Nannotax3 - ntax_mesozoic

Nannotax3 - ntax_mesozoic - Crucirhabdus Nannotax3 - ntax_mesozoic - Crucirhabdus

Crucirhabdus

Classification: ntax_mesozoic -> Stephanolithiales -> Parhabdolithaceae -> Crucirhabdus
Sister taxa: Bucanthus, Calcivascularis, Crucirhabdus, Diductius, Mitrolithus, Parhabdolithus, Timorella, Umbria

Distinguishing features:
Parent taxon (Parhabdolithaceae): Murolith (protolith type) coccoliths with bicylic rims and central-areas spanned by an axial-cross or transverse bar bearing a broad, often long, spine.
This taxon: Protolith coccoliths with low, sloping rim; central area wide with axial cross supporting a tall spine

Daughter taxa (time control age-window is: 0-800Ma)
				Crucirhabdus minutus Minute Crucirhabdus with relatively narrow central area and broad axial cross. In XPL the transverse bars appears as two birefringent dots filling the central area, and the longitudinal bars are inconpicuous.
				Crucirhabdus primulus Crucirhabdus with relatively low, narrow rim and wide central area spanned by axial cross bars. Additional lateral bars may be present, probably dependent on preservation state. A tall, hollow spine rises from the centre of the cross bars.
				Crucirhabdus sp. Specimens not identified to species level

Bown&Young1997 f2 10.jpg

Taxonomy:

Citation: Crucirhabdus Rood et al., 1973

taxonomic rank: Genus

Type species: Crucirhabdus primulus Rood et al., 1973

Synonyms: Apertius Goy, in Goy et al. 1979 [type species A. dorei is synonym of C. primulus cf. Bown 1987]

Farinacci & Howe catalog pages: Crucirhabdus + + * , Apertius *

Morphology:

Protolith coccoliths with low, sloping rim and relatively wide central area spanned by a tall-spine-bearing axial cross, with or without additional lateral bars. Bicyclic rim image in XPL.

Search data:

LITHS: murolith, elliptical, CA: cross-axial, ca_disjunct, process, CROSS-POLARS: rim-bicyclic, V-prominent, R-prominent,

Lith size: 1.5->6.5µm;
Data source notes: size range of included species

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 NJ5b subzone (100% up, 183.5Ma, in Toarcian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within NT2b subzone (194.83-218.41Ma, base in Norian 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
Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: Parhabdolithaceae

References:

Bown, P. R. & Cooper, M. K. E. (1998). Jurassic. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 34-85. gs O

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

Goy, G., Noël, D. & Busson, G. (1979). Les conditions de sédimentation des schistes-carton (Toarcien inf.) du bassin de Paris déduites de l'étude des nannofossiles calcaires et des diagraphies. Document des Laboratoires de Géologie de la Faculté des Sciences de Lyon. 75: 33-57. gs O

Rood, A. P., Hay, W. W. & Barnard, T. (1973). Electron microscope studies of Lower and Middle Jurassic coccoliths. Eclogae Geologicae Helvetiae. 66: 365-382. gs O