''Metasequoia foxii'' is an extinct

redwood Sequoioideae, popularly known as redwoods, is a subfamily of coniferous trees within the family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affini ...

species In biology, a species is the basic unit of 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 the appropriate s ...

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 ...

described from numerous fossils of varying growth stage. The species is solely known from the

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), E ...

sediments exposed in central

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...

, Canada. It is one of three extinct species belonging to the redwood genus ''

Metasequoia ''Metasequoia'', or dawn redwoods, is a genus of fast-growing deciduous trees, one of three species of pinophyta, conifers known as redwoods. The living species ''Metasequoia glyptostroboides'' is native to Lichuan, Hubei, Lichuan county in Hube ...

''.

History and classification

The species is known from a very large number of attached and isolated plant sections ranging from new seedlings to a large upright partial stump, collected from two outcrops of the

Paskapoo Formation The Paskapoo Formation is a stratigraphic unit of Middle to Late Paleocene age in the Western Canada Sedimentary Basin. The Paskapoo underlies much of southwestern Alberta, and takes the name from the Blindman River (''paskapoo'' means "blind man ...

exposed east of

Red Deer The red deer (''Cervus elaphus'') is one of the largest deer species. A male red deer is called a stag or hart, and a female is called a hind. The red deer inhabits most of Europe, the Caucasus Mountains region, Anatolia, Iran, and parts of wes ...

in central Alberta. The formation is composed of medium-grain buff to light gray sandstones interbedded with finer sandstones and mudstones lying at an almost flat level. The outcrop at the Munce’s Hill location, also known as One Jaw Gap, is heavily fractured which resulted in difficulty removing the fossils for study. A number of the larger specimens were photographed prior to removal from the outcrop face to aid in study. Present at the Munce’s Hill location was one large upright stump which Stockey, Rothwell and Falder interpreted as being preserved

in situ ''In situ'' (; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position." It can mean "locally", "on site", "on the premises", or "in place" to describe where an event takes place and is used in ...

. The fossils of the formation are preserved as coalified compressions which have been oxidized. ''Metasequoia foxii'' was described from a selection of 10,147 fossils. The group is composed of 3263 seeds, 1850 seedlings in various stages of development, the in situ trunk, 2536 branches and branchlets, 123 branchlets with pollen cones, and 2373 ovulate cones. 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 Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository ...

, number "UAPC-ALTA S28,476" is an isolated ovulate cone on a long stem. All the specimens studied are currently 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 at 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 Rutherfor ...

. 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 Ruth A. Stockey of the University of Alberta in

Edmonton 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 ancho ...

, Alberta, Canada with Gar W. Rothwell and Amy B. Falder of the

Ohio University Ohio University is a Public university, public research university in Athens, Ohio. The first university chartered by an Act of Congress and the first to be chartered in Ohio, the university was chartered in 1787 by the Congress of the Confeder ...

Athens, Ohio Athens is a city and the county seat of Athens County, Ohio. The population was 23,849 at the 2020 census. Located along the Hocking River within Appalachian Ohio about southeast of Columbus, Athens is best known as the home of Ohio Universit ...

, USA. Stockey, Rothwell, and Falder published their 2001

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 ...

for ''M. foxii'' 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, ...

''. The

etymology Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological chan ...

of the chosen specific name ''foxii'' is in recognition of vertebrate paleontologist Richard C. Fox from the University of Alberta, who suggested several fossil localities to the authors for study including the Munce’s Hill and Gao mine sites. ''M. foxii'' is one of three currently recognized extinct species in the genus ''

'', which is now represented by the single living species '' M. glyptostroboides''. The species '' M. milleri'' is known only from the early Eocene

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 ...

Allenby Formation The Allenby formation is a sedimentary rock formation in British Columbia which was deposited during the Ypresian stage of the Early Eocene. It consists of conglomerates, sandstones with interbedded shales and coal. The shales contain an abun ...

near

Princeton, British Columbia Princeton (originally Vermilion Forks) is a town in the Similkameen region of southern British Columbia, Canada."The rich history of Princeton or how Vermilion Forks made it on the map...", Princeton 2008 Visitors Guide, p. 4. It lies just east o ...

. Formerly up to 20 species of extinct ''Metasequoia'' were proposed, however the majority were synonymised into the form species '' M. occidentalis'' which is known from numerous sites in the northern hemisphere.

Description

The cell structure of ''M. foxii'' is fairly well preserved in the large stump. Samples taken from the specimen show notably large

rays Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (gra ...

up to 110 cells in height. The ray height for ''M. milleri'' is up to 80 cells and ''M. glyptostroboides'' has a ray of up to only 20 cells. As ''M. occidentalis'' is only known from compression fossils the ray size is unknown. While the overall height of ''M. foxii'' trees is not known, examination of the

tracheid A tracheid is a long and tapered lignified cell in the xylem of vascular plants. It is a type of conductive cell called a tracheary element. Angiosperms use another type of tracheary element, called vessel elements, to transport water through the ...

cells in conifers can be used to estimate the overall height of the tree. The diameter for tracheids in ''M. glyptostroboides'' is between 30–40 µm, while the diameter of tracheids in ''M. foxii'' is up to 55 µm. It is probable that ''M. foxii'' grew to be larger than the modern species which averages over in height. Unlike the other species of ''Metasequoia'', the ovulate cones of ''M. foxii'' have five ranks of helically arranged cone scale complexes, which is in contrast to the normally decussately arranged group of four cone scale complexes of the other species. ''M. milleri'' can be distinguished from ''M. foxii'' by the structure of the mature pollen cones which in ''M. milleri'' have sporophylls that are separated by elongation of the bud scales and transition from a helical arrangement to a disorganized one with maturation.

References

{{Taxonbar, from=Q1823084 foxii Plants described in 2001 Fossil taxa described in 2001 Paleocene plants Extinct flora of North America Prehistoric trees