Nannotax3 - ntax_mesozoic - Staurolithites

Nannotax3 - ntax_mesozoic - Staurolithites Nannotax3 - ntax_mesozoic - Staurolithites

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, C. - unidentified

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: 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 (time control age-window is: 0-800Ma)
				Staurolithites dibrachiatus Unicyclic rim and broad, medianly split, cross-bars.
				Staurolithites stradneri Small unicyclic 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

Bown&Young1997 f1 07.jpg

Taxonomy:

Citation: Staurolithites Caratini, 1963

Taxonomic rank: genus

Type species: Staurolithites laffittei Caratini, 1963.

Synonyms:

Ephippium Vekshina 1959 [type species unrecognisable and genus is a homonym of other (non-coccolith) genera, see Loeblich & Tappan 1963]
Vekshinella Loeblich and Tappan, 1963, emend Gartner 1968 [replacement name proposed for Ephippium, but as noted the type species is unrecognisable and Staurolithites has priority according to Perch-Nielsen 1985]
Vagalapilla Bukry, 1969 [alternative name propsed on basis that the generic concepts of Ephippium and Staurolithites were incompatble with
Staurorhabdus Noël, 1973 [similar to Staurolithites but with a higher rim. This generic distinction has not been considered useful so the genus has been considered a junior synonym].
Haslingfieldia Black, 1973 [imilar to Staurolithites but with a additional lateral bars in the central area. This generic distinction has not been considered useful so the genus has been considered a junior synonym.]
Zygostephanos Hoffmann 1970 [name proposed for a genus to include all loxolith coccoliths, based on a good description of the wall structure, irrespective of central structure (i.e. broadly equivalent to the entire Chiastozygaceae as currently recognised). The genus would have included the types of several other genera and so was superfluous.]

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:

Bownia Varol & Girgis (1994) - bicyclic (see Staurolithites mutterlosei for discussion)

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 *

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:

LITHS: murolith, elliptical, CA: cross-axial, diagonal cross, process, ca_disjunct, CROSS-POLARS: R-prominent, V-prominent, rim-bicyclic, rim-unicyclic,

Lith 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 Danian stage). Data source: Total of ranges of the species in this database
First occurrence (base): within Late Sinemurian Substage (192.90-196.30Ma, base in Sinemurian 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
Neptune data: This is a higher taxon page so Neptune data is not plotted. See also: customisable plot Parent: Chiastozygaceae

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 O

Bown, P. R. & Young, J. R. (1997). Mesozoic calcareous nannoplankton classification. Journal of Nannoplankton Research. 19(1): 21-36. gs

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

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

de Kaenel, E. & Bergen, J. A. (1996b). 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 O

De Kaenel, E., Mojon, P. -O. & Pictet, A. (2020). New biostratigraphical data (calcareous nannofossils, ammonites) and Early to Late Barremian transition in the Urgonien Jaune facies and Marnes de la Russille complex of the Swiss Jura Mountains. Swiss Journal of Palaeontology. 139(6): 1-43. 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

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, Paris. 75 [1972]: 95-156. gs

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

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: ;