Metasequoia foxii
Encyclopedia
Metasequoia foxii is an extinct redwood
species
in the family Cupressaceae
described from numerous fossils of varying growth stage. The species is solely known from the Paleocene
sediments exposed in central Alberta
, Canada. It is one of three extinct species belonging to the redwood genus Metasequoia
.
exposed east of Red Deer
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
. 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
specimen, number "UAPC-ALTA S28,476" is an isolated ovulate cone on a long stem. All the specimens studied are currently preserved in the paleobotanical
collections housed at the University of Alberta
. The specimens were studied by paleobotanists Ruth A. Stockey of the University of Alberta in Edmonton, Alberta, Canada with Gar W. Rothwell and Amy B. Falder of the Ohio University
in Athens, Ohio
, USA. Stockey, Rothwell, and Falder published their 2001 type description for M. foxii in the International Journal of Plant Sciences
. The etymology
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 52°18′24"N 113°37′47"W and Gao mine sites.
M. foxii is one of three currently recognized extinct species in the genus Metasequoia
, which is now represented by the single living species M. glyptostroboides
. The species M. milleri is known only from the early Eocene Ypresian
Allenby Formation near Princeton, British Columbia
. 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.
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 known from only compression fossils the ray size is unknown. While the overall height of M. foxii trees is not known, examination of the tracheid
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 200 feet (61 m) 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.
Redwood
-Trees:Conifers* Family Cupressaceae *** Sequoia sempervirens - coast redwood**** Albino redwood*** Sequoiadendron giganteum - giant sequoia*** Metasequoia glyptostroboides - dawn redwood* Family Pinaceae...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
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...
described from numerous fossils of varying growth stage. The species is solely known from the Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
sediments exposed in central Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
, Canada. It is one of three extinct species belonging to the redwood genus Metasequoia
Metasequoia
Metasequoia is a fast-growing, deciduous tree, and the sole living species, Metasequoia glyptostroboides, is one of three species of conifers known as redwoods. It is native to the Sichuan-Hubei region of China. Although the least tall of the redwoods, it grows to at least 200 feet in height...
.
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 FormationPaskapoo Formation
The Paskapoo Formation is a stratigraphical unit of Paleocene age in the Western Canadian Sedimentary Basin.It takes the name from the Blindman River , and was first described in outcrops along the river, north of Red Deer by J. B...
exposed east of Red Deer
Red Deer, Alberta
Red Deer is a city in Central Alberta, Canada. It is located near the midpoint of the Calgary-Edmonton Corridor and is surrounded by Red Deer County. It is Alberta's third-most-populous city – after Calgary and Edmonton. The city is located in aspen parkland, a region of rolling hills...
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
In situ is a Latin phrase which translated literally as 'In position'. It is used in many different contexts.-Aerospace:In the aerospace industry, equipment on board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may...
. 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
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
, and 2373 ovulate cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
. 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 "UAPC-ALTA S28,476" is an isolated ovulate cone on a long stem. All the specimens studied are currently preserved in the paleobotanical
Paleobotany
Paleobotany, also spelled as palaeobotany , is the branch of paleontology or paleobiology dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments , and both the evolutionary history of plants, with a...
collections housed at the University of Alberta
University of Alberta
The University of Alberta is a public research university located in Edmonton, Alberta, Canada. Founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta and Henry Marshall Tory, its first president, it is widely recognized as one of the best universities in Canada...
. The specimens were studied by paleobotanists Ruth A. Stockey of the University of Alberta in Edmonton, Alberta, Canada with Gar W. Rothwell and Amy B. Falder of the Ohio University
Ohio University
Ohio University is a public university located in the Midwestern United States in Athens, Ohio, situated on an campus...
in Athens, Ohio
Athens, Ohio
Athens is the largest city in, and the county seat of, Athens County, Ohio, United States. It is located along the Hocking River in the southeastern part of Ohio. A historic college town, Athens is home to Ohio University and is the principal city of the Athens, Ohio Micropolitan Statistical Area. ...
, USA. Stockey, Rothwell, and Falder published their 2001 type description for M. foxii in the International Journal of Plant Sciences
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, evolution, and ecology. The journal also regularly...
. The etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...
of the chosen specific name
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
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 52°18′24"N 113°37′47"W and Gao mine sites.
M. foxii is one of three currently recognized extinct species in the genus Metasequoia
Metasequoia
Metasequoia is a fast-growing, deciduous tree, and the sole living species, Metasequoia glyptostroboides, is one of three species of conifers known as redwoods. It is native to the Sichuan-Hubei region of China. Although the least tall of the redwoods, it grows to at least 200 feet in height...
, which is now represented by the single living species M. glyptostroboides
Metasequoia glyptostroboides
Metasequoia glyptostroboides, the dawn redwood, is a fast-growing, critically endangered deciduous conifer tree, sole living species of the genus Metasequoia, and one of three species of conifers known as redwoods. It is native to the Sichuan-Hubei region of China...
. The species M. milleri is known only from the early Eocene Ypresian
Ypresian
In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between and , is preceded by the Thanetian age and is followed by the Eocene Lutetian age....
Allenby Formation near Princeton, British Columbia
Princeton, British Columbia
Princeton is a small town in the Similkameen region of southern British Columbia, Canada. It lies just east of the Cascade Mountains, which continue south into Washington, Oregon and California. The Tulameen and Similkameen Rivers converge here...
. 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 raysWood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
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 known from only compression fossils the ray size is unknown. While the overall height of M. foxii trees is not known, examination of the tracheid
Tracheid
Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts. Tracheids are one of two types of tracheary elements, vessel elements being the other. All tracheary elements develop a thick lignified cell wall, and at maturity the protoplast...
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 200 feet (61 m) in height. Unlike the other species of Metasequoia, the ovulate cones of M. foxii have five ranks of helically
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
arranged cone scale complexes, which is in contrast to the normally decussately
Decussation
Decussation is used in biological contexts to describe a crossing.Examples include:* In the brain, where nerve fibers obliquely cross from one lateral part to the other, that is to say they cross at a level other than their origin...
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.