Maybe So, Maybe Not: Canis lepophagus at Hagerman Fossil Beds National Monument, Idaho, USA

A canid dentary is described from the Pliocene Glenns Ferry Formation at Hagerman Fossil Beds National Monument, south-central Idaho, USA. The specimen possesses traits in alliance with and measurements falling within or exceeding those of Canis lepophagus. The dentary, along with a tarsal IV (cuboid) and an exploded canine come from the base of the fossiliferous Sahara complex within the monument. Improved geochronologic control provided by new tephrochronologic mapping by the U.S. Geological Survey-National Park Service Hagerman Paleontology, Environments, and Tephrochronology Project supports an interpolated age of approximately 3.9 Ma, placing it in the early Blancan North American Land Mammal Age. It is conservatively referred to herein as Canis aff. C. lepophagus with the caveat that it is an early and robust example of that species. A smaller canid, initially assigned to Canis lepophagus and then to Canis ferox, is also known from Hagerman. Most specimens of Canis ferox, including the holotype, were recently reassigned to Eucyon ferox, but specimens from the Hagerman and Rexroad faunas were left as Canis sp. and possibly attributed to C. lepophagus. We agree that these smaller canids belong in Canis and not Eucyon but reject placing them within C. lepophagus; we refer to them here as Hagerman-Rexroad Canis. This study confirms the presence of two approximately coyote-sized canids at Hagerman and adds to the growing list of carnivorans now known from these fossil beds.

Late middle Miocene caviomorph rodents from Tarapoto, Peruvian Amazonia

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.

Cenozoic stratigraphy of South Africa: current challenges and future possibilities

The Cenozoic stratigraphy of South Africa has developed over the past 166 years since geological mapping of the region was initiated. The current status of lithostratigraphy and the global chronostratigraphic framework is discussed in the context of the diverse Cenozoic regolith across the region. Geological mapping here utilizes lithostratigraphy to organise the Cenozoic deposits, although some extensive units are characterised informally using lithological descriptors. Although there are no formal biostratigraphic units, the allied use of “Land Mammal Ages” compiled from fossil type sites is described. An analogous archaeological cultural-historical “technocomplex” stratigraphy is outlined to subdivide stone age cultural material commonly associated with Quaternary deposits and has often been used as a relative dating framework. A summary table of Cenozoic regolith is presented, differentiating deposits into their terrain morphologically defined Geomorphic Province context as a means of correlating similar deposits across the subcontinent. For mapping units based on lithological characteristics, the use of lithodemic nomenclature to characterise units in each geomorphic province is proposed as a temporary measure to enhance inter-regional correlation and encourage further research that could lead to formal lithostratigraphic descriptions.

Behavioural Responses to Temporary Separation of a Captive Herd of African Elephants (Loxodonta africana)

Elephants are highly intelligent animals with a huge capacity for social cognition, living in large, long-lived, related herds. In captivity, it is extremely difficult to meet all of the species’ ecological needs, as well as those required individual by individual, but improvements are continually being made. After identifying impaired welfare, one collection made the decision to relocate four female African Elephants (Loxodonta africana) to a different facility. As the worlds’ largest land mammal, many safety, welfare, and logistical considerations were undertaken. The elephants travelled in two pairs, a mother–daughter pair and an older unrelated female and a younger unrelated female with a strong social bond. As a result, there was a short gap in between transports, allowing for further habituation to transport crates and the heat of summer. The changes in both social and individual behaviours of the two females remaining when their group was temporarily reduced from four to two were investigated using one-zero sampling. The study determined the daily activities of the elephants comparing ‘before transport’ to ‘after transport’ for the two remaining elephants to establish any changes in their behaviours as a result of this disturbance. Post transport, there was an increase in both human-audible vocalisations and temporal gland secretions, and hugely decreased play behaviour was observed. The dynamic between the remaining pair was also altered with more tactile behaviours from mother to daughter seen but more submission from daughter to mother. This led to the conclusion that the elephants, although mostly unrelated and living in an ‘unnatural’ captive setting, had the same signs of stress and behavioural change as would a highly related group if separated.

Micromammals and the Late Quaternary of southern Africa

Improvements in excavation methods, dating, analytical techniques and statistical applications have all led to a substantial increase in recoverable environmental evidence from micromammals. Because these animals are so small the information they provide is on a smaller geographical scale than that afforded by most other lines of evidence. However, with increasing amounts of data and greater interpretational precision in all spheres, the chances are improving of being able to mesh information from different scales. Blombos, Pinnacle Point and Klasies River on the southern coast of South Africa have clearly demonstrated that micromammalian data can contribute to multidisciplinary interpretations of past conditions, in this case during MIS 5 and 6. Little attention has been paid to the generally small samples from Iron Age sites but the presence of the House rat Rattus rattus may provide important information about human movements and may also contribute to our understanding of the Anthropocene once this has been formally defined. Micromammals have not yet been used as chronostratigraphic indicators in southern Africa but it may be possible to develop biochronologies using them and to incorporate this material into African Land Mammal Ages.

The Early Pleistocene ectothermic vertebrates of Pietrafitta (Italy) and the last Western European occurrence of Latonia Meyer, 1843

The Early Pleistocene site of Pietrafitta (central Italy) produced a rich vertebrate assemblage from the Late Villafranchian Land Mammal Age (late MN18). Geological and paleobotanical data from Pietrafitta indicate a lacustrine environment, surrounded by a humid deciduous broadleaved forest with a temperate climate. The vertebrate assemblage consists of at least 40 taxa including actinopterygians, amphibians, reptiles, birds, and mammals. Here, we concentrate on the ichthyofaunal and herpetofaunal remains. The ichthyofauna includes Barbus Cuvier and Cloquet, 1816, Scardinius Bonaparte, 1837, aff. Squalius Cuvier, 1817, and Tinca Cuvier, 1817. The two anuran genera are the large-sized alytid frog Latonia Meyer, 1843 and the “green frog” Pelophylax Fitzinger, 1843. Three snake precloacal vertebrae were recognized, one attributed to Colubrines indet., another one to ­Natrix sp. Laurenti, 1768, and the largest and most complete vertebra is referred to the genus Vipera s.l. Laurenti, 1768 (cf. gr. “Oriental vipers”). The chelonian fossils, including some complete carapaces and plastrals, are attributed to the European pond turtle (Emys gr. Orbicularis Linnaeus, 1758) and Hermann’s tortoise (Testudo hermanni Gmelin, 1789).

A latest Eocene (Chadronian) brontothere (Mammalia, Perissodactyla) from the Antero Formation, South Park, Colorado

ABSTRACT Late Eocene brontotheres are documented most prevalently from formations in the Great Plains of North America. Here we describe UCM 109045, a mandible and lower dentition of a brontothere recovered from a latest Eocene (Chadronian) locality in the Antero Formation in South Park, Colorado. This is a high-altitude locality in which vertebrate fossils are rare. Lower incisor number and presence of a long postcanine diastema indicate that UCM 109045 does not belong to Megacerops coloradensisLeidy, 1870, by far the most abundant brontothere from the Chadronian North American Land Mammal Age. Instead, UCM 109045 is morphologically most similar to Protitanops curryiStock, 1936, from the early Chadronian of the southwestern United States, and nomen dubium Megacerops primitivusLambe, 1908, from the Chadronian of Saskatchewan, Canada. It is possible that Megacerops kuwagatarhinusMader and Alexander, 1995, is a junior synonym of M. primitivus. If UCM 109045 belongs to Megacerops primitivus (= M. kuwgatarhinus), it would support the hypothesis that only two species of brontothere—M. primitivus (= M. kuwgatarhinus) and M. coloradensis—survived into the latest Eocene. Regardless of its exact identification, the discovery of UCM 109045 in the Antero Formation provides insight into a poorly understood, high-altitude locality in North America from just before brontothere extinction at the Eocene–Oligocene boundary.

Carnivorous mammals from the middle Eocene Washakie Formation, Wyoming, USA, and their diversity trajectory in a post-warming world

The middle Eocene Washakie Formation of Wyoming, USA, provides a rare window, within a single depositional basin, into the faunal transition that followed the early Eocene warming events. Based on extensive examination, we report a minimum of 27 species of carnivorous mammals from this formation, more than doubling the previous taxic count. Included in this revised list are a new species of carnivoraform, Neovulpavus mccarrolli n. sp., and up to ten other possibly new taxa. Our cladistic analysis of early Carnivoraformes incorporating new data clarified the array of middle Eocene taxa that are closely related to crown-group Carnivora. These anatomically relatively derived carnivoraforms collectively had an intercontinental distribution in North America and east Asia, exhibiting notable variations in body size and dental adaptation. This time period also saw parallel trends of increase in body size and dental sectoriality in distantly related lineages of carnivores spanning a wide range of body sizes. A new, model-based Bayesian analysis of diversity dynamics accounting for imperfect detection revealed a high probability of substantial loss of carnivore species between the late Bridgerian and early Uintan North American Land Mammal ‘Ages’, coinciding with the disappearance of formerly common mammals such as hyopsodontids and adapiform primates. Concomitant with this decline in carnivore diversity, the Washakie vertebrate fauna underwent significant disintegration, as measured by patterns of coordinated detection of taxa at the locality level. These observations are consistent with a major biomic transition in the region in response to climatically induced opening-up of forested habitats.UUID: http://zoobank.org/9162f1a6-a12c-4d55-ba1d-dc66e8cda261

Lipid Oxidation during Thermogenesis in High-Altitude Deer Mice (Peromyscus maniculatus)

When at their maximum thermogenic capacity (cold-induced V̇O2max), small endotherms reach levels of aerobic metabolism as high, or even higher, than running V̇O2max. How these high rates of thermogenesis are supported by substrate oxidation is currently unclear. The appropriate utilization of metabolic fuels that could sustain thermogenesis over extended periods may be important for survival in cold environments, like high altitude. Previous studies show that high capacities for lipid use in high-altitude deer mice may have evolved in concert with greater thermogenic capacities. The purpose of this study was to determine how lipid utilization at both moderate and maximal thermogenic intensities may differ in high- and low- altitude deer mice, and strictly low-altitude white-footed mice. We also examined the phenotypic plasticity of lipid use after acclimation to cold hypoxia (CH), conditions simulating high altitude. We found that lipids were the primary fuel supporting both moderate and maximal rates of thermogenesis in both species of mice. Lipid oxidation increased 3-fold in mice from 30oC to 0oC, consistent with increases in oxidation of [13C]-palmitic acid. CH acclimation led to an increase in [13C]-palmitic acid oxidation at 30oC but did not affect total lipid oxidation. Lipid oxidation rates at cold-induced V̇O2max were two- to four-fold those at 0oC and increased further after CH acclimation, especially in high-altitude deer mice. These are the highest mass-specific lipid oxidation rates observed in any land mammal. Uncovering the mechanisms that allow for these high rates of oxidation will aid our understanding of the regulation of lipid metabolism.

Paleobiology of a large mammal community from the late Pleistocene of Sonora, Mexico

A paleontological deposit near San Clemente de Térapa represents one of the very few Rancholabrean North American Land Mammal Age sites within Sonora, Mexico. During that time, grasslands were common, and the climate included cooler and drier summers and wetter winters than currently experienced in northern Mexico. Here, we demonstrate restructuring in the mammalian community associated with environmental change over the past 40,000 years at Térapa. The fossil community has a similar number of carnivores and herbivores whereas the modern community consists mostly of carnivores. There was also a 97% decrease in mean body size (from 289 kg to 9 kg) because of the loss of megafauna. We further provide an updated review of ungulates and carnivores, recognizing two distinct morphotypes of Equus, including E. scotti and a slighter species; as well as Platygonus compressus; Camelops hesternus; Canis dirus; and Lynx rufus; and the first regional records of Palaeolama mirifica, Procyon lotor, and Smilodon cf. S. fatalis. The Térapa mammals presented here provide a more comprehensive understanding of the faunal community restructuring that occurred in northern Mexico from the late Pleistocene to present day, indicating further potential biodiversity loss with continued warming and drying of the region.