Discoaster virginianus


Classification: Coccolithophores -> Discoasterales -> Discoasteraceae -> Discoaster -> D. musicus group -> Discoaster virginianus
Sister taxa: D. sanmiguelensis, D. ulnatus, D. patulus, D. musicus, D. carneyi, D. virginianus, D. transitus, D. micros, D. arneyi, D. premicros,

Daughter taxa: Variants described by de Kaenel et al. 2017 (blue => in age window 0-800Ma)
Like D. virginianus but with no free rays
Like D. virginianus but with short free rays

Taxonomy:

Citation: Discoaster virginianus (Self-Trail 2014) de Kaenel & Bergen, in de Kaenel et al. 2017
Rank: Species
Basionym: Catinaster virginianus Self-Trail 2014
Variants: The forms D. catinatus and D. gamberi were separated by de Kaenel et al. (2017) on the basis of free ray length. These forms clearly intergrade and were all included within the original species concpet of Self-Trail (2014).
Notes & discussion: Recombined into Discoaster by de Kaenel et al. (2017) on the grounds that this is homoeomorph of Catinaster, which evolved from Discoaster musicus in the middle Miocene.

Distinguishing features: small to medium sized Catinaster-like species with stem on both proximal and distal sides

Farinacci & Howe catalog pages: Catinaster virginianus + *


Evolution & Phylogeny: Self-Trail (2014) noted that various authors had recorded Catinaster-like specimens in NN5 and documented common occurrence of small to medium Catinaster in sediments from Virginia dated to NN5-8. She concluded that this was likely an ancestral species with limited geographical occurrence. Bergen et al (2017) provide the alternative interpretation that these are unrelated forms which evolved from D. musicus by reduction of the rays (NB Paleo-Alampay et al. 1998 describe and illustrate two alternative evolutionary pathways from Discoaster to Catinaster either by contraction of rays and fusion of the bifurcations to form a cup or by loss of ffree-rays leaving only the central area. The latter trend apears to have formed D. virginianus and the former true Catinaster).

Search data:
TagsLITHS: nannolith-radiate, N: basket-like, RIM: tips-bifurcate,
CSPH: not known, V-UNITS: all, R-UNITS: none, DETAILS: 1ou,
MetricsLith size: 4.5->8┬Ám; Segments: 6->6;
Sources: size from OD
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): within NN8 zone (10.55-10.89Ma, top in Tortonian stage). Data source: original description
First occurrence (base): within NN5 zone (13.53-14.91Ma, base in Langhian stage). Data source: 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: D. musicus group

    References:

    de Kaenel, E., Bergen, J. A., Browning, E., Blair, S. A. & Boesiger, T. M. (2017). Uppermost Oligocene to Middle Miocene Discoaster and Catinaster taxonomy and stratigraphy in the circum North Atlantic Basin: Gulf of Mexico and ODP Leg 154. Journal of Nannoplankton Research. 37(2-3): 215-244. gs

    Self-Trail, J. (2014). Catinaster virginianus sp. nov.: A new species of Catinaster from the middle miocene Mid-Atlantic Coastal Plain. Journal of Nannoplankton Research. 33(1): 49-57. gs


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    Discoaster virginianus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 20-10-2019

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    Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=244 Go to Archive.is to create a permanent copy of this page - citation notes



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