclic LM image.	Chiphragmalithus acanthodes Chiphragmalithus armatus Chiphragmalithus barbatus Chiphragmalithus calathus Chiphragmalithus muzylevii Chiphragmalithus vandenberghei Chiphragmalithus sp.
	Isthmolithus Narrowly elliptical to oblong (or parallelogram-like), relatively high muroliths with one or two transverse bars. R-unit relict or absent and so LM image is unicyclic.	Isthmolithus recurvus Isthmolithus rhenanus Isthmolithus unipons Isthmolithus sp.
	Neococcolithes Muroliths with diagonal to H-shaped cross bars. R-unit relict or absent and so LM image is unicyclic.	Neococcolithes dubius Neococcolithes lososnensis Neococcolithes minutus Neococcolithes nudus Neococcolithes protenus Neococcolithes purus Neococcolithes radiatus Neococcolithes sp.
	Davidhakania Like Neococcolithes, but with diagonal cross, R-unit present but small.	Davidhakania eosaepes Davidhakania imbriei Davidhakania partingtonii Davidhakania saepes
	Nannotetrina Typically large (>8 µm) cruciform nannoliths with high curving ridges running from the centre to ray tips.	Nannotetrina spinosa Nannotetrina pappii Nannotetrina fulgens Nannotetrina alata Nannotetrina cristata Nannotetrina plana Nannotetrina ruda Nannotetrina sp.

Romein 1979 fig48.png
BownNewsam-2017-fig3.jpg

Taxonomy:

Citation: Zygodiscaceae Hay & Mohler 1967

Taxonomic rank: family

Synonyms:

Zygodiscaceae * Hay & Mohler 1967

Distinguishing features:
Parent taxon (Zygodiscales): 2N: Heterococcoliths with V-units forming upper/outer cycle of imbricated elements and R-units forming basal plate and central mass of irregular elements. Usually motile
N: Form holococcoliths formed of single block
This taxon: Muroliths with rim formed from well-developed V- and variably developed R-units, with opposite imbrication directions, and central area structures that include disjunct transverse bars and diagonal crosses. R-units vestigial or not observed in several genera (Chiphragmalithus, Isthmolithus, Neococcolithes).

Morphology:

Muroliths with rim formed from well-developed V- and variably developed R-units, with opposite imbrication directions, and central area structures that include disjunct transverse bars (Zygodiscus, Lophodolithus) and diagonal crosses (Neochiastozygus, Neococcolithes, Chiphragmalithus).
R-units are vestigial or absent in several genera (Chiphragmalithus, Isthmolithus, Neococcolithes, Nannotetrina) and in these genera the central structures are formed of vertical septa that extend from the proximal surface to the distal surface and often protrude above the wall. The nannolith Nannotetrina was long suspected to be related to this group (Bramlette & Sulivan 1961, Perch-Nielsen 1985), by further reduction of the rim and expansion of the central structure, and this was demonstrated by Bown & Newsam (2017) through lineage study in well-preserved material from IODP expedition 342. Outer rim shows anti-clockwise imbrication, inner rim clockwise imbrication. These imbrication directions, and the closer spaced elements, distinguish them from the Mesozoic Eiffelithales.

Size:

Coccoliths vary in size from small to very large, mostly medium to large size and including some taxa producing very big coccoliths (e.g. Nannotetrina, Lophodolithus).

Search data:

Lith size: 3->30µm;

The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of Oligocene Epoch (100% up, 23Ma, in Aquitanian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NP1 zone (65.47-66.04Ma, base in Danian stage). Data source: Total of ranges of species in this database

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. Parent: Zygodiscales

References:

Aubry, M. -P. (1990). Handbook of Cenozoic calcareous nannoplankton. Book 4: Heliolithae (Helicoliths, Cribriliths, Lopadoliths and others). Micropaleontology Press, American Museum of Natural History, New York. 1-381. gs

Bown, P. R. & Newsam, C. (2017). Calcareous nannofossils from the Eocene North Atlantic Ocean (IODP Expedition 342 Sites U1403–1411). Journal of Nannoplankton Research. 37(1): 25-60. gs O

Bramlette, M. N. & Sullivan, F. R. (1961). Coccolithophorids and related nannoplankton of the Early Tertiary in California. Micropaleontology. 7(2): 129-188. gs

Hay, W. W. & Mohler, H. P. (1967). Calcareous nannoplankton from Early Tertiary rocks at Point Labau, France and Paleocene-Early Eocene correlations. Journal of Paleontology. 41(6): 1505-1541. gs

Perch-Nielsen, K. (1985). Cenozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge (1): 427-555. gs

Romein, A. J. T. (1979). Lineages in Early Paleogene calcareous nannoplankton. Utrecht Micropaleontological Bulletin. 22: 1-231. gs O

Zygodiscaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 19-8-2026

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Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=1514 Go to Archive.is to create a permanent copy of this page - citation notes

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