Trimerophytopsida (or Trimeropsida) is a class of early from the Devonian, informally called trimerophytes. It contains genera such as Psilophyton. This group is probably paraphyletic, and is believed to be the ancestral group from which both the and spermatophyte evolved. Different authors have treated the group at different using the names Trimerophyta, Trimerophytophyta, Trimerophytina, Trimerophytophytina and Trimerophytales.
Taxonomy
At first most of the early land plants other than the bryophytes (i.e. the polysporangiophytes) were placed in a single class Psilophyta, established in 1917 by Kidston and Lang.
As additional fossils were discovered and described, it became apparent that the Psilophyta were not a homogeneous group of plants. In 1968 Banks first proposed splitting this taxon into three groups, which he put at the
taxonomic rank of
Subphylum; he clarified his proposal in 1975. One of the three groups was the Trimerophytina.
[, cited in ] The subdivision is based on the type genus
Trimerophyton, which might be expected to produce 'Trimerophytophytina' as the name of the subdivision, but the
International Code of Nomenclature for algae, fungi, and plants allows the 'phyton' part of a genus name optionally to be omitted before '-ophyta', '-ophytina' and '-opsida'.
[, Article 16.4]
The group has also since been treated as a division under the name Trimerophyta[, p. 227] or Trimerophytophyta, as a class under the name Trimeropsida or Trimerophytopsida (as here),[See, e.g., ] and as an order under the name Trimerophytales.[, p. 57]
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Subphylum † Trimerophytina Banks 1975
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Class † Trimerophytopsida Foster & Gifford 1974 Trimeropsida
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Order †Trimerophytales Banks ex Kasper et al. 1974 Psilophytales
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Family †Trimerophytaceae Banks 1967 Psilophytaceae
See also
Bibliography
