The biogeographic origins of late Paleocene–early Eocene mammalian immigrants to the Western Interior of North America

1990 ◽  
pp. 71-106 ◽  
Author(s):  
David W. Krause ◽  
Mary C. Maas
Keyword(s):  
North America ◽  
Early Eocene ◽  
Late Paleocene

scholarly journals An alternative interpretation of the Paleogene turtle Cardichelyon rogerwoodi as a hinged kinosternoid

2020 ◽  
Vol 94 (3) ◽  
pp. 557-567
Author(s):  
Walter G. Joyce ◽  
Julien Claude
Keyword(s):  
Phylogenetic Analysis ◽  
North America ◽  
Alternative Interpretation ◽  
Early Eocene ◽  
External Data ◽  
Late Paleocene ◽  
Large Head

AbstractCardichelyon rogerwoodi is an enigmatic fossil turtle from the late Paleocene to early Eocene of North America. Previous analyses suggested affiliation with Testudinoidea, in particular the big-headed turtle Platysternon megacephalum, based on the presence of multiple musk-duct foramina and a large head. We here highlight previously undocumented characteristics for this turtle, notably the presence of short costiform processes, a rib-like axillary process, and a posterior plastral hinge. Phylogenetic analysis places Cardichelyon rogerwoodi within Testudinoidea, but the exclusion of testudinoids suggest an affiliation with Dermatemydidae. Using consilience with external data we favor placement within Kinosternoidea. Cardichelyon rogerwoodi is therefore an aberrant, hinged kinosternoid that developed in situ in North America during the Paleocene long before the arrival of testudinoids on this continent in the early Eocene.

Zingiberopsis, a fossil genus of the ginger family from Late Cretaceous to early Eocene sediments of Western Interior North America

1978 ◽  
Vol 56 (9) ◽  
pp. 1136-1152 ◽  
Author(s):  
Leo J. Hickey ◽  
Rayma Kempinsky Peterson
Keyword(s):  
New Species ◽  
North America ◽  
Late Cretaceous ◽  
New Combination ◽  
Early Eocene ◽  
Clear Trend ◽  
Late Paleocene ◽  
Fossil Genus ◽  
A New Species

Zingiberopsis attenuata Hickey and Peterson is a new species of monocotyledon from the Paleocene Paskapoo Formation of Alberta. Leaves of this species with their parallel veins grouped into three size sets are intermediate between the Late Cretaceous Zingiberopsis magnifolia (Knowlton) Hickey, new combination, with four discrete sets and Zingiberopsis isonervosa Hickey, of late Paleocene and early Eocene age, with only one set. Zingiberopsis has large, elliptic to ovate leaves with a costa composed of a number of concurrent strands, a set of parallel veins emerging at low angles from the costa, and relatively distantly spaced transverse veins running between adjacent parallel veins. Morphology of the genus matches that of Alpinia in the Zingiberaceae except for greater irregularity of the parallel vein set at and near their origin on the costa and the lack of any evidence of a ligule on the petiole as in Alpinia. Species of Zingiberopsis demonstrate a clear trend toward loss of the wider parallel vein subsets over the approximately 20-million-year range of the genus. In addition, the overlooked character of the arrangement of the parallel vein subsets across the width of the leaf may have potential in the taxonomic determination of monocotyledonous leaves.

A new glyptosaurine lizard from the earliest Eocene of Dormaal, Belgium

2012 ◽  
Vol 183 (6) ◽  
pp. 627-633 ◽  
Author(s):  
Robert M. Sullivan ◽  
Marc Augé ◽  
Eric Wille ◽  
Richard Smith
Keyword(s):  
North America ◽  
Western Europe ◽  
Reference Level ◽  
New Taxon ◽  
Early Eocene ◽  
Lower Eocene ◽  
Lower Tooth ◽  
Late Paleocene ◽  
Sudden Appearance ◽  
Tooth Count

Abstract A new glyptosaurine lizard ?Placosaurus ragei, n. sp., is recognized as being distinct from Paraplacosauriops quercyi in having a lightly built dentary, incipient heterodont teeth, lower tooth count (19), and teeth that are more gracile compared to other European glyptosaurine lizards. ?Placosaurus ragei also differs from “Placosaurus” europaeus, which has a prominent homodont dentition and is more massive. A second specimen, an isolated, nearly complete parietal, partly covered with hexagonal and polygonal osteoderms, is referable to the European glyptosaurin Placosaurus and is provisionally referred to the species ?Placosaurus ragei. A third specimen, an incomplete right frontal fragment of an indeterminate “melanosaurin,” may represent a new taxon, or may be referable to the well-known Western European taxon Placosauriops. Taxa pertaining to both tribes (Glyptosaurini and “Melanosaurini”) of glyptosaurine lizards have been recovered from the lower Eocene deposits of Dormaal, Belgium. Their apparent sudden appearance is interpreted as marking entry into western Europe. The Dormaal locality has been correlated to reference level MP7 and thus is considered to be of early Eocene age. Glyptosaurine lizards probably dispersed into western Europe, from North America, through the Greenland bridge during late Paleocene/early Eocene time.

Icacinaceae in the early middle Paleocene Raton Formation, Colorado

2018 ◽  
Vol 55 (2) ◽  
pp. 75-86 ◽  
Author(s):  
Keith Berry
Keyword(s):  
North America ◽  
Tropical Rainforest ◽  
Tropical Rainforests ◽  
Early Eocene ◽  
Western North America ◽  
South Central ◽  
Late Paleocene ◽  
Single Locality

Icacinicaryites corruga is reported from the upper coal zone of the Raton Formation in south-central Colorado. Prior to this report, this endocarp imprint was known from only a single locality near Pagosa Springs in southwestern Colorado (Animas Formation). This demonstrates that Icacinaceae, which characterized the late Paleocene – early Eocene tropical rainforests of western North America, already were present in Colorado’s early middle Paleocene tropical rainforest. This determination agrees with the results of a reevaluation of the stratigraphic distribution of previous records of Icacinaceae from the Paleocene of western North America.

Taxonomy and distribution of the buccinid gastropod Brachysphingus from uppermost Cretaceous and Lower Cenozoic marine strata of the Pacific Slope of North America

1997 ◽  
Vol 71 (5) ◽  
pp. 847-861 ◽  
Author(s):  
Richard L. Squires
Keyword(s):  
North America ◽  
Fossil Record ◽  
Turbidity Currents ◽  
Early Eocene ◽  
Shallow Marine ◽  
Marine Strata ◽  
Late Paleocene ◽  
The Pacific ◽  
Early Paleocene ◽  
Pacific Slope

Brachysphingus is a low-spired bucciniform neogastropod known only from the fossil record of California and northern Baja California. The earliest species, Brachysphingus gibbosus Nelson, 1925, ranges in age from latest Cretaceous or possibly earliest Paleocene to the late Paleocene. During the early Paleocene, the smoothish B. gibbosus evolved into the axially ribbed B. sinuatus Gabb, 1869, which is the senior primary synonym of B. gabbi Stewart, 1927. During the late Paleocene, B. sinuatus evolved into B. mammilatus Clark and Woodford, 1927, which is the youngest species of Brachysphingus and which lasted into the early Eocene.All three species of Brachysphingus were shallow-marine dwellers subject to transport into deeper waters via turbidity currents.

Calcardea junnei Gingerich, 1987 from the late Paleocene of North America is not a heron, but resembles the early Eocene Indian taxon Vastanavis Mayr et al., 2007

2018 ◽  
Vol 93 (2) ◽  
pp. 359-367 ◽  
Author(s):  
Gerald Mayr ◽  
Philip D. Gingerich ◽  
Thierry Smith
Keyword(s):  
North America ◽  
Early Eocene ◽  
Late Paleocene ◽  
Large Bird ◽  
Willwood Formation ◽  
Partial Skeleton

AbstractWe revisit the holotype of Calcardea junnei Gingerich, 1987 from the latest Paleocene (Clarkforkian) of the Willwood Formation (Wyoming, USA). The species is based on a partial skeleton and was originally assigned to the Ardeidae (herons). As we show, this classification cannot be upheld and Calcardea Gingerich, 1987 more closely resembles the taxon Vastanavis Mayr et al., 2007 (Vastanavidae), a parrot-like bird from the early Eocene of India. Even though C. junnei is a large bird, its long wings and short tarsometatarsus argue against a predominantly terrestrial way of living, and the morphology of the tarsometatarsus and pedal phalanges instead suggest strong grasping feet. We conclude that an assignment of Calcardea to the landbird clade (Telluraves) is better supported than its classification into the waterbird clade (Aequornithes), which includes Ardeidae and other ‘ciconiiform’ and ‘pelecaniform’ taxa. Calcardea junnei is one of the oldest known representatives of Telluraves and its morphology shows plesiomorphic features, which contributed to its previous misidentification as a heron. Calcardea exhibits a distinctive osteology and affords a glimpse of a previously unknown late Paleocene avian morphotype.

Late Paleocene–Early Eocene Paleosols and a New Measure of the Transport Distance of Alaska’s Yakutat Terrane

2017 ◽  
Vol 125 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Tim White ◽  
Dwight Bradley ◽  
Peter Haeussler ◽  
David B. Rowley
Keyword(s):  
Early Eocene ◽  
Transport Distance ◽  
Late Paleocene
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