Staurolithites


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

Distinguishing features: Loxolith muroliths with relatively narrow rim and wide central area spanned by axial cross bars. The cross is usually spine bearing. Inner/proximal rim cycle is variably developed and so the LM image may be unicyclic or bicyclic. NB The bicyclic/unicyclic separation is simply controlled by how far the inwards the R-units develop so, although it is a useful identification criterion, it almost certainly has no real phylogenetic significance and would be a very poor character for defining genera.


Daughter taxa: (blue => in age window 0-800Ma)
Unicyclic, no special features
Staurolithites crux
Small to medium-sized Staurolithites with a narrow rim that is not discernibly bicyclic in the LM, and an axially aligned central cross.
Staurolithites dibrachiatus
Unicyclic rim and broad, medianly split, cross-bars.
Staurolithites stradneri
Small Staurolithites with narrow rim and wide central area spanned by narrow cross bars.
Unicyclic with a distinguishing feature
Staurolithites dentatus
Staurolithites with partial grill of minor crossbars extending from the main crossbars
Staurolithites eiffellithoides
minute (<2µm long)
Staurolithites flavus
Rim unicyclic, crossbars brighter than rim and each bar behaves as a single crystal unit.
Staurolithites halfanii
Small (3-4 µm), rim unicyclic, crossbars faint, with bright spine-top
Staurolithites minutus
Small (holotype 3.7 µm) with virtually closed central area and very small cross
Staurolithites ngurumahambaensis
Small (holotype 3 µm), unicyclic, transverse bar much brighter than longitudinal bar
Staurolithites quadriarcullus
Small (2-4 µm) Staurolithites with relatively broad, tapering axial cross bars, open spine base
Staurolithites siesseri
A large species of Staurolithites (c. 8µm) with a broad, unicyclic, birefringent rim and blocky, birefringent, largely featureless axial cross
unicyclic -rotated or twisted bcrossbars
Staurolithites coroniformis
Smallish species (<6µm) with high rim and S-shaped longitudinal cross-bar
Staurolithites gausorhethium
Staurolithites with a narrow axial cross that may be slightly rotated from axial; the longitudinal bars curve as they meet the coccolith rim. Unicyclic rim image, though the rim is crossed by curving extincton lines.
Staurolithites leptostaurus
Small, delicate Staurolithites with cross bars that are rotated from axial by 30-40°. Unicyclic rim image in XPL.
bicyclic rim - simple axial cross
Staurolithites ormae
Small (3-5-4.5 µm), with bicylic rim, cross robust and strongly birefringent, without median extinction lines.
Staurolithites handleyi
Small (3-4 µm), rim bicyclic, crosbars bright in 0° position
Staurolithites laffittei
Medium sized (5-7 µm), bicyclic, with simple cross-bars
Staurolithites dorfii
Medium sized (5-6 µm), broadly elliptical with bicylic rim, wide central area and narrow crossbars.
Staurolithites lumina
Medium sized (4-6 µm), bicyclic, with broad birefringent cross bars, and narrow inner rim cycle.
bicyclic rim - axial cross with median extinction
Staurolithites imbricatus
Large (7-9 µm), narrowly elliptical, rim diffusely bicyclic rim. Both rim and cross display grey interference colours. At 45° to the polarising directions the cross bars display a distinct, median extinction line. The cross bars show patches of brighter interference colours near their junction with the rim.
Staurolithites dicandidula
Rim bicyclic, bars bright and with medial extinction line
Staurolithites mitcheneri
Small (holotype 4 µm) bicyclic Staurolithites with narrow central area filled with a narrow axial cross. The bright inner cycle is broader than the outer cycle.
bicyclic - rotated or twisted central cross
Staurolithites angustus
Large (~7 µm), Staurolithites species with bars rotated 10-20° from axial; the bars of this cross are split along their length and flare towards their juncture with the rim.
Staurolithites mutterlosei
Distinctive Staurolithites with a rim composed of two equally birefringent cycles, separated by spirally-arranged extinction gyres, and a central cross slightly rotated from axial.
Staurolithites zoensis
Medium sized (6-7 µm), bicyclic, axial cross slightly twisted.
bicyclic - large, complex central cross
Staurolithites aachenus
cross with complex structure
Staurolithites aenigma
Rim bicyclic central area with plate around the cross
Staurolithites ellipticus
Bicyclic with thick cross-bars which flare toward the centre, where they suport the base of a hollow spine.
Staurolithites elongatus
long elliptical with broad crossbars
Staurolithites integer
Broad cross almost fills central area and shows windmill-like extinction
Staurolithites mielnicensis
Bicyclic species with narrow rim, triangular feet to the crossbars give the species a distinctive LM appearance.
Staurolithites parma

Staurolithites sp.
Specimens not identified to species level

Taxonomy:

Citation: Staurolithites Caratini, 1963
Rank: Genus
Type species: Staurolithites laffittei Caratini, 1963.
Synonyms: Two names are in current use by different groups of workers: Staurolithites Caratini 1963 and Vagalapilla Bukry 1969 with the same generic concept of an Eiffelthid coccolith with an axial cross ndcentral spine  Bukry 1969 proposed Vagalapilla on the grounds that Ephippium and Staurolithites were based on different generic concepts (in Ephippium the spine extends on the proximal side whilst Caratini did not mention a spine in diagnosis of Staurolithites). This argument is incorrect, since generic concepts can be emended. Nonetheless Bukry provides a good description of the genus.

Most authors have followed Perch-Nielsen (1985, p.351) in using Staurolithites since it has priority over Vekshinella and Vagalapilla, whislt Ephippium is invalid. However de Kaenel & Bergen (1996) and more recently de Kaenel et al. (2020) have argued that because thetype species of Staurolithites, S. laffittei, is poorly described the genus should be ignored. However, the species is now in fairly common use, following the usage of Burnett (1998). Given this S. laffittei cannot be ignored and needs to be included in the generic concept, hence the correct name is Staurolithites.
Variants:
Taxonomic discussion: Numerous names have been proposed for loxolith muroliths with an axial cross but it is now accepted that Staurolithites has priority and so the various species are now conventionally placed in this genus.

Farinacci & Howe catalog pages: Staurolithites * , Ephippium * , Vekshinella + * , Vagalapilla * , Staurorhabdus * , Haslingfieldia * , Bownia * , Zygostephanos *

Distinguishing features: Loxolith muroliths with relatively narrow rim and wide central area spanned by axial cross bars. The cross is usually spine bearing. Inner/proximal rim cycle is variably developed and so the LM image may be unicyclic or bicyclic. NB The bicyclic/unicyclic separation is simply controlled by how far the inwards the R-units develop so, although it is a useful identification criterion, it almost certainly has no real phylogenetic significance and would be a very poor character for defining genera.


Morphology: Practically a form-genus for loxoliths with an axial cross, supporting a spine. Staurolithites is the oldest valid genus name proposed for loxoliths with an axial cross, and the other (widely used) genera listed below are considered synonymous.

Search data:
TagsLITHS: murolith, elliptical, CA: cross-axial, ca_disjunct, process, diagonal cross, CROSS-POLARS: rim-bicyclic, rim-unicyclic, V-prominent, R-prominent,
MetricsLith size: 3->12µm;
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 Maastrichtian stage). Data source: Total of range of species in this database
First occurrence (base): in mid part of Sinemurian Stage (47% up, 195.3Ma, in Sinemurian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Black, M. (1973). British Lower Cretaceous Coccoliths. I-Gault Clay (Part 2). Palaeontographical Society Monograph. 127: 49-112. 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

Bukry, D. (1969). Upper Cretaceous coccoliths from Texas and Europe. University of Kansas Paleontological Contributions, Articles. 51 (Protista 2): 1-79. gs V O

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

Caratini, C. (1963). Contribution à l'étude des coccolithes du Cénomanien supérieur et du Turonien de la région de Rouen. PhD thesis, Université d'Alger, Faculté des Sciences, Publication du Laboratoire de Géologique Appliquée. -. gs

de Kaenel, E. & Bergen, J. A. (1996). Mesozoic calcareous nannofossil biostratigraphy from sites 897, 899, and 901, Iberia Abyssal Plain: New biostratigraphic evidence. Proceedings of the Ocean Drilling Program, Scientific Results. 149: 27-59. gs V 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 V O

Loeblich, A. R. & Tappan, H. (1963). Type fixation and validation of certain calcareous nannoplankton genera. Proceedings of the Biological Society of Washington. 76: 191-198. gs

Noël, D. (1973). Nannofossiles calcaires de sédiments jurassiques finement laminés. Bulletin du Muséum National d'Histoire Naturelle. 75: 95-156. 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

Varol, O. & Girgis, M. (1994). New taxa and taxonomy of some Jurassic to Cretaceous calcareous nannofossils. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 192: 221-253. gs

Vekshina, V. N. (1959). Coccolithophoridae of the Maastrichtian deposits of the West Siberian lowlands. Trudyi Instituta Geologii i Geogiziki, Sibiriskoe Otlodelenie, Akademiya Nauk SSSR (Nauka) Moscow. 2: 56-81. gs

Missing or ambiguous references: de Kaenel et al. 2020;


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Staurolithites compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 22-1-2021

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Short stable page link: http://mikrotax.org/Nannotax3/index.php?id=11108 Go to Archive.is to create a permanent copy of this page - citation notes



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