Leporids (Mammalia, Lagomorpha) from the Diamond O Ranch Local Fauna, Latest Middle Eocene of Southwestern Montana

2009 ◽  
Vol 78 (3) ◽  
pp. 253-271 ◽  
Author(s):  
Łucja Fostowicz-Frelik ◽  
Alan R. Tabrum
Keyword(s):  
Middle Eocene ◽  
Local Fauna ◽  
Southwestern Montana

Herpetofauna of the Calf Creek Local Fauna (Lower Oligocene: Cypress Hills Formation) of Saskatchewan

1972 ◽  
Vol 9 (12) ◽  
pp. 1612-1631 ◽  
Author(s):  
J. Alan Holman
Keyword(s):  
Middle Eocene ◽  
Tropical Climate ◽  
Local Fauna ◽  
Lower Oligocene ◽  
Bridger Formation

A Lower Oligocene deposit, the Calf Creek local fauna of the Cypress Hills Formation, near Eastend, Saskatchewan, yielded the remains of one salamander, three anurans, three turtles, a crocodilian, six lizards, and three snakes. All of the 13 herpetological families identified are extant. The four amphibian genera identified are extant, but only two of nine reptilian genera identified are living today. One genus and species and one species of iguanid lizard, one species of xantusiid lizard, and one species of small boid snake are described as new. The Calf Creek local fauna herpetofauna indicates a subtropical or tropical climate. The herpetofauna of the Calf Creek local fauna shows several differences from the herpetofauna of the Middle Eocene Tabernacle Butte local fauna of the Bridger Formation of Wyoming.

Vertebrate paleontology, geology, and geochronology of the Tapera de López and Scarritt Pocket, Chubut Province, Argentina

1986 ◽  
Vol 60 (4) ◽  
pp. 920-951 ◽  
Author(s):  
Larry G. Marshall ◽  
Richard L. Cifelli ◽  
Robert E. Drake ◽  
Garniss H. Curtis
Keyword(s):  
South America ◽  
Middle Eocene ◽  
Lower Boundary ◽  
Vertebrate Paleontology ◽  
Early Eocene ◽  
Local Fauna ◽  
Early Oligocene ◽  
Land Mammal ◽  
Mammal Faunas ◽  
Upper Boundary

Fossil land mammals were collected by G. G. Simpson in 1933–1934 at and near the Tapera de López in central Chubut Province, Patagonia, southern Argentina, from rocks now mapped as the Sarmiento Formation. These fossils are assigned to land mammal faunas of Casamayoran (Early Eocene), Mustersan (Middle Eocene), and Deseadan (late Early Oligocene through Early Miocene) age.40K-40Ar age determinations of eight basalt and two tuff units associated with the Deseadan age local fauna at Scarritt Pocket establish a geochronologic framework that calibrates the biostratigraphic record at this locality. The radioisotope dates obtained at Scarritt Pocket range from 23.4 Ma to about 21.0 Ma, and equate with earliest Miocene time. The Scarritt Pocket local fauna is the youngest dated Deseadan age fauna yet known in South America.Seven other localities have, or were reputed to have, local faunas of Deseadan age associated with dated volcanic units. Six of these localities are in Argentina (Gran Barranca, Cerro Blanco, Valle Hermoso, Pico Truncado, Cañadón Hondo, Quebrada Fiera de Malargüe) and one in Bolivia (Estratos Salla in the Salla-Luribay Basin). The stratigraphic relationships of the volcanic units with these local faunas is discussed, and the taxonomic content of each is reassessed.The Deseadan Land Mammal Age is defined by the earliest record of the land mammal genus Pyrotherium, which is from below a basalt dated at 33.6 Ma at Pico Truncado. Other early records of Pyrotherium occur below basalts dated at about 29 Ma at the Gran Barranca and Valle Hermoso, and from a 28.5 Ma level of the Estratos Salla. Thus, the lower boundary for Deseadan time is about 34 Ma.The youngest record of Pyrotherium is in the upper levels of the Estratos Salla dated at about 24 Ma. However, the Scarritt Pocket local fauna, which lacks Pyrotherium, permits placement of the upper boundary for Deseadan time at about 21.0 Ma. Late Deseadan time is surely, and the end of Deseadan time is apparently, marked by the last record of such groups as Proborhyaeninae (Proborhyaena), Rhynchippinae (Rhynchippus), Archaeohyracidae (Archaeohyrax), and the genera Platypittamys (Octodontidae), Scarrittia (Leontiniidae), Propachyrucos and Prohegetotherium (Hegetotheriidae), and Argyrohyrax (Interatheriidae), as these taxa are recorded in the Scarritt Pocket local fauna. Thus, Deseadan time extends from about 34.0 Ma to about 21.0 Ma, making it the Land Mammal Age with the longest known duration in South America.

Rodents (Mammalia) from Diamond O Ranch Local Fauna, Southwestern Montana

2017 ◽  
Vol 84 (4) ◽  
pp. 301-318 ◽  
Author(s):  
William W. Korth ◽  
Alan R. Tabrum
Keyword(s):  
Local Fauna ◽  
Southwestern Montana

Uintan land mammals (excluding rodents) from an estuarine facies of the Laredo Formation (Middle Eocene, Claiborne Group) of Webb County, Texas

1990 ◽  
Vol 64 (3) ◽  
pp. 454-468 ◽  
Author(s):  
James W. Westgate
Keyword(s):  
Coastal Plain ◽  
Rocky Mountains ◽  
Middle Eocene ◽  
Mammalian Fauna ◽  
East Texas ◽  
Gulf Coastal Plain ◽  
Local Fauna ◽  
West Texas ◽  
Mammal Fauna ◽  
Land Mammal

A newly discovered vertebrate fossil assemblage, the Casa Blanca local fauna, comes from the Laredo Formation, Claiborne Group, of Webb County, Texas, and is the first reported Eocene land-mammal fauna from the coastal plain of North America. The mammalian fauna is correlated with the Serendipity and Candelaria local faunas of west Texas, the Uinta C faunas of the Rocky Mountains, the Santiago Formation local fauna of southern California, and the Swift Current Creek local fauna of Saskatchewan. The vertebrate-bearing deposit lies approximately 32 m above a horizon containing the marine gastropod Turritella cortezi, which ranges from east Texas to northeast Mexico in the lower half of the Cook Mountain and Laredo Formations and is a guide fossil for the Hurricane Lentil in the Cook Mountain Formation. Nannoplankton found in these middle Eocene formations belong to the upper half of Nannoplankton Zone 16 and allow correlation with European beds of late Lutetian to early Bartonian age.Over 700 specimens represent at least 30 species of 28 mammal genera. The Casa Blanca fauna is the southernmost and easternmost North American land-mammal fauna of definite Eocene age, and is the westernmost Paleogene vertebrate fauna from the Gulf Coastal Plain.

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