Nannotax3 - ntax_mesozoic - Truncatoscaphus

Truncatoscaphus


Classification: ntax_mesozoic -> Stephanolithiales -> Stephanolithiaceae -> Truncatoscaphus
Sister taxa: Cylindralithus, Darwinilithus, Rotelapillus, Stephanolithion, Stoverius, Stradnerlithus ⟩⟨ Corollithion, Rhombolithion, Truncatoscaphus ⟩⟨ Paralithella, Rectocorona, Thurmannolithion

Distinguishing features:
Parent taxon (Stephanolithiaceae): Murolith (protolith type) coccoliths with rims of non-imbricate V-units and weakly-developed, or vestigial, proximal/inner-cycles (R-units), with central-areas spanned by one to numerous bars. 
This taxon: Polygonal (subhexagonal), often elongate and narrow; muroliths with central area spanned by a longitudinal bar and 6 or more lateral bars.


Daughter taxa (time control age-window is: 0-800Ma)
Truncatoscaphus hexaporus
Small Truncatoscaphus with central area spanned by a longitudinal bar and 4 lateral bars, delimiting 6 holes.
Truncatoscaphus octoporus
Small Truncatoscaphus with central area spanned by a longitudinal bar and 6 lateral bars (delimiting 8 holes).
Truncatoscaphus pauciramosus
Truncatoscaphus with central area spanned by a longitudinal bar and 8 lateral bars (delimiting 10 holes).
Truncatoscaphus intermedius
Elongate, narrow Truncatoscaphus with central area spanned by a longitudinal bar and 12 lateral bars.
Truncatoscaphus delftensis
Minute (<3µm), elongate Truncatoscaphus with central area spanned by a longitudinal bar and 12 or more lateral bars. Holotype material includes forms with asymmetric bar arrangement.
Truncatoscaphus macmillanii
small (<4µm) Truncatoscaphus with longitudinal bar, four diagonal bars forming central cross and additional delicate lateral bars
Truncatoscaphus sp.
Specimens not identified to species level

Taxonomy:

Citation: Truncatoscaphus Rood et al., 1971
Rank: Genus
Type species: Zygolithus delftensis Stradner & Adamiker, 1966

Taxonomic discussion:
The species are not well differentiated and the genus may be over-divided, but Perch-Nielsen (1985, 1986, p. 840) argues that there is a trend of increasing number of pores with time.

Farinacci & Howe catalog pages: Truncatoscaphus *

Distinguishing features:
Parent taxon (Stephanolithiaceae): Murolith (protolith type) coccoliths with rims of non-imbricate V-units and weakly-developed, or vestigial, proximal/inner-cycles (R-units), with central-areas spanned by one to numerous bars. 
This taxon: Polygonal (subhexagonal), often elongate and narrow; muroliths with central area spanned by a longitudinal bar and 6 or more lateral bars.


Morphology: Typically small, fragile coccoliths with narrow, elongate outline. Only present when preservation is good and so reported stratigraphic ranges are often discontinuous.

Search data:
TagsLITHS: murolith, quadrate, polygonal, CA: ca_disjunct, grill, process, CROSS-POLARS: rim-unicyclic, V-prominent,
MetricsLith size: 2->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 Turonian Stage (100% up, 89.8Ma, in Turonian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Aalenian Stage (0% up, 174.2Ma, in Toarcian 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. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 34-85. gs

Perch-Nielsen, K. (1985b). Mesozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge 329-426. gs

Perch-Nielsen, K. (1986b). New Mesozoic and Paleogene calcareous nannofossils. Eclogae Geologicae Helvetiae. 79(3): 835-847. gs V O

Rood, A. P., Hay, W. W. & Barnard, T. (1971). Electron Microscope Studies of Oxford Clay Coccoliths. Eclogae Geologicae Helvetiae. 64: 245-272. gs V O


nannotaxlogo400px

Truncatoscaphus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 28-11-2021

Taxon Search:
Advanced Search

Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11259 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics