Pteridospermatophyta

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Pteridospermatophyta
Temporal range: 376 – 66 Ma Late Devonian – End Cretaceous (Possible Eocene survival)
Fossil seed fern leaves from the Late Carboniferous of northeastern Ohio.
Fossil seed fern leaves from the Late Carboniferous of northeastern Ohio.
Scientific classificationEdit this classification
Kingdom: Plantae
Clade: Polysporangiophytes
Clade: Tracheophytes
Clade: Spermatophytes
Groups included
Excluded

The term Pteridospermatophyta (or "seed ferns" or "Pteridospermatopsida") is a polyphyletic group of extinct seed-bearing plants (spermatophytes). The earliest fossil evidence for plants of this type is the genus Elkinsia of the late Devonian age.[1] They flourished particularly during the Carboniferous and Permian periods. Pteridosperms declined during the Mesozoic Era and had mostly disappeared by the end of the Cretaceous Period, though some pteridosperm-like plants seem to have survived into Eocene times, based on fossil finds in Tasmania.[2]

The concept of pteridosperms goes back to the late 19th century when palaeobotanists came to realise that many Carboniferous fossils resembling fern fronds had anatomical features more reminiscent of the modern-day seed plants, the cycads. In 1899 the German palaeobotanist Henry Potonié coined the term "Cycadofilices" ("cycad-ferns") for such fossils, suggesting that they were a group of non-seed plants intermediate between the ferns and cycads.[3] Shortly afterwards, the British palaeobotanists Frank Oliver and Dukinfield Henry Scott (with the assistance of Oliver's student at the time, Marie Stopes) made the critical discovery that some of these fronds (genus Lyginopteris) were associated with seeds (genus Lagenostoma) that had identical and very distinctive glandular hairs, and concluded that both fronds and seeds belonged to the same plant.[4] Soon, additional evidence came to light suggesting that seeds were also attached to the Carboniferous fern-like fronds Dicksonites,[5] Neuropteris[6] and Aneimites.[7] Initially it was still thought that they were "transitional fossils" intermediate between the ferns and cycads, and especially in the English-speaking world they were referred to as "seed ferns" or "pteridosperms". Today, despite being regarded by most palaeobotanists as only distantly related to ferns, these spurious names have nonetheless established themselves. Nowadays, four orders of Palaeozoic seed plants tend to be referred to as pteridosperms: Lyginopteridales, Medullosales, Callistophytales and Peltaspermales.

Their discovery attracted considerable attention at the time, as the pteridosperms were the first extinct group of vascular plants to be identified solely from the fossil record. In the 19th century the Carboniferous Period was often referred to as the "Age of Ferns" but these discoveries during the first decade of the 20th century made it clear that the "Age of Pteridosperms" was perhaps a better description.

During the 20th century the concept of pteridosperms was expanded to include various Mesozoic groups of seed plants with fern-like fronds, such as the Corystospermaceae. Some palaeobotanists also included seed plant groups with entire leaves such as the Glossopteridales and Gigantopteridales, which was stretching the concept. In the context of modern phylogenetic models,[8] the groups often referred to as pteridosperms appear to be liberally spread across a range of clades, and many palaeobotanists today would regard pteridosperms as little more than a paraphyletic 'grade-group' with no common lineage. One of the few characters that may unify the group is that the ovules were borne in a cupule, a group of enclosing branches, but this has not been confirmed for all "pteridosperm" groups.

With regard to the enduring value of the division, many palaeobotanists still use the pteridosperm grouping in an informal sense to refer to the seed plants that are not angiosperms, coniferoids (conifers or cordaites), ginkgophytes or cycadophytes (cycads or bennettites). This is particularly useful for extinct seed plant groups whose systematic relationships remain speculative, as they can be classified as pteridosperms with no valid implications being made as to their systematic affinities. Also, from a purely curatorial perspective the term pteridosperms is a useful shorthand for describing the fern-like fronds that were probably produced by seed plants, which are commonly found in many Palaeozoic and Mesozoic fossil floras.

Phylogeny[]

An alternative phylogeny of spermatophytes based on the work by Novíkov & Barabaš-Krasni 2015[9] with plant taxon authors from Anderson, Anderson & Cleal 2007[10] showing the relationship of extinct clades.

Spermatophytina
 

† Doweld

 
 
 

†Lyginopteridopsida Novák, emend. Anderson, Anderson & Cleal

 
 
 

† Doweld

 
 
 

†Callistophytales Rothwell, emend. Anderson, Anderson & Cleal

 
 
 

†Peltaspermopsida Doweld

 
 
 

† Doweld

 
 
Anthophyta
 

† Doweld

 
 
 
 

† Pant ex Doweld

 
 

† Doweld

 
 
 
 

† Scott

 
 
 

† Thomas ex Frenguelli  

 
 

Magnoliopsida (Flowering plants)

 
 
 
 
 
Acrogymnospermae
 

Cycadopsida (Cycads)

 
 
 

Ginkgoopsida (Maidenhair trees)

 
 

Pinopsida (Conifers)

 
 
 
 
 
 
 
 
 
seed ferns
 

Taxonomy[]

Pteridospermatophyte fossil
  • Family ?† Wang & Pfefferkorn 2009
  • Order ?† Anderson & Anderson (2003)
    • Family † Anderson & Anderson (2003)
  • Order ?†Calamopityales Němejc (1963) [Buteoxylales Taylor & Taylor (1992)]
    • Family †Calamopityaceae (Solm. (1896)) Scott (1909) [Buteoxylaceae Barnard & Long (1973); Stenomyelaceae Scott (1923)]
  • Order ?†Erdtmanithecales Friis and Pedersen (1996)
    • Family † Friis and Pedersen (1996)
  • Order ?† Anderson & Anderson (2003)
    • Family † Anderson & Anderson (2003)
  • Order † Doweld (2001) [Corystospermales; Ptilozamitales (Němejc 1950)]
    • Family † Doweld (2001) [Cardiolepidaceae Meyen 1977]
    • Family †Umkomasiaceae Petriella (1981) (Corystospermaceae (Thomas (1933)) Stockey & Rothwel nom. illeg.; Zuberiaceae Němejc (1968); Pachypteridaceae de Zigno; Ptilozamitaceae Němejc (1950)]
  • Class ?† Doweld (2001) [Clealopsida; Dicranophyllopsida Němejc 1968]
    • Order † Meyen (1984) emend. Anderson, Anderson & Cleal (2007)
      • Family † Němejc (1959) ex Archangelsky & Cúneo (1990)
    • Order † Meyen (1978) ex Meyen (1984)
      • Family † Zhou (1997)
      • Family † (Rigby (1972) Anderson & Anderson (1985)
  • Class † Doweld (2001) [Moresnetiophyta Doweld (2001); Elkinsiophytina]
    • Order † Němejc (1968)
      • Family † Němejc (1968)
    • Order † Doweld (1998)
      • Family † Doweld (2001)
      • Family † Doweld (1998
      • Family † Doweld (2001)
      • Family † Vega & Archangelsky (2001)
    • Order † Doweld (2001) [Elkinsiales Rothwell, Scheckler & Gillespie (1989); Hydraspermatales Krassilov (1989)]
      • Family † Long (1975)
      • Family † Long (1975)
      • Family †Moresnetiaceae Němejc (1963) emend. Anderson, Anderson & Cleal (2007) [Genomospermaceae Long (1975); Elkinsiaceae Rothwell, Scheckler & Gillespie (1989) ex Cleal; Hydraspermaceae]
  • Class †Lyginopteridopsida Novák (1961) emend. Anderson, Anderson & Cleal (2007) [Lagenostomatopsida Cleal (1993); Lyginopteridophyta Doweld (2001); Lyginopteridophytina]
    • Order ?† Doweld (2001)
      • Family † Doweld (2001)
      • Family † Doweld (2001) nom cons. [Potonieaceae (Halle (1933)) Remy & Remy (1959) emend. Anderson & Anderson (2007)]
    • Order †Lyginopteridales (Corsin (1960)) Havlena (1961) [Lagenostomatales Seward ex Long (1975); Lyginodendrales Nemejc (1968); Sphenopteridales Schimper 1869]
      • Family † Naugolnykh (2012)
      • Family † Němejc (1950) nom. nud.
      • Family † Long (1975)
      • Family †Lyginopteridaceae Potonie (1900) emend. Anderson, Anderson & Cleal (2007) [Lagenostomataceae Long (1975; Pityaceae Scott (1909); Lyginodendraceae Scott (1909); Sphenopteridaceae Gopp. (1842); Pseudopecopteridaceae Lesquereux (1884); Megaloxylaceae Scott (1909), nom. rej.; Rhetinangiaceae Scott (1923), nom. rej.; Tetratmemaceae Němejc (1968)]
  • Class † Doweld (2001) [Medullosopsida nom. nud.; Trigonocarpopsida nom. nud.; Medullosae]
    • Order † Doweld (2001)
      • Family † Doweld (2001) emend. Anderson, Anderson & Cleal (2007)
    • Order † Doweld (2001) (Medullosales Corsin (1960); Trigonocarpales Seward 1917 nom. inv.; Neuropteridales Schimper (1869); Rhexoxylales]
      • Family † Halle (1933) emend. Anderson, Anderson & Cleal (2007) [Rachivestitaceae; Perispermaceae]
      • Family † Doweld (2001) emend. Anderson, Anderson & Cleal (2007)
      • Family † Doweld (2001) emend. Anderson, Anderson & Cleal (2007)
      • Family † Göppert (1842)
      • Family † Laveine (1966) [incl. Odontopteridaceae Trapl (1926) sensu Corsin (1960); Neurodontopteridaceae Laveine (1966)]
      • Family † Doweld (2001) ( (Gopp. (1842)) Sterzel (1896); Whittleseyaceae Remy & Remy (1959); Protoblechnaceae Wagner (1967); Neuralethospermaceae Laveine (1967))
      • Family † Corsin ex Wagner (1965) [Callipteridiaceae; Callipteraceae]
      • Family †Alethopteridaceae (Lesquereux (1884)) Corsin (1960) emend. Anderson, Anderson & Cleal (2007)
      • Family †Cyclopteridaceae Corsin ex Wagner (1964)
  • Class † [Callistophytina]
    • Order †Callistophytales Rothwell (1981) emend. Anderson, Anderson & Cleal (2007) [Poroxylales Němejc (1968)]
      • Family † Doweld (2001) [Eremopteridaceae]
      • Family †Callistophytaceae Stidd & Hall (1970), nom. cons. [Mariopteridaceae Němejc (1968); Callospermariaceae Long (1975)]
  • Class †Peltaspermopsida Doweld (2001) [Peltaspermidae Němejc (1968); Psygmophyllopsida Koidzumi (1939)]
    • Order † Doweld (2001)
      • Family † Doweld (2001)
      • Family † Doweld (2001)
    • Order † Doweld (2001) [Psygmophyllales Nakai (1943)]
      • Family † Zalessky (1937) emend. Naugolnykh
      • Family † Petrescu & Dragastan (1981)
      • Family † Němejc (1968) [Florin emend.]
    • Order †Peltaspermales Taylor (1981) [Lepidopteridales Němejc (1968)]
      • Family † Doweld (2001)
      • Family †Peltaspermaceae (Thomas (1933)) Pilger & Melchoir (1954)) [Compsopteridaceae Petrescu & Dragastan (1981); Cycadopteridaceae Laguzen (1887); Thinnfeldiaceae Zimmerman (1959); Lepidopteridaceae Němejc (1968)]
      • Family † Naugolnykh (2012)
  • Class † Doweld (2001)
    • Order † Doweld (2001) [Taeniopteridales]
      • Family † Doweld (2001) [Spermopteridaceae Doweld (2001)]
    • Order †Gigantopteridales Li & Yao (1983) [Gigantonomiales Meyen (1987)]
      • Family †Emplectopteridaceae Wagner (1967)
      • Family † Koidzumi (1936) [Cardioglossaceae Koidzumi ex Jongmans (1958); Gigantonomiaceae Meyen (1987)]
  • Class † Pant ex Doweld (2001) [Pentoxylophytina Lemoigne (1988); Pentoxyla]
    • Order †Pentoxylales Pilger & Melchior (1954)
      • Family † Anderson & Anderson (2003)
      • Family † Pilger & Melchior (1954) [Pentoxyleae Sahni (1948)]
  • Class † Doweld (2001) [Ottokariopsida Anderson & Anderson (2007); Glossopteridopsida Plumstead (1956)]
    • Family † Nicholson & Lydekker (1889)
    • Order † McLoughlin ex Doweld (2001) [Ottokariales Anderson & Anderson (1985)]
      • Family † Doweld (2001)
      • Family † Rigby (1978) [Ottokariaceae Anderson & Anderson (1985); Scutaceae Rigby (1978), nom. illeg.]
    • Order † Doweld (2001)
      • Family † Doweld (2001)
      • Family † Doweld (2001)
      • Family † Anderson & Anderson (1985)
    • Order † Doweld (2001) (Glossopteridales Luber & Schwedov (1963), nom. rej.]
      • Family † Anderson & Anderson (1985) (Glossopteridaceae (Trapl (1926)) Zimmermann (1930), nom rej.]
  • Class † Scott (1923) [Cycadeoideophyta Taylor (1981); Cycadeoideidae Němejc (1968); Bennettitopsida Engler (1897); Bennettitophyta Kravtsov & Poljarnaja (1995); Bennettitidae Davitashvili (1949); Cycadoidea]
    • Order † Anderson & Anderson (2003)
      • Family † Anderson & Anderson (2003)
    • Order † Berry (1920) [Bennettitales (Engler (1892)) Schaffn.; Williamsoniales Berry (1920); Wielandiales Nemejc (1950) nom. nud. ]
      • Family † Anderson & Anderson
      • Family † Anderson & Anderson
      • Family † Bock 1969
      • Family † Doweld (2001) [Sturiellaceae Němejc]
      • Family † Anderson & Anderson
      • Family † Němejc (1968)
      • Family †Williamsoniaceae (Carruthers (1870)) Nathorst (1943)
      • Family † Nakai (1943) [Wielandiellaceae (Novak (1954)) Němejc (1968)]
      • Family † R. Br. ex Wieland (1908) [Bennettitaceae Engler (1892); Pterophyllaceae Nakai (1943)]
  • Class † Thomas ex Frenguelli (1946) [Caytoniophytina Doweld (2001); Caytonia]
    • Order †Caytoniales Gothan (1932)
      • Family †Caytoniaceae (Thomas (1925)) Kräusel (1926)
  • Class † Anderson & Anderson
    • Order † Anderson & Anderson (2007)
      • Family † Anderson & Anderson (2007)
      • Family † Anderson & Anderson (2007)

References[]

  1. ^ Rothwell G. W.; Scheckler S. E.; Gillespie W. H. (1989). "Elkinsia gen. nov., a Late Devonian gymnosperm with cupulate ovules". Botanical Gazette. 150 (2): 170–189. doi:10.1086/337763. S2CID 84303226.
  2. ^ McLoughlin S.; Carpenter R.J.; Jordan G.J.; Hill R.S. (2008). "Seed ferns survived the end-Cretaceous mass extinction in Tasmania". American Journal of Botany. 95 (4): 465–471. doi:10.3732/ajb.95.4.465. PMID 21632371.
  3. ^ Potonié, H. (1899). Lehrbuch der Pflanzenpaläontologie. Berlin.
  4. ^ Oliver F. W.; Scott D. H. (1904). "On the structure of the Palaeozoic seed Lagenostoma Lomaxi, with a statement of the evidence upon which it is referred to Lyginodendron". Philosophical Transactions of the Royal Society of London, Series B. 197 (225–238): 193–247. doi:10.1098/rstb.1905.0008.
  5. ^ Grand'Eury C (1904). "Sur les graines Neuropteridées". Comptes Rendus de l'Académie des Sciences de Paris. 140: 782–786.
  6. ^ Kidston R (1904). "On the fructification of Neuropteris heterophylla, Brongniart". Philosophical Transactions of the Royal Society of London, Series B. 197 (225–238): 1–5. doi:10.1098/rstb.1905.0001.
  7. ^ White D (1904). "The seeds of Aneimites". Smithsonian Institution, Miscellaneous Collection. 47: 322–331.
  8. ^ Hilton, J. & Bateman, R. M. (2006), "Pteridosperms are the backbone of seed-plant phylogeny", Journal of the Torrey Botanical Society, 33: 119–168, doi:10.3159/1095-5674(2006)133[119:PATBOS]2.0.CO;2
  9. ^ Novíkov & Barabaš-Krasni (2015). Modern plant systematics. Liga-Pres. p. 685. doi:10.13140/RG.2.1.4745.6164. ISBN 978-966-397-276-3.
  10. ^ Anderson, Anderson & Cleal (2007). Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology. Strelitzia. 20. SANBI. p. 280. ISBN 978-1-919976-39-6. S2CID 82519880.

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