Nannotax3 - ntax_main - Cretarhabdus

Nannotax3 - ntax_main - Cretarhabdus Nannotax3 - ntax_main - Cretarhabdus

Cretarhabdus

Classification: ntax_main -> Mesozoic nannofossils -> Podorhabdales -> Cretarhabdaceae -> Cretarhabdus
Sister taxa: Mattiolia, Wisea ⟩⟨ Speetonia ⟩⟨ Cruciellipsis, Flabellites, Grantarhabdus, Helenea ⟩⟨ Cretarhabdus, Retecapsa, Pickelhaube, Miravetesina

Daughter taxa (time control age-window is: 0-800Ma)
				Cretarhabdus conicus Medium to very large (7-15 µm) cretarhabdid coccoliths with a distinct central area axial cross and net.
				Cretarhabdus inaequalis Small (3-6 µm) Cretarhabdus with an irregular central grill. The bars of the grill are distinctly birefringent in XPL.
				Cretarhabdus madingleyensis Medium to large (7-12 µm) with relatively wide central area and multiple lateral bars (~4 in each quadrant).
				Cretarhabdus striatus Large to very large (9-15 µm) Cretarhabdus with distinctive wide central net that includes narrow axial cross bars and multiple narrow lateral bars. The bars of the net are birefringent.
				Cretarhabdus sp. Specimens not identified to species level

Bown&Young1997 f5 02.jpg
Bown&Young1997 f5 04.jpg
Lambert87-fig5-1.JPG

Taxonomy:

Citation: Cretarhabdus Bramlette & Martini, 1964

Taxonomic rank: genus

Type species: Cretarhabdus conicus Bramlette and Martini, 1964.

Synonyms:

Allemanites Grün in Grün & Allemann 1975
Stradneria Reinhardt (1964) (type species C. limbicrassa is a junior synonym of Cretarhabdus conicus)
Cretarhabdella Black 1971 (type species C. lateralis is a junior synonym of Cretarhabdus conicus)
Polypodorhabdus Noël, 1965 - cf. Young & Bown 2014

Taxonomic discussion: Cretarhabdus is separated from Retecapsa on the grounds of having a fine net rather than relatively few cross-bars. This is subjective and arguably not very satisfactory, but it is widely used.

Distinguishing features:
Parent taxon (Cretarhabdaceae): Regular placoliths; central-area spanned by elevated distal structure typically with cross bars and central spine.
The distal shield usuallyappers to be weakly bicyclic in the SEM, with a narrow outer-cycle and broad inner-cycle; elements usually radial and non-imbricate. LM image is moderately birefringent. V/R structure unclear.
This taxon: Cretarhabdids with central area net that often includes axial cross bars.

Farinacci & Howe catalog pages: Cretarhabdus + + * , Allemanites * , Cretarhabdella * , Polypodorhabdus * , Stradneria *

Search data:

LITHS: placolith, elliptical, CA: cross-axial, ca_disjunct, grill, process, CROSS-POLARS: rim-unicyclic, R-prominent,

Lith size: 3->15µm;
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 Maastrichtian Stage (100% up, 66Ma, in Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Oxfordian Stage (154.78-161.50Ma, base in Oxfordian 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
See also: customisable plot Parent: Cretarhabdaceae

References:

Black, M. (1971a). Coccoliths of the Speeton Clay and Sutterby Marl. Proceedings of the Yorkshire Geological Society. 38: 381-424. gs

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

Bramlette, M. N. & Martini, E. (1964). The great change in calcareous nannoplankton fossils between the Maestrichtian and Danian. Micropaleontology. 10(2): 291-322. gs

Burnett, J. A. (1998). Upper Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 132-199. gs O

Grün, W. & Allemann, F. (1975). The Lower Cretaceous of Caravaca (Spain): Berriasian Calcareous Nannoplankton of the Miravetes Section (Subbetic Zone, Prov. of Murcia). Eclogae Geologicae Helvetiae. 68: 147-211. gs O

Lambert, B. (1987). Nannofossiles calcaires de l'Albien supérieur et du Vraconnien du Cameroun méridional. Cahiers de Micropaléontologie. 2(2): 33-60. gs O

Young, J. R. & Bown, P. R. (2014). Some emendments to calcareous nannoplankton taxonomy. Journal of Nannoplankton Research. 33(1): 39-46. gs