Bennettitales (the cycadeoids) is an extinct order The Latin suffix -formes meaning "having the form of" is used for the scientific name of orders of birds and fishes, but not for those of mammals and invertebrates of seed plants The spermatophytes (also known as phanerogams) comprise those plants that produce seeds. They are a subset of the embryophytes or land plants. The living spermatophytes form five groups: that first appeared in the Triassic The Triassic is a geologic period that extended from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events. The extinction event that closed the Triassic Period has recently been more accurately period and became extinct toward the end of the Cretaceous The Cretaceous , Latin for "chalky", usually abbreviated K for its German translation Kreide (chalk), is a geologic period and system from circa 145.5 ± 4 to 65.5 ± 0.3 million years (Ma) ago. In the geologic timescale, the Cretaceous follows on the Jurassic Period and is followed by the Paleogene Period of the Cenozoic Era. It is the.[1] Some were characterized by thick trunks and pinnately Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts . The term contrasts compound leaves that bore a superficial resemblance to those of cycads Cycads are seed plants characterized by a large crown of compound leaves and a stout trunk. They are evergreen, dioecious plants having large pinnately compound leaves. They are frequently confused with and mistaken for palms or ferns, but are only distantly related to both, and instead belong to the division Cycadophyta, differing primarily in stomatal arrangement.[2]
It comprises two groups, the Cycadeoidaceae, represented by Cycadeoidea, Cycadella, and Monanthesia which had stout trunks and bisporangiate strobili A cone is an organ on plants in the division Pinophyta (conifers) that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity. The name "cone" derives from the fact that the shape (cones serving as their reproductive structures), and the Williamsoniaceae including Williamsonia, Williamsoniella, Wielandella and Ischnophyton which had slender, branching trunks and either bisporangiate or monosporangiate strobili. Bennettitales have been placed among the anthophytes The anthophytes were thought to be a clade comprising plants bearing flower-like structures. The group contained the angiosperms - the extant flowering plants - as well as the Gnetales and the extinct Bennettitales, which for some time were considered to be close relatives of the flowering plants The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Together with gymnosperms, they are the only extant groups of seed-producing plants, but they can be distinguished from the gymnosperms by a series of synapomorphies (derived characteristics). These characteristics include flowers, on account of their flower-like structures.[1] However, more detailed morphological studies have shown the "anthophytes" to be polyphyletic, with the Bennettitales more closely related to the cycads, ginkgo Ginkgo is a genus of highly unusual non-flowering plants with one extant species, G. biloba, which is regarded as a living fossil and conifers than to the angiosperms.[3] Molecular fossil evidence, however, indicates the possibility that Bennettitales and Angiosperms (along with Gigantopteridales) form a clade, based on the presence of oleanane in fossils of these groups.[4]
Gallery
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A fossilised Bennettitales, squashed by later compression. |
Side view. Note embedded "flowers". |
A flower-like structure. |
Fossil leaf of Zamites mariposana from the Jurassic The Jurassic is a geologic period and system that extends from about 199.6± 0.6 Ma to 145.5± 4 Ma, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the "Age of Reptiles". The start of the period is marked by the major Triassic–. |
References
- ^ a b Speer, Brian R., 2000. Introduction to the Bennettitales http://www.ucmp.berkeley.edu/seedplants/bennettitales.html (accessed 13 Oct 2005).
- ^ Pigg, Kathleen. 2005 The Cycads, Cycadeoids (Bennettitales) and Ginkgophytes http://lsweb.la.asu.edu/kpigg/CYCAD.html (accessed 21 Sept 2007).
- ^ Crepet, W. L. (2000). "Progress in understanding angiosperm history, success, and relationships: Darwin's abominably "perplexing phenomenon"". Proceedings of the National Academy of Sciences 97 (24): 12939. doi A digital object identifier is a character string used to uniquely identify an electronic document or other object. Metadata about the object is stored in association with the DOI name and this metadata may include a location, such as a URL, where the object can be found. The DOI for a document is permanent, whereas its location and other metadata:10.1073/pnas.97.24.12939. PMID A PMID is a unique number assigned to each PubMed citation of life sciences and biomedical scientific journal articles. The related Pubmed Central archive may additionally assign a separate number, a PMCID (PubMed Central Identifier), normally written with a PMC prefix 11087846. PMC PubMed Central is a free digital database of full-text scientific literature in biomedical and life sciences. It grew from the online Entrez PubMed biomedical literature search system. PubMed Central was developed by the U.S. National Library of Medicine as an online archive of biomedical journal articles 34068. http://www.pnas.org/cgi/reprint/97/24/12939.
- ^ Taylor, D. W. and Hongqi Li and Dahl, Jeremy and Fago, F. J. and Zinneker, D. and Moldowan, J. M. (2006). "Biogeochemical evidence for the presence of the angiosperm molecular fossil oleanane in Paleozoic and Mesozoic non-angiospermous fossils". Paleobiology 32(2): 179–90. doi A digital object identifier is a character string used to uniquely identify an electronic document or other object. Metadata about the object is stored in association with the DOI name and this metadata may include a location, such as a URL, where the object can be found. The DOI for a document is permanent, whereas its location and other metadata:10.1666/0094-8373(2006)32[179:BEFTPO]2.0.CO;2. http://paleobiol.geoscienceworld.org/cgi/content/abstract/32/2/179.
External links
Categories: Prehistoric plants | Mesozoic life |
