Chamaecyparis eureka is an extinct species of conifer in the family Cupressaceae

Cupressaceae

The Cupressaceae or cypress family is a conifer family with worldwide distribution. The family includes 27 to 30 genera , which include the junipers and redwoods, with about 130-140 species in total. They are monoecious, subdioecious or dioecious trees and shrubs from 1-116 m tall...

. It is known from fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 foliage found in the Buchanan Lake Formation deposits, dated to the middle Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 Lutetian

Lutetian

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

 stage , from western Axel Heiberg Island

Axel Heiberg Island

Axel Heiberg Island is an island in the Qikiqtaaluk Region, Nunavut, Canada. Located in the Arctic Ocean, it is the 31st largest island in the world and Canada's seventh largest island. According to Statistics Canada, it has an area of ....

, located in the Arctic Ocean

Arctic Ocean

The Arctic Ocean, located in the Northern Hemisphere and mostly in the Arctic north polar region, is the smallest and shallowest of the world's five major oceanic divisions...

 in the Qikiqtaaluk Region, Nunavut

Nunavut

Nunavut is the largest and newest federal territory of Canada; it was separated officially from the Northwest Territories on April 1, 1999, via the Nunavut Act and the Nunavut Land Claims Agreement Act, though the actual boundaries had been established in 1993...

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. C. eureka is the oldest confirmed member of the genus Chamaecyparis

Chamaecyparis

Chamaecyparis is a genus of conifers in the cypress family Cupressaceae, native to eastern Asia and western and eastern North America. In the nursery trade it is often incorrectly known as "false cypress" for lack of other common name, so as to distinguish it from other similar genera bearing...

, which includes five to six living species, depending on circumscription, which are native to Eastern Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, and North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

.

Description of the new species by M. E. A. Kotyk, James Basinger, and Elisabeth McIlver was based on the study of more than 850 twigs and 650 seed cone specimens; the holotype

Holotype

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...

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

University of Saskatchewan

The University of Saskatchewan is a Canadian public research university, founded in 1907, and located on the east side of the South Saskatchewan River in Saskatoon, Saskatchewan, Canada. An "Act to establish and incorporate a University for the Province of Saskatchewan" was passed by the...

, Saskatoon

Saskatoon

Saskatoon is a city in central Saskatchewan, Canada, on the South Saskatchewan River. Residents of the city of Saskatoon are called Saskatonians. The city is surrounded by the Rural Municipality of Corman Park No. 344....

, Saskatchewan, Canada. They published their 2003 type description of the species in the Canadian Journal of Botany volume number 81. and named the species eureka to reflect the type locality placement in the Eureka Sound group, Axel Heiberg Island.

C. 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

Cupressus

The genus Cupressus is one of several genera within the family Cupressaceae that have the common name cypress; for the others, see cypress. It is considered a polyphyletic group...

and Fokienia

Fokienia

Fokienia is a genus in the family Cupressaceae. In its characteristics, Fokienia is intermediate between the genera of Chamaecyparis and Calocedrus, though genetically much closer to the former...

. 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

Chamaecyparis pisifera

Chamaecyparis pisifera Chamaecyparis pisifera Chamaecyparis pisifera (Sawara Cypress or Sawara is a species of false cypress, native to central and southern Japan, on the islands of Honshū and Kyūshū....

and to a lesser extent to the western North American C. lawsoniana

Chamaecyparis lawsoniana

Chamaecyparis lawsoniana is a cypress in the genus Chamaecyparis, family Cupressaceae, known by the name Lawson's Cypress in the horticultural trade, or Port Orford-cedar in its native range . C...

. 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.