Axopodorhabdaceae


Ancestry: Mesozoic -> Podorhabdales -> Axopodorhabdaceae
Sister taxa: Axopodorhabdaceae, Biscutaceae, Calyculaceae, Cretarhabdaceae, Mazaganellaceae, Prediscosphaeraceae, Tubodiscaceae,

Short diagnosis: Regular placoliths; central-area, with cross-bars or perforated plate; often with tall, hollow spines.
Distal shield elements non-imbricate V-units; proximal shield and inner cycle formed from R-units. Rim often appears beaded in LM


Daughter taxa (blue => in age window 0-300Ma) Granddaughter taxa
Elliptical; central area with axial cross and tall spine

Subcircular with very high rim; central-area narrow, with grill.

Elliptical to subrectangular; central-area with coarsely-perforate net.

Elliptical; central area with one cycle of about 12 perforations and central hollow spine

Ellpitical, rim narrow rim; central area wide, spanned by multiperforate net, with or without axial cross and spine.

Elliptical; central area narrow, spanned by a transverse bar.

Elliptical; central area spanned by six broad bars delineating six large perforations, including one at each end of the central area. Central hollow spine.

Reniform; central-area net with two to numerous pores

Elliptical; central area spanned by eight bars delineating eight large perforations arranged either side of the long axis.

Eliptical; central area spanned by eight bars that delineate eight large perforations. Central hollow spine.

Elliptical; central area with one or two cycles of perforations and central hollow spine

Elliptical, rim broad; central area spanned by a granular bar supporting a broad, tall, hollow, flaring spine.

Similar to Cribrosphaerella but with perforations only in centre of central area



Ellptical; central area with diagonal cross or offset crossbars bars, supporting hollow spine

Taxonomy:

Citation: Axopodorhabdaceae Wind & Wise in Wise & Wind, 1977
Rank: Family
Type species: Axopodorhabdus Wind and Wise in Wise and Wind, 1977.

Farinacci & Howe catalog pages: Axopodorhabdaceae [no catalog entry yet]

Short diagnosis: Regular placoliths; central-area, with cross-bars or perforated plate; often with tall, hollow spines.
Distal shield elements non-imbricate V-units; proximal shield and inner cycle formed from R-units. Rim often appears beaded in LM


Morphology remarks: Placoliths with two shields and a central-area, spanned by axial cross-bars or granular plates with variable numbers of perforations; the central structure generally supports tall, hollow spines. The distal shield is formed from V-unit elements joined along radial or near-radial sutures that show little or no imbrication. The proximal shield and inner cycle (if present) are formed from R-units. LM image is generally dark, but bright inner-cycles may be visible. The image is characterised by clearly visible shield elements, often giving a 'beaded' appearance around the inner edge of the shields.
The informal term podorhabdid is useful and widely used to described the coccoliths classified together in the Axopodorhabdaceae.

Geological Range:
Last occurrence (top): within Maastrichtian Stage (66.04-72.05Ma, top in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): within Pliensbachian Stage (182.70-190.82Ma, base in Pliensbachian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Bown, P.R. & Cooper, M.K.E., (1998). Jurassic. In: Bown, P.R. (Editor), Calcareous nannofossil biostratigraphy. British Micropalaeontological Society Publication Series. Chapman & Hall, pp. 34-85.

Bown, P.R. & Young, J.R., (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research, 19(1): 21-36.

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.

Wise, S.W. & Wind, F.H., (1977). Mesozoic and Cenozoic calcareous nannofossils recovered by DSDP Leg 36 drilling on the Falkland Plateau, south-west Atlantic sector of the Southern Ocean. Initial Reports of the Deep Sea Drilling Project, 36(269-491).


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Axopodorhabdaceae compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 20-10-2017

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