''Carpinus perryae'' 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), ...

hornbeam Hornbeams are hardwood trees in the plant genus ''Carpinus'' in the family Betulaceae. Its species occur across much of the temperateness, temperate regions of the Northern Hemisphere. Common names The common English name ''hornbeam'' derives ...

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 ...

fruit In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...

s found in the

Klondike Mountain Formation The Klondike Mountain Formation is an Early Eocene (Ypresian) geological formation located in the northeast central area of Washington (state), Washington state. The formation is composed of volcanic rocks in the upper unit and volcanic plus lacu ...

deposits of northern

Washington state Washington, officially the State of Washington, is a state in the Pacific Northwest region of the United States. It is often referred to as Washington State to distinguish it from the national capital, both named after George Washington ...

, dated to the early

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

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 ...

stage. Based on described features, ''C. perryae'' is the oldest definite species in the genus ''Carpinus''.

History and classification

''Carpinus perryae'' was described from two

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

s, the

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 ...

and

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 (biology), isotype ...

fertile bracts, numbered UWBM 71171, specimen A and B respectively. Both

compression fossil A compression fossil is a fossil preserved in sedimentary rock that has undergone physical compression. While it is uncommon to find animals preserved as good compression fossils, it is very common to find plants preserved this way. The reason f ...

specimens are preserved together on a single rock slab that is part of the

Burke Museum The Burke Museum of Natural History and Culture (commonly as Burke Museum) is a natural history museum on the campus of the University of Washington, in Seattle, Washington (state), Washington, United States. It is administered by the University ...

paleobotanical collections. Found at the

s UWBM site B2737, which is designated the type locality, the fossils were described 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 Pigg, Manchester, and Wehr (2003) along with '' Corylus johnsonii'' and '' Palaeocarpinus barksdaleae''. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''perryae'' was coined as a

matronym A matronymic is a personal name or a parental name based on the given name of one's mother, grandmother, or any female ancestor. It is the female equivalent of a patronymic. Around the world, matronymic surnames are far less common than patrony ...

recognizing Madilane Perry for her work founding the

Stonerose Interpretive Center The Stonerose Interpretive center & Eocene Fossil Site is a 501c(3), 501c(3) non-profit public museum and fossil dig located in Republic, Washington. The center was established in 1989 and houses fossils that have been featured in ''National Geo ...

Republic, Washington Republic is a city in Ferry County, Washington, United States. The population was 992 at the 2020 census. It is the county seat of Ferry County. It was the largest mining camp in the Republic Mining District, and home to the "Hot Air Line" rail ...

. Pigg, Manchester, and Wehr (2003) noted at the time of description that ''Carpinus perryae'' was the oldest confirmed

fossil placed in ''

Carpinus Hornbeams are hardwood trees in the plant genus ''Carpinus'' in the family Betulaceae. Its species occur across much of the temperate regions of the Northern Hemisphere. Common names The common English name ''hornbeam'' derives from the hard ...

'', a status affirmed by Forest ''et al'' (2005) who used ''C perryae'' as a fossil calibration point for phylogenetic analysis of

Betulaceae Betulaceae, the birch family, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams, hazel-hornbeam, and hop-hornbeams, numbering a total of 167 species. They are mostly natives of ...

. Based on six morphological character states that are present in the fossils ranging from nutlet and bract shape to serration of the bract, ''C. perryae'' was determined to be most similar to species in ''Carpinus'' subgenus ''Carpinus'', such as ''

Carpinus monbeigiana Hornbeams are hardwood trees in the plant genus ''Carpinus'' in the family Betulaceae. Its species occur across much of the temperate regions of the Northern Hemisphere. Common names The common English name ''hornbeam'' derives from the hardn ...

''. A noted distinction between the modern species and the fossils is the overall bract shape, ovate in modern species, but obovate in ''C. perryae''.

Distribution and paleoecology

''Carpinus perryae'' is known from a single location in the

Eocene Okanagan Highlands The Eocene Okanagan Highlands or Eocene Okanogan Highlands are a series of Early Eocene geological formations which span a transect of British Columbia, Canada, and Washington state, United States. Known for a highly diverse and detailed plant ...

, an outcrop of the

Republic A republic, based on the Latin phrase ''res publica'' ('public affair' or 'people's affair'), is a State (polity), state in which Power (social and political), political power rests with the public (people), typically through their Representat ...

. The formation preserves an upland lake system surrounded by a mixed conifer–broadleaf forest with nearby volcanism. The pollen flora has notable 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 3 ...

and

golden larch ''Pseudolarix amabilis'' is a species of coniferous tree in the pine family Pinaceae. The species is commonly known as golden larch, but being more closely related to '' Keteleeria'', ''Abies'' and ''Cedrus'', is not a true larch (''Larix''). '' ...

, and distinct trace amounts of

fir Firs are evergreen coniferous trees belonging to the genus ''Abies'' () in the family Pinaceae. There are approximately 48–65 extant species, found on mountains throughout much of North and Central America, Eurasia, and North Africa. The genu ...

spruce A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...

cypress Cypress is a common name for various coniferous trees or shrubs from the ''Cupressus'' genus of the '' Cupressaceae'' family, typically found in temperate climates and subtropical regions of Asia, Europe, and North America. The word ''cypress'' ...

, and

palm Palm most commonly refers to: * Palm of the hand, the central region of the front of the hand * Palm plants, of family Arecaceae ** List of Arecaceae genera **Palm oil * Several other plants known as "palm" Palm or Palms may also refer to: Music ...

. Wolfe and Tanai (1987) interpreted the forest climate to have been

microthermal In climatology, the term microthermal is used to denote the continental climates of Eurasia and North America. Etymology The word ''microthermal'' is derived from two Greek words meaning "small" and "heat". This is misleading, however, since the ...

, having distinct seasonal temperature swings which dipped below freezing in the winters. However, further study has shown the lake system was surrounded by a warm temperate ecosystem that likely had a mesic upper microthermal to lower mesothermal climate, in which winter temperatures rarely dropped low enough for snow, and which were seasonably equitable. The Okanagan Highlands paleoforest surrounding the lakes have been described as precursors to the modern

temperate broadleaf and mixed forests Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions. These ...

of Eastern North America and Eastern Asia. Based on the fossil biotas, the lakes were higher and cooler then the

coeval {{Short pages monitor