''Acer washingtonense'' 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 one

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 ...

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

and four fossil

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 solely known from the

Early Eocene In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian i ...

sediments exposed in northeast

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 ...

, United States. It is one of three species belonging to the extinct section '' Torada''.

History and classification

''Acer washingtonense'' was described from a lone leaf specimen and four complete fruit specimens which were recovered from three different locations. The lone leaf and two of the samara's were found in an outcrop of shale on Knob Hill north of

Republic, Washington Republic is a city in Ferry County, Washington, United States. The population was 1,073 at the 2010 census, a 12.5% increase over the 2000 census. It is the county seat of Ferry County. It was the largest mining camp in the Republic Mining Distr ...

identified as Burke Museum of Natural History and Culture location UWBM B2737. The third samara fossil is from the Burke Museum location UWBM A0307 located within the town of Republic itself and the last samara was recovered from Resner Canyon,

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 ...

location USNM 11018. Both UWBM B2737 and UWBM A0307 are in the Republic Graben while USNM 11018 is in the Toroda Creek Graben. Each of the sites are considered outcroppings of early Eocene,

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 ...

, shale belonging to the

Klondike Mountain Formation The Klondike Mountain Formation is an Early Eocene (Ypresian) geological formation located in the northeast central area of Washington state. The formation, named for the type location designated in 1962, Klondike Mountain north of Republic, Wash ...

. The Klondike Mountain Formation, along with site of the same age in

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, ...

preserve upland temperate floras which were first interpreted as being Microthermal, however further study has shown them to be more mesothermal in nature. The plant community preserved in the Klondike Mountain formation is a mixed conifer-broad leaf forest with large pollen elements of

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 ...

and golden larch, but also having notable traces of

fir Firs (''Abies'') are a genus of 48–56 species of evergreen coniferous trees in the family (biology), family Pinaceae. They are found on mountains throughout much of North America, North and Central America, Europe, Asia, and North Africa. The ...

spruce A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

cypress Cypress is a common name for various coniferous trees or shrubs of northern temperate regions that belong to the family Cupressaceae. The word ''cypress'' is derived from Old French ''cipres'', which was imported from Latin ''cypressus'', the ...

, and palm. The species was described from a group of specimens, the holotype, number "UWBM 56253 A,B" and the paratypes "UWBM 56255", "UWBM 71135 A,B" and "UWBM 54308" 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 Burke Museum, part of the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...

Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...

while the paratype, "USNM 396011", is in the paleobotanical collections of the

, part of the

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...

Washington, D.C. ) , image_skyline = , image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...

The specimens were studied by paleobotanists

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. 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. toradense'' 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 ...

''washingtonense'' is in recognition of the type locality in Northeastern Washington State. ''A. washingtonense'' is one of three species assigned to the extinct section ''Torada'' and is designated the type species for the section. The three members of the section '' A. stonebergae'', '' A. toradense'', and ''A. washingtonense'' were known only from the Republic and Princeton fossil localities when first described. Of the three species, both ''A. stonebergae'' and ''A. toradense'' are only known from the samara fossils, and only ''A. washingtonense'' has been described from both leaves and samaras. The three are among a number of ''Acer'' species described from the Republic and Princeton sites by Wolfe and Tanai.

Description

Leaves of ''Acer washingtonense'' are simple in structure and with perfectly actinodromous vein structure and a generally wide elliptic shape. The leaves are shallowly three-lobed, with five primary veins and is wide by an estimated long in overall dimension. ''A. washingtonense'' has a simple structure to the teeth that is similar to the Alaskan fossil species '' A. alaskense'' and '' A. douglasense'' and the modern species '' A. spicatum''. The samaras have distinct bifurcating ridges on the nutlet which are unique to section Torada. The overall shape of the samara is ovoid with an average length of up to and a wing width of . The paired samaras for ''A. washingtonense'' have a 45° attachment angle and the attachment scar on the nutlet is . While very similar in morphology to ''A. toradense'', the two possibly related species can be separated by the coarse reticulum of veins which is found on ''A. toradense'' and not ''A. washingtonense''. The samaras of ''A. stonebergae'' are distinguishable from both ''A. toradense'' and ''A.washingtonense'' by their notably larger overall size.

References

{{Taxonbar, from=Q4673180 washingtonense Prehistoric angiosperms Plants described in 1987 Fossil taxa described in 1987 Ypresian plants of North America Extinct flora of North America Klondike Mountain Formation