''Ginkgo cranei'' is an extinct ''

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 ...

'' species in the family

Ginkgoaceae The Ginkgoaceae is a family of gymnosperms which appeared during the Mesozoic Era, of which the only extant representative is ''Ginkgo biloba'', which is for this reason sometimes regarded as a living fossil A living fossil is an extant tax ...

described from a series of isolated

fossil 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 preserved ...

ovulate organs and

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

. The species is known from upper Paleocene sediments exposed in the state of

North Dakota North Dakota () is a U.S. state in the Upper Midwest, named after the Native Americans in the United States, indigenous Dakota people, Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north a ...

, USA. It is the first ''Ginkgo'' species to be described from

Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...

period with reproductive structures.

History and classification

''Ginkgo cranei'' is represented by a group of fossil specimens from the Upper Paleocene aged

Sentinel Butte Formation The Sentinel Butte Formation is a geologic formation of Paleocene age in the Williston Basin of western North Dakota. It preserves significant assemblages of non-marine plant and animal fossil A fossil (from Classical Latin , ) is any pr ...

exposed near the town of

Almont, North Dakota Almont is a city in Morton County, North Dakota, United States. It is part of the " Bismarck, ND Metropolitan Statistical Area" or "Bismarck–Mandan". The population was 100 at the 2020 census. Almont was founded in 1906, incorporated in 1936, ...

. The specimens are preserved in a fine-grained yellow- to brown-colored

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

with a notably high iron content. Fossils found in the

s are often three-dimensionally preserved with stem and seed structure intact. The age of the formation is based on the recovery of late Tiffanian mammals in the upper section of the formation along with the floral and

palynological Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposit ...

assemblages of the formation. Many of the ''G. cranei'' seeds are preserved as casts with hollow crystalline interiors and exterior cuticle present. Associated with the ovulate organs are fossil leaves that were formerly assigned to the taxon ''

Ginkgo adiantoides ''Ginkgo adiantoides'' is an extinct ginkgo species in the family Ginkgoaceae from the Late Cretaceous to the Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by ...

''. The

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

s for ''G. cranei'' include two ovulate organ fossils, a

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

and a

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Of ...

. The holotype is numbered number UWSP42706 which, along with four other specimens, is currently preserved in the paleobotanical collections of

University of Wisconsin–Stevens Point The University of Wisconsin–Stevens Point (UW–Stevens Point or UWSP) is a public university in Stevens Point, Wisconsin. It is part of the University of Wisconsin System and grants associate, baccalaureate, and master's degrees, as well as ...

Stevens Point, Wisconsin Stevens Point is the county seat of Portage County, Wisconsin, United States. The city was incorporated in 1858. Its 2020 population of 25,666 makes it the largest city in the county. Stevens Point forms the core of the United States Census Bur ...

. The paratype, number PP34187, along with one additional specimen, are part of the

geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...

collections maintained at the

Field Museum of Natural History The Field Museum of Natural History (FMNH), also known as The Field Museum, is a natural history museum in Chicago, Illinois, and is one of the largest such museums in the world. The museum is popular for the size and quality of its educational ...

Chicago, Illinois (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

. A total of only seven ''G. cranei'' ovulate organ fossils were known at the time of the species description. The specimens were studied by

paleobotanist Paleobotany, which is also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeogr ...

Zhiyan Zhou of

Nanjing University Nanjing University (NJU; ) is a national public research university in Nanjing, Jiangsu. It is a member of C9 League and a Class A Double First Class University designated by the Chinese central government. NJU has two main campuses: the Xianl ...

, Cheng Quan of

Jilin University Jilin University (JLU; ; often abbreviated JLU or ) is a leading national research university located in Changchun, China. It is under the direct jurisdiction of China's Ministry of Education. It is a Chinese Ministry of Education Class A Doub ...

and Yu-Sheng (Christopher) Liu of

East Tennessee State University East Tennessee State University (ETSU) is a public research university in Johnson City, Tennessee. Although it is part of the State University and Community College System of Tennessee, the university is governed by an institutional Board of Tr ...

. Zhou and associates published their 2012

type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...

for ''G. cranei'' in the ''

International Journal of Plant Sciences The ''International Journal of Plant Sciences'' covers botanical research including genetics and genomics, developmental and cell biology, biochemistry and physiology, morphology and structure, systematics, plant-microbe interactions, paleobotany, ...

''. The chosen specific name ''cranei'' was in honor of Sir Peter Crane who, with Steven Manchester and David Dilcher, first discovered the Almont ''Ginkgo'' fossils.

Description

''G. cranei'' ovulate organs are noted for the presence of distinct epidermal cells that have thick, dome-like periclinal walls. Overall the ovulate organs range from by . Both the size and cell structuring is different from the living ''Ginkgo biloba'' ovulate organs, which are larger at and have less bulging periclinal walls. The stomata complexes found on ''G cranei'' ovulate organs and leaves are sparser in distribution and fewer in total number than the complexes on ''G. biloba''.

References

{{Taxonbar, from=Q5563144 cranei Flora of North Dakota Fossil taxa described in 2012 Paleocene plants Plants described in 2012 Extinct flora of North America Prehistoric trees