''Acer latahense'' 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 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 ...

. The species is known from the latest early to middle Miocene sediments exposed in the states of

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 ...

and

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

, USA. It is one of several extinct species placed in the living section '' Macrantha''.

History and classification

''Acer latahense'' is represented by a group of fossil specimens from three different geologic formations. Three of the leaves were recovered from the early Miocene to late Miocene aged 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 ...

near

Spokane Spokane ( ) is the largest city and county seat of Spokane County, Washington, United States. It is in eastern Washington, along the Spokane River, adjacent to the Selkirk Mountains, and west of the Rocky Mountain foothills, south of the Ca ...

in Washington state. Another leaf is from the similarly aged Mascall formation near Tipton, Oregon, while the last fossil is from the middle Miocene age Succor Creek Formation near

Nyssa, Oregon Nyssa is a city in Malheur County, Oregon, United States. The population was 3,267 at the 2010 census. The city is located along the Snake River on the Idaho border, in the region of far eastern Oregon known as the "Treasure Valley". It is pa ...

. Both the Latah and Mascall Formations are composed of temporary lake beds which are interbedded with lava flows belonging to the

Columbia River Basalt Group The Columbia River Basalt Group is the youngest, smallest and one of the best-preserved continental flood basalt province on Earth, covering over mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. The basalt grou ...

. While the very similar floral composition of the two formations has resulted in both occasionally being termed the Latah Flora, currently the Mascall and Latah are considered separate though coeval formations. The type specimens for ''Acer latahense'' are located in 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

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 ...

, a part and counterpart numbered USNM 396136A, B, and two

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 ...

leaves are currently preserved in the paleobotanical collections 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. One other paratype leaf is 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 ...

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 ...

, while the last paratype leaf is part of the University of Michigan Museum of Paleontology collections in

Ann Arbor, Michigan Ann Arbor is a city in the U.S. state of Michigan and the county seat of Washtenaw County, Michigan, Washtenaw County. The 2020 United States census, 2020 census recorded its population to be 123,851. It is the principal city of the Ann Arbor ...

. 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 ...

s Jack A. Wolfe 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. latahense'' 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 ''latahense'' is in recognition of the type location for the species at the "Brickyard site" outcrop, part of the Latah Formation in Washington State.

Description

Leaves of ''Acer latahense'' are simple in structure with a perfectly actinodromous vein structure in which the primary veins originate at the base of the lamina and run out towards the margin. The leaves are three-lobed with the lateral lobes being about one-third the length of the median lobe. The leaves have three or five primary veins and an estimated size range of long by wide in overall dimensions. The morphology of ''A. latahense'' suggests placement into the ''Acer'' section ''Macrantha''. This is based on the overall vein structure and small uniformly sized teeth and the structuring of the veins. The combination of leaf morphology characters is most similar to the living maple species ''

Acer rufinerve ''Acer rufinerve'', the grey-budded snake-bark-maple, redvein maple or Honshū maple ( Japanese: ウリハダカエデ ''urihadakaede'', "melon-skin maple"), is a species of tree in the snakebark maple group, related to '' Acer capillipes'' (Kyus ...

'', commonly called the redvein or Honshū maple. ''A. latahense'' is distinguishable by the lower number of teeth, which tend to be blunter, and by the structuring of the tertiary veins structure. The extinct species '' Acer palaeorufinerve'' is also notably similar to ''A. latahense'' but has a broader medial lobe. Wolfe and Tanai suggest ''A latahense'' may be a descendant species of ''A. palaeorufinerve''.

References

{{Taxonbar, from=Q4673158 latahense Prehistoric angiosperms Plants described in 1987 Fossil taxa described in 1987 Miocene plants Extinct flora of North America