''Acer browni'' is an extinct

maple ''Acer'' () is a genus of trees and shrubs commonly known as maples. The genus is placed in the family Sapindaceae.Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 nd more or less continuously updated since http ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

in the family

Sapindaceae The Sapindaceae are a family of flowering plants in the order Sapindales known as the soapberry family. It contains 138 genera and 1858 accepted species. Examples include horse chestnut, maples, ackee and lychee. The Sapindaceae occur in tempera ...

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 ...

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 ...

and

samara Samara ( rus, Сама́ра, p=sɐˈmarə), known from 1935 to 1991 as Kuybyshev (; ), is the largest city and administrative centre of Samara Oblast. The city is located at the confluence of the Volga and the Samara (Volga), Samara rivers, with ...

s. The species is known from the

early Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

middle Miocene The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million y ...

sediments exposed in Western

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

Washington state Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washington ...

, USA and Northern

Graham Island Graham Island () is the largest island in the Haida Gwaii archipelago (previously known as the Queen Charlotte Islands), lying off the mainland coast of British Columbia, Canada. It is separated by the narrow Skidegate Channel from the other pri ...

Haida Gwaii Haida Gwaii (; hai, X̱aaydag̱a Gwaay.yaay / , literally "Islands of the Haida people") is an archipelago located between off the northern Pacific coast of Canada. The islands are separated from the mainland to the east by the shallow Hecat ...

, Canada. It is one of several extinct species placed in the living section '' Parviflora''.

History and classification

The eleven leaf specimens used to describe ''Acer browni'' were recovered from five different sites. The largest group of specimens was recovered from the early Miocene, Aquitanian, Collawash site exposed near the

Collawash River The Collawash River is a tributary of the Clackamas River in the U.S. state of Oregon. Formed by the confluence of Elk Lake Creek and the East Fork Collawash River in the Cascade Range, it flows generally north-northwest from source to mouth thr ...

Clackamas County Clackamas County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 421,401, making it Oregon's third-most populous county. Its county seat is Oregon City. The county was named after the Native ...

Oregon. Two additional paratype leaves were recovered from outcrops of the

Latah Formation The Latah Formation is a series of late Miocene lacustrine sedimentary deposits which outcrop in eastern Washington and northwestern Idaho. The lake beds are interbedded with igneous rock of the Columbia River Basalt Group. The formation was ...

at the Vera site near

Veradale, Washington Veradale—originally known as Vera—is a locale and former census-designated place (CDP) in Spokane County, Washington, United States. The population was 9,387 at the 2000 United States Census, 2000 census. Veradale retains its own post office. H ...

. Another Washington site, on Bunker Creek west of

Centralia, Washington Centralia () is a city in Lewis County, Washington, United States. It is located along Interstate 5 near the midpoint between Seattle and Portland, Oregon. The city had a population of 18,183 at the 2020 census. Centralia is twinned with Cheh ...

produced one paratype leaf of middle Miocene age. The last paratype leaf is from the species' northernmost location, having been recovered from an outcrop of the late early Miocene Skonun Formation on the northern side of Graham Island in the

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

. In addition to the leaf specimens a series of paratype specimens were described for the associated samaras recovered at the Collawash site and

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

site USGS 8904 near the

Little Butte Creek Little Butte Creek is a tributary of the Rogue River in the U.S. state of Oregon. Its drainage basin consists of approximately of Jackson County and another of Klamath County. Its two forks, the North Fork and the South Fork, both begin h ...

Jackson County, Oregon Jackson County is one of the Oregon counties, 36 counties in the U.S. state of Oregon. As of the 2020 United States census, 2020 census, the population was 223,259. The county seat is Medford, Oregon, Medford. The county Oregon Geographic Names, ...

. The type specimens for ''Acer browni'' are placed into three different repositories. The

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 ...

leaf and thirteen of the

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 ...

s are currently preserved in the

paleobotanical 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 ...

collections housed at 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 and ...

, 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 Irish bishop and philosopher George Berkeley. It borders the cities of Oakland and Emer ...

. Three other paratype leaves and one paratype samara are housed in the

National Museum of Natural History The National Museum of Natural History 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. In 2021, with 7 ...

, part of the Smithsonian while the last paratype leaf is part of the

University of British Columbia The University of British Columbia (UBC) is a public university, public research university with campuses near Vancouver and in Kelowna, British Columbia. Established in 1908, it is British Columbia's oldest university. The university ranks a ...

collections in

Vancouver Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...

. 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 ...

Jack A. Wolfe Jack Albert Wolfe (1936–2005) was a United States Geological Survey paleobotanist and paleoclimatologist best known for his studies of Tertiary climate in western North America through analysis of fossil A fossil (from Classical Latin ...

of the United States Geological Survey, Denver office and Toshimasa Tanai of

Hokkaido University , or , is a Japanese national university in Sapporo, Hokkaido. It was the fifth Imperial University in Japan, which were established to be the nation's finest institutions of higher education or research. Hokkaido University is considered ...

. Wolfe and Tanai published their 1987

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 ''A. browni'' in the ''Journal of the Faculty of Science, Hokkaido University''. The

etymology Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological chan ...

of the chosen

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 ...

''browni'' is in recognition of paleobotanist Roland Wilbur Brown for his many contributions to

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

paleobotany.

Description

Leaves of ''Acer browni'' are simple in structure, with perfectly actinodromous vein structure and are generally oblate to widely elliptical in shape. The leaves are five-lobed with the basal two lobes small while the upper lateral lobes are about two-thirds as long as the median lobe and all lobes being triangular in outline. The leaves have five primary veins and range between long by wide in overall dimensions. ''A. browni'' has small teeth while the lobes have a distinct and complex bracing of veins formed by the joining of two external secondary veins. The combination of morphological features is not found in any modern species besides '' A. nipponicum'' and as such ''A. browni'' is placed into the section ''Parviflora''. The samaras of ''A. browni'' have a notably inflated nutlet and acutely diverging veins which rarely

anastomise An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be norma ...

. The overall shape of the nutlet is circular to elliptic with the average length of the samara up to and a wing width of . The paired samaras of the species have a 25° to 30° attachment angle and the distal region of the nutlet and wing forming distinct u-shaped shallow sulcus. While similar in morphology to ''A. nipponicum'', the two related species can be separated by the sulcus which is developed in ''A. browni'' but not seen in the samaras of ''A. nipponicum''.

References

{{Taxonbar, from=Q4673139 browni Plants described in 1987 Fossil taxa described in 1987 Miocene plants Extinct flora of North America Fossils of Canada Fossils of the United States