Nannotax3 - ntax_main - Staurolithites mutterlosei

Citation: Staurolithites mutterlosei Crux, 1989

Synonyms: Bownia mutterlosei (Crux, 1989) Varol & Girgis 1994

Distinguishing features:
Parent taxon (Staurolithites): 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.
This taxon: 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.

SEM images show a non-imbricating outer, distal wall cycle, which may explain the unusual birefringence pattern. Imbrication of the outer wall cycle is a fairly conservative feature of this genus, but degrees of imbrication may vary, and for the present this species is retained in Staurolithites. Varol and Girgis (1994) proposed a new genus, Bownia, with mutterlosei as the type species

Geological Range:
Last occurrence (top): within Early Cenomanian Substage (96.24-100.50Ma, top in Cenomanian stage). Data source: Bown et al. 1998
First occurrence (base): within Early Valanginian Substage (135.70-137.70Ma, base in Valanginian stage). Data source: Bown et al. 1998

References:

Bown, P. R. (2005c). Early to Mid-Cretaceous Calcareous Nannoplankton from the Northwest Pacific Ocean, Leg 198, Shatsky Rise. Proceedings of the Ocean Drilling Program, Scientific Results. 198: 1-82. gs O

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

Crux, J. A. (1989). Biostratigraphy and palaeogeographical applications of Lower Cretaceous nannofossils from north-western Europe. In, Crux, J. A. & van Heck, S. E. (eds) Nannofossils and their applications: Proceedings of the 2nd INA Conference, London 1987. British Micropalaeontological Society Publication Series . 143-211. gs

Gale, A. S., Kennedy, W. J., Burnett, J. A., Caron, M. & Kidd, B. E. (1996). The Late Albian to Early Cenomanian succession at Mont Risou, near Rosans (Drôme, SE France): an integrated study (ammonites, inoceramids, planktonic foraminifera, nannofossils, oxygen and carbon isotopes). Cretaceous Research. 17: 515-606. gs

Kanungo, S., Bown, P. R. & Gale, A. S. (2020). Cretaceous (Albian-Turonian) calcareous nannofossil biostratigraphy of the onshore Cauvery Basin, southeastern India. Cretaceous Research. 118 [2021]: 1-22. gs

Kennedy, W. J., et al. (2000). Integrated stratigraphy across the Aptian-Albian boundary in the Marnes Bleues, at the Col de Pre _-Guittard, Arnayon (Drome), and at Tartonne (Alpes-de-Haute-Provence), France: a candidate Global Boundary Stratotype Section and Boundary Point for the base of the Albian Stage. Cretaceous Research. 21: 591-720. 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

Staurolithites mutterlosei

References:

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