''Azolla primaeva'' is an
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
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 ...
of "
water fern Water fern is a common name for several plants and may refer to:
* Salviniales, an order of aquatic ferns
* '' Austroblechnum lanceolatum'', syn. ''Blechnum chambersii'', lance water fern
* '' Austroblechnum patersonii'', syn. ''Blechnum patersonii' ...
" in the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Salviniaceae
Salviniaceae (), is a family of heterosporous ferns in the order Salviniales. The Salviniaceae contain the two genera ''Azolla'' and ''Salvinia'', with about 20 known species in total. The oldest records of the family date to the Late Cretaceous ...
known from
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
s from the
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 ...
stage (), found in southern
British Columbia
British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...
.
The species was first described from poorly preserved material collected in the
Similkameen River
The Similkameen River runs through southern British Columbia, Canada, eventually discharging into the Okanagan River near Oroville, Washington, in the United States. Through the Okanagan River, it drains to the Columbia River. The river is said ...
area 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 ...
and later noted from outcrops at
Stump Lake
Stump Lake is a lake in the Nicola Country region of the South-Central Interior of British Columbia, Canada, northeast from and of a smaller size to Nicola Lake at approximately 11 km long. Stump Lake is the location of the community of St ...
northeast of Princeton. The fossils were described by
David P. Penhallow in the 1890 volume ''On Fossil Plants from the Smilkameen Valley and Other Places in the Southern Interior of British Columbia''.
Though the volume only lists
John William Dawson
Sir John William Dawson (1820–1899) was a Canadian geologist and university administrator.
Life and work
John William Dawson was born on 13 October 1820 in Pictou, Nova Scotia, where he attended and graduated from Pictou Academy. Of Scotti ...
as author, Dawson notes that the ''A primaevum'' description had been written by Penhallow.
Due to the poor nature of the type specimen the species was placed in the
form genus
Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of s ...
''
Azollophyllum'' as ''Azollophyllum primaevum'' indicating its similarity to the modern genus, but at the same time acknowledging lack of detail needed to confirm its placement in the genus.
Placement of the species was formally changed with the publication of a paper written by
Chester A. Arnold based on new fossil specimens collected near the former mining camp of
Ashnola, British Columbia, approximately 8 miles south of Princeton along the Similkimeen River. The fossils were recovered from strata of the
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 ...
, at the time considered
Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
age,
but now known to be of the
Early Middle Eocene.
The specimens were studied by Arnold of the
University of Michigan
, mottoeng = "Arts, Knowledge, Truth"
, former_names = Catholepistemiad, or University of Michigania (1817–1821)
, budget = $10.3 billion (2021)
, endowment = $17 billion (2021)As o ...
who published the 1955
type redescription for ''A. primaeva'' in the ''Contributions from the Museum of. Paleontology, University of Michigan'', Volume 12. Arnold noted the new specimens to consist of leafy vegetation and roots often forming mats in the rock. The plants are accompanied by
microspore massulae and
megasporangia
A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life c ...
.
![Azolla primaeva aquatic mat SRIC SR 21-009-023 img1](https://upload.wikimedia.org/wikipedia/commons/8/86/Azolla_primaeva_aquatic_mat_SRIC_SR_21-009-023_img1.jpg)
At the time this paper was published, four species of ''Azolla'' had been described from the fossil record. The oldest species at that time was ''
A. intertrappea'' from Eocene age strata in India and described in 1934 by
Birbal Sahni
Birbal Sahni Royal Society, FRS (14 November 1891 – 10 April 1949) was an Indian paleobotanist who studied the fossils of the Indian subcontinent. He also took an interest in geology and archaeology. He founded what is now the Birbal Sahni Ins ...
and H. S. Rao. Also in 1934,
Roland W. Brown described a similarly aged species, ''
A. berryi'', from the
Middle Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn ...
Green River Formation
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes in three basins along the present-day Green River in Colorado, Wyoming, and Utah. The sediments are deposited in very fine ...
. An
Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
species, ''
A. prisca'', was published from the
London Clay
The London Clay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 56–49 million years ago) age which crops out in the southeast of England. The London Clay is well known for its fossil content. The fossils from t ...
s of England eight years earlier in 1926 by
Marjorie E.J. Chandler and
Eleanor M. Reid. The youngest of the fossil species was ''
A. tertiaria'' described by
Edward W. Berry
Edward Wilber Berry (February 10, 1875 – September 20, 1945) was an American paleontologist and botanist; the principal focus of his research was paleobotany.
Early life
Berry was born February 10, 1875, in Newark, New Jersey, and finished hig ...
in 1927 from Pliocene fossils found in the
Esmeralda Formation
The Esmeralda Formation is a geologic formation in Nevada. It preserves fossils dating back to the Neogene period.
See also
* List of fossiliferous stratigraphic units in Nevada
* Paleontology in Nevada
Paleontology in Nevada refers to paleont ...
of Nevada.
Arnold notes that with the placement of ''A. primaeva'' into the genus ''Azolla'' means that its description in 1890 was actually the earliest species described from the fossil record.
After comparing the new fossil specimens to both modern and fossil species as much as he was able with the descriptions available, Arnold noted ''A. primaeva'' to be close in morphology to the living ''
A.filiculoides'' and the Eocene ''A. intertrappea'' of India.
Fossil specimens of ''Azolla'' have been recovered from the closely related strata of the
Klondike Mountain Formation
The Klondike Mountain Formation is an Early Eocene (Ypresian) geological formation located in the northeast central area of Washington state. The formation, named for the type location designated in 1962, Klondike Mountain north of Republic, Wash ...
around
Republic, Washington
Republic is a city in Ferry County, Washington, United States. The population was 1,073 at the 2010 census, a 12.5% increase over the 2000 census. It is the county seat of Ferry County. It was the largest mining camp in the Republic Mining Distr ...
, but have not been described to species.
References
{{Taxonbar, from=Q4832823
Salviniales
Paleogene plants
Plants described in 1890
Fossil taxa described in 1890
Eocene plants
Freshwater plants
Extinct flora of North America
†
Allenby Formation