''Sphenobaiera'' is a form genus for plant leaves found in rocks from

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 ...

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

periods. The genus ''Sphenobaiera'' is used for plants with wedge-shaped leaves that can be distinguished from ''

Ginkgo ''Ginkgo'' is a genus of non-flowering seed plants. The scientific name is also used as the English name. The order to which it belongs, Ginkgoales, first appeared in the Permian, 270 million years ago, and is now the only living genus within ...

'', ''

Ginkgoites ''Ginkgoites'' is a genus that refers to extinct plants belonging to Ginkgoaceae. Fossils of these plants have been found around the globe during the Triassic, Jurassic, Cretaceous, with fossils also known from the Paleogene. The name was created ...

'' and ''

Baiera ''Baiera'' is a genus of prehistoric gymnosperms in the order Ginkgoales. It is one of the oldest fossil foliage types of Ginkgoales, and is related to the genera ''Ginkgo'' and ''Ginkgoites''. Fossils of ''Baiera'' are found worldwide, and ha ...

'' by the lack of a petiole. It became extinct about . The family to which this genus belongs has not been conclusively established; an affinity with the

Karkeniaceae Karkeniaceae is an extinct family in the order Ginkgoales. It contains the single genus ''Karkenia''. It is distinguished by "Ovulate organs consisting of a peduncle and helically arranged, up to about 100 small, orthotropous but incurved ovules ...

has been suggested on morphological grounds.

Locations

''Sphenobaiera ikorfatensis'' (Seward) Florin f. ''papillata'' Samylina has been found in

Lower Cretaceous Lower may refer to: *Lower (surname) *Lower Township, New Jersey *Lower Receiver (firearms) *Lower Wick Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eight ...

formations of Western

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

, the

Upper Jurassic The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987. In European lithostratigraphy, the name ...

of the Asiatic USSR, and the basal rock unit of the Lakota formation of the

Black Hills The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼhonáaeva; hid, awaxaawi shiibisha) is an isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, United States. Black Elk P ...

, which Fontaine considered to be of Lower Cretaceous age. It is a

ginkgophyte Ginkgoales are a gymnosperm order containing only one extant species: ''Ginkgo biloba'', the ginkgo tree. It is monotypic, (the only taxon) within the class Ginkgoopsida, which itself is monotypic within the division Ginkgophyta . The order inc ...

. In Paleorrota geopark in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Upper Triassic The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. Th ...

period, the

Santa Maria Formation The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It is primarily Carnian in age (Late Triassic), and is notable for its fossils of cynodonts, "rauisuchian" pseudosuchians, and early dinosaurs and oth ...

.Passo das Tropas, Santa Maria, RS. Marco bioestratigráfico triássico na evolução paleoflorística do Gondwana na Bacia do Paraná
/ref>

References

Prehistoric gymnosperm genera Late Cretaceous plants Ginkgophyta {{cretaceous-plant-stub