Ulmus okanaganensis Temporal range: | |
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U. okanaganensis sucker-shoot leaf | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Rosales |
Family: | Ulmaceae |
Genus: | Ulmus |
Subgenus: | U. subg. Ulmus |
Species: | †U. okanaganensis |
Binomial name | |
†Ulmus okanaganensis Denk & Dillhoff | |
Ulmus okanaganensis is an extinct species of flowering plant in the family Ulmaceae related to the modern elms. The species is known from fossil leaves, flowers, and fruits found in the early Eocene deposits of northern Washington state, United States and similar aged formations in British Columbia, Canada.
U. okanaganensis fossils have been identified from five locations in Western North America. The type description listed occurrences at the 49 million year old Klondike Mountain Formation near Republic, Washington plus the British Columbian sites of One Mile Creek near Princeton, British Columbia, the McAbee Fossil Beds east of Cache Creek, and in the Driftwood Canyon Provincial Park northeast of Smithers. [1] In 2009 the species was reported from a fourth British Columbian site near Falkland. [2] Ages for the Okanagan Highland locations are, in general, Early Eocene, with the sites that have current uranium-lead or argon–argon radiometric dates being of Ypresian age, while the undated sites or those given older dates being possibly slightly younger and Lutetian in age. [3]
Roland Brown examined fossils from the Klondike Mountain formation in a 1936 paper and placed some leaves into the extinct species Zelkova oregoniana along with fossils from the Latah Formation in Washington, which the Republic fossils were thought to belong to, and the John Day Formation in Oregon. [4] Ulmaceous fruits from the Princeton area had been tentatively identified as a species of Chaetoptelea , [5] a southern North American genus that is now included into Ulmus. The discovery of leaves attached to branchlets with fruits, and attached to branchlets attached to flowers at several fossil sites led to a restudy of the Okanagan highlands leaves and fruits. Fossils of leaves and fruits that had previously been identified as Zelkova and Chaetoptelea along with additional specimens were studied by paleobotanists Thomas Denk and Richard Dillhoff, with the type description for U. okanaganensis being published in a 2005 Canadian Journal of Botany article. [1] They chose the specific name okanaganensis, in reference to the Okanagan Highlands, of Central British Columbia and northern Washington, where the species is a common paleofloral element of the Eocene lake deposits in the region. [1]
Based on phylogenetic analysis that was performed by Denk and Dillhoff, U. okanaganensis was placed as a member of Ulmus subgenus Ulmus, between U. section Microptelea and U. section Ulmus. Denk and Dillhoff noted that the results of the analysis also suggested the subgenus to be a grade basal to the derived species in Ulmus subgenus Oreoptelea. The morphology of the leaf edges and bases was noted to be similar to fossils found in Paleocene rocks of Ellesmere Island, late Paleocene to Early Eocene rocks of Spitsbergen, and Paleocene rocks of North-east China. [1] The species Early Eocene Ulmus fushunensis described in 2010 from the Jijuntun Formation of Liaoning Province, China, displays noted similarities to U. okanaganensis as well. [6]
The studied leaves of U. okanaganensis are split into three major morphotypes, leaves from sucker-shoot stems of the trees, leaves from the "elongation" or short branches, and leaves from the reproductive shoots.
The sucker-shoot leaves range up to 130 mm (5.1 in) in length. The short, thick petiole is bracketed by uneven lobes of the leaf base, with one lobe typically being distinctly larger than the other. The leaves have a pinnate vein structure, with the primary vein having between twelve and fourteen secondary veins branching from it at decreasingly sharp angles from apex to base of the leaf. The secondary veins and the exterior branches off the secondaries terminate in teeth along the leaf margins. The leaves have compound teeth, each of the large teeth on having a smaller tooth located basally between it and the next large tooth. All the teeth typically have convex sides that terminate at blunt tooth tips, though occasional teeth have straight or concave sides. [1]
In the elongation shoot leaves, the petioles are short and thick, though shorter and thinner than those of the sucker-shoot leaves. Similarly the leaves are smaller, ranging up to 80 mm (3.1 in) long, and the bases are typically only slightly asymmetrical. They have a cordate to auriculate leaf blade base and an acute leaf tip. The primary vein ranges between fully straight and slightly curved as it progresses from base to tip. There are a similar number of secondary veins to those in the other two leaf types, with a usual minimum of eleven pairs; however, the angle of the secondaries to the primary increases towards the base rather than decreasing as seen in the sucker-shoot leaves. [1]
The short-shoot leaves are range between 30 mm (1.2 in) and 80 mm (3.1 in) long, much like the length of the elongation shoot leaves. However the elongation shoot leaves are up to 30 mm (1.2 in) wide while short shoot leaves are 10–20 mm (0.39–0.79 in) wide. There are between eight and fourteen secondary veins, with up to three veins branching off the undersides of each secondary close to the leaf base, though one to no veins branch from the secondaries near the leaf tip. The teeth on short-shoot leaves are simple, with the apical side of each tooth usually concave and the basal side usually convex. [1]
The flowers and fruits develop on fascicles at the leaf nodes of branches. The fruits are small, ranging between 2.5–3.75 mm (0.098–0.148 in), with a pedicel up to 3.5 mm (0.14 in) long. Like species of the modern Ulmus section Chaetoptelea, the fruits do not have a surrounding wing, and the styles on the fruit apex are free. The U. sect. Chaetoptelea fruits are noted to be distinctly ciliate, having many fine hairs on the fruits, but only one fossil has been described showing ciliate, the other specimens are all smooth, possibly as a result of processes before fossilization. [1]
Tilia johnsoni is an extinct species of flowering plant in the family Malvaceae that, as a member of the genus Tilia, is related to modern lindens. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and a similar aged formation in British Columbia, Canada.
Neviusia dunthornei is an extinct species of flowering plants in the family Rosaceae. The species is solely known from the early Eocene, Ypresian stage, Allenby Formation Lacustrine deposits near the town of Princeton, British Columbia.
The McAbee Fossil Beds is a Heritage Site that protects an Eocene Epoch fossil locality east of Cache Creek, British Columbia, Canada, just north of and visible from Provincial Highway 97 / the Trans-Canada Highway. The McAbee Fossil Beds, comprising 548.23 hectares, were officially designated a Provincial Heritage Site under British Columbia's Heritage Conservation Act on July 19, 2012. The site is part of an old lake bed which was deposited about 52 million years ago and is internationally recognised for the diversity of plant, insect, and fish fossils found there. Similar fossil beds in Eocene lake sediments, also known for their well preserved plant, insect and fish fossils, are found at Driftwood Canyon Provincial Park near Smithers in northern British Columbia, on the Horsefly River near Quesnel in central British Columbia, and at Republic in Washington, United States. The Princeton Chert fossil beds in southern British Columbia are also Eocene, but primarily preserve an aquatic plant community. A 2016 review of the early Eocene fossil sites from the interior of British Columbia discusses the history of paleobotanical research at McAbee, the Princeton Chert, Driftwood Canyon, and related Eocene fossil sites such as at Republic.
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 abundance of insect, fish and plant fossils known from 1877 and onward, while the Princeton Chert was first indented in the 1950's and is known from anatomically preserved plants.
Rhus malloryi is an extinct species of flowering plant in the sumac family Anacardiaceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States. The species was first described from a series of isolated fossil leaves in shale. R. malloryi is one of four sumac species to be described from the Klondike Mountain Formation, and forms a hybrid complex with the other three species.
| authority = Wolfe & Wehr Langeria is an extinct genus of flowering plants in the family Platanaceae containing the solitary species Langeria magnifica. Langeria is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and similar aged formations in British Columbia, Canada.
Tsukada is an extinct genus of flowering plant in the family Nyssaceae related to the modern "dove-tree", Davidia involucrata, containing the single species Tsukada davidiifolia. The genus is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States and a similar aged formation in British Columbia, Canada.
Betula leopoldae is an extinct species of birch in the family Betulaceae. The species is known from fossil leaves, catkins, and inflorescences found in the early Eocene deposits of northern Washington state, United States, and similar aged formations in British Columbia, Canada. The species is placed as basal in Betula, either as a stem group species, or an early divergent species.
Rhus boothillensis is an extinct species of flowering plant in the sumac family Anacardiaceae. The species is known from fossil leaves found in the early Eocene deposits of northern Washington State, United States. The species was first described from fossil leaves found in the Klondike Mountain Formation. Rhus boothillensis likely hybridized with the other Klondike Mountain formation sumac species Rhus garwellii, Rhus malloryi, and Rhus republicensis.
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Paraconcavistylon is an extinct genus of flowering plant in the family Trochodendraceae comprises a single species, Paraconcavistylon wehrii. The genus is known from fossil fruits and leaves found in the early Eocene deposits of northern Washington state, United States, and southern British Columbia, Canada. The species was initially described as a member of the related extinct genus Concavistylon as "Concavistylon" wehrii, but subsequently moved to the new genus Paraconcavistylon in 2020 after additional study.
Comptonia columbiana is an extinct species of sweet fern in the flowering plant family Myricaceae. The species is known from fossil leaves found in the early Eocene deposits of central to southern British Columbia, Canada, plus northern Washington state, United States, and, tentatively, the late Eocene of Southern Idaho and Earliest Oligocene of Oregon, United States.
Amia? hesperia is an extinct species of bony fish in the bowfin family, Amiidae. The species is known from fossils found in the early Eocene deposits of northern Washington state in the United States and southeastern British Columbia. The species is one of eight fish species identified in the Okanagan Highlands.
Barghoornia is an extinct genus of flowering plants in the family Burseraceae containing the solitary species Barghoornia oblongifolia. The species is known from fossil leaves found in the early Eocene deposits of northern Washington state, United States.
Carpinus perryae is an extinct species of hornbeam known from fossil fruits found in the Klondike Mountain Formation deposits of northern Washington state, dated to the early Eocene Ypresian stage. Based on described features, C. perryae is the oldest definite species in the genus Carpinus.
Equisetum similkamense is an extinct horsetail species in the family Equisetaceae described from a group of whole plant fossils including rhizomes, stems, and leaves. The species is known from Ypresian sediments exposed in British Columbia, Canada. It is one of several extinct species placed in the living genus Equisetum.
Dipteronia brownii is an extinct species in the soapberry family (Sapindaceae) described in 2001. Fossils of D. brownii are known from stratigraphic formations in North America and Asia ranging in age between Paleocene to Early Oligocene.
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