Adoketophyton is a genus of extinct vascular plants of the Early Devonian (Pragian stage, around 410 million years ago). The plant was first described in 1977 based on fossil specimens from the Posongchong Formation, Wenshan district, Yunnan, China. These were originally named Zosterophyllum subverticillatum; later the species was transferred to a new genus as Adoketophyton subverticillatum.[4] One cladistic analysis suggested that it is a lycophyte, related to the zosterophylls.[5] Other researchers regard its placement within the vascular plants as uncertain.[4][6]
Like other Early Devonian plants, the sporophyte of Adoketophyton consisted of leafless stems (axes), approximately 1 to 2.5 mm in diameter. These branched equally or unequally (pseudomonopodially). Its vascular tissue was relatively simple, consisting of a central (centrarch) cylinder of primary xylem with G-type tracheids. Fossils suggest that stems which did not bear sporangia initially had coiled (circinnate) tips, consistent with other "zosterophylls", and similar to the way in which modern ferns grow. A unique feature of this genus among plants of similar age is the manner in which the sporangia (spore-forming organs) were borne. Fertile stems had terminal 'strobili', structures very superficially resembling an ear of wheat, which consisted of four vertical rows of fan-shaped leaf-like organs (sporophylls), each with a stalked sporangium on the side facing the stem (adaxial). The flattened sporangia were almost round and split (dehisced) along a distally thickened margin into two equal parts. The sporophylls may have had vascular tissue.[2][4]
Reconstruction showing the form of the strobilus of the extinct plant Adoketophyton parvulum, based on Zhu et al. 2011
A second species, A. parvulum, was described in 2011. The species differ in size overall; for example, the largest strobili found were 90 mm long in A. subverticillatum, but only 17 mm long in A. parvulum. The relative size of the sporophylls and the sporangia is also different: they were roughly the same height in A. parvulum, whereas the sporangia were a half to a third of the height of the sporophylls in A. subverticillatum.[2]
Phylogenyedit
A cladogram published in 2004 by Crane et al. places Adoketophyton in a paraphyleticstem group of broadly defined "zosterophylls", basal to the lycopsids (living and extinct clubmosses and relatives).[5]
Other researchers have concluded that the mixture of relatively 'primitive' vascular tissue and 'advanced' sporophylls suggests that the genus evolved separately from the lycopsids, so that its taxonomic placement is uncertain.[4][6]
Referencesedit
^ abLi, C.-S. & Edwards, D. (1992), "A new genus of early land plants with novel strobilar construction from the Lower Devonian Posongchong Formation of Yunnan Province, China", Palaeontology, 35: 257–272, cited in Hao, Wang & Beck 2003
^ abcZhu, Xiao; Xue, Jin-Zhuang; Hao, Shou-Gang & Wang, De-Ming (2011), "A new species of Adoketophyton from the Lower Devonian (Pragian) Posongchong Formation of Yunnan, China", Review of Palaeobotany and Palynology, 164 (3–4): 238–246, doi:10.1016/j.revpalbo.2011.01.003
^Dianne Edwards; Cheng-Sen Li (2018). "Diversity in affinities of plants with lateral sporangia from the Lower Devonian of Sichuan Province, China" (PDF). Review of Palaeobotany and Palynology. 258: 98–111. doi:10.1016/j.revpalbo.2018.07.002. S2CID 135201524.
^ abcdHao, Shougang; Wang, Deming & Beck, Charles B. (2003), "Observations on anatomy of Adoketophyton subverticillatum from the Posongchong Formation (Pragian, Lower Devonian) of Yunnan, China", Review of Palaeobotany and Palynology, 127 (3–4): 175–186, doi:10.1016/S0034-6667(03)00119-2
^ abCrane, P.R.; Herendeen, P. & Friis, E.M. (2004), "Fossils and plant phylogeny", American Journal of Botany, 91 (10): 1683–99, doi:10.3732/ajb.91.10.1683, PMID 21652317, S2CID 8493380
^ abHao, Shougang & Xue, Jinzhuang (2013), The early Devonian Posongchong flora of Yunnan: a contribution to an understanding of the evolution and early diversification of vascular plants, Beijing: Science Press, pp. 55–56, ISBN978-7-03-036616-0, retrieved 2019-10-25
adoketophyton, genus, extinct, vascular, plants, early, devonian, pragian, stage, around, million, years, plant, first, described, 1977, based, fossil, specimens, from, posongchong, formation, wenshan, district, yunnan, china, these, were, originally, named, z. Adoketophyton is a genus of extinct vascular plants of the Early Devonian Pragian stage around 410 million years ago The plant was first described in 1977 based on fossil specimens from the Posongchong Formation Wenshan district Yunnan China These were originally named Zosterophyllum subverticillatum later the species was transferred to a new genus as Adoketophyton subverticillatum 4 One cladistic analysis suggested that it is a lycophyte related to the zosterophylls 5 Other researchers regard its placement within the vascular plants as uncertain 4 6 AdoketophytonTemporal range Early Devonian PreꞒ Ꞓ O S D C P T J K Pg N Reconstruction Scientific classification Kingdom Plantae Clade Tracheophytes Clade Lycophytes Genus AdoketophytonC S Li amp D Edwards 1992 1 Type species Adoketophyton subverticillatum Li amp Cai 1977 Li amp Edwards 1992 Species A parvulum Zhu et al 2011 2 A pingyipuensis Edwards amp Li 2018 3 A subverticillatum Li amp Cai 1977 Li amp Edwards 1992 1 Contents 1 Description 2 Phylogeny 3 References 4 External linksDescription editLike other Early Devonian plants the sporophyte of Adoketophyton consisted of leafless stems axes approximately 1 to 2 5 mm in diameter These branched equally or unequally pseudomonopodially Its vascular tissue was relatively simple consisting of a central centrarch cylinder of primary xylem with G type tracheids Fossils suggest that stems which did not bear sporangia initially had coiled circinnate tips consistent with other zosterophylls and similar to the way in which modern ferns grow A unique feature of this genus among plants of similar age is the manner in which the sporangia spore forming organs were borne Fertile stems had terminal strobili structures very superficially resembling an ear of wheat which consisted of four vertical rows of fan shaped leaf like organs sporophylls each with a stalked sporangium on the side facing the stem adaxial The flattened sporangia were almost round and split dehisced along a distally thickened margin into two equal parts The sporophylls may have had vascular tissue 2 4 nbsp Reconstruction showing the form of the strobilus of the extinct plant Adoketophyton parvulum based on Zhu et al 2011 A second species A parvulum was described in 2011 The species differ in size overall for example the largest strobili found were 90 mm long in A subverticillatum but only 17 mm long in A parvulum The relative size of the sporophylls and the sporangia is also different they were roughly the same height in A parvulum whereas the sporangia were a half to a third of the height of the sporophylls in A subverticillatum 2 Phylogeny editA cladogram published in 2004 by Crane et al places Adoketophyton in a paraphyletic stem group of broadly defined zosterophylls basal to the lycopsids living and extinct clubmosses and relatives 5 lycophytes Hicklingia basal groups Adoketophyton Discalis Distichophytum Rebuchia Gumuia Huia Zosterophyllum myretonianum Z llanoveranum Z fertile core zosterophylls Zosterophyllum divaricatum Tarella Oricilla Gosslingia Hsua Thrinkophyton Protobarinophyton Barinophyton obscurum B citrulliforme Sawdonia Deheubarthia Konioria Anisophyton Serrulacaulis Crenaticaulis basal groups Nothia Zosterophyllum deciduum lycopsids extant and extinct members Other researchers have concluded that the mixture of relatively primitive vascular tissue and advanced sporophylls suggests that the genus evolved separately from the lycopsids so that its taxonomic placement is uncertain 4 6 References edit a b Li C S amp Edwards D 1992 A new genus of early land plants with novel strobilar construction from the Lower Devonian Posongchong Formation of Yunnan Province China Palaeontology 35 257 272 cited in Hao Wang amp Beck 2003 a b c Zhu Xiao Xue Jin Zhuang Hao Shou Gang amp Wang De Ming 2011 A new species of Adoketophyton from the Lower Devonian Pragian Posongchong Formation of Yunnan China Review of Palaeobotany and Palynology 164 3 4 238 246 doi 10 1016 j revpalbo 2011 01 003 Dianne Edwards Cheng Sen Li 2018 Diversity in affinities of plants with lateral sporangia from the Lower Devonian of Sichuan Province China PDF Review of Palaeobotany and Palynology 258 98 111 doi 10 1016 j revpalbo 2018 07 002 S2CID 135201524 a b c d Hao Shougang Wang Deming amp Beck Charles B 2003 Observations on anatomy of Adoketophyton subverticillatum from the Posongchong Formation Pragian Lower Devonian of Yunnan China Review of Palaeobotany and Palynology 127 3 4 175 186 doi 10 1016 S0034 6667 03 00119 2 a b Crane P R Herendeen P amp Friis E M 2004 Fossils and plant phylogeny American Journal of Botany 91 10 1683 99 doi 10 3732 ajb 91 10 1683 PMID 21652317 S2CID 8493380 a b Hao Shougang amp Xue Jinzhuang 2013 The early Devonian Posongchong flora of Yunnan a contribution to an understanding of the evolution and early diversification of vascular plants Beijing Science Press pp 55 56 ISBN 978 7 03 036616 0 retrieved 2019 10 25External links editCladogram from Crane Herendeen amp Friis 2004 Retrieved from https en wikipedia org w index php title Adoketophyton amp oldid 1193404421, wikipedia, wiki, book, books, library,
