The present work concerns xenarthrans from the collection of Santiago (Kaspar Jakob) Roth (1850–1924) housed at the Palaeontological Institute and Museum of the University of Zurich, one of the most important collections of Pleistocene mammals from Argentina in Europe. Roth was a paleontologist originally from Switzerland who prospected and collected a large amount of Pleistocene megafauna of the Pampean Region of Argentina. The xenarthrans are the main representatives of this collection in Zurich, with 150 specimens. Since 1920, this material has not been revised and is under studied. The present investigation corresponds to a taxonomic revision resulting in 114 reassignments, leading to document xenarthran diversity and discuss their paleoecologies. The high diversity reflects the paleoecology of the Pampean Region during the Pleistocene, with the various abiotic events that impacted the paleoenvironment of this region. Within the Cingulata, the Pampean Region fauna was probably dominated by glyptodonts with a high representation of Glyptodontinae and Neosclerocalyptinae while within the sloths the highest diversity and abundance is found in the Mylodontinae and Scelidotheriinae. These four clades represent both species with high ecological tolerance (e.g., Glyptodon munizi; Catonyx tarijensis) and ecologically highly specialized species (e.g., Neosclerocalyptus paskoensis; Scelidotherium leptocephalum). The presence of such ecological diversity underlines the status of the Pampean Region as a major interest for paleoecological and paleoenvironmental reconstruction.
A large part of extant and past mammalian morphological diversity is related to variation in size through allometric effects. Previous studies suggested that craniofacial allometry is the dominant pattern underlying mammalian skull shape variation, but cranial allometries were rarely characterized within cranial units such as individual bones. Here, we used 3D geometric morphometric methods to study allometric patterns of the whole skull (global) and of cranial units (local) in a postnatal developmental series of nine-banded armadillos (Dasypus novemcinctus ssp.). Analyses were conducted at the ontogenetic and static levels, and for successive developmental stages. Our results support craniofacial allometry as the global pattern along with more local allometric trends, such as the relative posterior elongation of the infraorbital canal, the tooth row reduction on the maxillary, and the marked development of nuchal crests on the supraoccipital with increasing skull size. Our study also reports allometric proportions of shape variation varying substantially among cranial units and across ontogenetic stages. The multi-scale approach advocated here allowed unveiling previously unnoticed allometric variations, indicating an untapped complexity of cranial allometric patterns to further explain mammalian morphological evolution.
The rise of Carnivora (Mammalia: Laurasiatheria) is an important evolutionary event that changed the structure of terrestrial ecosystems, starting at the dawn of the Eocene, 56 Mya. This radiation has been mainly analysed in North America, leaving the evolution of carnivoran diversity in other regions of the globe poorly known. To tackle this issue, we review the evolution of terrestrial carnivorous mammal diversity (Mesonychidae, Oxyaenidae, Hyaenodonta and Carnivoramorpha) in Europe. We reveal four episodes of intense faunal turnovers that helped establish the dominance of carnivoramorphans over their main competitors. We also identify two periods of general endemism. The remaining time intervals are characterized by dispersals of new taxa from North America, Asia and Africa. The European Palaeogene carnivorous mammal fauna appears to have been almost constantly in a transient state, strongly influenced by dispersals. Many of the bioevents we highlight for European carnivorous mammals are probably best seen as ecosystem-wide responses to environmental changes. In contrast to the North American record, European hyaenodonts remain more diverse than the carnivoramorphans for the entire Eocene. The replacement of hyaenodonts by carnivoramorphans as the most diverse and dominant predators only occurred after the ‘Grande Coupure’ at 33 Mya, about 16 Myr later than in North America.
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We present new species of an enigmatic family of mammals, which is endemic to Europe, the Paroxyclaenidae: Merialus bruneti sp. nov., Fratrodon tresvauxi gen. et sp. nov., Paraspaniella gunnelli gen. et sp. nov., and Sororodon tresvauxae gen. et sp. nov. The fossils described come from six localities of the Ypresian of the Paris Basin (France): Pourcy (MP7), Mutigny, Avenay, Cond e-en-Brie (MP8 þ 9), Grauves and Pr emontr e (MP10). They allow the description of three new genera and four new species belonging to the subfamilies Merialinae and Paroxyclaeninae. Two of these new species represent the earliest occurrence of each subfamily. Fossils from Mutigny, Avenay and Cond e-en-Brie indicate that merialines were more abundant than paroxyclaenines during the Ypresian. Surprisingly, merialines disappeared from the fossil record at the end of the Ypresianthe youngest records are close to MP10while the paroxyclaenines were present in Europe until the end of the middle Eocene. Based on comparison with the data presently available for European mammals during the Ypresian, we suggest the existence of two periods of faunal turnover that must be more extensively studied in the future in order to be fully characterized: the 'Intra-Ypresian Mammal Turnover' and the 'Ypresian-Lutetian Mammal Turnover'. Finally, because the oldest paroxyclaenids appear morphologically closer to cimolestids such as Procerberus than to pantolestans, it is suggested that similarities between paroxyclaenids and pantolestans could be due to convergence. http://zoobank.org/urn:lsid:zoobank.org:pub:8A3B21A0-6945-4CE4-975C-402736E92C51
The Paleogene mammals of Europe are rarely known from partial or complete skeletons. As a result, their systematics and ecology are often solely based on dental characters and postcranial remains, when available, are usually neglected. This explains why the locomotion of mammals of the Eocene-Oligocene transition, the "Grande Coupure", is poorly known. The aim of this study is to describe the tarsal bones (astragali and calcanei) and characterize the locomotion of amphicyonid carnivorans, one of the most abundant mammalian predator groups from the Phosphorites du Quercy (France) sites. The identification of taxa and the characterization of both posture and locomotion were carried out using four criteria: relative abundance (in comparison with dental data), morphology, size, and body mass. Seven morphotypes, four among astragali and three among calcanei, are identified as Amphicyonidae and show various postures: plantigrade, semi-digitigrade, and digitigrade. One morphotype of the astragalus and one of the calcaneus are identified as Cynodictis lacustris Gervais, 1852, which exhibits a digitigrade posture. The study of postcranial bones, such as tarsals, allows for a better understanding of the ecology of these animals and deserves more interest in future morphological and phylogenetic studies.
The Quercy Phosphorites Formation in France is world famous for its Eocene to Miocene faunas, especially those from the upper Eocene to lower Oligocene, the richest of all. The latter particularly helped to understand the ‘Grande Coupure’, a dramatic faunal turnover event that occurred in Europe during the Eocene-Oligocene transition. Fossils from the Quercy Phosphorites were excavated from the middle 19th century until the early 20th century in a series of sites and became subsequently dispersed over several research institutions, while often losing the temporal and geographical information in the process. In this contribution, we provide an overview and reassess the taxonomy of these barely known collections housed in three Belgian institutions: the Université de Liège, KU Leuven, and the Royal Belgian Institute of Natural Sciences. We focus our efforts on the carnivorous mammals (Hyaenodonta and Carnivoramorpha) and assess the stratigraphic intervals covered by each collection. These fossils are derived from upper Eocene (Priabonian), lower Oligocene (Rupelian), and upper Oligocene (Chattian) deposits in the Quercy area. The richness of the three collections (e.g., the presence of numerous postcranial elements in the Liège collection), the presence of types and figured specimens in the Leuven collection, and some identified localities in the RBINS collection make these collections of great interest for further studies on systematics and the evolution of mammals around the ‘Grande Coupure’.
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