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A large collection of dentigerous jaws quarried from the Gao Mine locality, late Paleocene, Paskapoo Formation, central Alberta, Canada, documents a new species of the early Paleogene phenacodontid "condylarth" Ectocion Cope, 1882. The new species, Ectocion stockeyae, the smallest of the genus, occurs well before the abrupt global warming at the Paleocene–Eocene Thermal Maximum, an event purportedly causing the rapid evolution of "dwarfed" mammals, including a species of Ectocion; however, there is no evidence of increased temperatures at Gao Mine to account for the small size of Ectocion stockeyae, raising questions of the relationship between temperature and body size in Ectocion. Ectocion stockeyae also exhibits sexual dimorphism of the canines, a pattern in mammals often associated with a population structure in which the males are relatively few and polygynous, resulting in intense male rivalry for mating success. The sample of Ectocion stockeyae from Gao Mine includes a substantial majority of "juvenile" individuals retaining deciduous posterior premolars, many even after eruption of the molars had been completed, suggesting short life spans, accelerated growth, and rapid dental development in this species as expressed in Schultz's Rule. [ABSTRACT FROM AUTHOR]

The history of subsidence and thermal evolution of the Kribi-Campo sub-basin in the Gulf of Guinea was constrained from 10 offshore wells using the post-compaction offloading technique. Four main subsidence phases were recognized: a first Barremian to Aptian phase (130–112 Ma); a second Albian to Senonian phase (112–65 Ma); a third Paleocene to Miocene phase (65–5 Ma); and a fourth Pliocene to Pleistocene phase (5–2 Ma). Maps of subsidence extent and rate and of deposition show an extensive subsidence zone in the western part of the basin around Kribi. Extension factor β values for the uniform extension model range from 1.04 to 1.06. Graphically, tectonic subsidence curves are framed by curves corresponding to β values of 1.03 and 1.09. Sediment paleotemperatures and geothermal gradients were obtained from the slopes of linear tectonic subsidence curves as a function of the square root of time, and they are in perfect agreement with values measured in the wells. For instance, a temperature gradient of 35.316 °C·km−1 was obtained for maximum temperatures, compared to a gradient of 35.554 °C·km−1 derived from well measurements. A comparison of calculated and measured vitrinite reflectance values R o shows good agreement. These vitrinite values indicate that the Cretaceous and Lower Tertiary host rocks probably reached thermal maturity. [Journal translation] [ABSTRACT FROM AUTHOR]

Although multituberculates are among the best-represented mammals of the Late Cretaceous and early Paleogene in North America, their evolution during the first several tens to hundreds of thousands of years following the Cretaceous–Paleogene (K–Pg) impact event is largely obscure. A better understanding of the early Paleogene record of multituberculates is crucial, for their dominance in early Paleocene mammalian faunas is unquestionably a result of rapid evolution during the immediate post-impact interval, and they accordingly played an important role in the evolution of mammalian communities more generally. I report on a new multituberculate from the early Paleocene of southwestern Alberta, in rocks of the Willow Creek Formation, the first such occurrence in this otherwise poorly known unit. The new multituberculate, Aenigmamys aries gen. et sp. nov., most closely resembles the ptilodontid Kimbetohia campi in comparable parts of the dentition and sheds light on the early evolution of Ptilodontidae, one of the major cimolodontan families that diversified during the Paleocene. The presence of Aenigmamys in mammalian faunas that lived soon after the K–Pg boundary implies a still-deeper evolutionary history for Ptilodontidae that may have extended into the Late Cretaceous. Aenigmamys is part of a new mammalian fauna from southwestern Alberta, the taxonomic composition of which includes a diversity of multituberculates, cimolestans, primates, and condylarths. The fauna correlates with those of middle Puercan age from other parts of the Western Interior of North America, and its high taxonomic diversity further corroborates previous hypotheses that multituberculate recovery — and mammalian recovery more generally — occurred relatively quickly after the K–Pg extinction event. [ABSTRACT FROM AUTHOR]

The Willow Creek Formation (upper Maastrichtian - lower Paleocene) of southwestern Alberta is a poorly fossiliferous formation that preserves a low end-Cretaceous dinosaur diversity compared with most correlative terrestrial deposits in the North American Western Interior. Although only three dinosaur taxa are known from skeletal remains ( Tyrannosaurus rex, Hadrosauridae indet., and Leptoceratopsidae indet.), study of hundreds of dinosaur eggshells recovered from several sites in the formation reveals the presence of a more diverse dinosaur assemblage. Morphological and histological analyses of the eggshells indicate the presence of at least seven dinosaur ootaxa ( Continuoolithus, Montanoolithus, Porituberoolithus, Prismatoolithus spp., Spheroolithus spp.). These ootaxa are referable to at least two ornithopod and five small theropod species, likely including dromaeosaurids, oviraptorosaurs, and troodontids. When considering the taxonomic affinity of eggshells and skeletal remains, the present study triples the known dinosaur diversity of the Willow Creek Formation, increasing the number of dinosaurs from three to at least nine species. Probable ornithopod eggshells comprise most of the eggshells preserved, although small theropods were likely an important component of the Willow Creek ecosystem, as most ootaxa can be ascribed to these dinosaurs. Although fossil bones are rarely found in the Willow Creek Formation, fossil eggshells are common compared with most other dinosaur-bearing formations in Alberta. The caliche-bearing deposits, indicative of arid to semi-arid conditions, typical of the formation were likely conducive to the preservation of calcareous eggshells. [ABSTRACT FROM AUTHOR]

Cimolestes Marsh is a North American eutherian mammal primarily known from latest Cretaceous deposits in Alberta, Wyoming, Saskatchewan, and Montana. At present, five species of Cimolestes are considered valid, all Lancian in age; they include one of the largest North American Late Cretaceous therian mammals as well as one of the smallest, a size range far exceeding that within other genera of tribosphenic therians contemporary with Cimolestes, such as the leptictoid eutherian Gypsonictops Simpson or genera of alphadontid or pediomyid marsupials. Moreover, the species of Cimolestes display a disparity of dental morphology in addition to size well in excess of interspecific differences within these genera. Given these considerations, Cimolestes is clearly a grade-taxon, uniting species sharing an adaptively subzalambdodont dentition, but showing divergent specializations within this pattern that are inconsistent with monophyly of its presently included species. To correct these imbalances, this paper limits Cimolestes to Cimolestes incisus Marsh and Cimolestes stirtoni Clemens; Cimolestes magnus Clemens and Russell, Cimolestes cerberoides Lillegraven, and Cimolestes propalaeoryctes Lillegraven are reclassified in the new genera Altacreodus, Ambilestes, and Scollardius, respectively. Altacreodus magnus, having a massive shearing dentition, is reconfirmed as showing a relationship to some Tertiary 'creodonts' not shared by other species of Lancian cimolestids; Ambilestes cerberoides exhibits a distinctive molar wear pattern that emphasized horizontal grinding, not orthal shear; Scollardius propalaeoryctes, the smallest species in this revision and having hyper-faunivorous molars, was not ancestral to Paleogene Palaeoryctidae, as indicated in part by contradictions in premolar number and morphology. [ABSTRACT FROM AUTHOR]

A very rare 11.2 m long wide-gauge trackway, made by an as yet undetermined large mammal, is described from the Lacombe Member (Late Paleocene) of the Paskapoo Formation (Paleocene). The exposure of the trackway was connected with the record-setting floods of 2013 in the province of Alberta as the tracks were exposed close to the base of the Brazeau Dam in west-central Alberta. The tracks are preserved on the top surface of a siltstone, but extensive erosion of the tracks resulted in the removal of details such as claw and digit traces, as well as any heel or palm impressions. The tracks are all circular to subcircular in outline, and it is not possible to determine the direction of travel of the trackmaker. Sequences of distinct pairings of adjacent tracks on both the left and right set of traces are present, and these are interpreted to represent manus-pes couples. The tracks do not show any overprinting. The mean pace angulations of the two best preserved sections range from 113° to 125°, while their mean stride lengths range from 95 to 96 cm. The lack of any distinctive anatomical details being preserved in the tracks prevents a precise identification of the trackmaker, but the sizes, shapes, and age of the tracks suggest that they could have been made by a large pantodont. [ABSTRACT FROM AUTHOR]

Albertosuchus knudsenii gen. et sp. nov. is described on the basis of an incomplete skeleton from the lower part (uppermost Cretaceous) of the Scollard Formation, southern Alberta, Canada. It is probably a crocodyloid, the only Canadian representative of the group and also the sole crocodylian known during the latest Cretaceous in Canada. Within the Crocodyloidea, A. knudsenii is one of the most basal forms and shares a sister-group relationship with the European genus Arenysuchus. However, it needs to be emphasized that because of its incompleteness, phylogenetic relationships proposed here for A. knudsenii may change when better-preserved specimens are found. Albertosuchus knudsenii differs from other crocodyloids in having no premaxilla-maxillary notch, a very short mandibular symphysis with the involvement of the splenial, and an extremely deep hypapophysis on the last cervical and anterior dorsal vertebrae. The discovery of A. knudsenii may expand the geographical range of the Crocodyloidea into Canada during the Cretaceous. Crocodylians in the lower part of the Scollard Formation are of low diversity compared with that of the corresponding Hell Creek Formation of Montana and Lance Formation of Wyoming, both farther to the south in the USA. [ABSTRACT FROM AUTHOR]

Pandemonium hibernalis sp. nov., from a middle? Puercan (earliest Paleocene) locality in the upper Scollard Formation, Wintering Hills, southern Alberta, represents the second discovered occurrence of the enigmatic plesiadapiform primate Pandemonium Van Valen and the first from Canada. The holotype of Pandemonium hibernalis is the only known specimen of Pandemonium documented by multiple teeth from a single individual. Pandemonium hibernalis closely resembles the type species Pandemonium dis from Purgatory Hill, middle-late Puercan, Tullock Formation, Montana, but differs in having wider, more bunodont lower molar crowns and a more expanded posterior talonid lobe of m3, specializations suggesting enhanced capacity for crushing and grinding of soft food materials during mastication. Pandemonium hibernalis joins other recent discoveries in Alberta and elsewhere in the North American Western Interior in documenting a moderate radiation of basal plesiadapiforms that evolved unexpectedly early during primate evolution. [ABSTRACT FROM AUTHOR]

Understanding aquifer architecture is critical for managing groundwater resources in western Canada. Recent regulations have yielded abundant new gamma-ray well-log data from the principal aquifer in Alberta, the Paleocene Paskapoo Formation. A major obstacle to utilizing this data is the fact that gamma-ray measurements in the shallow subsurface are made through surface casing, which suppresses gamma-ray readings and effectively prohibits stratigraphic characterization. Here we describe and demonstrate a relatively simple and efficient method for normalizing gamma-ray data from stratigraphic horizons that are behind surface casing and apply this method to the Paskapoo Formation in west-central Alberta. The gamma-ray normalization procedure adjusts the cased gamma-ray values so that high and low percentile values of the resulting gamma-ray statistical distribution are equal to those of the non-cased values. The effectiveness of this procedure is demonstrated by comparing the normalized gamma-ray values from cased intervals with those from nearby wells without casing. Good matches between these wells, as well as the transition between normalized curves at the base of cased zones and the gamma-ray curves at the uppermost portion of uncased zones, suggest this methodology is effective for studying the Paskapoo Formation. The normalized curve allows cased and uncased intervals to be correlated, enabling improved stratigraphic characterization and mapping of fluvial sand bodies behind surface casing. This new data provides the framework for better characterization of aquifer dimensions and the derivation of stratigraphic parameters used to constrain hydrogeological models and enhance groundwater recovery. [ABSTRACT FROM AUTHOR]

Turtle fossils of Paleocene age have been recovered from four formations in Alberta, Canada: the upper (Paleocene) part of the Scollard Formation, the upper (Paleocene) portion of the Willow Creek Formation, and the exclusively Paleocene Porcupine Hills and Paskapoo formations. At least three non-trionychid turtle taxa can be recognized. Definitely present are a generically indeterminate baenid, the macrobaenid Judithemys backmani, and the chelydrid Protochelydra zangerli. The carapace of a juvenile chelydrid could be either a juvenile of P. zangerli or a fourth, distinct taxon. The macrobaenid J. backmani and the chelydrid P. zangerli are the most abundant non-trionychid turtles from the Paleocene of Alberta. The turtles from the Paleocene of Alberta differ from those of comparable age in New Mexico, USA, and other more southern localities in the North American Western Interior in ( i) the presence of macrobaenids and chelydrids and ( ii) the absence of kinosternoids. These differences mirror those of the Late Cretaceous, suggesting that biogeographic patterns of non-trionychid turtle distributions that were established during the Late Cretaceous in the Western Interior continued well into the Paleocene. [ABSTRACT FROM AUTHOR]

Although mammals of Paleocene age are well known from Alberta, their record is largely restricted to one lithological unit, the Paskapoo Formation (a record that includes mammals from the Cochrane area erroneously attributed to the Porcupine Hills Formation). We report here the first occurrence of Paleocene mammals from the Porcupine Hills Formation at exposures near the western edge of the city of Calgary. The assemblage, termed the Bearspaw local fauna, documents a diversity of multituberculate and eutherian mammals, including new species of the pentacodontid Aphronorus bearspawensis sp. nov., the mixodectid Eudaemonema bohachae sp. nov., the hyopsodontid Promioclaenus thnetus sp. nov., and a new genus and species of multituberculate ( Alopocosmodon hadrus gen. et sp. nov.) tentatively referred to the Microcosmodontidae. The Bearspaw local fauna also details the first Canadian occurrences of several taxa, including Ptilodus wyomingensis, Aphronorus fraudator, Bryanictis microlestes, Elpidophorus minor, and possibly Goniacodon. Preliminary biostratigraphic analyses suggest that the Bearspaw local fauna is middle Torrejonian (To2) in age, correlating most closely with near-coeval Gidley Quarry of Montana and Rock Bench Quarry of Wyoming. In addition to improving the depauperate record of Torrejonian mammals in western Canada, the new fauna is important in documenting a mammal assemblage from a lithological unit that is thought to have been deposited in semi-arid conditions, rather than the wetter and more humid conditions of the Paskapoo Formation. Further, the Bearspaw localities, along with several other recently discovered localities in the Calgary and Cochrane areas, closely bracket the 27n-26r chron boundary and as such will be important in detailing the Torrejonian-Tiffanian transition in western Canada. [ABSTRACT FROM AUTHOR]

The Garbani Channel deposits, part of the Tullock Formation exposed in northeastern Montana, have yielded a large sample of vertebrates that probably lived during the Puercan 3 North American Land Mammal Age (NALMA). Four fossils in this sample - three isolated teeth and a medial phalanx - document the presence of a stylinodontid taeniodont, cf. Wortmania. Discovery of cf. Wortmania in the Tullock Formation extends the documented range of taeniodonts during Puercan 3 approximately 500 miles (800 km) northward from the San Juan Basin, New Mexico. Evaluation of the oldest records of taeniodonts, from the Lancian, Puercan, and Torrejonian NALMAs, highlights biases warranting future research. Recent phylogenetic analyses that resulted in numerous ghost lineages indicate that the available fossil record is far from complete. They open the possibility that the origin and initial radiation of taeniodonts occurred in areas yet to be sampled and their first occurrences might reflect immigration of invasive species. The available fossil record of taeniodonts is biased with significantly more abundant and complete specimens discovered in the San Juan Basin than at localities to the north. This bias is also apparent in the available samples of two other lineages of large Puercan mammals, the multituberculate Taeniolabis and the 'triisodontid' Eoconodon. Where they occur, taeniodonts are relatively rare members of any local fauna. Is their rarity a product of an ecological bias or a reflection of decreasing population size related to increasing body size? [ABSTRACT FROM AUTHOR]

In addition to having a rich assemblage of mammalian fossils, the Gao Mine locality in the Paskapoo Formation of south-central Alberta has yielded numerous plant specimens of late Paleocene (late Tiffanian or Ti5) age. The plant fossils are preserved in siltstones and fine-grained sandstones interpreted as overbank sediments that were deposited on an aggrading floodplain. The assemblage is dominated by the cupressaceous conifer Metasequoia foxii and the cercidiphyllaceous dicot Joffrea speirsiae, including their well-preserved seedlings. The flora also contains foliage of the ferns Onoclea and Speirseopteris and the woody dicots Palaeocarpinus, Aphananthe/ Celtis , Aesculus, Beringiaphyllum, ? Trochodendron, and Wardiaphyllum, as well as seedlings of unknown dicotyledonous angiosperms. Metasequoia foxii and Speirseopteris are unique to the floras of Gao Mine and the nearby Munce's Hill site (Tiffanian Ti4). The remainder of the taxa are common in late Paleocene floras of North Dakota, Montana, and Wyoming, all USA. The floras of the nearby Joffre Bridge Roadcut and Blindman River sites (both Tiffanian Ti3) are more diverse, but both of those sites encompass a wider range of depositional environments and may include higher percentages of allochthonous material. Most of the Gao Mine material is autochthonous. The seedlings were buried in place, along with the surrounding leaf litter, preserving a record of the local plant community. [ABSTRACT FROM AUTHOR]

A diverse, abundant, and well-preserved radiolarian fauna in Jiazhu, Zhongba County of Tibet, in the western sector of Yarlung Zangbo Suture Zone, is assigned to a late Paleocene radiolarian zone, the Buryella pentadica interval zone, spanning 59-56.5 Ma. Regionally, a late Paleocene basalt block in the bathyal-abyssal siliceous mudstone and graywacke yielded an age of 59.1 Ma (zircon SHRIMP U-Pb). The late Paleocene radiolarian fauna, the tectonic attribution of the radiolarian cherts and the basalt block indicate that oceanic crust persisted in the Zhongba area until the late Paleocene and the initial collision between the Indian and Eurasian plates post-dates the late Paleocene. It is inferred that the Neo-Tethys transformed into a remnant oceanic basin in the late Paleocene, at the terminal stage of the oceanic crust subduction, and the closure of the remnant oceanic basin in the studied region took place after the late Paleocene. In contrast to the previous investigations, we suggest that there was a remnant oceanic basin to the west of the Saga area and a foreland basin to the east of Saga in southern Tibet during the late Paleocene. We argue that the closure of the Neo-Tethys progressed from east to west. [ABSTRACT FROM AUTHOR]