Corylus, Carpinus, and Palaeocarpinus (Betulaceae) from the Middle Eocene Klondike Mountain and Allenby Formations of Northwestern North America

2003 ◽  
Vol 164 (5) ◽  
pp. 807-822 ◽  
Author(s):  
Kathleen B. Pigg ◽  
Steven R. Manchester ◽  
Wesley C. Wehr
Keyword(s):  
North America ◽  
Middle Eocene ◽  
Northwestern North America

Fagus (Fagaceae) fruits, foliage, and pollen from the Middle Eocene of Pacific Northwestern North America

2004 ◽  
Vol 82 (10) ◽  
pp. 1509-1517 ◽  
Author(s):  
Steven R Manchester ◽  
Richard M Dillhoff
Keyword(s):  
British Columbia ◽  
North America ◽  
Middle Eocene ◽  
Molecular Evidence ◽  
Secondary Vein ◽  
Early Oligocene ◽  
Fossil Evidence ◽  
Ca 50 ◽  
Northwestern North America

Fruits and leaves from the Middle Eocene of McAbee, British Columbia, and Republic, Washington, provide an earlier record for the genus Fagus than previously accepted for this member of the Fagaceae. The fruits are trigonal nuts borne within spiny four-valved cupules on long peduncles. The leaves are borne alternately on the twigs and are ovate to elliptic with craspedodromous secondary veins and simple teeth distributed one per secondary vein. The shale preserving these megafossils also contains dispersed pollen with morphology and ornamentation diagnostic of Fagus. Previously, the oldest Fagus occurrences confirmed by fruits were early Oligocene (ca. 32 Ma). The recognition of Middle Eocene (ca. 50 Ma) representatives helps to reduce the disparity between molecular evidence favoring Fagus as a primitive genus within Fagaceae, and fossil evidence, which had indicated older occurrences of Castanea and Quercus than Fagus.Key words: Eocene, Fagus, fossil, foliage, fruits, British Columbia.

Ulmus leaves and fruits from the Early–Middle Eocene of northwestern North America: systematics and implications for character evolution within Ulmaceae

2005 ◽  
Vol 83 (12) ◽  
pp. 1663-1681 ◽  
Author(s):  
Thomas Denk ◽  
Richard M. Dillhoff
Keyword(s):  
British Columbia ◽  
North America ◽  
Middle Eocene ◽  
Cladistic Analysis ◽  
Character Evolution ◽  
Modern Species ◽  
Perianth Tube ◽  
Fossil Flowers ◽  
Northwestern North America

Leaves and fruits of Ulmus from the Early–Middle Eocene of British Columbia and Washington are assigned to two species. Ulmus okanaganensis sp.nov. is based on leaves attached to flowering and fruiting twigs and isolated leaves and fruits. Leaves display a polymorphism ranging from large leaves with compound teeth with a blunt apex to small ones with simple teeth resembling those of Zelkova. In extant Ulmus, sucker-shoot leaves, elongation-shoot leaves, and leaves on short annual branches often display a very similar polymorphism. In the fossil, flowers are arranged in fascicles having short pedicels. Fascicles are formed in the axils of leaves of current-year shoots and appear together with the leaves. This is uncommon in modern species of Ulmus, where leaves appear either in spring on previous-year shoots or in autumn in the axils of leaves of current-year shoots. Fruits of U. okanaganensis are samaras with extremely reduced or absent wings. Unwinged fruits of modern Ulmus are typically ciliate along the margin of the endocarp and the persistent styles but only a single fruit of U. okanaganensis has been found preserving hairs. The small, shallowly lobed perianth is situated below the endocarp. A second type of foliage is assigned to Ulmus chuchuanus (Berry) LaMotte. This foliage is wider than that of U. okanaganensis and has more densely spaced secondary veins. It also has characteristic compound teeth with primary and subsidiary teeth displaying conspicuously different orientations. Leaves of U. chuchuanus co-occur with a second type of fruit but have not been found in attachment. These fruits are larger than in U. okanaganensis, with a narrow wing, persistent styles, and a large and wide persistent perianth that tapers abruptly into the perianth tube. A cladistic analysis suggests that U. okanaganensis is nested within the subgenus Ulmus, which is a paraphyletic grade basal to the subgenus Oreoptelea. Ulmus chuchuanus foliage shows affinities to the subgenus Ulmus, while the associated fruits display affinities to the subgenus Oreoptelea.

Supplemental material: Cenozoic to Recent plate configurations in the Pacific Basin: Ridge subduction and slab window magmatism in western North America

2006 ◽  
Author(s):  
J.K. Madsen ◽  
D.J. Thorkelson ◽  
R.M. Friedman ◽  
D.D. Marshall
Keyword(s):  
North America ◽  
Pacific Basin ◽  
Western North America ◽  
File Size ◽  
Tectonic Model ◽  
Ridge Subduction ◽  
The Pacific ◽  
Northwestern North America ◽  
Slab Window

Geosphere, February 2006, v. 2, p. 11-34, doi: 10.1130/GES00020.1. Movie 1 - Tectonic model for the Pacific Basin and northwestern North America from 53 Ma to 39 Ma. The file size is 1.3 MB.

New body mass estimates forOmomys carteri, a middle Eocene primate from North America

1999 ◽  
Vol 109 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Bret A. Payseur ◽  
Herbert H. Covert ◽  
Christopher J. Vinyard ◽  
Marian Dagosto
Keyword(s):  
North America ◽  
Body Mass ◽  
Middle Eocene

Late Quaternary paleoenvironments of Northwestern North America: implications for inland versus coastal migration routes

2001 ◽  
Vol 20 (1-3) ◽  
pp. 301-314 ◽  
Author(s):  
Carole A.S Mandryk ◽  
Heiner Josenhans ◽  
Daryl W Fedje ◽  
Rolf W Mathewes
Keyword(s):  
North America ◽  
Late Quaternary ◽  
Migration Routes ◽  
Northwestern North America

Chromosome races in Rumex arcticus (Polygonaceae)

1972 ◽  
Vol 50 (2) ◽  
pp. 378-380
Author(s):  
Gerald A. Mulligan ◽  
Clarence Frankton
Keyword(s):  
North America ◽  
North American ◽  
Bering Sea ◽  
Kamchatka Peninsula ◽  
The Arctic ◽  
Chromosome Races ◽  
High Polyploid ◽  
Seward Peninsula ◽  
Northwestern North America ◽  
The Bering Sea

Rumex arcticus Trautv., a species found on the mainland of northwestern North America and in northeastern U.S.S.R., contains tetraploid (2n = 40), dodecaploid (2n = 120), and perhaps 2n = 160 and 2n = 200 chromosome races. Most North American plants are tetraploid and are larger in size and have more compound and contiguous inflorescences than typical R. arcticus. Typical plants of R. arcticus occur in the arctic U.S.S.R., St. Lawrence Island in the Bering Sea, and at the tip of the Seward Peninsula of Alaska, and they all have 120 or more somatic chromosomes. High polyploid plants of R. arcticus that resemble North American tetraploids in appearance apparently occur on the Kamchatka Peninsula. These have been called R. kamtshadalus Komarov or R. arcticus var. kamtshadalus (Kom.) Rech. f. by some authors.

scholarly journals Additional records and stratigraphic distribution of the middle Eocene carettochelyid turtle Anosteira pulchra from the Uinta Formation of Utah, North America

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9775
Author(s):  
Brent Adrian ◽  
Patricia A. Holroyd ◽  
J. Howard Hutchison ◽  
KE Beth Townsend
Keyword(s):  
North America ◽  
New Records ◽  
Middle Eocene ◽  
Single Species ◽  
Uinta Basin ◽  
Stratigraphic Framework ◽  
Multiple Levels ◽  
Land Mammal ◽  
Anatomical Information ◽  
Insight Into

Background Anosteira pulchra is one of two species of the obligately-aquatic freshwater clade Carettochelyidae (pig-nosed turtles) from the Eocene of North America. Anosteira pulchra is typically rare in collections, and their distribution is poorly documented. The Uinta Formation [Fm.] contains a diverse assemblage of turtles from the Uintan North American Land Mammal Age. Whereas turtles are abundantly preserved in the Uinta Fm., A. pulchra has been reported only from a few specimens in the Uinta C Member. Methods We describe new records of Anosteira pulchra from the Uinta Basin and analyze the distribution of 95 specimens from multiple repositories in the previously published stratigraphic framework of the middle and upper Uinta Fm. Results Here we report the first records of the species from the Uinta B interval, document it from multiple levels within the stratigraphic section and examine its uncommon appearance in only approximately 5% of localities where turtles have been systematically collected. This study details and extends the range of A. pulchra in the Uinta Fm. and demonstrates the presence of the taxon in significantly lower stratigraphic layers. These newly described fossils include previously unknown elements and associated trace fossils, with new anatomical information presented. This study provides insight into the taxonomy of Anosteira spp. in the middle Eocene, and suggests the presence of a single species, though no synonymy is defined here due to limits in Bridger material.

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