''Alnus parvifolia'' 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 of

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 ...

in the family Betulaceae related to the modern

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 ...

es. The species is known from

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 ...

leaves and possible fruits found in

early Eocene In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian i ...

sites of northern

Washington state Washington (), officially the State of Washington, is a state in the Pacific Northwest region of the Western United States. Named for George Washington—the first U.S. president—the state was formed from the western part of the Washington ...

, United States, and central

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, ...

, Canada.

History and classification

A series of leaves was collected during geological mapping of the North Thompson River region by William Uglow in 1921. Of the areas visited, the Joseph Creek and Newhykulston sites in the Chu Chua District produced a number of fossils which were examined and described by

Edward Berry Rear Admiral Sir Edward Berry, 1st Baronet, KCB (17 April 1768 – 13 February 1831) was an officer in Britain's Royal Navy primarily known for his role as flag captain of Rear Admiral Horatio Nelson's ship HMS ''Vanguard'' at the Battle of ...

in 1926 Geological Survey of Canada bulletin. Berry grouped the Chu Chua betulaceous leaves into three new species and five already named species. A group of leaves from the

Chu Chua Formation Chu or CHU may refer to: Chinese history * Chu (state) (c. 1030 BC–223 BC), a state during the Zhou dynasty * Western Chu (206 BC–202 BC), a state founded and ruled by Xiang Yu * Chu Kingdom (Han dynasty) (201 BC–70 AD), a kingdom of the H ...

's Joseph Creek locality were described as the new species ''Betula parvifolia'', which was noted to be "not uncommon" at the site. Berry did not give any explanation for the species name ''parvifolia'' in his paper, only noting that the leaves were not similar to any ''Betula'' forms he was familiar with and suggested a single leaf from fossiliferous rocks in what is now the

Kitsilano Kitsilano () is a neighbourhood located in the city of Vancouver, British Columbia, Canada. Kitsilano is named after Squamish chief August Jack Khatsahlano, and the neighbourhood is located in Vancouver's West Side along the south shore of Engli ...

neighborhood of

Vancouver, British Columbia Vancouver ( ) is a major city in western Canada, located in the Lower Mainland region of British Columbia. As the List of cities in British Columbia, most populous city in the province, the 2021 Canadian census recorded 662,248 people in the ...

, might also belong to the species. In the name paper he placed a series of leaves from the Darlington Creek and Joseph Creek sites into the Miocene European species ''" Carpinus grandis"'' while specifically noting the taxon at that time was a catchall, with no true uniting features between the fossils of various localities which had been referred to the species. Three years after the initial description of the Chu Chua belutaceous species, Berry published a monographic revision of the Latah Formation of eastern Washington and Northern Idaho. At that time, Berry incorrectly assumed 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 ...

fossils of

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 ...

. were a northern outcrop of the Latah Formation, and as such, treated them in the same paper as conspecific with the Latah material. Among the descriptions, he named a new alder species, ''Alnus elliptica'' from a series of small leaves, and likened the leaves to modern ''Alnus alnobetula'' var. ''crispa''. One additional leaf from Republic was placed into ''" Prunus rustii"'', a species named from Latah Formation fossils three years earlier. Seven years later,

Roland W. Brown Roland Wilbur Brown (1893–1961) was an American paleobotanist and geologist. Biography Brown was born in 1893. In 1928, he was appointed as a geologist with the United States Geological Survey, where he remained until he retired in 1958. He als ...

reassessed a number of fossils from across the western United States, including the ''Prunus rustii'' leaf, which he moved to ''Alnus corallina''. Brown noted the secondaries of the Republic specimen run straight from the mainvein to the margin and terminate in the marginal teeth, with a vein fork to the tooth the one being supplied by the secondary. Included in the monograph on Republic dicots published by

Jack A. Wolfe Jack Albert Wolfe (1936–2005) was a United States Geological Survey paleobotanist and paleoclimatologist best known for his studies of Tertiary climate in western North America through analysis of fossil A fossil (from Classical Latin ...

and

Wesley Wehr Wesley Conrad Wehr (April 17, 1929 – April 12, 2004) was an American paleontologist and artist best known for his studies of Cenozoic fossil floras in western North America, the Stonerose Interpretive Center, and as a part of the Northwest ...

in 1987 was a reassessment of ''"Betula" parvifolia'' based on additional fossils collected in the late 1970s through early 1980s by Wolfe, Wehr, and

Kirk Johnson Kirk Cyron Johnson (born June 29, 1972) is a Canadian former professional boxer who competed from 1993 to 2010, and challenged once for the World Boxing Association, WBA heavyweight title in 2002. Amateur career Johnson represented Canada at ...

. Based on the expanded series of fossils, Wolfe and Wehr concluded the taxon was a species of alder rather than birch, and renamed it ''Alnus parvifolia''. They also included ''Alnus elliptica'' plus portions of the fossils that had previously been identified as ''"Carpinus grandis"'' by Berry and ''Alnus corallina'' by Brown. Additionally they included the species '' Alnus cuprovallis'' described by Daniel I. Axelrod (1966) in the expanded ''A. parvifolia'' as well, however this synonymy was rejected by Axelrod in his 1998 revision of Eocene age Thunder Mountain flora in Idaho. ''A. parvifolia'' has been placed into the living alder subgenus ''Alnus'' subg. ''Alnus'' and is suggested to be related closest to the living '' Alnus incana'' of western North America.

Distribution and paleoenvironment

''Alnus parvifolia'' has been found in various formations that comprise the Eocene Okanagan Highlands. Apart from the Chu Chua Formation, the species has been reported from the Kamloops Groups Tranquille Formation at Falkland and McAbee plus the

Coldwater Beds The Coldwater Beds are a geologic formation of the Okanagan Highlands in British Columbia, Canada. They preserve fossils dating back to the Ypresian stage of the Eocene period, or Wasatchian in the NALMA classification. Of the southern-most Okanagan Highlands sites, both the Klondike Mountain Formation and Allenby Formation around

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 ...

, have ''A. parvifolia'' leaves and fruiting bodies. ''Alnus'' has been reported at both of the two northern Okanagan Highlands localities, the Driftwood Shales near

Smithers Smithers is a surname of English origin. It derives from the Middle English term "smyther", referring to a metalsmith, and is thus related to the common occupational surname Smith. The name Smither is related. People *Alan Smithers (born 1938), ...

and

Horsefly Shales Horse-flies or horseflies are true flies in the family Tabanidae in the insect order Diptera. They are often large and agile in flight, and only the female horseflies bite animals, including humans, to obtain blood. They prefer to fly in su ...

near

Horsefly Horse-flies or horseflies are true flies in the family Tabanidae in the insect order Diptera. They are often large and agile in flight, and only the female horseflies bite animals, including humans, to obtain blood. They prefer to fly in sun ...

. However the leaves, fruits, and pollen from these two sites have not been identified to species. The highlands, including the Eocene formations between Driftwood canyon and Republic, have been described as one of the "Great Canadian '' Lagerstätten''" based on the diversity, quality and unique nature of the

floral A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

and

faunal Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoo ...

biotas that are preserved. The highlands temperate biome, preserved across a large transect of lakes, recorded many of the earliest appearances of modern genera, while also documenting the last stands of ancient lines. The warm temperate highland floras in association with downfaulted

lacustrine basin A lacustrine plain or lake plain is a plain formed due to the past existence of a lake and its accompanying sediment accumulation. Lacustrine plains can be formed through one of three major mechanisms: glacial drainage, differential uplift, and inla ...

s and active volcanism are noted to have no exact modern equivalents, however they have been compared to the upland ecological islands in the Virunga Mountains within the Albertine Rift of the

African rift valley The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. In the past it was considered to be part of ...

. In his unpublished 1996 PhD thesis, Patrick Fields suggested that Eocene age ''Alnus'' leaves from the area of

Salmon, Idaho Salmon is a city in Lemhi County, Idaho. The population was 3,112 at the 2010 census. The city is the county seat of Lemhi County. Located in the Lemhi River valley, Salmon is home to the Sacajawea Interpretive, Cultural and Education Center, wh ...

, are also ''Alnus parvifolia'', citing age and morphological similarity to published specimens from Republic. However the taxonomic changes suggested by Fields were never published officially and thus the inclusion is only hypothetical.

Paleoecology

Alnus parvifolia with Paleoovoidus species scars SRIC SR 01-08-23 A

Greenwood ''et al'' (2016) noted ''Alunus parvifolia'' to be the most common dicot fossil of the Klondike Mountain Formation and this is similarly true at Falkland where it is found in all three identified shale units, and likely was an important post-disturbance colonizer plant and nitrogen fixer. Royer ''et al.'' (2007) used ''A. parvifolia'' as a model species for study of fossil leaf economics, the combined traits of nutrient concentration, rate of photosynthesis, individual leaf lifespan, and palatability for herbivores. The results indicated the leaves were likely fast growing and had a thin leaf blade, as was expected for an upland temperate species. In 1991 an ''Alnus parvifolia'' leaf from the Burke Museum collections was briefly described by Standley Lewis and Mark Carroll. They reported the presence of numerous insect eggs on the leaf blade, and attributed them to leaf beetles of the family

Chrysomelidae The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle ...

. Noting that the curving linear rows of eggs were similar to those seen occasionally in oviposition by '' Altica'' genus flea beetles, they ascribed the fossils to the genus, suggesting them to be the first fossil evidence for ''Altica'' in the North American Eocene. Attribution of the trace fossils to ''Altica'' was brought into question by Conrad Labandeira (2002) as part of his initial report on the insect–plant interactions preserved in Klondike Mountain Formation fossils. He wrote that while ''Altica'' species eggs are rarely deposited in linear fashion, much more often they are clusters of eggs on the leaf surface, and never in echeloned arcs of eggs below the surface as seen in Republic and McAbee fossils. Labandeira suggested that the oviposition was performed by Coenagrionid family

damselflies Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies, which constitute the other odonatan suborder, Anisoptera, but are smaller and have slimmer bodies. Most species fold the wings along ...

, as they are found on a wide range of leaves that would have been present near the lake shore. Additionally the robust ovipositor of damselflies would leave a distinct scarring around the egg insertion site, a phenomenon shown in the fossils. The Republic fossils were referred to the ichnogenus '' Paleoovoidus'' by Sarzetti ''et al.'' (2009), but the researchers did not place them to a specific ichnospecies. In addition to ''Paleoovoidus'' species trace fossils, Labandeira (2002) also documented hole feeding on an ''A. parvifolia'' which he attributed as likely caused by adult Chrysomelidae beetles. The feeding took place between the secondary veins and meandered towards the main vein from its starting point in the mid-region of the leaf blade. Hole and margin feeding from an unidentified insect group on a leaf showed rims of reaction tissue, and a flap of necrotic leaf blade.

Description

In his 1926 description of the new species ''"Betula" parvifolia'', Berry noted the leaves to vary in both size and shape, though overall small. The range of form grades from elliptical through orbicular and have rounded bases and apexes. The sizes noted to range between and have widths between with the widest point of the leaf blades midway up the leaf. Petioles, where preserved, were deemed "stout", with a curved length that ranged between . The leaf margins were noted to have small, evenly spaced teeth with only the area near the petiole being smooth. Each leaf had between seven and eight pairs of secondary veins branching off the thick primary vein. They extended fully to the leaf margin, forking near the apical end to give rise to a tertiary vein from the basal side. Three years later, Berry's 1929 description of ''Alnus elliptica'' defined the elliptical leaves as long and wide with a very stout petiole averaging long. The margin showed closely spaced crenate teeth. Sub-parallelly branching off from the stout midvein at 45° angles, the regularly spaced secondaries extend to the margins along an almost fully straight path. None of the specimens showed well-preserved tertiaries.

References

External links

* * {{Taxonbar, from=Q21398185 † Ypresian plants of North America Extinct flora of North America † † Paleontology in Washington (state) Paleogene British Columbia Paleontology in British Columbia Klondike Mountain Formation Fossil taxa described in 1926 † Allenby Formation Tranquille Formation Coldwater Beds Chu Chua Formation