58 research outputs found
Synchrotron radiation reveals the identity of the large felid from Monte Argentario (Early Pleistocene, Italy)
We describe here a partial skull with associated mandible of a large felid from Monte Argentario, Italy (Early Pleistocene; ~1.5 million years). Propagation x-ray phase-contrast synchrotron microtomography of the specimen, still partially embedded in the rock matrix, allows ascribing it reliably to Acinonyx pardinensis, one of the most intriguing extinct carnivorans of the Old World Plio-Pleistocene. The analysis of images and 3D models obtained through synchrotron microtomography – here applied for the first time on a Plio-Pleistocene carnivoran – reveals a mosaic of cheetah-like and Panthera-like features, with the latter justifying previous attributions of the fossil to the extinct Eurasian jaguar Panthera gombaszoegensis. Similarly, we reassign to A. pardinensis some other Italian materials previously referred to P. gombaszoegensis (sites of Pietrafitta and Ellera di Corciano). The recognition of Panthera-like characters in A. pardinensis leads to reconsidering the ecological role of this species, whose hunting strategy was likely to be different from those of the living cheetah. Furthermore, we hypothesise that the high intraspecific variation in body size in A. pardinensis can be the result of sexual dimorphism, as observed today in all large-sized felids
Braincase With Natural Endocast of a Juvenile Rhinocerotinae From the Late Middle Pleistocene Site of Melpignano (Apulia, Southern Italy)
Cranial remains of juvenile fossil rhinoceroses are rarely described in literature and very few is known about the ontogenetic development of their inner anatomy. In this study, we report the first CT based description of a juvenile braincase and its natural brain endocast of a late Middle Pleistocene Rhinocerotinae from Melpignano (Apulia, Italy). The specimen belongs to an individual about 12–18 months old, representing to date the youngest Pleistocene rhinoceros of Mediterranean Europe documented by neurocranial material. Through digital visualization methods the neurocranium has been restored and the anatomy of both the brain and the paranasal sinuses has been obtained and compared with those of juvenile and adult Pleistocene rhinoceroses. We evidence a different morphological development of the inner cranial anatomy in fossil and extant African species
On the trail of medieval wolves: ancient DNA, CT-based analyses and palaeopathology of a 1000-year-old wolf cranium from the Po Valley (northern Italy)
The Middle Ages represented a crucial period for the evolutionary history of wolves (Canis lupus), marked by both significant ecosystem changes, especially through the degradation of wooded landscapes and heavy persecution, that drove this species to a dramatic demographic decline. In Europe, informative and well-documented wolf remains from the Medieval Ages are exceptionally rare and are mostly represented by teeth and postcranial elements. In this study, we describe a well-preserved wolf cranium dated to ca. 967–1157 AD from the Po Valley (northern Italy). The specimen was analysed through a multidisciplinary approach including CT-based, ancient DNA, and palaeopathological analyses. Morphological and genetic data supported the assignment of this sample to Canis lupus species. CT-based analyses indicated a typical wolf-like morphology falling into the extant variability of the medium-sized subspecies C. lupus italicus, whereas palaeopathological analyses indicated a severe periodontitis. Phylogenetic analyses showed that the Po valley wolf had a unique and never described mtDNA control region haplotype, testifying variability in the ancient Italian wolf, which has now been lost. This study provides the first comprehensive description of a wolf from the Middle Ages, adding useful information for a deeper knowledge about population dynamics, variability, and diseases of this species
Cranial Anatomy and Paleoneurology of the Extinct Sloth Catonyx tarijensis (Xenarthra, Mylodontidae) From the Late Pleistocene of Oruro, Southwestern Bolivia
Extinct scelidotheriine sloths are among the most peculiar fossil mammals from South America. In recent decades, the external cranial anatomy of Pleistocene scelidotheres such as Scelidotherium, Catonyx, and Valgipes has been the subject of numerous studies, but their endocranial anatomy remains almost completely unknown. Today, computed tomographic (CT) scanning methodologies permit the exploration of previously inaccessible anatomical areas through a completely non-destructive process. For this reason, we undertook an analysis of the external and internal cranial anatomy of Catonyx tarijensis from the late Pleistocene of the Department of Oruro, in southwestern Bolivia. One particularly well-preserved specimen allowed detailed observation of all the main cranial osteological features, including the ear region and an almost complete hyoid apparatus, previously unknown for this taxon. Moreover, CT-scanning and subsequent elaboration of digital models of this specimen allowed observation of the brain cavity and cranial sinuses, and reconstruction of the trajectory of the main cranial nerves for the first time in an extinct scelidotheriine sloth. Additionally, we recovered the first three-dimensional reconstructions of the nasal cavity and the turbinates of an extinct sloth. In contrast to the usual depiction, the combined information from the external and internal anatomy suggests reduced lingual protrusion in Catonyx tarijensis, or at least a consistently more limited protrusion of the tongue in comparison with other mylodontid sloths such as Glossotherium robustum. The new morphological information recovered from this extinct sloth is compared with the available information for both extant and extinct forms, providing insights in the paleobiology of the extinct species. The present study reveals the importance of applying these novel non-destructive techniques to elucidate the evolutionary history of sloths.Fil: Boscaini, Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales; ArgentinaFil: Iurino, Dawid A.. UniversitĂ degli studi di Roma "La Sapienza"; ItaliaFil: Mamani Quispe, Bernardino. Museo Nacional de Historia Natural de la Paz; BoliviaFil: Andrade Flores, RubĂ©n. Museo Nacional de Historia Natural de la Paz; BoliviaFil: Sardella, Raffaele. UniversitĂ degli studi di Roma "La Sapienza"; ItaliaFil: Pujos, François Roger Francis. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de NivologĂa, GlaciologĂa y Ciencias Ambientales; ArgentinaFil: Gaudin, Timothy. University Of Tennessee At Chattanooga; Estados Unido
3D Survey in Extreme Environment: The Case Study of LaetoliHominin Footprints in Tanzania
Many cultural assets are in risky situations and they are destined to disappear. Sometimes problems are caused bythe anthropic component (e.g. wars) or by natural disasters (e.g. earthquakes and landslides). At other times thecause of deterioration is due to the slow and inexorable action of atmospheric agents and other natural factorspresent in extreme areas, where preservation of Cultural Heritage is more complex.This contribution deals with 3D documentation of paleontological excavations in extreme contexts that arecharacterized by unfavorable climatic conditions, limited instrumentation and little time available. In particular, thecontribution is focused on the search for a good working procedure which, despite the problems mentioned above,can lead to valid results in terms of accuracy and precision, so that subsequent scientific studies are notcompromised. The proposed case study concerns the recent discovery of fossil footprints at the Site S in Laetoli,within the Ngorongoro Conservation Area (Tanzania), which is a UNESCO World Heritage Site. With the newdiscovery of Site S it was necessary to implement a 3D survey operative protocol with limited equipment and in avery short time. The 3D models, obtained through the “Structure from Motion” (SfM) technique and topographicsupport, were used to perform morphological and morphometric investigations on the new footprints. Through theanalysis it was possible to estimate height and weight of the footprint makers (hominins of the speciesAustralopithecus afarensis). The collected evidence supports marked intraspecific variation in this species, pointingout the occurrence of a considerable difference in size between sexes and suggesting inferences on reproductivebehavior and social structure of these ancient bipedal hominins.The contribution shows how important is to obtain good 3D documentation, even in extreme environment, in orderto reach reliable results for scientific analysis
Semiaquatic adaptations in a giant predatory dinosaur
Mysterious dinosaur a swimmer?
Dinosaurs are often appreciated for their size and oddity. In this regard, the North African carnivorous theropod
Spinosaurus
, with its huge dorsal sail and a body larger than
Tyrannosaurus rex
, has long stood out. This species also stands out because of its history. The unfortunate loss of the type specimen during World War II left much of what we know about
Spinosaurus
to be divined through speculation and reconstruction. Ibrahim
et al.
now describe new fossils of this unusual species. They conclude it was, at least partly, aquatic, a first for dinosaurs.
Science
, this issue p.
1613
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Frozen in the Ashes
Fossil footprints are very useful palaeontological tools. Their features can help to identify their makers and also to infer biological as well as behavioural information. Nearly all the hominin tracks discovered so far are attributed to species of the genus Homo. The only exception is represented by the trackways found in the late 1970s at Laetoli, which are thought to have been made by three Australopithecus afarensis individuals about 3.66 million years ago. We have unearthed and described the footprints of two more individuals at Laetoli, who were moving on the same surface, in the same direction, and probably in the same timespan as the three found in the 1970s, apparently all belonging to a single herd of bipedal hominins walking from south to north. The estimated stature of one of the new individuals (about 1.65 m) exceeds those previously published for Au. afarensis. This evidence supports the existence of marked morphological variation within the species. Considering the bipedal footprints found at Laetoli as a whole, we can hypothesize that the tallest individual may have been the dominant male, the others smaller females and juveniles. Thus, considerable differences may have existed between sexes in these human ancestors, similar to modern gorillas
hybrid x space a new approach for mpi reconstruction
Magnetic particle imaging (MPI) is a new medical imaging technique capable of recovering the distribution of superparamagnetic particles from their measured induced signals. In literature there are two main MPI reconstruction techniques: measurement-based (MB) and x-space (XS). The MB method is expensive because it requires a long calibration procedure as well as a reconstruction phase that can be numerically costly. On the other side, the XS method is simpler than MB but the exact knowledge of the field free point (FFP) motion is essential for its implementation. Our simulation work focuses on the implementation of a new approach for MPI reconstruction: it is called hybrid x-space (HXS), representing a combination of the previous methods. Specifically, our approach is based on XS reconstruction because it requires the knowledge of the FFP position and velocity at each time instant. The difference with respect to the original XS formulation is how the FFP velocity is computed: we estimate it from the experimental measurements of the calibration scans, typical of the MB approach. Moreover, a compressive sensing technique is applied in order to reduce the calibration time, setting a fewer number of sampling positions. Simulations highlight that HXS and XS methods give similar results. Furthermore, an appropriate use of compressive sensing is crucial for obtaining a good balance between time reduction and reconstructed image quality. Our proposal is suitable for open geometry configurations of human size devices, where incidental factors could make the currents, the fields and the FFP trajectory irregular
Ricostruzione 3D dei muscoli masticatori in Smilodon fatalis (Carnivora, Felidae, Machairodontinae).
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