Zeugrhabdotus diplogrammus


Classification: Mesozoic -> Eiffellithales -> Chiastozygaceae -> Zeugrhabdotus -> Zeugrhabdotus diplogrammus
Sister taxa: Z. acanthus, Z. angelozziae, Z. bicrescenticus, Z. biperforatus, Z. blowii, Z. burolletii, Z. burwellensis, Z. clarus, Z. cooperi, Z. diplogrammus, Z. elegans, Z. embergeri, Z. erectus, Z. fissus, Z. fluxus, Z. howei, Z. kerguelenensis, Z. noeliae, Z. petrizzoae, Z. praesigmoides, Z. reticulatus, Z. scutula, Z. sigmoides, Z. simplex, Z. sisyphus, Z. streetiae, Z. trivectis, Z. xenotus, Z. sp.,

Short diagnosis: Zeugrhabdotus with a bipartite transverse bar which is bright in XPL at the 0° position, darkest at 60°, but which is generally visible throughout rotation. Unicyclic rim image in XPL.


Taxonomy:

Citation: Zeugrhabdotus diplogrammus (Deflandre in Deflandre & Fert, 1954) Burnett in Gale et al., 1996
Rank: Species
Basionym: Zygolithus diplogrammus Deflandre in Deflandre & Fert, 1954
Synonyms:

Farinacci & Howe catalog pages: Zygolithus diplogrammus * Zygolithus stenopus *

Short diagnosis: Zeugrhabdotus with a bipartite transverse bar which is bright in XPL at the 0° position, darkest at 60°, but which is generally visible throughout rotation. Unicyclic rim image in XPL.


Morphology remarks: Z. bicrescenticus is very simlar but smaller and with a narrow central area. [my interpretation - JRY 2017]

Geological Range:
Notes: LAD in S England in Santonian, UC12 (Burnett 1998)
Last occurrence (top): within Campanian Stage (72.05-83.64Ma, top in Campanian stage). Data source: Burnett 1998
First occurrence (base): within Early Valanginian Substage (136.41-139.39Ma, base in Valanginian stage). Data source: Bown et al. 1998

Plot of occurrence data:

References:

Bown, P.R.; Rutledge, D.C.; Crux, J.A. & Gallagher, L.T., (1998). Early Cretaceous. In: Bown, P.R. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 86-131.

Burnett, J.A., (1998). Upper Cretaceous. In: Bown, P.R. (Editor), Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publications Series. Chapman & Hall, London, pp. 132-199.

Deflandre, G. & Fert, C., (1954). Observations sur les coccolithophoridés actuels et fossiles en microscopie ordinaire et électronique. Annales de Paléontologie, 40: 115-176.

Gale, A.S.; Kennedy, W.J.; Burnett, J.A.; Caron, M. & Kidd, B.E., (1996). The Late Albian to Early Cenomanian succession at Mont Risou, near Rosans (Drôme, SE France): an integrated study (ammonites, inoceramids, planktonic foraminifera, nannofossils, oxygen and carbon isotopes). Cretaceous Research, 17: 515-606.

Verbeek, J.W., (1977). Calcareous nannoplankton biostratigraphy of Middle and Upper Cretaceous deposits in Tunisia, southern Spain and France. Utrecht Micropaleontological Bulletins, 16: 1-157.


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Zeugrhabdotus diplogrammus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 15-12-2017

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Comments (1)

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Zainab

How to differentiate between small forms of this species and Z. bicrescenticus ?

In picture no. 14 (PospWiseLeg113-Maas-Pl9-Fig3a-b), it looks like T. orionatus? or does Z. diplogrammus has this feature when rotated under the LM?

Thanks

Gravatar
Jeremy Young (UK)

Zainab

Good question - I needed to check details before answering but you are right the image from Pospichal & Wise (1990) is not Z. diplogrammus so I am removing it. Z. bicrescenticus and Z. diplogrammus are very similar - with diplogrammus being larger and with a more open central area - but I am not sure if a clear separation has been defined.

Jeremy

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