''Trochodendron postnastae'' 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 ...
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...
in the family
Trochodendraceae
Trochodendraceae is the only family of flowering plants in the order Trochodendrales. It comprises two extant genera, each with a single species along with up to five additional extinct genera and a number of extinct species. The living specie ...
. The species is known from
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 ...
s found in
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene.
The sub-epoch lasted from 15.97 ± 0. ...
deposits of 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 ...
. ''T. postnastae'' are possibly the leaves belonging to the extinct trochodendraceous fruits ''
Trochodendron rosayi''.
Distribution and paleoenvironment
''Trochodendron postnastae'' fossils were found in the
Moose Mountain Flora, formerly called the Cascadia flora or Menagerie Wilderness flora, of
Linn County, Oregon
Linn County is one of the Oregon counties, 36 counties in the U.S. state of Oregon. As of the 2020 United States census, 2023 census population estimates, the population was 131,496. The county seat is Albany, Oregon, Albany. The county Oreg ...
. The flora is included in the
Little Butte Volcanic series outcropping near the town of
Cascadia in the central Oregon Cascades. Work on the flora by paleobotanist
Jack Wolfe in 1964 gave an estimated age of Early Miocene, this was later revised by Wolfe and Tanai in 1987 to a Late
Oligocene
The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
estimation.
In the descriptive paper naming ''T. postnastae'' Manchester ''et al'' reported that
radioisotope dating of
plagioclase
Plagioclase ( ) is a series of Silicate minerals#Tectosilicates, tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continu ...
crystals collected by Robert Rosé from the fossiliferous horizon of the Moose Mountain flora had been performed. Using crystals obtained from tuffaceous sandstones,
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 ...
provided an age of 14.91 ± 0.23
Ma placing the flora as Middle Miocene
Langhian
The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene Epoch/Series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma (million years ago) during the Middle Miocene.GeoWhen (2007)
The Langhian was ...
stage.
''T. postnastae'' is found associated with species such as ''
Acer cascadense'', ''
Acer smileyi'', ''
Concavistylon kvacekii'', ''
Ozakia emryi'',
and ''
Trochodendron rosayi''.
[
]
Taxonomy
The species 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 ...
was originally collected during the 1950s by Eleanor Gordon Thompson and donated to the University of California Museum of Paleontology
The University of California Museum of Paleontology (UCMP) is a paleontology museum located on the campus of the University of California, Berkeley.
The museum is within the Valley Life Sciences Building (VLSB), designed by George W. Kelham ...
in Berkeley, California
Berkeley ( ) is a city on the eastern shore of San Francisco Bay in northern Alameda County, California, United States. It is named after the 18th-century Anglo-Irish bishop and philosopher George Berkeley. It borders the cities of Oakland, Cali ...
as specimen UCMP 201235. An additional series of leaves collected by Robert Rosé and part of the Florida Museum of Natural History
The Florida Museum of Natural History (FLMNH) is Florida's official state-sponsored and chartered natural history museum. Its main facilities are located at 3215 Hull Road on the campus of the University of Florida in Gainesville, Florida, Gaine ...
's collections in Gainesville, Florida
Gainesville is the county seat of Alachua County, Florida, United States, and the most populous city in North Central Florida, with a population of 145,212 in 2022. It is the principal city of the Gainesville metropolitan area, Florida, Gainesv ...
were also studied, but not included in the type series. The fossils 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 ...
s Steven Manchester, Kathleen Pigg, and Melanie DeVore with their 2019 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 ...
being published in the journal ''Fossil Imprint''. The etymology
Etymology ( ) is the study of the origin and evolution of words—including their constituent units of sound and meaning—across time. In the 21st century a subfield within linguistics, etymology has become a more rigorously scientific study. ...
of the specific name Specific name may refer to:
* in Database management systems, a system-assigned name that is unique within a particular database
In taxonomy, either of these two meanings, each with its own set of rules:
* Specific name (botany), the two-part (bino ...
''postnastae'' is a reference to the older Ypresian
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...
age '' Trochodendron nastae'' which it resembles.[ ''T. nastae'' was in turn named as a matronym honoring trochodendralean ]botanist
Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...
Charlotte G. Nast.