Ctenis

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Ctenis
Temporal range: Triassic to Eocene
Ctenis nilsonii.jpg
Scientific classification
Kingdom:
Plantae
(unranked):
Cycadophyta
(unranked):
Cycadopsida
Order:
Cycadales
Genus:
Ctenis

Lindley & Hutton 1834[1]
Species
  • C. sulcicaulis(Type species)
  • C. clarnoensis
  • C. coronata
  • C. exilis
  • C. harrisii
  • C. kaneharai
  • C. latepinnata
  • C. laxa
  • C. lyrata
  • C. mallards
  • C. minuta
  • C. nathorsti
  • C. nilssonii
  • C. stanovensis
  • C. stewartiana

Ctenis is a genus of fossil foliage attributable to the Cycadales, being one of the most common genera of cycad fossil leaves in the Mesozoic.

Taxonomy[]

The genus was first erected by Lindley and Hutton in "The fossil flora of Great Britain",[2] based on material of Ctenis falcata from the Jurassic of Yorkshire. This species was later synonimized with Cycadites sulcicaulis, leading to the new combination Ctenis sulcicaulis[3]. Later, Seward,[4] Florin, and Harris[5] added details of the cuticle to the diagnosis of the genus.

Description[]

The leaves of Ctenis are once pinnate, and the pinnae have multiple parallel veins that often anastomosize (i.e. fuse together).[6][7] The cuticle of Ctenis has stomata with guard cells arranged in a random fashion, and the stomatal apparatus has often a cuticular ring surrounding the stomatal pit. The cuticular surface is usually striate.

Distribution[]

Though Ctenis-like leaves are known from the Late Permian Umm Irna Formation of Jordan,[8] Ctenis becomes more common from the Late Triassic onwards. In the Jurassic, many Ctenis species are retrieved from Europe, North America, and Asia.[9][6] In the Early Cretaceous, Ctenis is still found in Europe (i.e. in the Wealden[10]) and Asia,[11] but from the Late Cretaceous it seems to retreat to more Northern Latitudes in the Siberian region[12] and North America[13] and Southern latitudes in Australia. The last members of this genus are found in the Eocene of North America.[7]

Paleoecology[]

Little is known about the ecology of the Ctenis-producing plants. However, in the locality in Wyoming (Campanian), Ctenis is found in the fern wetland together with ferns from the Dipteridaceae, Gleicheniaceae, and Matoniaceae.[14] This suggests that at least some members of the genus inhabited wet environments with peaty soils.

References[]

  1. ^ Lindley, J. and Hutton, W., 1834. The Fossil Flora of Great Britain, Vol. 2. Ridgway & Sons, London.
  2. ^ Hutton, William; Lindley, John (1831). The fossil flora of Great Britain; or, Figures and descriptions of the vegetable remains found in a fossil state in this country /. London: J. Ridgway. doi:10.5962/bhl.title.102097.
  3. ^ www.fossilplants.info http://www.fossilplants.info/species.htm?id=F456DA84-C91F-E4E8-0FD9-30BA84286650. Retrieved 2021-01-09. Missing or empty |title= (help)
  4. ^ Seward, A. C. (1898). Fossil plants; a text-book for students of botany and geology, by A. C. Seward. Cambridge: Cambridge University Press. doi:10.5962/bhl.title.21744.
  5. ^ Harris, Thomas Maxwell; Miller, José; Millington, Wendy (1961). The Yorkshire Jurassic flora. London: BM(NH). doi:10.5962/bhl.title.118957.
  6. ^ a b Harris, Thomas Maxwell (1964). The Yorkshire Jurassic flora. Vol.2: Caytoniales, Cycadales, and Pteridosperms. London: BM(NH). doi:10.5962/bhl.title.118957.
  7. ^ a b Erdei, Boglárka; Manchester, Steven R. (2015-01-01). "Ctenis clarnoensis sp. n., an Unusual Cycadalean Foliage from the Eocene Clarno Formation, Oregon". International Journal of Plant Sciences. 176 (1): 31–43. doi:10.1086/678467. ISSN 1058-5893. S2CID 85225125.
  8. ^ Blomenkemper, Patrick; Kerp, Hans; Abu Hamad, Abdalla; DiMichele, William A.; Bomfleur, Benjamin (2018-12-21). "A hidden cradle of plant evolution in Permian tropical lowlands". Science. 362 (6421): 1414–1416. Bibcode:2018Sci...362.1414B. doi:10.1126/science.aau4061. ISSN 0036-8075. PMID 30573628.
  9. ^ Kimura, Tatsuaki; Sekido, Shinji (1972). "Ctenis species from the Itoshiro sub-group (Lower Cretaceous), the Tetori group, central Honshu, Japan". Transactions and Proceedings of the Paleontological Society of Japan. New Series. 86: 360–368.
  10. ^ Watson, Joan; Alvin, Kenneth L. (February 1996). "An English Wealden floral list, with comments on possible environmental indicators". Cretaceous Research. 17 (1): 5–26. doi:10.1006/cres.1996.0002.
  11. ^ Bugdaeva, E. V.; Markevich, V. S. (December 2009). "The coal-forming plants of rhabdopissites in the Lipovtsy coal field (Lower Cretaceous of Southern Primorye)". Paleontological Journal. 43 (10): 1217–1229. doi:10.1134/S0031030109100049. ISSN 0031-0301. S2CID 140675460.
  12. ^ Vakhrameev, V.A. (January 1987). "Climates and the distribution of some gymsosperms in Asia during the Jurassic and Cretaceous". Review of Palaeobotany and Palynology. 51 (1–3): 205–212. doi:10.1016/0034-6667(87)90030-3.
  13. ^ Wing, Scott L.; Hickey, Leo J.; Swisher, Carl C. (May 1993). "Implications of an exceptional fossil flora for Late Cretaceous vegetation". Nature. 363 (6427): 342–344. Bibcode:1993Natur.363..342W. doi:10.1038/363342a0. ISSN 0028-0836. S2CID 4349769.
  14. ^ "Wing - Big Cedar Ridge". naturalhistory2.si.edu. Retrieved 2021-04-29.
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