Swiss Journal of Palaeontology最新文献

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.

Supplementary information: The online version contains supplementary material available at 10.1186/s13358-023-00265-7.

Here I reviewed the Pleistocene caviomorphs collected by Santiago Roth (collection from Catalog No. 5) and housed at the paleontological collection of the Paläontologisches Institut und Museum, Universität Zürich, Zurich (Switzerland). The fossils were found in Pleistocene strata from Buenos Aires and Santa Fé provinces (Argentina) during the late nineteenth century. The material includes craniomandibular remains assigned to Lagostomus maximus (Chinchilloidea: Chinchillidae), craniomandibular and postcranial (thoracic and sacral vertebra, left scapula, left femur, and right tibia) bones identified as Dolichotis sp. (Cavioidea: Caviidae), and a fragmented hemimandible and isolated tooth of Myocastor sp. (Octodontoidea: Echimyidae). Other rodent specimens from this collection (Ctenomys sp. and Cavia sp.) are possibly sub-recent materials.

The "human fossil" from Baradero, Buenos Aires Province, Argentina, is a collection of skeleton parts first recovered by the paleontologist Santiago Roth and further studied by the anthropologist Rudolf Martin. By the end of the nineteenth century and beginning of the twentieth century it was considered one of the oldest human skeletons from South America's southern cone. Here, we present the results of an interdisciplinary approach to study and contextualize the ancient individual remains. We discuss the context of the finding by first compiling the available evidence associated with the historical information and any previous scientific publications on this individual. Then, we conducted an osteobiographical assessment, by which we evaluated the sex, age, and overall preservation of the skeleton based on morphological features. To obtain a 3D virtual reconstruction of the skull, we performed high resolution CT-scans on selected skull fragments and the mandible. This was followed by the extraction of bone tissue and tooth samples for radiocarbon and genetic analyses, which brought only limited results due to poor preservation and possible contamination. We estimate that the individual from Baradero is a middle-aged adult male. We conclude that the revision of foundational collections with current methodological tools brings new insights and clarifies long held assumptions on the significance of samples that were recovered when archaeology was not yet professionalized.

Trionychid (softshell) turtles have a peculiar bauplan, which includes shell reductions and cranial elongation. Despite a rich fossil record dating back to the Early Cretaceous, the evolutionary origin of the trionychid bauplan is poorly understood, as even old fossils show great anatomical similarities to extant species. Documenting structural detail of fossil trionychids may help resolve the evolutionary history of the group. Here, we study the cranial and mandibular anatomy of Plastomenus thomasii using µCT scanning. Plastomenus thomasii belongs to the Plastomenidae, a long-lived (Santonian-Eocene) clade with uncertain affinities among trionychid subclades. The skulls of known plastomenids are characterized by unusual features otherwise not known among trionychids, such as extremely elongated, spatulate mandibular symphyses. We use anatomical observations for updated phylogenetic analyses using both parsimony and Bayesian methods. There is strong support across methods for stem-cyclanorbine affinities for plastomenids. The inclusion of stratigraphic data in our Bayesian analysis indicates that a range of Cretaceous Asian fossils including Perochelys lamadongensis may be stem-trionychids, suggesting that many features of trionychid anatomy evolved prior to the appearance of the crown group. Divergence time estimates from Bayesian tip-dating for the origin of crown Trionychia (134.0 Ma) and Pan-Trionychidae (123.8 Ma) constrain the evolutionary time span during which the trionychid bauplan has evolved to a range of < 11 million years. Bayesian rate estimation implies high morphological rates during early softshell turtle evolution. If correct, plastomenids partially fill the stratigraphic gap which results from shallow divergence times of crown cyclanorbines during the late Eocene.

Supplementary information: The online version contains supplementary material available at 10.1186/s13358-023-00267-5.