Distinguishing features:
Parent taxon (Chiastozygaceae): Typical Eiffelithales - rim with well outer/upper clockwise-imbricate V-units and lower/inner R-units. Central area open or spanned by disjunct cross or bar supporting a spine.
This taxon: Murolith (loxolith) coccoliths with central area spanned by complex transverse structures principally constructed from two or four projections. Delicate lateral bars may also be present but are generally only seen in exceptional preservation.
Daughter taxa (time control age-window is: 0-800Ma)![]() | ||||
![]() | ![]() | Tranolithus bitraversus | ||
![]() | ![]() | Tranolithus gabalus Small murolith (loxolith) with narrow rim and central area spanned by a transverse structure formed from two projections from the rim. | ||
Tranolithus incus Species with 4 blocky rim elements extending into central area and defining anvil-shaped opening. Low bridge | ||||
![]() | Tranolithus macleodiae Projections are a pair of perforate angular blocks. | |||
![]() | ![]() | Tranolithus minimus | ||
![]() | Tranolithus orionatus Loxolith coccoliths with a transverse structure/bar composed of four lateral struts, a median granular component, and a central hollow spine base. In addition, the coccolith has a proximal grill composed of lateral bars. | |||
![]() | Tranolithus praeorionatus Medium sized (c. 5.0 µm) murolith coccolith with a transverse bar composed of four, short, triangular-shaped struts and a median granular section. The struts, which protrude from the inner rim edge, are conspicuous when the coccolith is orientated parallel to the polarising directions; the median part of the tranverse bar is only visible when the coccolith is rotated to 45°. | |||
Tranolithus salillum | ||||
Tranolithus simplex medium-sized with a narrow rim and broad central area spanned by a simple transverse bar. Unicyclic | ||||
![]() | ![]() | Tranolithus sp. Specimens not identified to species level |
Taxonomy:
Farinacci & Howe catalog pages: Tranolithus + + + + + * , Pontilithus * , Barringtonella *
Distinguishing features:
Parent taxon (Chiastozygaceae): Typical Eiffelithales - rim with well outer/upper clockwise-imbricate V-units and lower/inner R-units. Central area open or spanned by disjunct cross or bar supporting a spine.
This taxon: Murolith (loxolith) coccoliths with central area spanned by complex transverse structures principally constructed from two or four projections. Delicate lateral bars may also be present but are generally only seen in exceptional preservation.
Morphology:
LITHS: murolith, elliptical, CA: bar, process, ca_disjunct, CROSS-POLARS: V-prominent, rim-unicyclic, |
Lith size: 2->10µm; Data source notes: size range of included species |
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 Pliensbachian Stage (184.20-192.90Ma, base in Pliensbachian stage). Data source: Total of ranges of species in this database
Plot of occurrence data:
Black, M. (1972a). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 1). Palaeontographical Society Monograph. 126: 1-48. gs Bown, P. R. & Young, J. R. (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 21-36. gs Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Lower Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series . 86-131. gs O Gartner, S. (1968). Coccoliths and related calcareous nannofossils from Upper Cretaceous deposits of Texas and Arkansas. University of Kansas Paleontological Contributions, Articles. 48 (Protista 1): 1-56. 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 Perch-Nielsen, K. (1985). Mesozoic calcareous nannofossils. In, Bolli, H. M., Saunders, J. B. & Perch-Nielsen, K. (eds) Plankton Stratigraphy. Cambridge University Press, Cambridge (1): 329-426. gs Reinhardt, P. (1966). Zur Taxonomie und Biostratigraphie des fossilen Nannoplanktons aus dem Malm, der Kreide und dem Alttertiär Mitteleuropas. Freiberger Forschungshefte. C196: 5-109. gs Stover, L. E. (1966). Cretaceous coccoliths and associated nannofossils from France and the Netherlands. Micropaleontology. 12(2): 133-167. gsReferences:
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Tranolithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 18-2-2025
Short stable page link: https://mikrotax.org/Nannotax3/index.php?id=11236 Go to Archive.is to create a permanent copy of this page - citation notes |
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