''Zamites'' is a genus of fossil tree known from the

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

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 Continent#Subcontinents, subcontinent of Eurasia ...

and

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

through the

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

of North America. It was erected as a

form taxon Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of s ...

for leaves that superficially resembled the extant

cycad Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male o ...

Zamia ''Zamia'' is a genus of cycad of the family Zamiaceae, native to North America from the United States (in Georgia and Florida) throughout the West Indies, Central America, and South America as far south as Bolivia. The genus is considered to be ...

'', however it is now believed to belong to a similar but phylogenetically different group, the cyacadeoids (

Bennettitales Bennettitales (also known as cycadeoids) is an extinct order of seed plants that first appeared in the Permian period and became extinct in most areas toward the end of the Cretaceous. Bennettitales are among the most common Mesozoic seed plants ...

). The fronds are linear or lanceolate in shape, and pinnately compound, with pinnae with parallel veins and smooth margins, and symmetrical and constricted at the base where they are attached obliquely to the upper surface of the

rachis In biology, a rachis (from the grc, ῥάχις [], "backbone, spine") is a main axis or "shaft". In zoology and microbiology In vertebrates, ''rachis'' can refer to the series of articulated vertebrae, which encase the spinal cord. In this c ...

. It has been interpreted as a Bennettitalean plant in the family

Williamsoniaceae ''Williamsoniaceae'' is a family within the Bennettitales, an extinct group of seed plants within the Cycadophyta subdivision. Members of this family are believed to have been around two meters tall and with widely serrate leaves along a central ...

.''Zamites'' in IRMNG
/ref> As explained by Zijlstra & van Konijnenburg-van Cittert (2020), the application of the genus name ''Zamites'' has over time drifted away from Brongniart's original concept to one where the species ''Z. gigas'' (Lindl. & Hutton) Morris has been treated as a ''de facto'' type, to the degree that none of Brongniart's four original species would now be assigned to it, instead being allocated to ''

Otozamites ''Otozamites'' is an extinct form genus of leaves belonging to the Bennettitales Bennettitales (also known as cycadeoids) is an extinct order of seed plants that first appeared in the Permian period and became extinct in most areas toward the ...

'' and possibly elsewhere; this includes ''Z. bucklandii'', designated as the type of ''Zamites'' by Pfeiffer in a publication dating from 1871-1875, but now (as ''O. bucklandii'') the type of ''Otozamites''. Technically, unless otherwise addressed, this renders ''Otozamites'' a synonym of ''Zamites'' and would mean that ''Z. gigas'' plus all the species recognisably closer to it than to ''Z. bucklandii'' would require a new genus name. Zijlstra & van Konijnenburg-van Cittert chose to attempt to circumvent this situation by proposing that ''Zamites'' should be re-defined based on designating ''Z. gigas'' as a new type to replace ''Z. bucklandii'', a proposal that was recommended for acceptance by the Nomenclature Committee for Fossils in 2022.

Species

Species include: * '' Z. arcticus'' * '' Z. bayeri'' * '' Z. californica'' * '' Z. mariposana''

Distribution

Fossils of ''Zamites'' have been found in:''Zamites''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was crea ...

.org ;Triassic (to Jurassic) Antarctica, Austria, China, France, Germany, Honduras, Hungary, Italy, Japan, Mexico, Romania, Tajikistan, Ukraine, and the United States (New Mexico, North Carolina, Utah, Virginia, Virginia/North Carolina). ;Jurassic (to Cretaceous) Antarctica, Argentina, Azerbaijan, Belarus, Chile, China, Colombia ( Valle Alto Formation, Caldas), Egypt, France, Georgia, Germany, Iran, Italy, Japan, Kazakhstan, Mexico, Mongolia, Portugal, Romania, the Russian Federation, Serbia and Montenegro, Switzerland, Tajikistan, Turkey, Ukraine, the United Kingdom, and the United States (Montana, Wyoming). ;Cretaceous Canada (Alberta, British Columbia), Ecuador, Japan, Mexico, South Africa, Spain, and the United States (Montana, Virginia, Wyoming). ;Eocene United States (California)

References

Bennettitales Triassic first appearances Triassic plants Jurassic plants Early Cretaceous plants Late Cretaceous plants Paleocene plants Eocene plants Eocene genus extinctions Mesozoic trees Mesozoic Antarctica Mesozoic life of Asia Mesozoic life of Europe Mesozoic life of North America Cretaceous Canada Jurassic Mexico Cretaceous Mexico Jurassic United States Cretaceous United States Mesozoic life of South America Prehistoric plants of South America Jurassic Argentina Fossils of Argentina Jurassic Chile Fossils of Chile Jurassic Colombia Fossils of Colombia Cretaceous Ecuador Fossils of Ecuador Fossil taxa described in 1828 Fossils of Serbia {{Paleobotany-stub