Percivalia dunkleyjonesii

Classification: Mesozoic -> Eiffellithales -> Rhagodiscaceae -> Percivalia -> Percivalia dunkleyjonesii
Sister taxa: P. arata, P. bullata, P. dunkleyjonesii, P. fenestrata, P. hauxtonensis, P. howardii, P. imperfossa, P. pearsonii, P. pontilitha, P. porosa, P. nebulosa, P. sp.,

Distinguishing features: Central area filled by indistinct cross transverse bar of which apears as "bright buttons"


Citation: Percivalia dunkleyjonesii Lees, 2007
Rank: Species

Farinacci & Howe catalog pages: Percivalia dunkleyjonesii *

Distinguishing features: Central area filled by indistinct cross transverse bar of which apears as "bright buttons"

Morphology remarks: This medium-sized species possesses a narrow, bicyclic rim and a central plate of laterally-oriented laths at the centre of which is an indistinct cross. This axial cross has two distinctive ‘buttons’, outlined by dark extinction lines, making up the short-axis bars. The ‘buttons’ are visible when the coccolith is oriented both at 0 ̊ and 45 ̊. The entire central area shows low birefringence.
Differentiation: This new species is distinguished from all other Percivalia species by the distinctive ‘buttons’ and central-area laths.
Remarks: The rim and inner cycle of this species are somewhat reminiscent of Percivalia, although scanning electron microscopy is needed to confirm the generic assignment." [Lees 2007]

Size: Holotype dimensions: L = 6.82μm, W = 4.84μm.

Search data:
TagsLITHS: murolith, elliptical, CA: plate, closed, R-UNITS: R-prominent, DETAILS: rim-unicyclic,
MetricsLith size: 6->8µm;
Sources: holotype +/-1µm
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within Cenomanian Stage (93.90-100.50Ma, top in Cenomanian stage). Data source: Lees 2007 (original description)
First occurrence (base): within Turonian Stage (89.77-93.90Ma, base in Turonian stage). Data source: Lees 2007 (original description)

Plot of occurrence data:

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


    Lees, J. A. (2007). New and rarely reported calcareous nannofossils from the Late Cretaceous of coastal Tanzania: outcrop samples and Tanzania Drilling Project Sites 5, 9 and 15. Journal of Nannoplankton Research. 29(1): 39-65. gs :: view :: open


    Percivalia dunkleyjonesii compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 4-6-2020

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