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ABSTRACT The 'Age of Mammals' began in the Paleocene epoch, the 10 million year interval immediately following the Cretaceous-Palaeogene mass extinction. The apparently rapid shift in mammalian ecomorphs from small, largely insectivorous forms to many small-to-large-bodied, diverse taxa has driven a hypothesis that the end-Cretaceous heralded an adaptive radiation in placental mammal evolution. However, the affinities of most Paleocene mammals have remained unresolved, despite significant advances in understanding the relationships of the extant orders, hindering efforts to reconstruct robustly the origin and early evolution of placental mammals. Here we present the largest cladistic analysis of Paleocene placentals to date, from a data matrix including 177 taxa (130 of which are Palaeogene) and 680 morphological characters. We improve the resolution of the relationships of several enigmatic Paleocene clades, including families of 'condylarths'. Protungulatum is resolved as a stem eutherian, meaning that no crown-placental mammal unambiguously pre-dates the Cretaceous-Palaeogene boundary. Our results support an Atlantogenata-Boreoeutheria split at the root of crown Placentalia, the presence of phenacodontids as closest relatives of Perissodactyla, the validity of Euungulata, and the placement of Arctocyonidae close to Carnivora. Periptychidae and Pantodonta are resolved as sister taxa, Leptictida and Cimolestidae are found to be stem eutherians, and Hyopsodontidae is highly polyphyletic. The inclusion of Paleocene taxa in a placental phylogeny alters interpretations of relationships and key events in mammalian evolutionary history. Paleocene mammals are an essential source of data for understanding fully the biotic dynamics associated with the end-Cretaceous mass extinction. The relationships presented here mark a critical first step towards accurate reconstruction of this important interval in the evolution of the modern fauna. [ABSTRACT FROM AUTHOR]

Phenacolophidae is a group of little known archaic ungulates from the Late Paleocene to Middle Eocene of Asia. Its phylogenetic relationships with other altungulates have remained uncertain, partly because most phenacolophids are represented by poorly preserved material. Here we report a new phenacolophid,Sanshuilophus zhaoigen. et sp. nov., from the Lower Eocene Huayong Formation of the Sanshui Basin, Guangdong, China. Although still fragmentary, the new specimens show that the new taxon is characterised by relatively large body size (except forZaisanolophus), sub-molariform premolars, relatively higher bilophodont molars that lack the mesostyle, and tooth enamel microstructure with true prisms and typical Hunter-Schreger bands (HSB). With the new specimens and a review of the published phenacolophid material, we are able to provide an alternative identification for the tooth loci for the type specimen ofPhenacolophusand further present an emended diagnosis for Phenacolophidae. The tooth morphology and enamel microstructure provide new evidence to support the notion that phenacolophids differ from species of Embrithopoda in having low-crown teeth, considerably slanting lophids, distinct paralophids and lacking the arsinoitheriid radial enamel. Phenacolophidae should not be included in Tethytheria but probably represent a stem group for altungulates, if not for all archaic ungulates. [ABSTRACT FROM AUTHOR]

Recent studies show Xenarthra to be even more isolated systematically from other placental mammals than traditionally thought. The group not only represents 1 of 4 primary placental clades, but proposed links to other fossorial mammal taxa (e.g., Pholidota, Palaeanodonta) have been contradicted. No unambiguous Paleocene fossil xenarthran remains are known, and Eocene remains consist almost exclusively of isolated cingulate osteoderms and isolated postcrania of uncertain systematic provenance. Cingulate skulls are unknown until the late middle Eocene, and the oldest sloth and anteater skulls are early Oligocene and early Miocene age, respectively; there are no nearly complete xenarthran skeletons until the early Miocene. Ecological reconstructions of early xenarthrans based on extant species and the paleobiology of extinct Neogene taxa suggest the group's progenitors were myrmecophagous with digging and perhaps some climbing adaptations. The earliest cingulates were terrestrial diggers and likely myrmecophagous but soon diverged into numerous omnivorous lineages. Early sloths were herbivores with a preference for forested habitats, exhibiting both digging and climbing adaptations. We attribute the rarity of early xenarthran remains to low population densities associated with myrmecophagy, lack of durable, enamel-covered teeth, and general scarcity of fossil localities from tropical latitudes of South America. The derivation of numerous omnivorous and herbivorous lineages from a myrmecophagous ancestor is a curious and unique feature of xenarthran history and may be due to the peculiar ecology of the native South American mammal fauna. Further progress in understanding early xenarthran evolution may depend on locating new Paleogene fossil sites in northern South America. [ABSTRACT FROM AUTHOR]

Abstract: Arctostylopids are enigmatic mammals known from the Paleocene and Early Eocene of Asia and North America. Based on molar similarities, they have most often been grouped with the extinct Notoungulata from South and Central America, but tarsal evidence links them to Asian basal gliriforms. Although Palaeostylops is the best-known arctostylopid genus, some points of its content and species level taxonomy remain uncertain. Here we report 255 upper and lower jaw fragments of Palaeostylops, five calcanea, three astragali, as well as the first known arctostylopid distal tibia. This new material was collected from the late Paleocene of the Flaming Cliffs area in Mongolia, in a single lens almost exclusively containing arctostylopid remains. Our study of the morphology and size of the new Palaeostylops dental material confirms the validity of two species, P. iturus and P. macrodon, and illustrates their morphological and biometrical variability and diagnostic differences. The distal tibia of Palaeostylops is relatively unspecialised and resembles the Asian gliriforms Pseudictops and Rhombomylus. We also review the relevance of the historically important genus Palaeostylops in view of other, more recently described but less abundant arctostylopid genera. Palaeostylops remains the reference taxon for the arctostylopid anterior dentition and postcranial morphology. For both anatomical regions, arctostylopids differ significantly from notoungulates, and present a mosaic of characters also seen in basal gliriforms. The notoungulate-like molars of Palaeostylops are highly specialized for arctostylopids and the arctostylopid molar morphotype is therefore better illustrated by the early middle Paleocene Asiostylops. This morphotype does not present any similarities to notoungulates, but shares a number of derived characters with basal gliriforms. Among gliriforms, the primitive arctostylopid morphotype is most similar to Astigale from the early Paleocene of South China, and we suggest that Arctostylopidae may therefore be more closely related to Astigalidae than to any other group. [Copyright &y& Elsevier]

In this study, I investigated the source(s) of variation in the body temperatures of mammals. I also attempted to reconstruct ancestral normothermic rest-phase body temperature states using a maximum parsimony approach. Body temperature at the familial level is not correlated with body mass. For small mammals, except the Macroscelidae, previously identified correlates, such as climate adaptation and zoogeography explained some, but not all, T apomorphies. At the species level in large cursorial mammals, there was a significant correlation between body temperature and the ratio between metatarsal length and femur length, the proxy for stride length and cursoriality. With the exception of two primate families, all supraendothermic ( T > 37.9°C) mammals are cursorial, including Artiodactyla, Lagomorpha, some large Rodentia, and Carnivora. The ruminant supraendothermic cursorial pulse is putatively associated with global cooling and vegetation changes following the Paleocene-Eocene Thermal Maximum. Reconstructed ancestral body temperatures were highly unrealistic deep within the mammalian phylogeny because of the lack of fossil T data that effectively creates ghost lineages. However, it is anticipated that the method of estimating body temperature from the abundance of C-O bonds in the carbonate component of tooth bioapatite in both extant and extinct animals may be a very promising tool for estimating the T of extinct mammals. Fossil T data are essential for discerning derived T reversals from ancestral states, and verifying the dates of supraendothermic pulses. [ABSTRACT FROM AUTHOR]

A previously undescribed tooth from the Muñani Formation at the Laguna Umayo locality, Peru, represents the new didolodontid Umayodus raimondi gen. et sp. nov., here diagnosed by the presence of a well developed metastylid and ectostylid, and a twinned hypoconulid. This taxon is closely related to the middle Paleocene genera Escribania and Raulvaccia from the locality of Punta Peligro in Patagonia, Argentina. Phylogenetic analysis here performed indicates that they constitute a monophyletic group within Didolodontidae, supported by five derived characters: the hypocone well developed and close to the protocone; the strongly concave precingulum; the contact between the postcristid and the entoconid; the contact of the crista pre-paraconular, precingulum and parastyle; and the mesiodistal enlargement of the m3 talonid. Their paleogeographic distribution fit with those of the actual Andean Region of the Austral Kingdom. The previously assumed Thanetian--Ypresian age assignment for the Laguna Umayo LU3 fauna is here reinforced by faunistic comparisons with the earliest Eocene Murgon fauna, in Australia, and the Itaboraian South American Land Mammal Age, represented from faunas of Patagonia, Argentina and São José de Itaboraí, Brazil. [ABSTRACT FROM AUTHOR]

We report the discovery of the earliest European carnivoraforms, based on two new taxa from the latest Paleocene of France and Romania. A new species of Vassacyon, V. prieuri, from the locality of Rivecourt (MP6b; Oise, France) (MP = Mammalian Paleogene reference levels) is described based on a dentary fragment and isolated teeth. This species displays several primitive features compared with species of Vassacyon known from the early Eocene of North America and Europe. A second Paleocene carnivoraform, cf. Gracilocyon sp., is described based on fragmentary specimens from the locality of Jibou (MP6b; Transylvania, Romania). Carnivoraformes were previously unknown in Europe before the Eocene, and Vassacyon prieuri and cf. Gracilocyon sp. are their oldest records in Europe. These discoveries favor the hypothesis of a dispersal of these two genera from Europe to North America during the Paleocene-Eocene Thermal Maximum. Vassacyon prieuri and cf. Gracilocyon sp. strengthen support for the level MP6b and its correlation with the Clarkforkian. The geographic origin of the Carnivoraformes remains unknown. However, based on the observed biochronological and geographic distributions of the carnivoraforms, we infer a possible Asian origin for this group. In this scenario, Gracilocyon and Vassacyon dispersed to Europe during the Clarkforkian MP6b time, probably together with rodent taxa, whereas Uintacyon dispersed from Asia to North America shortly after rodents and tillodonts. http://zoobank.org/urn:lsid:zoobank.org:pub:FC885E7F-877A-4454-9902-DF118B8C8693 SUPPLEMENTAL DATA—Supplemental materials are available forthis article for free at www.tandfonline.com/UJVP Citation for this article: Solé, F., T. Smith, E. de Bast, V. Codrea, and E. Gheerbrant. 2016. New carnivoraforms from the latest Paleocene of Europe and their bearing on the origin and radiation of Carnivoraformes (Carnivoramorpha, Mammalia). Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1082480. [ABSTRACT FROM AUTHOR]