''Agathoxylon'' (previously known as ''Dadoxylon'') is a form genus of araucarian

fossil wood Fossil wood, also known as fossilized tree, is wood that is preserved in the fossil record. Over time the wood will usually be the part of a plant that is best preserved (and most easily found). Fossil wood may or may not be petrified, in ...

, including massive

tree trunks In botany, the trunk (or bole) is the stem and main wooden axis of a tree, which is an important feature in tree identification, and which often differs markedly from the bottom of the trunk to the top, depending on the species. The trunk is the ...

. Although identified from the late Palaeozoic to the end of the Mesozoic, ''Agathoxylon'' is common from the Carboniferous to

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

Description

''Agathoxylon'' were large trees that bore long strap-like leaves and trunks with small, narrow rays. Often the original cellular structure is preserved as a result of

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is o ...

in solution in the ground water becoming deposited within the wood cells. This mode of

fossilization A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

is termed

permineralization Permineralization is a process of fossilization of bones and tissues in which mineral deposits form internal casts of organisms. Carried by water, these minerals fill the spaces within organic tissue. Because of the nature of the casts, permineral ...

Systematics

As a genus, ''Dadoxylon'' was poorly defined, and apart from Araucariaceae, has been associated with fossil wood as diverse as

Cordaitales Cordaitales are an extinct order of gymnosperms, known from the early Carboniferous to the late Permian. Many Cordaitales had elongated strap-like leaves, resembling some modern-day conifers of the Araucariaceae and Podocarpaceae. They had cone ...

Glossopteridales Glossopteridales is an extinct order of plants belonging to Pteridospermatophyta, or seed ferns, also known as Arberiales and Ottokariales. They arose at the beginning of the Permian () on the southern continent of Gondwana, but became extinct a ...

and

Podocarpaceae Podocarpaceae is a large family of mainly Southern Hemisphere conifers, known in English as podocarps, comprising about 156 species of evergreen trees and shrubs.James E. Eckenwalder. 2009. ''Conifers of the World''. Portland, Oregon: Timber Pre ...

. Furthermore, it may be the same form genus as '' Araucarioxylon'', hence the usage ''Dadoxylon'' (''Araucarioxylon''). The genus ''Agathoxylon'', classified under the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Araucariaceae Araucariaceae – also known as araucarians – is an extremely ancient family of coniferous trees. The family achieved its maximum diversity during the Jurassic and Cretaceous periods and the early Cenozoic, when it was distributed almost world ...

, has nomenclatural priority over the genera ''Araucarioxylon'' and ''Dadoxylon''. Several ''Dadoxylon'' species, such as ''D. brandlingii'' and ''D. saxonicum'' have been identified as '' Araucarites''. ''D. arberi'' and ''D.'' sp.1 were synonymised with the glossopterid species '' Australoxylon teixterae'' and ''A. natalense'', respectively; while ''D.'' sp. 2 was transferred to '' Protophyllocladoxylon''.

Species

*''Agathoxylon africanum'' (Bamford 1999) ''Araucarioxylon africanum'' Daptocephalus Assemblage Zone, Middleton Formation and Normandien Formation to Cynognathus Assemblage Zone, Burgersdorp Formation and Driekoppen Formation,

Beaufort Group The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup in South Africa. It is composed of a lower Adelaide Subgroup and an upper Tarkastad Subgroup. It follows conformably after the Ecca Group and unconformably underli ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...

, and Lebung Group,

Botswana Botswana (, ), officially the Republic of Botswana ( tn, Lefatshe la Botswana, label= Setswana, ), is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory being the Kal ...

*''Agathoxylon agathioides'' (Kräusel & Jain): La Matilde Formation,

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, t ...

*''Agathoxylon antarcticus'' (Poole & Cantrill 2001) Pujana ''et al.'' 2014 ''A. matildense'', ''Araucarioxylon antarcticus'' Santa Marta Formation,

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest co ...

*''Agathoxylon arberi'' (Seward 1919) ''Dadoxylon arberi''*''Agathoxylon australe'' ''Dadoxylon australe''*''Agathoxylon bougheyi'' Williams ''Dadoxylon bougheyi'' Madumabisa Mudstone Formation,

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most central point. Its neighbours are ...

and Somabula Beds,

Zimbabwe Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Botswana to the south-west, Zambia to the north, and Mozam ...

*''Agathoxylon cordaianum'' Hartig 1848 *''Agathoxylon desnoyersii'' (Phillipe 2011) ''Araucarioxylon desnoyersii''*''Agathoxylon duplicatum'' (Vogellehner 1965) ''Dadoxylon duplicatum''

Germany Germany, officially the Federal Republic of Germany (FRG),, is a country in Central Europe. It is the most populous member state of the European Union. Germany lies between the Baltic and North Sea to the north and the Alps to the sou ...

*''Agathoxylon jamudhiense'' (Maheshwari 1963) ''Dadoxylon jamudhiense''

India India, officially the Republic of India ( Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the ...

*''Agathoxylon karooensis'' (Bamford 1999) ''Araucarioxylon karooensis'' ''Daptocephalus'' AZ, Middleton and Normandien Formations, South Africa *''Agathoxylon kellerense'' (Lucas and Lacey 1984) ''Araucarioxylon kellerense'', ''Dadoxylon kellerense'' Santa Marta Formation, Antarctica *''Agathoxylon lemonii'' Tidwell & Thayn 1986:

Dakota Formation The Dakota is a sedimentary rock, sedimentary geologic unit name of Formation (stratigraphy), formation and Group (stratigraphy), group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and ...

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

*''Agathoxylon maharashtraensis'' (Prasad 1982) ''Dadoxylon maharashtraensis'' India *''Agathoxylon parenchymatosum'' (Vogellehner 1965) ''Araucarioxylon parenchymatosum'', ''Dadoxylon parenchymatosum''

Forest Sandstone Formation The Forest Sandstone is a geological formation in southern Africa, dating to roughly between 200 and 190 million years ago and covering the Hettangian to Sinemurian stages of the Jurassic Period in the Mesozoic Era. As its name suggests, it ...

*''Agathoxylon pseudoparenchymatosum'' (Gothan 1908) Pujana ''et al.'' 2014 ''Araucarioxylon chilense'', ''A. kerguelense'', ''A. novaezeelandii'', ''A. pseudoparenchymatosum'', ''Dadoxylon kaiparaense'', ''D. kergulense'', ''D. pseudoparenchymatosum'' Santa Marta Formation, Antarctica *''Agathoxylon santacruzense'' Kloster and Gnaedinger 2018: La Matilde Formation, Argentina *''Agathoxylon santalense'' (Sah & Jain): La Matilde Formation, Argentina *''Agathoxylon sclerosum'' (Walton) Kräusel 1956 ''Dadoxylon sclerosum'', ''Kaokoxylon sclerosum''

Malay Peninsula The Malay Peninsula ( Malay: ''Semenanjung Tanah Melayu'') is a peninsula in Mainland Southeast Asia. The landmass runs approximately north–south, and at its terminus, it is the southernmost point of the Asian continental mainland. The are ...

Dwyka Group The Dwyka Group is one of four geological groups that compose the Karoo Supergroup. It is the lowermost geological group and heralds the commencement of sedimentation of the Karoo Supergroup. Based on stratigraphic position, lithostratigraphic c ...

Molteno Formation The Molteno Formation is a geological formation found in several localities in Lesotho and South Africa. It lies mainly south of Maseru, near Burgersdorp, Aliwal North, Dordrecht, Molteno, and Elliot. It extends as far north as Matatiele in the ...

Stormberg Group The Stormberg Group is one of the four geological groups that comprises the Karoo Supergroup in South Africa. It is the uppermost geological group representing the final phase of preserved sedimentation of the Karoo Basin. The Stormberg Group ro ...

, South Africa, and Ntawere Formation,

*''Agathoxylon termieri'' (Attims) Gnaedinger & Herbst: La Matilde Formation, Argentina *''Agathoxylon ulmitus'' Iamandei & Iamandei 2004:

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, a ...

*''Agathoxylon woodworthii'' (Knowlton 1899) ''Dadoxylon woodworthii''

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

Distribution

''Agathoxylon'' is common in many parts of the world, found in sites of both

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final st ...

and

Laurasia Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pan ...

and reported from

southern Africa Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...

, the

Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europ ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located enti ...

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

, and North America. In southern Africa, ''Agathoxylon'' is widespread in the

Karoo Supergroup The Karoo Supergroup is the most widespread stratigraphic unit in Africa south of the Kalahari Desert. The supergroup consists of a sequence of units, mostly of nonmarine origin, deposited between the Late Carboniferous and Early Jurassic, a pe ...

. In

, it is especially encountered in the

Pebbly Arkose Formation The Pebbly Arkose Formation is a Late Triassic geologic formation found in southern Africa. Geology Description The formation comprises mainly coarse, arkosic sandstones. Extent The Pebbly Arkose Formation is found in Botswana, Zambia ...

, and also reported frequently from the Angwa Sandstone Formation.

References

{{Taxonbar, from1=Q106344950, from2=Q5208106 Araucariaceae Paleozoic genus first appearances Mesozoic genera Late Cretaceous genus extinctions Paleozoic life of New Brunswick Paleozoic life of Nova Scotia Paleozoic life of Prince Edward Island Fossils of Antarctica Fossils of Argentina Fossils of Botswana Fossils of Germany Fossils of India Fossils of Namibia Fossils of Romania Fossils of South Africa Fossils of Turkey Fossils of Zambia Fossils of Zimbabwe Fossil taxa described in 1848 Prehistoric gymnosperm genera