Metasequoia foxii

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Metasequoia foxii
Temporal range: late Tiffanian Paleocene
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Cupressaceae
Genus: Metasequoia
Species:
M. foxii
Binomial name
Metasequoia foxii

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 . [1]

Contents

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 exposed east of Red Deer in central Alberta. [1] 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. [1]

Metasequoia foxii was described from a selection of 10,147 fossils. [1] 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. [1] 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 . [1] 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″N113°37′47″W / 52.30667°N 113.62972°W / 52.30667; -113.62972 [2] [3] and Gao mine sites. [1]

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. [1]

Description

The cell structure of M. foxii is fairly well preserved in the large stump. Samples taken from the specimen show notably large rays 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 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. [1] 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. [1]

Related Research Articles

Pinophyta Division of plants including extinct and current conifers

The Pinophyta, also known as Coniferophyta or Coniferae, or commonly as conifers, are a division of vascular land plants containing a single extant class, Pinopsida. They are cone-bearing seed plants, a subset of gymnosperms. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews. As of 1998, the division Pinophyta was estimated to contain eight families, 68 genera, and 629 living species.

Gymnosperm Clade of non-flowering, naked-seeded plants

The gymnosperms, also known as Acrogymnospermae, are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the composite word in Greek: γυμνόσπερμος, literally meaning "naked seeds". The name is based on the unenclosed condition of their seeds. The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in yew, Torreya, Ginkgo.

<i>Metasequoia</i> Genus of conifers

Metasequoia, or dawn redwoods, is a genus of fast-growing deciduous trees, one of three species of conifers known as redwoods. The living species Metasequoia glyptostroboides is native to Lichuan county in Hubei province, China. Although the shortest of the redwoods, it grows to at least 165 feet in height. Local villagers refer to the original tree from which most others derive as Shui-shan (水杉), or "water fir", which is part of a local shrine. Since its rediscovery in 1944, the dawn redwood has become a popular ornamental, with examples found in various parks in a variety of countries.

<i>Metasequoia glyptostroboides</i> Species of conifer

Metasequoia glyptostroboides, the dawn redwood, is a fast-growing, endangered deciduous conifer. It is the sole living species of the genus Metasequoia, one of three genera in the subfamily Sequoioideae of the family Cupressaceae. It now survives only in wet lower slopes and montane river and stream valleys in the border region of Hubei and Hunan provinces and Chongqing municipality in south-central China, notably in Lichuan county in Hubei. Although the shortest of the redwoods, it can grow to 120 ft (37 m) in height.

<i>Cyathea cranhamii</i>

Cyathea cranhamii is an extinct species of tree fern. It was described based on permineralised sori from the Early Cretaceous deposits of Apple Bay in Vancouver Island, British Columbia.

Lepidodendrales Extinct order of vascular tree-like plants

Lepidodendrales were primitive, vascular, arborescent (tree-like) plants related to the lycopsids. Members of Lepidodendrales are the best understood of the fossil lycopsids due to the vast diversity of Lepidodendrales specimens and the diversity in which they were preserved; the extensive distribution of Lepidodendrales specimens as well as their well-preservedness lends paleobotanists exceptionally detailed knowledge of the coal-swamp giants’ reproductive biology, vegetative development, and role in their paleoecosystem. The defining characteristics of the Lepidodendrales are their secondary xylem, extensive periderm development, three-zoned cortex, rootlike appendages known as stigmarian rootlets arranged in a spiralling pattern, and megasporangium each containing a single functional megaspore that germinates inside the sporangium. Many of these different plant organs have been assigned both generic and specific names as relatively few have been found organically attached to each other. Some specimens have been discovered which indicate heights of 40 and even 50 meters and diameters of over 2 meters at the base. The massive trunks of some species branched profusely, producing large crowns of leafy twigs; though some leaves were up to 1 meter long, most were much shorter, and when leaves dropped from branches their conspicuous leaf bases remained on the surface of branches. Strobili could be found at the tips of distal branches or in an area at the top of the main trunk. The underground organs of Lepidodendrales typically consisted of dichotomizing axes bearing helically arranged, lateral appendages serving an equivalent function to roots. Sometimes called "giant club mosses", they are in fact more closely related to quillworts than to club mosses.

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. It was first described from outcrops along that river, near its confluence with the Red Deer River north of the city of Red Deer, by J.B. Tyrrell in 1887. It is important for its freshwater aquifers, its coal resources, and its fossil record, as well as having been the source of sandstone for the construction of fire-resistant buildings in Calgary during the early 1900s.

Sequoioideae Subfamily of coniferous trees (redwoods)

Sequoioideae, popularly known as redwoods, is a subfamily of coniferous trees within the family Cupressaceae. It includes the largest and tallest trees in the world.

<i>Abies milleri</i> Species of conifer

Abies milleri, an extinct species of fir known from fossil remains found in deposits from the early Eocene Ypresian stage in Washington State, USA, is the oldest confirmed record for the fir genus. The species was described from 81 fossil specimens collected from Burke Museum site number A0307 in Ferry County, Washington. The holotype specimen, number # UWBM 31299, and the eleven paratype specimens are currently deposited in the collections of the Burke Museum in Seattle, where they were studied and described by Howard E. Schorn and Wesley C. Wehr. Schorn and Wehr published their 1986 type description for A. milleri in the Burke Museum Contributions in Anthropology and Natural History, Volume 1. The specific epithet, milleri, was coined in honor of Charles N. Miller Jr for his contributions to the study and understanding of the conifer family Pinaceae. The studied specimens were excavated from the Tom Thumb Tuff member of the Klondike Mountain Formation in the city of Republic.

Pinus matthewsii is an extinct species of conifer in the pine family. The species is solely known from the Pliocene sediments exposed at Ch’ijee's Bluff on the Porcupine River near Old Crow, Yukon, Canada.

<i>Araucaria mirabilis</i> Extinct species of conifer

Araucaria mirabilis is an extinct species of coniferous tree from Patagonia, Argentina. It belongs to the genus Araucaria.

<i>Ginkgo cranei</i>

Ginkgo cranei is an extinct Ginkgo species in the family Ginkgoaceae described from a series of isolated fossil ovulate organs and leaves. The species is known from upper Paleocene sediments exposed in the state of North Dakota, USA. It is the first Ginkgo species to be described from Paleogene period with reproductive structures.

The Princeton Chert is a fossil locality in British Columbia, Canada, which comprises an anatomically preserved flora of Eocene Epoch age, with rich species abundance and diversity. It is located in exposures of the Allenby Formation on the east bank of the Similkameen River, 8.5 km (5.3 mi) south of the town of Princeton, British Columbia.

Pinus driftwoodensis is an extinct species of conifer in the pine family solely known from early Eocene sediments exposed in south central British Columbia. The species was described from an isolated fossil ovulate cone associated with a series of wood, needles and pollen cones in chert. P. driftwoodensis was the eighth pine species to be described from a permineralized ovulate cone and the second from the Okanagan highlands.

<i>Metasequoia occidentalis</i> Extinct species of conifer

Metasequoia occidentalis is an extinct redwood species of the family Cupressaceae that is found as fossils throughout the Northern Hemisphere. It is one of three extinct species of Metasequoia that are currently recognized as valid.

<i>Glyptostrobus europaeus</i> Extinct species of conifer

Glyptostrobus europaeus is an extinct conifer species of the family Cupressaceae that is found as fossils throughout the Northern Hemisphere. The sole living species of Glyptostrobus was described from China in 1926. The name of the genus comes from the Greek "glypto" meaning grooved or carved, and "strobilus" meaning cone. The species name "europaeus" refers to the fact that it was first described from Europe.

Pinus yorkshirensis is an extinct species of pine tree. The fossil pine cone came from Hauterivian and Barremian-aged sedimentary rocks located in the Speeton Clay in Yorkshire.

<i>Metasequoia heerii</i> Extinct species of conifer

Metasequoia heerii is an extinct redwood species of the family Cupressaceae that is found as fossils throughout the Northern Hemisphere. It is one of several proposed extinct species of Metasequoia that were previously referred to Sequoia.

Hughmillerites is a fossil cypress, found in the Late Jurassic of Scotland and Early Cretaceous of Canada.

References

  1. 1 2 3 4 5 6 7 8 9 10 Stockey, R. A.; Rothwell, G. W.; Falder, A. B. (2001). "Diversity among Taxodioid Conifers: Metasequoia foxii sp. nov. from the Paleocene of Central Alberta, Canada". International Journal of Plant Sciences. 162 (1): 221–234. doi:10.1086/317914. JSTOR   10.1086/317914.
  2. Falder, Amy B; Stockey, Ruth A; Rothwell, Gar W (1999). "In situ fossil seedlings of a Metasequoia-like taxodiaceous conifer from Paleocene river floodplain deposits of central Alberta, Canada". American Journal of Botany. 86: 900–902. doi:10.2307/2656710.
  3. "Alberta Township System to Geographic Degrees". Alberta Geological Survey. Archived from the original on 2011-12-12.