''Neviusia dunthornei'' 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 ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

s in the family

Rosaceae Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are ''Alchemilla'' (270), ''Sorbus ...

. The species is solely known from the early

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' ...

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,

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 ...

Lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

deposits near the town of

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 ...

History and classification

''Neviusia dunthornei'' is known from only two fossils, 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 ...

, number "UWBM 54169", and the

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Of ...

number "UWBM 97148". Both specimens are 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 in the

Burke Museum of Natural History and Culture The Burke Museum of Natural History and Culture (Burke Museum) is a natural history museum in Seattle, Washington, in the United States. Established in 1899 as the Washington State Museum, it traces its origins to a high school naturalist club fo ...

, part of the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...

Seattle, Washington Seattle ( ) is a port, seaport city on the West Coast of the United States. It is the county seat, seat of King County, Washington, King County, Washington (state), Washington. With a 2020 population of 737,015, it is the largest city in bo ...

, USA. The species was described from the two leaf specimens both found at the One Mile Creek locality, UWBM number 53355 in 1991 by Wesley Wehr and Peter Dunthorne. This locality is placed in the early Eocene

, designated the type locality. The Allenby Formation is part of the Eocene Okanogan Highlands floras which span from 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 ...

Ferry County, Washington Ferry County is a county located on the northern border of the U.S. state of Washington. As of the 2020 census, the population was 7,178, making it the fourth-least populous county in Washington. The county seat and largest city is Republic. Th ...

north west to

Driftwood Canyon Provincial Park Driftwood Canyon Provincial Park is a provincial park in British Columbia, Canada. Driftwood Canyon Provincial Park covers 23 ha of the Bulkley River Valley, on the east side of Driftwood Creek, a tributary of the Bulkley River, 10 km nort ...

near

Smithers, British Columbia Smithers is a town in northwestern British Columbia, approximately halfway between Prince George and Prince Rupert. With a population of 5,351 in 2016, Smithers provides service coverage for most of the Bulkley Valley. History Region First Nation ...

. 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 Melanie L. DeVore and Steven M. Moore of

Georgia College and State University Georgia College & State University (Georgia College or GC) is a public liberal arts university in Milledgeville, Georgia. The university enrolls approximately 7,000 students and is a member of the University System of Georgia and the Council ...

, Kathleen B. Pigg of

Arizona State University Arizona State University (Arizona State or ASU) is a public research university in the Phoenix metropolitan area. Founded in 1885 by the 13th Arizona Territorial Legislature, ASU is one of the largest public universities by enrollment in the ...

and Wesley C. Wehr of the Burke Museum. Melanie DeVore and coauthors published the 2004

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 ''N. dunthornei'' in the journal ''

Rhodora ''Rhododendron canadense'', the rhodora or Canada rosebay, is a deciduous flowering shrub that is native to northeastern North America. Classification Today's botanists consider the rhodora to be a distant relative of the other North American ...

''. Melanie DeVore and coauthors chose the specific name ''dunthornei'', in honor of Peter Dunthorne of

Sedro-Woolley, Washington Sedro-Woolley is a city in Skagit County, Washington, United States. It is part of the Mount Vernon– Anacortes, Washington Metropolitan Statistical Area and had a population of 12,421 at the 2020 census. The city is home to North Cascade ...

in recognition of the collecting work throughout the Okanagan highlands which he helped and participated with. The holotype of ''Neviusia dunthornei'' is a complete

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

though the leaf blade is folded near the base, while the paratype is more fragmentary. Together the two compression-impression fossil leaves, preserved in light green-grey

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

display the leaf shape, margin, and morphology of the vein structure and teeth. The overall morphology and structure of the ''N. dunthornei'' leaves compare to the living species known as the Shasta snow-wreath ('' N. cliftonii''), being broadly

ovate Ovate may refer to: *Ovate (egg-shaped) leaves, tepals, or other botanical parts *Ovate, a type of prehistoric stone hand axe *Ovates, one of three ranks of membership in the Welsh Gorsedd *Vates In modern English, the nouns vates () and ovat ...

, with secondary veins subopposite and a similar overall vein patterning. The leaf margins are

serrate Serration is a saw-like appearance or a row of sharp or tooth-like projections. A serrated cutting edge has many small points of contact with the material being cut. By having less contact area than a smooth blade or other edge, the applied pr ...

with two to three orders of teeth present. Unlike ''N. dunthornei'' the leaves of '' N. alabamensis'' are in general more elongate with finer teeth and secondary veins which are more alternate. ''N. dunthornei'' differs from both modern genera in the leaves having an overall thicker

midrib This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

. The presence of ''Neviusia'' in the Eocene Okanogan Highlands floras suggests the tribe

Kerrieae Kerrieae is a tribe of the rose family, Rosaceae, belonging to the subfamily Amygdaloideae Amygdaloideae is a subfamily within the flowering plant family Rosaceae. It was formerly considered by some authors to be separate from Rosaceae, and t ...

originated in Asia and radiated to North America but did not become a major floristic component. This is supported by the absence of any Kerrieae tribe genera in the Mississippi embayment Eocene formations such as the

Claiborne Formation The Claiborne Formation or Claiborne Group is a geologic formation in Arkansas, Illinois, Kentucky, and Texas. It preserves fossils dating back to the Paleogene period . See also * List of fossiliferous stratigraphic units in Kentucky Thi ...

References

{{Taxonbar, from=Q4315804 †dunthornei Prehistoric angiosperms Plants described in 2004 Eocene plants Extinct flora of North America Fossil taxa described in 2004 Allenby Formation