''Diploporus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

s in the

yew Yew is a common name given to various species of trees. It is most prominently given to any of various coniferous trees and shrubs in the genus '' Taxus'': * European yew or common yew (''Taxus baccata'') * Pacific yew or western yew ('' Taxus ...

family

Taxaceae Taxaceae (), commonly called the yew family, is a coniferous family (biology), family which includes six Extant taxon, extant and two extinct genera, and about 30 species of plants, or in older interpretations three genera and 7 to 12 species. ...

, containing the single species ''Diploporus torreyoides'' known from the

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

of north central

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

and the

Late Paleocene The Thanetian is, in the International Commission on Stratigraphy, ICS Geologic timescale, the latest age (geology), age or uppermost stage (stratigraphy), stratigraphic stage of the Paleocene epoch (geology), Epoch or series (stratigraphy), Serie ...

of south central

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

. The species was first 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 preserve ...

seeds in

chert Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...

History and classification

''Diploporus torreyoides'' has been identified from a single location in the

Clarno Formation John Day Fossil Beds National Monument is a National monument (United States), U.S. national monument in Wheeler County, Oregon, Wheeler and Grant County, Oregon, Grant counties in east-central Oregon. Located within the John Day River basin an ...

, the Clarno nut beds, type locality for both the formation and the species. The nut beds are approximately east of the

unincorporated community An unincorporated area is a parcel of land that is not governed by a local general-purpose municipal corporation. (At p. 178.) They may be governed or serviced by an encompassing unit (such as a county) or another branch of the state (such as th ...

of Clarno, Oregon and currently considered to be middle Eocene in age, based on averaging zircon fission track

radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to Chronological dating, date materials such as Rock (geology), rocks or carbon, in which trace radioactive impurity, impurities were selectively incorporat ...

which yielded an age of 43.6 and 43.7 ± 10

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

and

Argon–argon dating Argon–argon (or 40Ar/39Ar) dating is a radiometric dating method invented to supersede Potassium-argon dating, potassiumargon (K/Ar) dating in accuracy. The older method required splitting samples into two for separate potassium and argon measur ...

which yielded a 36.38 ± 1.31 to 46.8 ± 3.36 mya date. The average of the dates resulted in an age range of 45 to 43 mya. The beds are composed of silica and

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

cemented

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...

aceous sandstones, siltstones, and conglomerates which preserve either a lake delta environment, or alternatively periodic floods and volcanic mudflows preserved with hot spring activity. An unidentified species of ''Diploporus'' has been reported from the Sentinel Butte Formation 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 19 ...

and the Beicegal Creek, North Dakota. 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 microorganisms and microscopic fragments of mega-organisms that are composed of acid-resistant organic material and occur in sediments, sedimentary rocks, and even some metasedimentary rocks. Palynomorphs are the mic ...

assemblages of the formation. The species was described from a group of seventy five type specimens, the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen UF8542, which is currently preserved in the paleobotanical collections of the

University of Florida The University of Florida (Florida or UF) is a public university, public land-grant university, land-grant research university in Gainesville, Florida, United States. It is a senior member of the State University System of Florida and a preem ...

and a large series of

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 (biology), isotype ...

s, totaling seventy-four specimens. The paratypes are in the collections of the

National Museum of Natural History The National Museum of Natural History (NMNH) is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. With 4.4 ...

, the University of Florida, and the

Oregon Museum of Science and Industry The Oregon Museum of Science and Industry (OMSI, ) is a science and technology museum in Portland, Oregon, United States. It contains three auditoriums, including a large-screen theatre, planetarium, and exhibition halls with a variety of hands- ...

. The fossils were part of approximately 20,000 specimens collected from 1942 to 1989 by Thomas Bones, A. W. Hancock, R. A. Scott, Steven R. Manchester, and a number of high school students. The ''Diploporus'' specimens were studied by

paleobotanist Paleobotany or palaeobotany, also known as paleophytology, is the branch of botany dealing with the recovery and identification of plant fossils from geological contexts, and their use for the biological reconstruction of past environments (pale ...

Steven R. Manchester of the University of Florida. He published his 1994

type description A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

for ''Diploporus torreyoides'' in the journal ''

Palaeontographica Americana The Paleontological Research Institution, or PRI, is a paleontological organization in Ithaca, New York, with a mission including both research and education. PRI is affiliated with Cornell University, houses one of the largest fossil collecti ...

'' In his type description Manchester noted the generic name is derived from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

words ''Diplo'' meaning "twofold" and ''poros'' meaning "passage" in reference to the paired vascular scars. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''torreyoides'', reflects the similarities between ''Diploporus'' and the living genus ''

Torreya ''Torreya'' is a genus of conifers comprising six or seven species placed in the family Taxaceae, though sometimes formerly placed in Cephalotaxaceae. Four species are native to eastern Asia; the other two are native to North America. They a ...

''.

Description

The seeds of ''Diploporus'' are subovoid and bilaterally symmetrical with a slightly pointed tip and round base. The seeds have an overall length raging between and a width between . There is a sharp crest along the upper third of the seed that is formed by the dorsal and ventral faces. As with other Taxacaeae genera ''Diploporus'' has a pair of vascular scars on sides, located at the widest point. The seeds are identified from ''

Taxus ''Taxus'' is a genus of coniferous trees or shrubs known as yews in the family Taxaceae. Yews occur around the globe in temperate zones of the northern hemisphere, northernmost in Norway and southernmost in the South Celebes. Some populations ex ...

'' and ''

'' species by several features of the exterior morphology. The overall shape of the base is not as pointed as that of ''Torreya'' but not as truncate as the base of ''Taxus'' and in size, ''Diploporus'' seeds are larger than ''Taxus'' seeds, but smaller than ''Torreya''.

References

{{Taxonbar, from=Q16752364 Taxaceae Prehistoric gymnosperm genera Fossil taxa described in 1994 Eocene plants Flora of Oregon Flora of North Dakota Monotypic gymnosperm genera Extinct flora of North America Prehistoric plants of North America Clarno Formation