Wessiea
Encyclopedia
Wessiea is an extinct
monotypic
genus
of fern
in the Dryopteridaceae
family with the sole species Wessiea yakimaensis. Wessia is known from Langhian
age Miocene
fossil
s found in Central Washington.
The genus was described from specimens of slicified
rhizomes and frond bases in blocks of chert
. The cherts were recovered from the "Ho ho" site, one of the "county line hole" fossil localities north of Interstate 82
in Yakima County, Washington
. The "Ho ho" site works strata which is part of the Museum Flow Package within the interbeds of the Sentinel Bluffs Unit of the central Columbia Plateau N2 Grande Ronde Basalt, Columbia River Basalt Group
. The Museum Flow Package interbeds, designated the type locality
, are dated to the middle Miocene
and are approximately 15.6 million years old.
The holotype
specimen, rhizomes and fronds #1–3 and 3 E2 #1–3, are preserved in chert block 3A1 and housed in the Burke Museum of Natural History and Culture
as specimen number "UWBM 56441". The paratype, number 3F1 #2 top on specimen "UWBM 56441", is a rhizome which shows root gaps, roots and frond bases. The specimens of chert were studied by paleobotanists Kathleen B. Pgg of Arizona State University
and Gar W. Rothwell of Ohio University
. Drs Pigg and Rothwell published their 2001 type description for Wessiea yakimaensis in the American Journal of Botany
volume 88, Anatomically preserved Woodwardia virginica (Blechnaceae) and a new Filicalean fern from the Middle Miocene Yakima Canyon Flora of central Washington, USA. In their type description they note the etymology
for the generic name
is in honor of Wesley C. Wehr
for his numerous contributions to Tertiary paleobotany of western North America. The specific epithet
yakimaensis, is a reference to the type locality in the Yakima Canyon. Drs Pigg and Rothwell noted the similarity between Wessiea and both the modern genus Diplazium
and the fossil genus Makotopteris.
Wessiea possesses rhizomes which are 1.5–3 mm (0.0590551181102362–0.118110236220472 in) in diameter. The frond bases where preserved in the chert are in a distinct helical arrangement. It is found in the chert blocks intertwined with the extinct Osmunda wehrii
and anatomically preserved Woodwardia virginica, which still lives in the forests of eastern coastal North America
.
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally 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 recover may have been lost before this point...
monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
in the Dryopteridaceae
Dryopteridaceae
Dryopteridaceae, is a family of leptosporangiate ferns in the order Polypodiales. They are known colloquially as the wood ferns. They comprise about 1700 species and have a cosmopolitan distribution. They may be terrestrial, epipetric, hemiepiphytic, or epiphytic. Many are cultivated as...
family with the sole species Wessiea yakimaensis. Wessia is known from Langhian
Langhian
The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene epoch/series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma . The Langhian was a continuing warming period defined by Lorenzo Pareto in 1864, it was originally established in the Langhe area north...
age Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s found in Central Washington.
The genus was described from specimens of slicified
Petrifaction
In geology, petrifaction, petrification or silicification is the process by which organic material is converted into stone by impregnation with silica. It is a rare form of fossilization...
rhizomes and frond bases in blocks of chert
Chert
Chert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...
. The cherts were recovered from the "Ho ho" site, one of the "county line hole" fossil localities north of Interstate 82
Interstate 82
Interstate 82 is a Interstate Highway that extends from I-90 in Ellensburg, Washington to I-84 near Umatilla, Oregon in the United States. In the state of Washington, it serves the cities of Ellensburg, Yakima, and the Tri Cities , and in Oregon, it serves Umatilla and Hermiston...
in Yakima County, Washington
Yakima County, Washington
Yakima County is the second largest county by area in the U.S. state of Washington. It is named after the Yakama tribe of Native Americans. In the 2010 census, its population was 243,231...
. The "Ho ho" site works strata which is part of the Museum Flow Package within the interbeds of the Sentinel Bluffs Unit of the central Columbia Plateau N2 Grande Ronde Basalt, Columbia River Basalt Group
Columbia River Basalt Group
The Columbia River Basalt Group is a large igneous province that lies across parts of the Western United States. It is found in the U.S. states of Washington, Oregon, Idaho, Nevada, and California...
. The Museum Flow Package interbeds, designated the type locality
Type locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
, are dated to the middle Miocene
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene....
and are approximately 15.6 million years old.
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, rhizomes and fronds #1–3 and 3 E2 #1–3, are preserved in chert block 3A1 and housed in the Burke Museum of Natural History and Culture
Burke Museum of Natural History and Culture
The Burke Museum of Natural History and Culture has been a Washington state museum since 1899. It is located at the University of Washington campus at the intersection of N.E. 45th Street and 17th Avenue N.E. in Seattle, Washington, USA, in the University District. It is the only major natural...
as specimen number "UWBM 56441". The paratype, number 3F1 #2 top on specimen "UWBM 56441", is a rhizome which shows root gaps, roots and frond bases. The specimens of chert were studied by paleobotanists Kathleen B. Pgg of Arizona State University
Arizona State University
Arizona State University is a public research university located in the Phoenix Metropolitan Area of the State of Arizona...
and Gar W. Rothwell of Ohio University
Ohio University
Ohio University is a public university located in the Midwestern United States in Athens, Ohio, situated on an campus...
. Drs Pigg and Rothwell published their 2001 type description for Wessiea yakimaensis in the American Journal of Botany
American Journal of Botany
The American Journal of Botany is a peer-reviewed scientific journal which includes research papers on all aspects of plant biology. It is published by the Botanical Society of America on a monthly basis since 1914....
volume 88, Anatomically preserved Woodwardia virginica (Blechnaceae) and a new Filicalean fern from the Middle Miocene Yakima Canyon Flora of central Washington, USA. In their type description they note 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...
for the generic name
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
is in honor of Wesley C. Wehr
Wesley C. Wehr
Wesley Conrad Wehr was an American paleontologist and artist best known for his studies of Tertiary fossil floras in western North America, the Stonerose Interpretive Center, and as a part of the Northwest School of art.-Early life:...
for his numerous contributions to Tertiary paleobotany of western North America. The specific epithet
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...
yakimaensis, is a reference to the type locality in the Yakima Canyon. Drs Pigg and Rothwell noted the similarity between Wessiea and both the modern genus Diplazium
Diplazium
Diplazium is a genus of the cliff fern family that specifically includes the approximately 400 known species of twinsorus ferns. The Greek root is diplazein meaning double: the indusia in this genus lie on both sides of the vein...
and the fossil genus Makotopteris.
Wessiea possesses rhizomes which are 1.5–3 mm (0.0590551181102362–0.118110236220472 in) in diameter. The frond bases where preserved in the chert are in a distinct helical arrangement. It is found in the chert blocks intertwined with the extinct Osmunda wehrii
Osmunda wehrii
Osmunda wehrii is an extinct species of fern in the modern Osmundaceae family genus Osmunda. Osmunda wehrii is known from Langhian age Miocene fossils found in Central Washington.-History and classification:...
and anatomically preserved Woodwardia virginica, which still lives in the forests of eastern coastal North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
.