''Pinus matthewsii'' is an extinct

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

conifer Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ex ...

in the

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family (biology), family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanic ...

family. The species is solely known from the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Porcupine River The Porcupine River (''Ch’ôonjik'' in Gwich’in) is a tributary of the Yukon River in Canada and the United States. It rises in the Ogilvie Mountains north of Dawson City, Yukon, Canada. From there it flows north through the community of ...

near

Old Crow, Yukon Old Crow is a community in the Canadian territory of Yukon. Located in a periglacial environment, the community is situated on the Porcupine River in the far northern part of the territory. Old Crow is the only Yukon community that cannot be re ...

, Canada.

Type locality

''Pinus matthewsii'' was described from the three

ovulate 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 all found at the Ch’ijee's Bluff locality, number HH228. This locality is in the Bluefish Basin and considered part of one of the most complete records of the Pliocene and Early Pleistocene in northwestern North America. The Bluefish and neighboring Old Crow basins were part of the unglaciated Beringian refugium of North America, which harbored the ancestors of the modern

subsection

Contortae Contortae as a term has appeared in several senses in botanical taxonomy, most conspicuously as follows: Order Contortae Order Contortae is no longer recognised in botanical taxonomy. After a varied history in the nineteenth century, predominant op ...

. The subsection is thought to have radiated out from the refugium into the species '' P. contorta'' and '' P. banksiana''. All the cones were preserved in the basal "unit 1" section of the Ch’ijee's Bluff outcrop. Unit 1 is composed of sands, gravels and clays, thought to have been forest floor which was rapidly covered by alluvial sediments.

History and classification

''Pinus matthewsii'' is known from only three fossils, 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 seve ...

, number "UAPC-ALTA P610", and the

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). O ...

s number "UAPC-ALTA 609" and "UAPC-ALTA 611". All three specimens, plus

thin section In optical mineralogy and petrography, a thin section (or petrographic thin section) is a thin slice of a rock or mineral sample, prepared in a laboratory, for use with a polarizing petrographic microscope, electron microscope and electron m ...

slides are preserved in the

paleobotanical 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 ...

collections housed in the

University of Alberta The University of Alberta, also known as U of A or UAlberta, is a public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford,"A Gentleman of Strathcona – Alexander Cameron Ruth ...

Edmonton, Alberta Edmonton ( ) is the capital city of the Canadian province of Alberta. Edmonton is situated on the North Saskatchewan River and is the centre of the Edmonton Metropolitan Region, which is surrounded by Alberta's central region. The city anch ...

, Canada. 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 Athena D. McKown and Ruth A. Stockey of the University of Alberta Department of Biological Sciences, and Charles E. Schweger of the Department of Anthropology. Athena McKown and coauthors published the 2002

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 ...

for ''P. matthewsii'' in the ''

International Journal of Plant Sciences The ''International Journal of Plant Sciences'' covers botanical research including genetics and genomics, developmental and cell biology, biochemistry and physiology, morphology and structure, systematics, plant-microbe interactions, paleobotany ...

''. In describing the species Athena McKown and coauthors chose the

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''matthewsii'', in honor of John V. Matthews Jr. of the

Geological Survey of Canada The Geological Survey of Canada (GSC; french: Commission géologique du Canada (CGC)) is a Canadian federal government agency responsible for performing geological surveys of the country, developing Canada's natural resources and protecting the e ...

in recognition of his work on

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non- avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

and Quaternary paleoenvironmental reconstructions, through

palynology Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits ...

and

paleobotany 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 (paleogeog ...

, of

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S ...

and Yukon locations. The ovulate cones of ''Pinus matthewsii'' range from in length and . While the overall morphology and structure of ''P. matthewsii'' cones compare to cones of the living species ''Pinus banksiana'', notable differences occur. The elongated cones of ''P. banksiana'' have an asymmetrically reflexed cone base, while ''P. matthewsii'' are symmetrical and oval. Cones of ''P. matthewsii'' and ''P. contorta'' are also similar in structuring, however the combination of characters that are present in ''P. matthewsii'' are not found in any one of the subspecies of ''P. contorta''. Similar to the modern habits of ''P. contorta'', it is suggested that ''P. matthewsii'' may have been a shade intolerant tree which acted as a colonizer. This is supported by the seeds preserved within the cones, the seeds being small with long detachable

wings A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is exp ...

. The combination of characters would support a large wind dispersal range.

References

{{Taxonbar, from=Q3388846 matthewsii Plants described in 2002 Pliocene life Trees of Canada Extinct flora of North America Fossil taxa described in 2002 Prehistoric trees