''Chamaecyparis eureka'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

species of conifer in the family

Cupressaceae Cupressaceae is a conifer family, the cypress family, with worldwide distribution. The family includes 27–30 genera (17 monotypic), which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdio ...

. It is 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 preserved ...

foliage found in the

Buchanan Lake Formation The Buchanan Lake Formation is a geologic formation on Axel Heiberg Island in Nunavut, and part of the Eureka Sound Group. The formation is divided into four members and preserves fossils dating back to the Lutetian stage. See also * List of ...

deposits, dated to the middle

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

Lutetian The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Midd ...

stage (), from western Axel Heiberg Island, located in the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...

in the Qikiqtaaluk Region, Nunavut,

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. ''C. eureka'' is the oldest confirmed member of the genus '' Chamaecyparis'', which includes five to six living species, depending on circumscription, which are native to Eastern

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. Description of the new species by M. E. A. Kotyk, James Basinger, and Elisabeth McIver was based on the study of more than 850 twigs and 650

seed cone A conifer cone (in formal botanical usage: strobilus, plural strobili) is a seed-bearing organ on gymnosperm plants. It is usually woody, ovoid to globular, including scales and bracts arranged around a central axis, especially in conifers an ...

specimens; 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 ...

specimen, number "USPC-6357", and the five paratypes are housed in the University of Saskatchewan Paleobotanical Collection,

Saskatoon Saskatoon () is the largest city in the Provinces and territories of Canada, Canadian province of Saskatchewan. It straddles a bend in the South Saskatchewan River in the central region of the province. It is located along the Trans-Canada Hig ...

, Saskatchewan, Canada. They published their 2003

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 ...

of the species in the ''

Canadian Journal of Botany ''Botany'' is a monthly peer-reviewed scientific journal that is published by Canadian Science Publishing. It was established in 1935 as the ''Canadian Journal of Research, Section C: Botanical Sciences'' and renamed in 1951 as ''Canadian Journal ...

'' volume number 81. and named the species ''eureka'' to reflect the type locality placement in the

Eureka Sound group The Eureka Sound Group is a geologic group in Nunavut. It preserves fossils dating back to the Paleogene period. See also * List of fossiliferous stratigraphic units in Nunavut This is a list of fossiliferous stratigraphic units in Nunavut, Can ...

, Axel Heiberg Island. ''Chamaecyparis eureka'' has been placed in the genus ''Chamaecyparis'', based on the morphology of the seed cones, which differ significantly in the important characters from cone of related genera '' Cupressus'' and ''

Fokienia ''Fokienia'' is a genus of conifer tree belonging to the cypress family. In its characteristics, ''Fokienia'' is intermediate between the genera of ''Chamaecyparis'' and ''Calocedrus''. Genetically ''Fokienia'' is much closer to ''Chamaecyparis'' ...

''. The general structure is that of a woody cone borne on the tip of a leafy branch; the cones are elongated to globose in overall shape. The cone scales bear between three and five winged seeds. ''C. eureka'' is most similar in character to the extant Japanese species '' Chamaecyparis pisifera'' and to a lesser extent to the western North American '' C. lawsoniana''. The seed cones of ''C. eureka'' tend to be intermediate between the ranges normal for ''C. pisifera'', which are smaller, and ''C. lawsoniana'', which are larger. While the seed body and number of resin tubercles in ''C. eureka'''s winged seeds are most similar to those of ''C. pisifera'', no seed specimens have yet to be recovered with intact wings, so a more in-depth comparison to living species was not possible.

References

{{Taxonbar, from=Q5069348 †eureka Plants described in 2003 Eocene plants Extinct flora of North America Fossil taxa described in 2003 Prehistoric trees Buchanan Lake Formation