Fossil Mammals Research Articles

Testudo cf. graeca from the new Late Miocene locality of Platania (Drama basin, N. Greece) and a reappraisal of previously published specimens

In this paper we describe a new Neogene mammalian site and one of the latest discoveries of a fossil tortoise in Greece, from Platania locality, in Drama basin, Northern Greece. The preliminary study of the numerous fossil mammal remains shows that the recovered fauna is of Late Miocene age. The tortoise material consists of a partial shell and a limb bone that belong to the same individual. They are attributed to the Testudo cf. graeca, and are members of the Testudo s.s. lineage, characterized by the presence of a hypo–xiphiplastral hinge. This new material indicates that the presence of T. graeca in Greece could expand into the Late Miocene. Comparisons with other fossils of the genus Testudo s.s. from Greece, allowed the revision of previously published specimens of T. graeca.

Did the giant extinct shark Carcharocles megalodon target small prey? Bite marks on marine mammal remains from the late Miocene of Peru

We report on bite marks incising fossil mammal bones collected from upper Miocene deposits of the Pisco Formation exposed at Aguada de Lomas (southern Peru) and attributed to the giant megatooth shark Carcharocles megalodon. The bitten material includes skull remains referred to small-sized baleen whales as well as fragmentary cetacean and pinniped postcrania. These occurrences, the first in their kind from the Southern Hemisphere, significantly expand the still scarce record of bite marks for C. megalodon; moreover, for the first time a prey (or scavenging item) of C. megalodon is identified at the species level (as Piscobalaena nana, a diminutive member of the extinct mysticete family Cetotheriidae). Due to the fragmentary nature of the studied material, the exact origin of the detected marks (i.e., by scavenging or by active predation) cannot be ascertained. Nevertheless, relying on actualistic observations and size-based considerations, we propose that diminutive mysticetes (e.g., cetotheriids) were some of the target prey of adult C. megalodon, at least along the coast of present-day Peru. C. megalodon is thus here interpreted as an apex predator whose trophic spectrum was focused on relatively small-sized prey. Lastly, we propose a link between the recent collapse of various lineages of diminutive mysticetes (observed around 3Ma) and the extinction of C. megalodon (occurring around the end of the Pliocene).

Fossil mammals of Caladenia Cave, northern Swan Coastal Plain, south-western Australia

Fossil mammals of Caladenia Cave, northern Swan Coastal Plain, south-western Australia

Fossil mammals of Caladenia Cave, northern Swan Coastal Plain, south-western Australia

Fossil mammals of Caladenia Cave, northern Swan Coastal Plain, south-western Australia

河北阳原–蔚县盆地形成–消亡的深部构造机理

阳原–蔚县盆地位于大同盆地东段，由于该盆地东段泥河湾及其附近地区发现并发掘了大量哺乳动物群化石和古人类活动遗迹，使其成为我国乃至中亚地区地质生态变化以及人类起源与演化研究的重要基地。本文的科学问题是为什么如此适宜哺乳动物群生物繁衍栖息之地，却在很短的时期就演变成为山峦起伏、沟壑纵横、环境恶劣的丘陵地带？本研究认为：这与燕山运动以来张宣地区的隆起以及喜山运动以来汾渭裂谷系的断陷密切相关。它们均受深部上涌地幔热柱的控制和影响，导致了该区的地壳变形、岩浆活动，从而引起灾害频发、气候改变、环境变化、生态变异等。本文以地幔热柱(幔枝构造)理论为指导，探讨深部地幔上涌柱活动导致阳原–蔚县盆地的形成–消亡的机理及其演化过程。 Yangyuan-Yuxian basin is located in the eastern margin of the Datong basin. Because a large number of mammalian fossils and ancient human remains were found and excavated at NIHEWAN and the surrounding areas of the eastern basin, it became an important base of geo ecological changes and the origin and evolution study of human of China and Central Asia. Why this land, which is so suitable for mammalian faunas to produce and inhabit, becomes hilly areas with rolling hills, criss-cross ravines and gullies and bad environment in a very short period of time? Research thinks, this is closely related to the uplift of Zhangjiakou-Xuanhua region since Yanshan movement and the rifting of Fen Wei rift system since joy mountain movement. They are controlled and influenced by the deep upper mantle plume. And the changes of the natural environment, such as crustal deformation, magmatic activity, caused frequent disasters, climate change, environmental change, ecological variation, and so on. This paper, based on the theory of mantle plume (mantle branch structure) as a guide, explores the mechanism and evolution of formation and the demise of Yangyuan-Yuxian basin caused by the deep mantle upwelling plume activity.

A Jugal in the Rough: The Evolutionary Importance of the Zygoma.

A Jugal in the Rough: The Evolutionary Importance of the Zygoma.

Dental Data Perform Relatively Poorly in Reconstructing Mammal Phylogenies: Morphological Partitions Evaluated with Molecular Benchmarks.

Phylogenetic trees underpin reconstructions of evolutionary history and tests of evolutionary hypotheses. They are inferred from both molecular and morphological data, yet the relative value of morphology has been questioned in this context due to perceived homoplasy, developmental linkage, and nonindependence of characters. Nevertheless, fossil data are limited to incomplete subsets of preserved morphology, and different regions are treated as equivalent. Through meta-analysis of 40 data sets, we show here that the dental and osteological characters of mammals convey significantly different phylogenetic signals, and that osteological characters are significantly more compatible with molecular trees. Furthermore, the application of simplified paleontological filters (retaining only dental data) results in significantly greater loss of phylogenetic signal than random character ablation. Although the mammal fossil record is largely comprised of teeth, dental data alone are generally found to be less reliable for phylogenetic reconstruction given their incongruence with osteological and molecular data. These findings highlight the need for rigorous meta-analyses of distributions of homoplasy in morphological data. These tests, and consequent refinements to phylogenetic analyses that they permit, promise to improve the quality of all macroevolutionary studies that hinge on accurate trees. [Homoplasy; Mammalia; morphology; osteology; phylogeny; teeth

Late Oligocene-Early Miocene magnetochronology of the mammalian faunas in the Lanzhou Basin-environmental changes in the NE margin of the Tibetan Plateau.

A large number of terrestrial mammalian fossils were reported in the well-exposed Paleogene and Neogene fluvio-lacustrine strata in Western China. Their accurate ages are crucial to understand the mammalian and environmental evolution associated with the step-wise uplift of the Tibetan Plateau. At present their ages are surprisingly poorly constrained. Here, we present a high-resolution magnetostratigraphic dating of the Late Oligocene–Early Miocene mammal assemblages from a 233-m thick fluvio-lacustrine section in the Lanzhou Basin located at the northeastern margin of the Tibetan Plateau, China. The results suggest that the section spans from the polarity subchron C6Cn.2r to C5En, i.e. ranging from ca 23 to 18 Ma. This magnetochronology provides considerably more robust ages for three associated land mammalian faunal assemblages. Updated ages end the debate on existing ambiguous and distinctly different magnetostratigraphic correlations for those Late Oligocene–Early Miocene assemblages. The new ages now enable precise correlation of these faunas to the European Land Mammal and North American Land Mammal Ages. The faunal assemblages further suggest a mixed setting of woodlands and grasslands associated with a humid environment in the Lanzhou Basin during the Late Oligocene–Early Miocene, in contrast to its modern poor vegetation cover and arid environment.

Cenozoic Evolution of TRopical-Equatorial MAmmals (TREMA)–an Introduction to the Symposium Proceedings Volume

This special issue of the Journal of Mammalian Evolution coincides with the proceedings from a symposium held in conjunction with the 4th International Palaeontological Congress (IPC4, Mendoza, Argentina; September 28, 2014), entitled “Cenozoic evolution of TRopical-Equatorial MAmmals,” and abbreviated as TREMA. In this short introduction to the symposium proceedings, in which we present the contents of the current issue, we discuss the pivotal role of the mammalian fossil record at low latitudes for understanding the origin, structural organization, and dynamics of present mammalian biodiversity.

A re-evaluation of the taphonomic methodology for the study of small mammal fossil assemblages of South America

Fil: Fernandez, Fernando Julian. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina

COMPARATIVE TAPHONOMY OF THE MAMMALIAN REMAINS FROM THE CABBAGE PATCH BEDS OF WESTERN MONTANA (RENOVA FORMATION, ARIKAREEAN): CONTRASTING DEPOSITIONAL ENVIRONMENTS AND SPECIMEN PRESERVATION

The study of faunal change through time in the fossil record requires a careful assessment of the potential biases introduced by the filtering of death assemblages by depositional environments and other agents of accumulation such as predators. The investigation of taphonomy of the mammalian remains from the Arikareean-aged Cabbage Patch beds of western Montana reported here used both sedimentological evidence and characteristics of the preservation of the fossil specimens to test two hypotheses regarding their preservation pattern: (1) the pattern of faunal change through the section is not a product of differences in the preservation of fossils and (2) the taphonomic characteristics of fossil specimens are linked to the environments in which they were preserved. The interpretation of the sedimentological data, combined with the analyses of the taphonomic filtering of mammalian fossils, suggests that the attritional accumulation of fossils in floodplain settings was the result of predator activity, attrition, and local reworking by fluvial processes. The fossils from these deposits experienced little transport. Moreover, despite complexities in the dataset, select specimen characteristics, including size, shape, and surface modifications, can be linked to the depositional environments determined from sedimentological data. The fossils recovered from a high energy deposit of the lower Cabbage Patch are significantly different from those found in low energy deposits. These low depositional energy fossil assemblages appear to be sufficiently taphonomically similar to be used in faunal analyses despite a change in postmortem filtering through the section.

Taphonomy of mammalian fossil bones from the debris-flow deposits of Somosaguas-North (Middle Miocene, Madrid Basin, Spain)

Debris-flow hosted assemblages dominated by mammalian remains are very scarce in the fossil record and few examples are reported. Herein we present a detailed taphonomic study of Somosaguas-North (Madrid Basin, Spain), a Middle Miocene mammalian-dominated site embedded in debris-flow deposits, in order to increase our knowledge of the mode of formation of fossiliferous assemblages in this depositional context. The assemblage includes 6592 large-mammal remains belonging to at least 10 different species. Fossils are found in matrix-supported, poorly-sorted coarse arkosic sandstones and fine conglomerates, which are interpreted as the result of successive debris-flow deposits. Breakage constitutes a pervasive taphonomic alteration in the bone assemblage; however, together with unidentifiable bone fragments, we also found complete to almost complete skeletal elements. Bone remains are isolated, a fact that is indicative of a time of exposure of the carcasses long enough to enable decay and complete disarticulation. There are no associations of elements belonging to the same individual, which suggests that, prior to or during debris-flow transport, bones were profusely dispersed. Based on the taphonomic evidence, we suggest that Somosaguas-North assemblage was formed by successive debris-flow transport and burial of pre-existing thanatocoenoses. Bones from those thanatocoenoses were modified by biostratinomic agents (trampling, weathering) in varying degrees depending on their time of exposure. Debris-flow transport produced further abrasion and breakage in collagen-depleted bones. Our results are congruent with an environmental context of semiarid landscapes presenting long arid periods and highly irregular hydrological seasonality. Finally, we compared the Somosaguas-North assemblage with other debris-flow hosted vertebrate assemblages. Although Somosaguas-North shares taphonomic features with some of these sites, it is not possible to define consistent and single taphonomic patterns for debris-flow assemblages, given the varied taphonomic histories of the remains prior to and during debris-flow transport.

Chronostratigraphic constraints on Middle Pleistocene faunal assemblages and Acheulian industries from the Cretone lacustrine basin, central Italy

ABSTRACTIntegrated40Ar/39Ar, trace‐element, stratigraphic, palaeontological and palaethnological data provide geochronological and biochronological constraints for the sedimentary and tectonic history of a Middle Pleistocene fluvial–lacustrine basin near Rome (Cretone Basin, central Italy), which has yielded a significant record of mammal fossil remains and Palaeolithic industry. This work is a case study of the interplay between tectonics and glacio‐eustacy, which strongly influenced the evolution of the Tyrrhenian Sea margin of central Italy. Dating of tephra layers interbedded within the Cretone Basin lacustrine succession and reconstruction of relict terraced surfaces allow correlation with similar, geochronologically constrained, marine isotopic stages (MIS) 15–5 terraced deposits along the coast. Coupled extensional tectonics and regional uplift over the last 600 ka caused the progressive uplifting and westward migration of the main fluvial–lacustrine basin and the formation of a smaller satellite basin at its eastern margin. Here, stable environmental conditions during MIS 13–5 indicated continuous human and large mammal frequentation, as testified by lithic industry and fossil remains ascribable to the Acheulean and later early Middle Palaeolithic technocomplexes and Galerian–Aurelian mammal faunas, respectively. In addition to providing independent age constraints to glacial sea‐level oscillations of this region, the reconstructed chronostratigraphic setting for the Cretone Basin provides evidence for one of the oldest Acheulean lithic assemblage of central Italy, as well as new biochronological and palaeobiogeographical data for some Middle Pleistocene mammal species of Italy.

Tectonosedimentary evolution model of an intracontinental flexural (foreland) basin for paleoclimatic research

Intracontinental flexural (foreland) basin sediments are now frequently used as archives for detailed paleoclimatic and sedimentary environmental reconstruction, fossil and stratigraphic correlation, and tectonic evolution and uplift of basin and orogen. However, sedimentologic characteristics vary considerably in time-space with the evolution of flexural basin, apt to cause misinterpretation of climatic change and stratigraphic correlation. Based on high resolution fossil mammal and magnetostratigraphic constraints and sedimentary facies analysis, here we took the Linxia Basin at the front of the NE Tibetan Plateau as a case to demonstrate and figure out a model how sedimentology and stratigraphy vary temporospatially with the evolution of such flexural basin. The results show that the Linxia Basin is a type intracontinental foreland basin subjected to two phases of flexural deformation exerted by the West Qin Ling (Mts.) and NE Tibetan Plateau to the south. Phase I began latest at the beginning of the Miocene (23.3Ma), indicated by a balanced fast flexural subsidence and mostly fine sediment infilling giving rise to the early underlying unconformity. It manifests as an obvious sediment wedge with high filling rate, thickening toward mountains and an occurrence of a mountains-parallel big river – shallow lake system along the foredeep, suggesting a less high mountain topography. In the late Phase I, from ~13Ma to 8Ma, the subsidence and thickening rates began to decrease, accompanied by faults and deformation propagating gradually into the basin, causing gradual basinward migration of the foredeep and its accompanying river-lake system. Since ~8Ma in Phase II, the West Qin Ling and NE Tibetan began to uplift rapidly and thrust/load onto the Linxia Basin, causing strong mountain erosion, thrust-fold belt propagation and basin overfilling. This forced the mountains-parallel river - lake system to turn to the mountains-perpendicular alluvial - braided river system, and finally to an outflow system by the Quaternary onset of the Yellow River in the basin. Concurrent are rapid rotation of the basin, occurrence of growth strata and late unconformities, widespread expansion of boulder conglomerates, great decreasing and increasing sedimentation rates above and before the hanging wall of the fault-fold system and new supplementary provenance from the thrust-fold system. This demonstrates that in stable climate, same lithologic units such as distinct lacustrine sediments and alluvial conglomerates will migrate basinwards with the foredeep moving into basin, causing a great diachroneity and often misleads to recognize the same lithologic unit in space as one unit in time. A dynamic model is presented that should help to avoid such pitfalls in tectonic basin evolution, especially concerning stratigraphic correlation and paleoclimatic change research.

A large eagle (Aves, Accipitridae) from the early Miocene of Panama

AbstractWe report the first Tertiary bird fossil from Central America, an ungual phalanx from a large, unknown genus and species of Accipitridae from the early Miocene Centenario Fauna, Panama. This specimen provides another example of a Neogene bird from North and Central America with its possible closest living relatives occurring today in Africa. In contrast, there is no evidence of African affinities among the reptile or mammal fossils from the Centenario Fauna.

Four Commentaries on the Pope’s Message on Climate Change and Income Inequality. IV. Pope Francis’ Encyclical Letter Laudato Si’, Global Environmental Risks, and the Future of Humanity.

Four Commentaries on the Pope’s Message on Climate Change and Income Inequality. IV. Pope Francis’ Encyclical Letter Laudato Si’, Global Environmental Risks, and the Future of Humanity.

Resolving the evolution of the mammalian middle ear using Bayesian inference.

BackgroundThe minute, finely-tuned ear ossicles of mammals arose through a spectacular evolutionary transformation from their origins as a load-bearing jaw joint. This involved detachment from the postdentary trough of the mandible, and final separation from the dentary through resorption of Meckel’s cartilage. Recent parsimony analyses of modern and fossil mammals imply up to seven independent postdentary trough losses or even reversals, which is unexpected given the complexity of these transformations. Here we employ the first model-based, probabilistic analysis of the evolution of the definitive mammalian middle ear, supported by virtual 3D erosion simulations to assess for potential fossil preservation artifacts.ResultsOur results support a simple, biologically plausible scenario without reversals. The middle ear bones detach from the postdentary trough only twice among mammals, once each in the ancestors of therians and monotremes. Disappearance of Meckel’s cartilage occurred independently in numerous lineages from the Late Jurassic to the Late Cretaceous. This final separation is recapitulated during early development of extant mammals, while the earlier-occurring disappearance of a postdentary trough is not.ConclusionsOur results therefore suggest a developmentally congruent and directional two-step scenario, in which the parallel uncoupling of the auditory and feeding systems in northern and southern hemisphere mammals underpinned further specialization in both lineages. Until ~168 Ma, all known mammals retained attached middle ear bones, yet all groups that diversified from ~163 Ma onwards had lost the postdentary trough, emphasizing the adaptive significance of this transformation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12983-016-0171-z) contains supplementary material, which is available to authorized users.

Villafranchian-Galerian mammal faunas transition in South-Western Europe. The case of the late Early Pleistocene mammal fauna of the Frantoio locality, Arda River (Castell’Arquato, Piacenza, Northern Italy)

We investigated the fossil mammal assemblage from the late Early Pleistocene (early Galerian) site of the Arda River. Seven taxa were identified: one carnivore (Ursus dolinensis), five artiodactyls (Sus strozzii, Pseudodama farnetesis, Praemegaceros sp., Bison sp., and Hippopotamus sp.) and one perissodactyl (Stephanorhinus hundsheimensis). The Arda River faunal assemblage includes taxa already present in the Villafranchian, such as Pseudodama and Sus strozzii. The bear U. dolinensis and the bison, a more evolved form than Bison (Eobison), are taxa typical of the beginning of the Galerian mammal age. Paleontological, sedimentological and paleobotanical data point towards the presence of woodlands settled on an alluvial plain with patches of grassland dated around 1.0 Ma. The continental sediments of the Arda River represent one of the first steps of the forming of the alluvial Po valley.

Examining Fluvial Stratigraphic Architecture Using Ground‐Penetrating Radar at the Fanta Stream Fossil and Archaeological Site, Central Ethiopia

The Fanta Stream site is an archaeological and paleontological locality in Addis Ababa, Ethiopia. The site contains a rich assemblage of fossil mammals and Acheulean artifacts of approximately 600 ka located in a rare high‐altitude context. A ground‐penetrating radar (GPR) survey was conducted in order to provide three‐dimensional imaging of the subsurface, which the authors use to interpret the geometry and distribution of fossil‐containing stratigraphic units. Utilizing the stream's natural cut bank exposure, we calibrate GPR data to known geologic units through radar facies analysis. Shallow, high‐amplitude coherent reflection geometries are attributed to volcanic tuff deposits, as these units exhibit subparallel continuous reflections consistent with planar stratified sedimentary deposition. Deeper, discontinuous reflection packages are interpreted as conglomeritic, fossil‐containing deposits. The results of the GPR survey outline the location of the Fanta Stream's paleodepositional features as well as suggest the extent of fossiliferous stratigraphic units for use in future excavations.

Facies analysis of the Balta Formation: Evidence for a large late Miocene fluvio-deltaic system in the East Carpathian Foreland

Deposits of the Balta Fm are preserved in a large arcuate sediment body that covers about 60,000km2 and is up to 350m thick. The Balta Fm spans ca. 5Ma as constrained by underlying Tortonian (Bessarabian) and overlying Messinian (early Pontian) Paratethys strata. It contains frequent terrestrial mammal fossils and fresh- as well as brackish-water (Paratethys) molluscs and ostracods. Over the past 140years our understanding of the sedimentary architecture of the formation and its origins has remained in its infancy, which has limited insight into the evolution of the East Carpathian Foreland. Here, we provide the first modern sedimentary facies analysis of the Balta Fm, which is integrated with an extensive review of previously published local literature. It is supported with micropalaeontological results and a wealth of historical borehole information. We show that the Balta Fm has a tripartite vertical division. Its lowermost part is clay dominated and consists of subordinate delta front sand bodies interspersed between muds. The middle unit contains separate delta plain channels or channel belts encased in thick muds. These are overlain by a unit with amalgamated delta plain channel deposits with only minor amounts of associated mud. The abundance of upper flow regime sedimentary structures in channel sands, the absence of peats (or coals) and the presence of calcareous nodules suggest a strongly seasonal and relatively dry climate with a flashy discharge regime. Deposition of the Balta Fm in an area previously characterized by distal shelf and prodelta environments indicates large-scale progradation triggered by high sediment volume from the uplifting Carpathian Orogen and enhanced by a general lowering of Paratethys sea-level. The tripartite internal architecture of the Balta Fm indicates that progradation continued during deposition. Its wedge-shaped geometry suggests that tectonic activity in the Carpathians generated a 300km wide foreland basin that allowed for significant delta-plain aggradation despite of the generally regressive trend in Paratethys sea-level.