Loxolithus


Classification: Mesozoic -> Eiffellithales -> Chiastozygaceae -> Loxolithus
Sister taxa: Amphizygus, Archaeozygodiscus, Gorkaea, Placozygus, Reinhardtites, Tranolithus, Zeugrhabdotus, Staurolithites, Diadorhombus, Rhabdophidites, Ahmuellerella, Bukrylithus, Heteromarginatus, Misceomarginatus, Monomarginatus, Neocrepidolithus, Vacherauvillius, Chiastozygus, Braloweria, Clepsilithus, Crepidolithus, Loxolithus, Tubirhabdus,

Distinguishing features: Loxolith coccoliths with broad, open central-area, probably spanned by a rarely preserved, finely perforate net


Daughter taxa: (blue => in age window 0-800Ma)
Loxolith coccoliths with broad, open central-area, probably spanned by a rarely preserved finely perforate net (e.g., see Lambert, 1993, Pl. 5, figs 1 and 2, named Millbrookia perforata therein). Typically the rim is unicyclic in XPL.
Large Loxolithus species with bicyclic rim image.
Specimens not identified to species level

Taxonomy:

Citation: Loxolithus Noël, 1965
Rank: Genus
Type species: Cyclolithus armilla Black, in Black & Barnes, 1959.
Variants: Retemediaformis Varol 1991 - similar but with grill visble in light microscope [my interpretation - JRY 2017]

Farinacci & Howe catalog pages: Loxolithus * , Retemediaformis *

Distinguishing features: Loxolith coccoliths with broad, open central-area, probably spanned by a rarely preserved, finely perforate net


Morphology remarks: This is a problematic genus since the morphlogy can be created by disolution but specimens in which the  central area is spanned by a finely perforate net have also been documented -  e.g., see Lambert, 1993, Pl. 5, figs 1 and 2, named Millbrookia perforata therein.

Geological Range:
Last occurrence (top): at top of Maastrichtian Stage (100% up, 66Ma, in Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Hauterivian Stage (0% up, 133.9Ma, in Hauterivian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Black, M. & Barnes, B. (1959). The structure of Coccoliths from the English Chalk. Geological Magazine. 96: 321-328. gs

Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs

Noël, D. (1965). Sur les Coccolithes du Jurassique Européen et d'Afrique du Nord. Éditions du Centre National de la Recherche Scientifique, Paris. -. gs

Varol, O. (1991). New Cretaceous and Tertiary Calcareous Nannofossils. Neues Jahrbuch für Geologie und Paläontologie Abhandlungen. 182: 211-237. gs


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Loxolithus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-9-2019

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=10606 Go to Archive.is to create a permanent copy of this page - citation notes



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