Cosmochlaina
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| Cosmochlaina Fossil range: Upper Silurian - lowermost Devonian |
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 Cuticle of Cosmochlaina , retrieved from the Burgsvik beds by acid maceration
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Cosmochlaina (from Greek: kosmos=ornament; xlaina=wrapper/cloak) is a form genus of nematophyte - an early (Siluran - Devonian) plant known only from fossil cuticles,[3] often found in association with tubular structures.[4] Where Nematothallus is sometimes used to relate only to tube-like structures, Cosmochlaina refers to the cuticle fragments. The form genus was put forwards by Dianne Edwards, and is diagnosed by inwards-pointing flanges and randomly oriented pseudo-cellular units.[5] Projections on the outer surface are always present, and sometimes also appear on the inner surface; however, the surface of the cuticle itself is always smooth.[5] The holes in the cuticle are often covered by round flaps, loosely attached along a side.[5]
It has been suggested that the pores of Cosmochlaina represent broken-off rhizoids, on the basis that the rotting and maceration of extant liverworts produces a similar perforated texture.[6] However, the status of this form genus in any one kingdom is not secure; members could, for example, represent arthropod cuticle.[7] Alternatively, different species may in fact represent different parts of the same organism.[5]
[edit] See also
- Nematothallus, a closely related sister taxon
- Evolutionary history of plants
[edit] References
- ^ Strother, P.K. (1993). "Clarification of the Genus Nematothallus Lang". Journal of Paleontology 67 (6): 1090–1094.
- ^ Lang, W.H. (1937). "On the Plant-Remains from the Downtonian of England and Wales". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 227 (544): 245–291. doi:.
- ^ Kenrick, P.; Crane, P.R. (1997). "The origin and early evolution of plants on land". Nature 389: 33–39. doi:.
- ^ Gensel, P.G.; Johnson, N.G.; Strother, P.K. (1990). "Early Land Plant Debris (Hooker's" Waifs and Strays"?)". PALAIOS 5 (6): 520–547. doi:.
- ^ a b c d Edwards, D. (1986). "Dispersed cuticles of putative non-vascular plants from the Lower Devonian of Britain". Botanical journal of the Linnean Society 93 (3): 259–275. doi:.
- ^ Graham, L.E.; Wilcox, L.W.; Cook, M.E.; Gensel, P.G. (2004). "Resistant tissues of modern marchantioid liverworts resemble enigmatic Early Paleozoic microfossils". Proceedings of the National Academy of Sciences 101 (30): 11025–11029. doi:.
- ^ Taylor, T.N. (1988). "The Origin of Land Plants: Some Answers, More Questions". Taxon 37 (4): 805–833. doi:.
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