Pteridospermatophyta
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]
| Pteridospermatophyta Temporal range: Late Devonian – End Cretaceous (Possible Eocene survival) | |
|---|---|
| Fossil seed fern leaves from the Late Carboniferous of northeastern Ohio. | |
| Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Polysporangiophytes |
| Clade: | Tracheophytes |
| Clade: | Spermatophytes |
| Groups included | |
| Excluded | |
| |
With regard to the enduring utility of this 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.
History of classification
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.
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 |
| seed ferns | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Taxonomy
- Family ?†Nystroemiaceae Wang & Pfefferkorn 2009
- Order ?†Alexiales Anderson & Anderson (2003)
- Family †Alexiaceae 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 †Erdtmanithecaceae Friis and Pedersen (1996)
- Order ?†Hlatimbiales Anderson & Anderson (2003)
- Family †Hlatimbiaceae Anderson & Anderson (2003)
- Order †Umkomasiales Doweld (2001) [Corystospermales; Ptilozamitales (Němejc 1950)]
- Family †Angaropeltidaceae 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 ?†Arberiopsida Doweld (2001) [Clealopsida; Dicranophyllopsida Němejc 1968]
- Order †Dicranophyllales Meyen (1984) emend. Anderson, Anderson & Cleal (2007)
- Family †Dicranophyllaceae Němejc (1959) ex Archangelsky & Cúneo (1990)
- Order †Aberiales Meyen (1978) ex Meyen (1984)
- Family †Schmeissneriaceae Zhou (1997)
- Family †Arberiaceae (Rigby (1972) Anderson & Anderson (1985)
- Order †Dicranophyllales Meyen (1984) emend. Anderson, Anderson & Cleal (2007)
- Class †Moresnetiopsida Doweld (2001) [Moresnetiophyta Doweld (2001); Elkinsiophytina]
- Order †Tetrastichiales Němejc (1968)
- Family †Tetrastichiaceae Němejc (1968)
- Order †Pullarithecales Doweld (1998)
- Family †Gnetopsidaceae Doweld (2001)
- Family †Pullarithecaceae Doweld (1998
- Family †Calathiopsidaceae Doweld (2001)
- Family †Austrocalyxaceae Vega & Archangelsky (2001)
- Order †Moresnetiales Doweld (2001) [Elkinsiales Rothwell, Scheckler & Gillespie (1989); Hydraspermatales Krassilov (1989)]
- Family †Eurystomataceae Long (1975)
- Family †Eospermatacesidae Long (1975)
- Family †Moresnetiaceae Němejc (1963) emend. Anderson, Anderson & Cleal (2007) [Genomospermaceae Long (1975); Elkinsiaceae Rothwell, Scheckler & Gillespie (1989) ex Cleal; Hydraspermaceae]
- Order †Tetrastichiales Němejc (1968)
- Class †Lyginopteridopsida Novák (1961) emend. Anderson, Anderson & Cleal (2007) [Lagenostomatopsida Cleal (1993); Lyginopteridophyta Doweld (2001); Lyginopteridophytina]
- Order ?†Hexapterospermales Doweld (2001)
- Family †Colpospermaceae Doweld (2001)
- Family †Hexapterospermaceae 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 †Angaranthaceae Naugolnykh (2012)
- Family †Heterangiaceae Němejc (1950) nom. nud.
- Family †Physostomataceae 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)]
- Order ?†Hexapterospermales Doweld (2001)
- Class †Pachytestopsida Doweld (2001) [Medullosopsida nom. nud.; Trigonocarpopsida nom. nud.; Medullosae]
- Order †Codonospermales Doweld (2001)
- Family †Codonospermaceae Doweld (2001) emend. Anderson, Anderson & Cleal (2007)
- Order †Pachytestales Doweld (2001) (Medullosales Corsin (1960); Trigonocarpales Seward 1917 nom. inv.; Neuropteridales Schimper (1869); Rhexoxylales]
- Family †Potonieaceae Halle (1933) emend. Anderson, Anderson & Cleal (2007) [Rachivestitaceae; Perispermaceae]
- Family †Polylophospermaceae Doweld (2001) emend. Anderson, Anderson & Cleal (2007)
- Family †Stephanospermaceae Doweld (2001) emend. Anderson, Anderson & Cleal (2007)
- Family †Trigonocarpaceae Göppert (1842)
- Family †Neuropteridaceae Laveine (1966) [incl. Odontopteridaceae Trapl (1926) sensu Corsin (1960); Neurodontopteridaceae Laveine (1966)]
- Family †Pachytestaceae Doweld (2001) (Medullosaceae (Gopp. (1842)) Sterzel (1896); Whittleseyaceae Remy & Remy (1959); Protoblechnaceae Wagner (1967); Neuralethospermaceae Laveine (1967))
- Family †Callipteridaceae Corsin ex Wagner (1965) [Callipteridiaceae; Callipteraceae]
- Family †Alethopteridaceae (Lesquereux (1884)) Corsin (1960) emend. Anderson, Anderson & Cleal (2007)
- Family †Cyclopteridaceae Corsin ex Wagner (1964)
- Order †Codonospermales Doweld (2001)
- Class †Callistophytopsida [Callistophytina]
- Order †Callistophytales Rothwell (1981) emend. Anderson, Anderson & Cleal (2007) [Poroxylales Němejc (1968)]
- Family †Cornucarpaceae Doweld (2001) [Eremopteridaceae]
- Family †Callistophytaceae Stidd & Hall (1970), nom. cons. [Mariopteridaceae Němejc (1968); Callospermariaceae Long (1975)]
- Order †Callistophytales Rothwell (1981) emend. Anderson, Anderson & Cleal (2007) [Poroxylales Němejc (1968)]
- Class †Peltaspermopsida Doweld (2001) [Peltaspermidae Němejc (1968); Psygmophyllopsida Koidzumi (1939)]
- Order †Sporophyllitales Doweld (2001)
- Family †Sporophyllitaceae Doweld (2001)
- Family †Leuthardtiaceae Doweld (2001)
- Order †Trichopityales Doweld (2001) [Psygmophyllales Nakai (1943)]
- Family †Psygmophyllaceae Zalessky (1937) emend. Naugolnykh
- Family †Syniopteridaceae Petrescu & Dragastan (1981)
- Family †Trichopityaceae Němejc (1968) [Florin emend.]
- Order †Peltaspermales Taylor (1981) [Lepidopteridales Němejc (1968)]
- Family †Autuniaceae Doweld (2001)
- Family †Peltaspermaceae (Thomas (1933)) Pilger & Melchoir (1954)) [Compsopteridaceae Petrescu & Dragastan (1981); Cycadopteridaceae Laguzen (1887); Thinnfeldiaceae Zimmerman (1959); Lepidopteridaceae Němejc (1968)]
- Family †Vetlugospermaceae Naugolnykh (2012)
- Order †Sporophyllitales Doweld (2001)
- Class †Phasmatocycadopsida Doweld (2001)
- Order †Phasmatocycadales Doweld (2001) [Taeniopteridales]
- Family †Phasmatocycadaceae Doweld (2001) [Spermopteridaceae Doweld (2001)]
- Order †Gigantopteridales Li & Yao (1983) [Gigantonomiales Meyen (1987)]
- Family †Emplectopteridaceae Wagner (1967)
- Family †Gigantopteridaceae Koidzumi (1936) [Cardioglossaceae Koidzumi ex Jongmans (1958); Gigantonomiaceae Meyen (1987)]
- Order †Phasmatocycadales Doweld (2001) [Taeniopteridales]
- Class †Pentoxylopsida Pant ex Doweld (2001) [Pentoxylophytina Lemoigne (1988); Pentoxyla]
- Order †Pentoxylales Pilger & Melchior (1954)
- Family †Lindthecaceae Anderson & Anderson (2003)
- Family †Pentoxylaceae Pilger & Melchior (1954) [Pentoxyleae Sahni (1948)]
- Order †Pentoxylales Pilger & Melchior (1954)
- Class †Dictyopteridiopsida Doweld (2001) [Ottokariopsida Anderson & Anderson (2007); Glossopteridopsida Plumstead (1956)]
- Family †Gangamopteridaceae Nicholson & Lydekker (1889)
- Order †Dictyopteridiales McLoughlin ex Doweld (2001) [Ottokariales Anderson & Anderson (1985)]
- Family †Breyteniaceae Doweld (2001)
- Family †Dictyopteridiaceae Rigby (1978) [Ottokariaceae Anderson & Anderson (1985); Scutaceae Rigby (1978), nom. illeg.]
- Order †Lidgettoniales Doweld (2001)
- Family †Denkaniaceae Doweld (2001)
- Family †Parthaceae Doweld (2001)
- Family †Lidgettoniaceae Anderson & Anderson (1985)
- Order †Rigbyales Doweld (2001) (Glossopteridales Luber & Schwedov (1963), nom. rej.]
- Family †Rigbyaceae Anderson & Anderson (1985) (Glossopteridaceae (Trapl (1926)) Zimmermann (1930), nom rej.]
- Class †Cycadeoideopsida Scott (1923) [Cycadeoideophyta Taylor (1981); Cycadeoideidae Němejc (1968); Bennettitopsida Engler (1897); Bennettitophyta Kravtsov & Poljarnaja (1995); Bennettitidae Davitashvili (1949); Cycadoidea]
- Order †Fredlindiales Anderson & Anderson (2003)
- Family †Fredlindiaceae Anderson & Anderson (2003)
- Order †Cycadeoideales Berry (1920) [Bennettitales (Engler (1892)) Schaffn.; Williamsoniales Berry (1920); Wielandiales Nemejc (1950) nom. nud. ]
- Family †Benneticarpaceae Anderson & Anderson
- Family †Laurozamitiaceae Anderson & Anderson
- Family †Macrotaeniopteridaceae Bock 1969
- Family †Sturianthaceae Doweld (2001) [Sturiellaceae Němejc]
- Family †Varderkloeftiaceae Anderson & Anderson
- Family †Westersheimiaceae Němejc (1968)
- Family †Williamsoniaceae (Carruthers (1870)) Nathorst (1943)
- Family †Williamsoniellaceae Nakai (1943) [Wielandiellaceae (Novak (1954)) Němejc (1968)]
- Family †Cycadeoideaceae R. Br. ex Wieland (1908) [Bennettitaceae Engler (1892); Pterophyllaceae Nakai (1943)]
- Order †Fredlindiales Anderson & Anderson (2003)
- Class †Caytoniopsida Thomas ex Frenguelli (1946) [Caytoniophytina Doweld (2001); Caytonia]
- Order †Caytoniales Gothan (1932)
- Family †Caytoniaceae (Thomas (1925)) Kräusel (1926)
- Order †Caytoniales Gothan (1932)
- Class †Axelrodiopsida Anderson & Anderson
- Order †Axelrodiales Anderson & Anderson (2007)
- Family †Zamiostrobacea Anderson & Anderson (2007)
- Family †Axelrodiaceae Anderson & Anderson (2007)
- Order †Axelrodiales Anderson & Anderson (2007)
References
- ^ 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.
- ^ 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.
- ^ Potonié, H. (1899). Lehrbuch der Pflanzenpaläontologie (in German). Berlin, DE.
- ^ 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.
- ^ Grand'Eury C (1904). "Sur les graines Neuropteridées". Comptes Rendus de l'Académie des Sciences de Paris. 140: 782–786.
- ^ 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.
- ^ White D (1904). "The seeds of Aneimites". Smithsonian Institution, Miscellaneous Collection. 47: 322–331.
- ^ 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, S2CID 86395036
- ^ 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.
- ^ Anderson, Anderson & Cleal (2007). Brief history of the gymnosperms: classification, biodiversity, phytogeography and ecology. Strelitzia. Vol. 20. SANBI. p. 280. ISBN 978-1-919976-39-6. S2CID 82519880.
External links
- Seed ferns