Girvanella

Girvanella
Scientific classification
Domain: Bacteria
Phylum: Cyanobacteria
Class: Cyanophyceae
Order: Oscillatoriales
Genus: †Girvanella
Nicholson & Etheridge, 1878
Type species
Girvanella problematica
Nicholson & Etheridge, 1878 emend. Wood, 1957
Species
  • †G. kasakiensis Maslov, 1949 emend. Mamet & Roux, 1975
  • †G. problematica Nicholson & Etheridge, 1878 emend. Wood, 1957
  • †G. staminea Garwood, 1931
  • †G. wetheredii Chapman, 1908
Synonyms

Nicholsonia Korde, 1973

Girvanella is a fossil thought to represent the calcified sheath of a filamentous cyanobacterium known from the Burgess Shale[1] and other Cambrian fossil deposits.[2]

Girvanella was originally described as a foraminifera.[3] It was later assigned to the now-obsolete family porostromata.[4] In 2020, it was assigned to the order Oscillatoriales.[5]

Girvanella is characterised by having flexing, tubular filaments with a uniform diameter usually between 10 and 30 microns (rarely up to 100 microns). The walls of these tubules are relatively thick and calcareous. These tubules are typically (but not always) twisted together into nodules, and often encrust other objects including foraminifera.[3]

Fossils of Girvanella are found from the Cambrian through the Cretaceous.[3]

Girvanella fossils are found in a wide range of environmental conditions, most commonly shallow-shelf carbonate facies, but also in nonmarine limestones. Recent caliche deposts in Barbados may be referable to Girvanella.[3]

References

  1. ↑ Caron, Jean-Bernard; Jackson, Donald A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS. 21 (5): 451–65. doi:10.2110/palo.2003.P05-070R. JSTOR 20173022.
  2. ↑ Riding, R. (1975). "Girvanella and other algae as depth indicators". Lethaia. 8 (2): 173–179. doi:10.1111/j.1502-3931.1975.tb01310.x.
  3. 1 2 3 4 "Calcareous algae, Volume 4 - 1st Edition". www.elsevier.com. Retrieved 2020-09-28.
  4. ↑ Monty, C. L. (1981). Monty, Claude (ed.). "Spongiostromate vs. Porostromate Stromatolites and Oncolites". Phanerozoic Stromatolites. Berlin, Heidelberg: Springer: 1–4. doi:10.1007/978-3-642-67913-1_1. ISBN 978-3-642-67913-1.
  5. ↑ Lijing Liu; Yasheng Wu; Hongping Bao; Hongxia Jiang; Lijing Zheng; Yanlong Chen (2020). "Diversity and systematics of Middle-Late Ordovician calcified cyanobacteria and associated microfossils from Ordos Basin, North China". Journal of Paleontology. 95: 1–23. doi:10.1017/jpa.2020.82. S2CID 226349226.


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