scholarly journals Rodents (Mammalia)from Fitterer Ranch, Brule Formation (Oligocene), North Dakota

2019 ◽  
pp. iv-45 ◽  
Author(s):  
William W. Korth ◽  
Robert J. Emry ◽  
Clint A. Boyd ◽  
Jeff J. Person
Keyword(s):  
North Dakota ◽  
Rodent Species ◽  
Single Specimen ◽  
Early Oligocene ◽  
Land Mammal ◽  
Brule Formation

Korth, William W., Robert J. Emry, Clint A. Boyd, and Jeff J. Person. Rodents (Mammalia) from Fitterer Ranch, Brule Formation (Oligocene), North Dakota. Smithsonian Contributions to Paleobiology, number 103, vi + 45 pages, 17 figures, 15 tables, 1 appendix, 2019.—Eighteen rodent species are recognized from the Fitterer Ranch fauna of North Dakota on the basis of more than a thousand collected specimens. Of the species recognized, four are new: the prosciurine aplodontiids Prosciurus hogansoni and Altasciurus leonardi, the heliscomyid Heliscomys borealis, and the cricetid Eumys lammersi. A previously described castorid from this fauna, Oligotheriomys primus Korth, 1998, is considered a synonym of “Eutypomys” magnus Wood, 1937, on the basis of the recovery of lower dentitions but is retained in the genus Oligotheriomys. A single specimen is questionably referred to Microparamys, a genus elsewhere limited to the Eocene (Clarkforkian-Chadronian land mammal ages). The rodent fauna appears to be a combination of predominantly Orellan and Whitneyan species (early Oligocene), suggesting that the section might transcend the Orellan-Whitneyan boundary. However, the rodent fauna does not alter significantly from the lowest to the highest horizons.

Marsupials (Mammalia, Metatheria) from the Brule Formation (Whitneyan, Oligocene) North Dakota

2020 ◽  
Vol 95 (1) ◽  
pp. 193-204
Author(s):  
William W. Korth ◽  
Clint A. Boyd ◽  
Robert J. Emry ◽  
Jeff J. Person
Keyword(s):  
New Species ◽  
North America ◽  
North Dakota ◽  
Great Plains ◽  
Single Specimen ◽  
Marsupial Species ◽  
Fourth Species ◽  
Latest Eocene ◽  
Land Mammal ◽  
Brule Formation

AbstractFive marsupial species are recognized from the Brule Formation at two localities in southwestern North Dakota: Fitterer Ranch and Obritsch Ranch (middle Oligocene; Whitneyan North American Land Mammal Age [NALMA]). The herpetotheriids Herpetotherium fugax Cope, 1873a, Copedelphys superstes new species, and the peradectid Nanodelphys hunti (Cope, 1873b) are represented at both localities. A fourth species is H. sp., cf. H. merriami (Stock and Furlong, 1922), represented by a single specimen from Fitterer Ranch, being limited elsewhere to the later Arikareean NALMA. A fifth species is represented by two isolated lower cheek teeth, interpreted as m1s, from Fitterer Ranch that are unique in lacking a trigonid (only two cusps present) while having a well-developed talonid. These specimens are referred to an indeterminate herpetotheriine species. The new species of Copedelphys is distinct from other species of the genus in that the anterior two lower molars are enlarged relative to the posterior molars. Overall, this new species is more similar in proportions to the latest Eocene (Chadronian) C. titanelix (Matthew, 1903) than the Oligocene (Orellan and Whitneyan) C. stevensoni (Cope, 1873b). This study adds a third and fourth Whitneyan marsupial fauna from the Great Plains region of North America, increases the known diversity of Whitneyan marsupials, and provides further evidence that marsupial diversity during the late Paleogene in North America was relatively stable until the late early Arikareean NALMA.UUID: http://zoobank.org/b8534802-b9ed-4120-baca-fc72917f7d6a

An avian eggshell from the Brule Formation (Oligocene) of North Dakota

2018 ◽  
Vol 38 (4) ◽  
pp. (1)-(9) ◽  
Author(s):  
Daniel R. Lawver ◽  
Clint A. Boyd
Keyword(s):  
North Dakota ◽  
Brule Formation

A new family, genus, and species of crab (Crustacea, Decapoda, Brachyura) from the upper Cretaceous (Campanian) of Manitoba, Canada

2007 ◽  
Vol 44 (12) ◽  
pp. 1741-1752 ◽  
Author(s):  
Rodney M Feldmann ◽  
Rong-Yu Li ◽  
Carrie E Schweitzer
Keyword(s):  
North Dakota ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
New Genus ◽  
Single Specimen ◽  
New Genus And Species ◽  
New Family ◽  
Extinction Event

Discovery of a single specimen of brachyuran decapod from the Campanian Millwood Member in southern Manitoba, Canada, permits description of a new genus and species, Cretacocarcinus smithi. Comparison of sternal architecture and general carapace morphology with potentially related taxa documents that the new genus, along with Camarocarcinus Holland and Cvancara, form a new family, Camarocarcinidae, tentatively assigned to the Raninoidea. The Camarocarcinidae are interpreted to have originated in the upper Midcontinental Seaway in the Late Cretaceous, survived the K–T extinction event(s), and dispersed into southern North Dakota, USA; Greenland; and Denmark in the Paleocene.

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.

Lower jaw of the Early Paleocene mammal Alveugena and its interpretation as a transitional fossil

2010 ◽  
Vol 84 (6) ◽  
pp. 1217-1225 ◽  
Author(s):  
Deborah L. Rook ◽  
John P. Hunter ◽  
Dean A. Pearson ◽  
Antoine Bercovici
Keyword(s):  
North Dakota ◽  
Late Cretaceous ◽  
Cladistic Analysis ◽  
Union Formation ◽  
Transitional Form ◽  
Lower Jaw ◽  
Fort Union Formation ◽  
Early Paleocene ◽  
Age Relations ◽  
Land Mammal

The Paleogene Order Taeniodonta Cope, 1876—peculiar heavy-bodied mammals, some with evergrowing cheek teeth—are grouped with the Late Cretaceous eutherian Cimolestes Marsh, 1889, along with a host of other taxa in a superordinal group, the Cimolesta. Taeniodonts were thought to have arisen from Cimolestes indirectly, through Paleocene Procerberus Sloan and Van Valen, 1965. The recently described Paleocene Alveugena Eberle, 1999, until now known only from the upper dentition, has been put forth as a transitional form between cimolestids and taeniodonts on phylogenetic and biostratigraphic grounds. An older taeniodont, the Late Cretaceous Schowalteria Fox and Naylor, 2003, has since been described, complicating taeniodont origins. We describe here a lower jaw that we refer to Alveugena from the lower part of the Ludlow Member of the Fort Union Formation in North Dakota. The lower jaw comes from strata of early Early Paleocene age (Puercan 1 North American Land Mammal Age) ~8.5 m above a Cretaceous-Paleogene boundary, identified using palynological criteria. A cladistic analysis is here presented using new data on Schowalteria and Alveugena, added to that of Cimolestes, Procerberus formicarum Sloan and Van Valen, 1965, P. grandis Middleton and Dewar, 2004, and Onychodectes. This analysis revealed Alveugena as the sister taxon of the taeniodonts but with a closer relationship to Cimolestes than Procerberus, suggesting that taeniodonts evolved from a Cimolestes-like ancestor. We discuss the age relations of early taeniodonts and related taxa and propose a scenario of ancestor-descendent relations that minimizes, but does not eliminate, implied stratigraphic gaps.

A latest Chadronian (Late Eocene) mammalian fauna from the Cypress Hills, Saskatchewan

1994 ◽  
Vol 31 (8) ◽  
pp. 1335-1341 ◽  
Author(s):  
John E. Storer
Keyword(s):  
North America ◽  
Strong Evidence ◽  
Late Eocene ◽  
Mammalian Fauna ◽  
Local Fauna ◽  
Early Oligocene ◽  
Land Mammal

The Kealey Springs West (KSW) local fauna from the Cypress Hills Formation (Eocene to Miocene), Saskatchewan, is probably latest Chadronian in age, and is the northernmost assemblage representing a time near the Eocene–Oligocene boundary in North America. Presence of Pseudocylindrodon neglectus is strong evidence that the assemblage is Chadronian. Herpetotherium valens, Protosciurus, Namatomys cf. N. lloydi, and Centimanomys also suggest a Chadronian age. The assemblage contains Adjidaumo maximus and Palaeolagus cf. P. hemirhizis, species that have been cited as characteristic of the early part of the Orellan Land Mammal Age (early Oligocene), and the typically Orellan Heliscomys hatcheri and Eumys elegans. Several other tara in the KSW assemblage are known from both the Chadronian (late Eocene) and Orellan.

scholarly journals Late middle Miocene caviomorph rodents from Tarapoto, Peruvian Amazonia

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258455
Author(s):  
Myriam Boivin ◽  
Laurent Marivaux ◽  
Walter Aguirre-Diaz ◽  
Aldo Benites-Palomino ◽  
Guillaume Billet ◽  
...  
Keyword(s):  
Middle Miocene ◽  
Rodent Species ◽  
South American ◽  
Formal Description ◽  
Tarsal Bone ◽  
Late Middle Miocene ◽  
Peruvian Amazonia ◽  
Land Mammal ◽  
Caviomorph Rodents ◽  
San Martín

Miocene deposits of South America have yielded several species-rich assemblages of caviomorph rodents. They are mostly situated at high and mid- latitudes of the continent, except for the exceptional Honda Group of La Venta, Colombia, the faunal composition of which allowed to describe the late middle Miocene Laventan South American Land Mammal Age (SALMA). In this paper, we describe a new caviomorph assemblage from TAR-31 locality, recently discovered near Tarapoto in Peruvian Amazonia (San Martín Department). Based on mammalian biostratigraphy, this single-phased locality is unambiguously considered to fall within the Laventan SALMA. TAR-31 yielded rodent species found in La Venta, such as the octodontoid Ricardomys longidens Walton, 1990 (nom. nud.), the chinchilloids Microscleromys paradoxalis Walton, 1990 (nom. nud.) and M. cribriphilus Walton, 1990 (nom. nud.), or closely-related taxa. Given these strong taxonomic affinities, we further seize the opportunity to review the rodent dental material from La Venta described in the Ph.D. volume of Walton in 1990 but referred to as nomina nuda. Here we validate the recognition of these former taxa and provide their formal description. TAR-31 documents nine distinct rodent species documenting the four extant superfamilies of Caviomorpha, including a new erethizontoid: Nuyuyomys chinqaska gen. et sp. nov. These fossils document the most diverse caviomorph fauna for the middle Miocene interval of Peruvian Amazonia to date. This rodent discovery from Peru extends the geographical ranges of Ricardomys longidens, Microscleromys paradoxalis, and M. cribriphilus, 1,100 km to the south. Only one postcranial element of rodent was unearthed in TAR-31 (astragalus). This tiny tarsal bone most likely documents one of the two species of Microscleromys and its morphology indicates terrestrial generalist adaptations for this minute chinchilloid.

scholarly journals Cranial endocast of the stem lagomorph Megalagus and brain structure of basal Euarchontoglires

2020 ◽  
Vol 287 (1929) ◽  
pp. 20200665
Author(s):  
Sergi López-Torres ◽  
Ornella C. Bertrand ◽  
Madlen M. Lang ◽  
Mary T. Silcox ◽  
Łucja Fostowicz-Frelik
Keyword(s):  
Eye Movements ◽  
Visual Tracking ◽  
Brain Morphology ◽  
Olfactory Bulbs ◽  
Critical Gap ◽  
Early Oligocene ◽  
Encephalization Quotient ◽  
Early Specialization ◽  
Brule Formation ◽  
The Brain

Early lagomorphs are central to our understanding of how the brain evolved in Glires (rodents, lagomorphs and their kin) from basal members of Euarchontoglires (Glires + Euarchonta, the latter grouping primates, treeshrews, and colugos). Here, we report the first virtual endocast of the fossil lagomorph Megalagus turgidus , from the Orella Member of the Brule Formation, early Oligocene, Nebraska, USA. The specimen represents one of the oldest nearly complete lagomorph skulls known. Primitive aspects of the endocranial morphology in Megalagus include large olfactory bulbs, exposure of the midbrain, a small neocortex and a relatively low encephalization quotient. Overall, this suggests a brain morphology closer to that of other basal members of Euarchontoglires (e.g. plesiadapiforms and ischyromyid rodents) than to that of living lagomorphs. However, the well-developed petrosal lobules in Megalagus , comparable to the condition in modern lagomorphs, suggest early specialization in that order for the stabilization of eye movements necessary for accurate visual tracking. Our study sheds new light on the reconstructed morphology of the ancestral brain in Euarchontoglires and fills a critical gap in the understanding of palaeoneuroanatomy of this major group of placental mammals.

scholarly journals Biochronology and biogeography of Paradaphoenus (Carnivora: Amphicyonidae) within the Great Plains Region of North America

2018 ◽  
Author(s):  
Clint A Boyd ◽  
Ed Welsh
Keyword(s):  
North America ◽  
South Dakota ◽  
North Dakota ◽  
Great Plains ◽  
Geographic Range ◽  
Single Specimen ◽  
Local Fauna ◽  
White River ◽  
The Common ◽  
Size And Morphology

The amphicyonid, or “bear-dog,” Paradaphoenus was a small-bodied, hypercarnivorous carnivoran that lived in North America during the Oligocene. Specimens of Paradaphoenus are rare, in part owing to the common inaccurate referral of specimens to the abundant canid Hesperocyon, which was similar in size and morphology. Four new specimens of Paradaphoenus are noted from North Dakota and South Dakota that expand the geographic range of this taxon within the Great Plains region of North America and expand our knowledge of its anatomy. A single specimen from either a transitional Orellan/Whitneyan or early Whitneyan fauna in the Little Badlands area of North Dakota is referred to Paradaphoenus minimus. That taxon is elsewhere restricted to Orellan faunae, making that specimen the youngest occurrence of P. minimus yet recognized. The remaining specimens are from two early Whitneyan faunas, the Cedar Pass local fauna in South Dakota and a new locality within the Little Badlands area of North Dakota, and are referred to Paradaphoenus tooheyi. These discoveries highlight the difficulties of elucidating the biostratigraphic and biogeographic distributions of relatively rare taxa within the White River Chronofauna given the propensity for many specimen identifications to be biased in favor of more abundant, well-known taxa.

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