Acer toradense
Encyclopedia
Acer toradense is an extinct maple
species
in the family Sapindaceae
described from two fossil
samara
s. The species is solely known from the Early Eocene sediments exposed in northeast Washington State, USA and the adjacent area of south central British Columbia
, Canada. It is one of three species belonging to the extinct section Torada.
fossil was recovered from Resner Canyon, location National Museum of Natural History
USNM 11018 in the Toroda Creek Graben of Northeast Washington State. Location USNM 11018 is an outcropping of early Eocene, Ypresian
, shale belonging to the Klondike Mountain Formation
. The paratype
specimen was recovered from sediments of the Ypresian Allenby Formation exposed in the Blue Flame mine near Princeton, British Columbia
. Both the Allenby and Klondike Mountain Formations 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 confer-broad leaf forest with large pollen elements of birch
and golden larch, but also having notable traces of fir
, spruce
, cypress
, and palm
. The Allenby formation is similar with the birch and golden larch as strong pollen signals and traces of fir and spruce, however the cypress and palm are not distinct signals.
Acer toradense was described from a pair of specimens, the holotype, number "USNM 396010 A,B" which is currently preserved in the paleobotanical
collections housed at the National Museum of Natural History
, part of the Smithsonian Institution
in Washington, D.C.
and the paratype, "UBCB 2400", is in the paleobotanical collection of the University of British Columbia
in Victoria, British Columbia
. The specimens were studied by paleobotanists Jack A. Wolfe
of the United States Geological Survey, Denver office
and Toshimasa Tanai of Hokkaido University
. Wolfe and Tanai published their 1987 type description for A. toradense in the Journal of the Faculty of Science, Hokkaido University. The etymology
of the chosen specific name
toradense is in recognition of the type locality in the Toroda Creek Graben. A. toradense is one of three species assigned to the extinct section Torada. 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, 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.
Maple
Acer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in the family Sapindaceae
Sapindaceae
Sapindaceae, also known as the soapberry family, is a family of flowering plants in the order Sapindales. There are about 140-150 genera with 1400-2000 species, including maple, horse chestnut and lychee....
described from two fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
samara
Samara (fruit)
A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...
s. The species is solely known from the Early Eocene sediments exposed in northeast Washington State, USA and the adjacent area of south central British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, Canada. It is one of three species belonging to the extinct section Torada.
History and classification
The species was described from a pair of complete fruit specimens. The holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
fossil was recovered from Resner Canyon, location National Museum of Natural History
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. Admission is free and the museum is open 364 days a year....
USNM 11018 in the Toroda Creek Graben of Northeast Washington State. Location USNM 11018 is an outcropping of early Eocene, Ypresian
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
, shale belonging to the Klondike Mountain Formation
Klondike Mountain Formation
The Klondike Mountain Formation is an early Eocene geologic formation that records the sedimentation in the southern most of a string of highland subtropical/Temperate lakes in Washington state and British Columbia. The formation is best known for exceptionally well preserved plant and insect fossils...
. The paratype
Paratype
Paratype is a technical term used in the scientific naming of species and other taxa of organisms. The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany...
specimen was recovered from sediments of the Ypresian Allenby Formation exposed in the Blue Flame mine near Princeton, British Columbia
Princeton, British Columbia
Princeton is a small town in the Similkameen region of southern British Columbia, Canada. It lies just east of the Cascade Mountains, which continue south into Washington, Oregon and California. The Tulameen and Similkameen Rivers converge here...
. Both the Allenby and Klondike Mountain Formations preserve upland temperate floras which were first interpreted as being Microthermal
Microthermal
In climatology, the term microthermal is used to denote the continental climates of Eurasia and North America.The word microthermal is derived from two Greek words meaning "having little heat." This is misleading, however, since the term is intended to describe only the temperature conditions that...
, however further study has shown them to be more mesothermal
Mesothermal
In climatology, the term mesothermal is used to refer to certain forms of climate found typically in the Earth's Temperate Zones. It has a moderate amount of heat, with winters not cold enough to sustain snow cover...
in nature. The plant community preserved in the Klondike Mountain formation is a mixed confer-broad leaf forest with large pollen elements of birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...
and golden larch, but also having notable traces of fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...
, spruce
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 regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
, cypress
Taxodium
Taxodium is a genus of one to three species of extremely flood-tolerant conifers in the cypress family, Cupressaceae...
, and palm
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...
. The Allenby formation is similar with the birch and golden larch as strong pollen signals and traces of fir and spruce, however the cypress and palm are not distinct signals.
Acer toradense was described from a pair of specimens, the holotype, number "USNM 396010 A,B" which is currently preserved in the paleobotanical
Paleobotany
Paleobotany, also spelled as palaeobotany , is the branch of paleontology or paleobiology dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments , and both the evolutionary history of plants, with a...
collections housed at the National Museum of Natural History
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. Admission is free and the museum is open 364 days a year....
, part of the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
in Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
and the paratype, "UBCB 2400", is in the paleobotanical collection of the University of British Columbia
University of British Columbia
The University of British Columbia is a public research university. UBC’s two main campuses are situated in Vancouver and in Kelowna in the Okanagan Valley...
in Victoria, British Columbia
Victoria, British Columbia
Victoria is the capital city of British Columbia, Canada and is located on the southern tip of Vancouver Island off Canada's Pacific coast. The city has a population of about 78,000 within the metropolitan area of Greater Victoria, which has a population of 360,063, the 15th most populous Canadian...
. The specimens were studied by paleobotanists Jack A. Wolfe
Jack A. Wolfe
Jack Albert Wolfe was an American paleontologist best known for his studies of Tertiary climate in western North America through analysis of fossil angiosperm leaves.-External links:...
of the United States Geological Survey, Denver office
United States Geological Survey
The United States 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, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
and Toshimasa Tanai of Hokkaido University
Hokkaido University
Hokkaido University is one of the most prestigious universities in Japan. It can be seen in the several rankings such as shown below.-General Rankings:...
. Wolfe and Tanai published their 1987 type description for A. toradense in the Journal of the Faculty of Science, Hokkaido University. The etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
of the chosen specific name
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
toradense is in recognition of the type locality in the Toroda Creek Graben. A. toradense is one of three species assigned to the extinct section Torada. The three members of the section A. stonebergae
Acer stonebergae
Acer stonebergae is an extinct maple species in the family Sapindaceae described from two fossil samaras. The species is solely known from the Early Eocene sediments exposed in northeast Washington State, USA and the adjacent area of south central British Columbia, Canada...
, A. toradense, and A. washingtonense
Acer washingtonense
Acer washingtonense is an extinct maple species in the family Sapindaceae described from one fossil leaf and four fossil samaras. The species is solely known from the Early Eocene sediments exposed in northeast Washington State, USA...
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, 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.