Search

International audience; The evolutionary history of the Cingulata, as for many groups, remains a highly debated topic to this day, particularly for one of their most emblematic representatives: the glyptodonts. There is no consensus among morphological and molecular phylogenies regarding their position within Cingulata. As demonstrated by recent works, the study of the internal anatomy constitutes a promising path for enriching morphological matrices for the phylogenetic study of armadillos. However, internal cranial anatomy remains understudied in the Cingulata. Here we explored and compared the anatomy of intracranial osseous canals and cavities in a diverse sample of extant and extinct cingulates, including the earliest well-preserved glyptodont crania. The virtual 3D reconstruction (using X-ray microtomography) of selected canals, that is, the nasolacrimal canal, the palatine canal, the sphenopalatine canal, the canal for the frontal diploic vein, the transverse canal, the orbitotemporal canal, the canal for the capsuloparietal emissary vein and the posttemporal canal, and alveolar cavities related to cranial vascularization, innervation or tooth insertion allowed us to compare the locations, trajectories, and shape of these structures and to discuss their potential interest for cingulate systematics. We tentatively reconstructed evolutionary scenarios for eight selected traits related to these structures in which glyptodonts often showed a close resemblance to pampatheres, to the genus Proeutatus, and/or to chlamyphorines. This latter pattern was partly congruent with recent molecular hypotheses, but more research is needed on these resemblances and on the potential effects of development and allometry on the observed variations. Overall, these comparisons have enabled us to highlight new anatomical variation that may be of great interest to further explore the evolutionary history of cingulates and the origins of glyptodonts on a morphological basis.

The evolutionary history of the Cingulata, as for many groups, remains a highly debated topic to this day, particularly for one of their most emblematic representatives: the glyptodonts. There is no consensus among morphological and molecular phylogenies relative to their position within Cingulata. As demonstrated by recent works, the study of the internal anatomy constitutes a promising path for enriching morphological matrices for the phylogenetic study of armadillos. However, internal cranial anatomy remains under-studied in the Cingulata. Here we explored and compared the anatomy of intracranial osseous canals and cavities in a diverse sample of extant and extinct cingulates, including the earliest well-preserved glyptodont crania. The virtual 3D reconstruction (using X-ray microtomography) of selected canals, i.e., the nasolacrimal canal, the palatine canal, the sphenopalatine canal, the canal for the frontal diploic vein, the transverse canal, the orbitotemporal canal, the canal for the capsuloparietal emissary vein and the posttemporal canal, and alveolar cavities related to cranial vascularization, innervation or tooth insertion allowed us to compare the locations, trajectories and shape of these structures and to discuss their potential interest for cingulate systematics. We tentatively reconstructed evolutionary scenarios for eight selected traits on these structures, in which glyptodonts often showed a greater resemblance to pampatheres, to the genusProeutatusand/or to chlamyphorines. This latter pattern was partly congruent with recent molecular hypotheses, but more research is needed on these resemblances and on the potential effects of development and allometry on the observed variations. Overall, these comparisons have enabled us to highlight new anatomical variation that may be of great interest to further explore the evolutionary history of cingulates and the origins of glyptodonts on a morphological basis.

Glyptodonts (Mammalia, Xenarthra, Glyptodontidae) represent a diversified radiation of large armored herbivores, mainly related to open biomes in South America, with an extensive fossil history since the late Eocene (ca. 33 Ma) until their extinction in the latest Pleistocene–earliest Holocene. During the Pliocene and Pleistocene, glyptodonts arrived in Central and North America as part of the Great American Biotic Interchange. Within glyptodont diversity, one of the most enigmatic groups (and also one of the least known) are the Doedicurinae, mainly recognized by the enormous Pleistocene Doedicurus, with some specimens reaching ca. two tons. Almost nothing is known about the Neogene evolutionary history of this lineage. Some very complete specimens of the previously scarcely known Eleutherocercus solidus, which in turn becomes the most complete Neogene Doedicurinae, are here described in detail and compared to related taxa. The materials come from the Andalhuala and Corral Quemado formations (north-western Argentina), specifically from stratigraphic levels correlated to the Messinian–Piacenzian interval (latest Miocene–Pliocene). The comparative study and the cladistic analysis support the hypothesis that Doedicurinae forms a well supported monophyletic group, located within a large and diversified clade mostly restricted to southern South America. Within Doedicurinae, the genus Eleutherocercus (E. antiquus + E. solidus) is the sister group of the Pleistocene Doedicurus. Unlike most of the late Neogene and Pleistocene lineages of glyptodonts, doedicurins show along its evolutionary history a latitudinal retraction since the Pleistocene, ending with the giant Doedicurus restricted to the Pampean region of Argentina, southernmost Brazil, and southern Uruguay. This hypothetic relationship between body mass and latitudinal distribution suggests that climate could have played an active role in the evolution of the subfamily.

Glyptodontidae are a conspicuous lineage of Cingulata with a long evolutionary history (late Eocene to the late Pleistocene-Holocene). Quaternary forms are the best known, but in recent years the knowledge of Neogene taxa, particularly from southern South America has been greatly improved. This is especially evident forthe late Miocene-Pliocene (Montehermosan and Chapadmalalan Stages; ca. 5?3.2 Ma) of the Argentine Atlantic coast. However, little is still known about the glyptodont assemblages from the Marplatan Stage (ca. 3.3?2 Ma), a key interval for the understanding of the typical Pleistocene forms. The most complete records of Marplatan Glyptodontidae of the genus Neosclerocalyptus Paula Couto (one of the most frequently recorded in the Pleistocene of southern South America) are here reported. The remains were found in the El Polvorín Formation(Olavarría, Buenos Aires Province) and represent also the most complete glyptodonts for the interval Montehermosan-Marplatan of the Argentine Atlantic coast. The comparative study reveals that Neosclerocalyptus underwent no significant morphological and morphometric changes throughout its evolution (ca. 3 Ma), except for a gradual increase in hypertrophy of the ossified nasal cartilages, which reach the maximum development in the terminal species of the latest Pleistocene, Neosclerocalyptus paskoensis. The phylogenetic analysis places Neosclerocalyptus sp. as the most basal taxon of the lineage, suggesting the anagenetic evolution of the clade. New findings currently under study show that some taxa (e.g., Plohophorus) extended their biochrons beyond the Chapadmalalan, with a strong increase of body size, and that the Marplatan was a transitional period between the Montehermonsan-Chapadmalalan and the Pleistocene, during which Neogene genera are found together with otherstypically Pleistocene Fil: Quiñones, Sofía Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: de Los Reyes, Leonardo Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina Fil: Zurita, Alfredo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Cuadrelli, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Miño Boilini, Ángel Ramón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina

Xenarthran osteoderms are integumentary bones with high fossilization potential presenting a high degree of morphological and histological diversity. Here, new data on the osteoderms histology of two glyptodonts, Panochthus and Neuryurus are presented. The poor spatial organization of the mineralized fibers and a large trabecular area in the middle zone identified in Neuryurus indicate a different bone pattern than the one found in Panochthus, which is mainly characterized by a middle zone with less spongiosa. Through the Bone Profiler program, the degree of compactness of the specimens was obtained, with about 70% for Neuryurus sp. and approximately 90% for Panochthus sp., showing the difference in bone pattern. These values confirm the visible difference in the histological patterns of these taxa, especially in the middle zone. This work demonstrates the microstructural variation studied in osteoderms and shows the importance of paleohistology as a starting point for a better understanding of extinct taxa.

This article presents the first results of an archaeo-palaeontological study which began in 2007 at the sites of Chazumba I and II in the Barranca del Muerto, located in the Sierra Madre del Sur (Santiago Chazumba, Oaxaca, Mexico). The excavation work is part of a larger international cooperation project titled “Biodiversity and Quaternary hunter–gatherer societies from Mexico”, led by the Institut de Paleoecologia Humana i Evolucio Social (IPHES, Tarragona, Spain) and the Instituto Nacional de Antropologia e Historia of Mexico. The main objective of the project is to study hunter–gatherer groups and their relationships with Pleistocene fauna and rock art. To date, five excavation campaigns have been carried out (2007, 2008, 2010, 2013, 2014), which have primarily yielded faunal remains from the Late Pleistocene and from within a still undetermined period during the Rancholabrean Age (NALMA). The fauna is represented by megaherbivores (giant sloth, glyptodont and gomphothere, among others) and mesoherbivores (deer, prong-horns, horses and even small mammals, reptiles and amphibians). Some lithic materials have been recovered in association with these remains and several fossils have been examined to determine the presence of cut marks. There is an AMS 14C date of 27,720–27,500 cal BP obtained from a charcoal sample from sediments on top of the bone layers. Further sample assays are warranted in order to confirm the antiquity of the archaeological assemblage.

Using carbon and oxygen isotopic relationships from dental enamel, diet and habitat were inferred for both mesomammals and megamammals that lived in Cedral (San Luis Potosi, north-central México) during Late Pleistocene time. δ13C and δ18O values show that bison, some horses and mammoth were eating C4 plants and lived in open areas, while tapir, camel and some llamas ate C3 plants and inhabited closed areas. All other studied herbivores (pronghorn, glyptodont, mylodont ground sloth, javelina, mastodon, and other llamas, horses and mammoth) had a C3/C4 mixed diet, living in areas with some percentage of tree coverage. On the other hand, American lion and dire wolf ate either C4 or mixed-diet herbivores, and short-faced bear ate C3 herbivores. At Cedral, more humid conditions existed than presently, allowing the presence of a forested area near the grassland.

The earliest complete glyptodonts (Glyptodontidae, Cingulata) found belong to the Propalaehoplophorinae from Santa Cruz Formation (late early Miocene, Burdigalian) in Patagonia, Argentina. Although several skulls and mandibles have been described from this formation, and assigned to five genera (Propalaehoplophorus Ameghino, Cochlops Ameghino, Asterostemma Ameghino, Eucinepeltus Ameghino, and Metopotoxus Ameghino), the fossil record and knowledge of juvenile specimens of glyptodonts are still poor. Here, we provide a detailed morphological description of a mandible of a juvenile propalaehoplophorinae glyptodont from the Santa Cruz Formation, using micro-computed tomography and scanning electron microscopy images. We compare the juvenile mandible with adult specimens and discuss the taxonomic assignment, the juvenile and adult mandibular and dental characters, and dental eruption and tooth wear. Fil: Gonzalez Ruiz, Laureano Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Brandoni, Diego. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina Fil: Zurita, Alfredo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina Fil: Green, Jeremy. University Of Kent; Reino Unido Fil: Novo, Nelson Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina Fil: Tauber, Adan Alejo. Universidad Nacional de Córdoba; Argentina Fil: Tejedor, Marcelo Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina

Many animal species evolved some form of body armor, such as scales of fish and bony plates or osteoderms of reptiles. Although a protective function is often taken for granted, recent studies show that body armor might comprise multiple functionalities and is shaped by trade-offs among these functionalities. Hence, despite the fact that natural body armor might serve as bio-inspiration for the development of artificial protective materials, focussing on model systems in which body armor serves a solely protective function might be pivotal. In this study, we investigate the osteoderms of Glyptotherium arizonae, an extinct armadillo-like mammal in which body armor evolved as protection against predators and/or tail club blows of conspecifics. By using a combination of micro-computed tomography, reverse-engineering, stress simulations and mechanical testing of 3D printed models, we show that the combination of dense compact layers and porous lattice core might provide an optimized combination of strength and high energy absorption.

The Palaehoplophorini is a tribe of glyptodonts represented by fragmentary specimens for which the oldest records occur in the Pedregoso and Río Mayo formations (middle-late Miocene) in Patagonia (Argentina). The mammal fossils from those formations were the basis for the recognition of the Mayoan fauna, placed between the Friasian sensu stricto/Colloncuran-Laventan and the Chasicoan faunas. The only identified glyptodont from Río Mayo Formation is Palaehoplophorus meridionalis represented only by its type material (i.e., caudal tube) and the precise provenance is unknown. We describe a new specimen of Palaehoplophorus meridionalis collected in the Río Mayo Formation represented by associated osteoderms of the dorsal carapace and postcranial elements, plus part of the type and assigned specimens that remain unpublished from the old collection. This is the first description of osteoderms from the dorsal carapace of this species and postcranial elements (the first for a Palaehoplophorini), and the first glyptodont with precise provenance from Río Mayo Formation. As result of improving the description and emending the diagnosis, we agree with previous authors about the basal position of Palaehoplophorus meridionalis within the tribe. Finally, we review the Glyptodontidae association of the Mayoan fauna, which are exclusively represented by Palaehoplophorini (Palaehoplophorus meridionalis and Palaehoplophoroides rothi) and Glyptodontidae indet. This association supports a greater affinity of this fauna with the younger Chasicoan than with the older Friasian sensu stricto/Colloncuran-Laventan faunas. Fil: Gonzalez Ruiz, Laureano Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Reato, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina Fil: Cano, Daniel Martín. Universidad Nacional del Sur. Departamento de Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Martínez, Oscar A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina

In North American glyptodonts, the identification of the genus Glyptotherium revolves primarily around characters of the carapace. However, previous studies suggest the possibility of a wide range of intraspecific variation. We report two glyptodont specimens from the Mexican states of Tamaulipas and Tlaxcala. We offer a description of their skeletal and carapace elements as well as a brief review of glyptodont distribution in Mexico. Our initial analysis led us to conclude that the glyptodont from Tamaulipas bears similarities to Glyptotherium cylindricum whereas the Tlaxcala specimen resembles Glyptotherium floridanum. However, further study of previously unreported skeletal elements, in association with characters of the carapace, suggested similarity between the two species. Hence we assigned the two glyptodonts to the species G. cylindricum, which has nomenclatural priority. The addition of new morphological characteristics helped to discern synonymy of these two glyptodont species.

Neuryurus is a Neogene–Quaternary glyptodont known heretofore only by dermal skeleton remains from Argentina, Uruguay, and Brazil. Herein, new material of Neuryurus is reported, including associate...

Among the fossils of hitherto unknown mammals that Darwin collected in South America between 1832 and 1833 during the Beagle expedition [1] were examples of the large, heavily armored herbivores later known as glyptodonts. Ever since, glyptodonts have fascinated evolutionary biologists because of their remarkable skeletal adaptations and seemingly isolated phylogenetic position even within their natural group, the cingulate xenarthrans (armadillos and their allies [2]). In possessing a carapace comprised of fused osteoderms, the glyptodonts were clearly related to other cingulates, but their precise phylogenetic position as suggested by morphology remains unresolved [3,4]. To provide a molecular perspective on this issue, we designed sequence-capture baits using in silico reconstructed ancestral sequences and successfully assembled the complete mitochondrial genome of Doedicurus sp., one of the largest glyptodonts. Our phylogenetic reconstructions establish that glyptodonts are in fact deeply nested within the armadillo crown-group, representing a distinct subfamily (Glyptodontinae) within family Chlamyphoridae [5]. Molecular dating suggests that glyptodonts diverged no earlier than around 35 million years ago, in good agreement with their fossil record. Our results highlight the derived nature of the glyptodont morphotype, one aspect of which is a spectacular increase in body size until their extinction at the end of the last ice age., Facultad de Ciencias Naturales y Museo

The Chui Creek, located in the southernmost Brazil, is a fossiliferous outcrop known since the late 1960s, which bears important records of late Pleistocene mammals, other vertebrates and invertebrate fossils. The presence of some taxa (e.g. Hydrochoerus hydrochaeris Linnaeus, Tapirus terrestris Linnaeus, Ozotoceros bezoarticus Linneaus), although mentioned on the literature, is still to be confirmed. Specimens from Chui Creek belonging to several collections are reexamined and new excavations and geological surveys in the area are being conducted. The new records include isolated teeth of cf. Ursidae and Rodentia (Myocastor cf. M. coypus Molina); a complete and articulated skull and jaw of a tayassuid, Catagonus Ameghino, as well as a left dentary of a juvenile ground sloth, Eremotherium cf. E. laurillardi Lund. The ongoing systematic revision led to the confirmation of the presence of the glyptodont Doedicurus Burmeister, represented by a portion of the carapace; the cervid genera Antifer Ameghino and Morenelaphus Carette; and the equids Equus Linnaeus and Hippidion Owen, represented by cranial and dental remains. These findings expand the knowledge on the diversity of the extinct fauna found in the Chui Creek, and have biogeographic, biostratigraphic and paleoenvironmental implications, which are herein discussed.

The glyptodonts (Mammalia: Cingulata) are characterized by an exoskeleton comprising most notably an armored tail and an immobile dorsal carapace formed by a large number of osteoderms. In 1889, Florentino Ameghino published the first phylogenetic scenario for the glyptodonts, based on the sequential application of two transformation series related to the morphology of the tail armor and carapace osteoderms. From the early to mid 1900s, several authors used Ameghino's transformation series subordinated to a model of evolution in which derived glyptodont groups had arisen independently from separate pre-middle Miocene ancestors. This approach, in which the morphological states of Ameghino's series were considered analogous rather than homologous, provided different phylogenetic scenarios and the paraphyletic classification still in use. Two recent cladistic analyses based on cranial and postcranial (including caudal tube) characters support the monophyly of glyptodonts and suggest novel intra-clade relationships. However, neither analysis included the classic osteoderm characters used by earlier authors. Therefore, we propose new osteoderm and carapace characters and evaluate their performance in a new cladistic analysis. We found that: a) some osteoderm characters used by earlier authors to support ancestor-descendent hypotheses are in fact fully homoplastic autapomorphies (e. g., multiplication of the number of rows of peripheral figures); b) characters previously believed to have originated independently in several groups (e. g., presence of caudal tube) are synapomorphies at a wider hierarchical level; c) some ancestor-descendant pre-cladistic hypotheses are incompatible with the topology and synapomorphy distribution obtained; and d) there is no reason to favor exoskeletal characters in glyptodont systematics. Fil: Fernicola, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Universidad Nacional de Luján. Departamento de Ciencias Básicas; Argentina Fil: Porpino, Kleberson de O.. Universidade Federal do Rio Grande do Norte; Brasil

Values for δ13C and δ18O obtained from molar samples from three individuals pertaining to Glyptotherium sp. from Cedral (San Luis Potosí, México) are provided and are utilized to infer general aspects of glyptodont diet and habitat. On average this animal showed a C3/C4 mixed diet, with a high consumption of C4 plants. Comparisons of the δ13CVPDB and δ18OVPDB values for glyptodonts with horses, mastodons, mammoths and tapirs from the same locality show that glyptodonts from Cedral lived in an open habitat.

Vizcaino, S.F., Blanco, R.E., Bender, J.B. & Milne, N. 2010: Proportions and function of the limbs of glyptodonts. Lethaia, Vol. 44, pp. 93–101. This study examines the limb bone proportions and strength of glyptodonts (Xenarthra, Cingulata). Two methods are used to estimate the body mass and location of the centre of gravity of the articulated specimens. These estimates, together with measurements of the femur and humerus, are used to calculate strength indicators (SI). The other long bones of the limbs are used to calculate limb proportion indices that give an indication of digging ability, speed, and limb dominance in armadillos, the glyptodonts’ living closest relatives. The results show that regardless of how the body mass and centre of gravity are calculated, the majority of the glyptodont’s weight is borne by the hindlimbs. The SI calculations show that femora are sturdy enough to bear these loads. The fact that the femora have higher SI than the humerii indicates that sometimes the hindlimbs are required to bear an even greater proportion of the body weight, possibly when rising to a bipedal posture or pivoting on their hindlimbs to deliver a blow with their armoured tail. The analysis of limb proportions indicates that both the hindlimb and the forelimb have proportions that correlate strongly with body mass. This outcome supports the other results, but also shows that forelimbs must be also involved in manoeuvring the glyptodont body. □Glyptodonts, Mammalia, Xenarthra, limbs, strength indicators.

One of the basal Glyptodontidae groups is represented by the Propalaehoplophorinae (late Oligocene — middle Miocene), whose genera (Propalaehoplophorus, Eucinepeltus, Metopotoxus, Cochlops, andAsterostemma) were initially recognized in Argentinian Patagonia. Among these,Asterostemma was characterized by its wide latitudinal distribution, ranging from southernmost (Patagonia) to northernmost (Colombia, Venezuela) South America. However, the generic assignation of the Miocene species from Colombia and Venezuela (A.? acostae, A. gigantea, andA. venezolensis) was contested by some authors, who explicitly accepted the possibility that these species could correspond to a new genus, different from those recognized in southern areas. A new comparative study of taxa from Argentinian Patagonia, Colombia and Venezuela (together with the recognition of a new genus and species for the Pliocene of the latter country) indicates that the species in northern South America are not Propalaehoplophorinae, but represent the first stages in the cladogenesis of the Glyptodontinae glyptodontids, the history of which was heretofore restricted to the late Miocene — early Holocene of southernmost South America. Accordingly, we propose the recognition of the new genusBoreostemma for the species from northern South America and the restriction ofAsterostemma to the Miocene of Patagonia. Thus, the available data indicate that the Glyptodontinae would in fact have arisen in the northernmost regions of this continent. Their arrival to more southerly areas coincides with the acme of the “Age of Southern Plains”. The Propalaehoplophorinae are geographically restricted to Patagonia.

Arthritic lesions have been frequently diagnosed in the fossil record, with spondyloarthropathy (a type of erosive and pan-mammalian arthritis) being one of the most common types described to date for mammals, though not restricted to this group. Here, we identify spondyloarthropathy in fossil bones from the late Pleistocene in Brazil assignable to a large glyptodont individual. Bone erosions in the peripheral joints (viz., the ulna, radius, left femur and tibiae-fibulae) associated with osteosclerosis allow the diagnosis of spondyloarthropathy. The presence of osteophytes in seven bones of the forelimbs (viz., the ulna and radius) and hind limbs (viz., the tibiae-fibulae, left femur and patellae) and a subchondral cyst in one element (viz., the left femur) indicate secondary osteoarthritis. A calcified deposition on the articular surface of the left patella indicates the presence of calcium pyrophosphate deposition disease, which, like the observed osteoarthritic alterations, likely represents a complication of spondyloarthropathy. This is the first report of spondyloarthropathy for xenarthrans.

A date of 4300 ± 90 BP for extinct megafauna in Argentina is discussed. The fossil remains come from the Guerrero Member (area) of the Luján Formation near the city of Luján, Buenos Aires Province. The age of the top of the Guerrero Member is constrained by more than 60 radiocarbon dates obtained from the overlying Río Salado Member of Luján Formation, Las Escobas Formation, and Puesto Callejón Viejo Soil, most of them older than 4300 BP. In view of its low collagen content, the 14C measurement of bone sample from Luján should not be accepted uncritically. Because of the poor bone preservation and the possible introduction of "young" contaminants that were not completely eliminated, the 14C date of 4300 ± 90 BP is not reliable. Both biostratigraphic and 14C dating evidence indicates that the date of 4300 BP for the last representative of extinct megafauna in South America is unsupported., Facultad de Ciencias Naturales y Museo

The glyptodont (Glyptodontidae Burmeister 1879, in Ameghino 1889), a giant cousin of the armadillo, has long been thought to have disappeared in South America at least 10,000 years ago at the end of the Pleistocene. There are indications that the glyptodont had some interaction with ancient hunter-gatherers peoples (Politis et al. 1987; Politis 1995), but the precise time of its extinction has never been well established. Most recently, a brief mention of 14C dates of 7500 to 6500 BP (Geotimes 1996) for glyptodont remains discovered at La Moderna (Azul Department, Buenos Aires province, Argentina), has aroused excitement because the new younger dates have changed the traditional idea about the survival and extinction of this beast.

Glyptodonts had muscular tails terminating, in many cases, with a rigid bony sheath which, inDoedicurus and Panochthus , was a formidable club. Some carapaces show fractures which have been interpreted as resulting from intraspecific fights. We estimate the energy that the tail muscles could have supplied for a blow and the energy required to fracture the carapace, and obtain results of the same order of magnitude. Thus it is not unreasonable to interpret the observed damage as resulting from fights. A space between the thoracic and lumbar vertebral column and the carapace may have been occupied by a fatty pad which would have served as a protective cushion, reducing the force of impacts.

The form and function of the masticatory apparatus of the fossil genera Vassallia and Holmesina are analyzed so that the possible dietary behaviors of these pampathere xenarthrans might be inferred. Analysis is based on comparisons of dental morphology and skeletal features (through RFTRA) associated with the masticatory musculature among the pampatheres, the extant dasypodids Euphractus and Dasypus, and the glyptodont Propalaeohoplophorus. A method is proposed for generating a moment arm of the massetericus independently of the muscle's line of action, which allows direct comparison among extant and fossil mammals. The masticatory apparatus of the pampatheres strongly resembles that of Euphractus among extant forms, but the development of muscular attachment sites indicates a more powerful musculature, particularly the massetericus; the taxa differ most markedly in dental morphology. Long moment arms about the jaw joint and large ratios of muscle to bite moments indicate forceful rather than quick movements. The various skeletal and dental features analyzed suggest that the masticatory apparatus of the pampatheres was more powerful and efficient in transverse chewing than in dasypodids and that they were primarily grazers consuming mainly coarse vegetation. These features, some shared with herbivorous ungulates, include wide, relatively flat mandibular condyles; condyles well dorsal to muscular insertion sites; expanded angular processes; unfused symphysis; a posteriorly extended tooth row; open-rooted teeth; mesial teeth that bear mainly transverse striations; distal teeth that are mesiodistally elongated, bear basined occlusal surfaces, and in Vassallia possess a central island of resistant dentine that acted as a functional analogue of an ectoloph; and teeth with a stepwise arrangement. The results of this study indicate that detailed analysis and comparison of morphology lead to useful predictions of behavior.

Farina, R.A. 1995 11 30 Limb bone strength and habits in large glyptodonts. The masses of some large Pleistocene species of the fossil family Glyptodontidae (Mammalia; Xenarthra) were estimated from the volumes of models. Their centres of mass were also estimated. Dimensions of limb bones and limb muscles were used to assess the athleticism of these species, using an approach previously applied to dinosaurs. The femora show higher athletic indicators (even when supporting the whole weight of the animal) than humeri in the quadrupedal stance. It is therefore proposed that performing strenuous locomotor activities bipedally was not only possible but even advantageous for minimizing risk of bone failure. The muscular dimensions analysed are consistent with this conclusion. The possible biological meaning of these mechanical results is considered. Since the smaller and older (early Miocene) glyptodont Propalaehoplophorus does not share this condition, it is suggested that it was developed later in the history of the group, perhaps as a feature related to the acquisition of large size. Glyptodonts, fossil, Xenarthra, biomechanics, locomotion, extinct megafauna, palaeobiology, evolution.

Glyptodonts together with armadillos, pampatheres and peltephilines constitute the Cingulata, one of the three clades of the Xenarthra. The most remarkable feature of this group is the presence of an armored exoskeleton along the head, body and tail. Only a few contributions have described in detail the endoskeleton. In the case of the skull, almost no attention has been focused on the narial region. The objective of this study is to provide a description of the narial anatomy of the glyptodont Neosclerocalyptus. This genus has the most expanded and globular narial region among glyptodonts and was recently described as part of the fronto-nasal sinuses system. Our analysis based on CT scanning shows that this region includes an independent ossification of the nasal cartilage that housed the maxillo-atrioturbinates. This ossification would represent a neomorphic feature produced by a terminal addition of an ossified stage via peramorphosis. Other remarkable anatomical features are the presence of an expanded paranasal sinuses system that involves the nasal, frontal, parietal and squamosal bones, and the wide separation between the maxillo-atrioturbinates and ethmoturbinates. Functional consequences of this rearrangement are not readily predicted or inferred. Thus, this neomorphic ossification would constitute a morphological novelty, but not necessarily a functional one., Facultad de Ciencias Naturales y Museo

How animals cope with increases in body size is a key issue in biology. Here, we consider scaling of xenarthrans, particularly how femoral form and function varies to accommodate the size range between the 3 kg armadillo and its giant relative the 300 kg glyptodont. It has already been noted that femoral morphology differs between these animals and suggested that this reflects a novel adaptation to size increase in glyptodont. We test this idea by applying a finite element analysis of coronal plane forces to femoral models of these animals, simulating the stance phase in the hind limb; where the femur is subject to bending owing to longitudinal compressive as well as abduction loads on the greater trochanter. We use these models to examine the hypothesis that muscles attaching on the third trochanter (T3) can reduce this bending in the loaded femur and that the T3 forces are more effective at reducing bending in glyptodont where the T3 is situated at the level of the knee. The analysis uses traditional finite element methods to produce strain maps and examine strains at 200 points on the femur. The coordinates of these points before and after loading are also used to carry out geometric morphometric (GM) analyses of the gross deformation of the model in different loading scenarios. The results show that longitudinal compressive and abductor muscle loading increases bending in the coronal plane, and that loads applied to the T3 reduce that bending. In the glyptodont model, the T3 loads are more effective and can more readily compensate for the bending owing to longitudinal and abductor loads. This study also demonstrates the usefulness of GM methods in interpreting the results of finite element analyses.

Warm, humid regions are not ideal for long-term DNA preservation. Consequently, little ancient DNA research has been carried out involving taxa that lived in, for example, tropical and subtropical regions. Those studies that have isolated ancient DNA from warm environments have mostly been limited to the most recent several thousand years. Here, we discuss an ancient DNA experiment in which we attempt to amplify mitochondrial DNA from remains of armadillo, glyptodont, and pampathere from sites in Florida, USA, all believed to be around 10,000-12,000 years old. We were successful in recovering DNA from only one of these samples. However, based on the amount and distribution of DNA damage, the ancient DNA recovered was well-preserved despite the age and preservation environment. In this case study chapter, we discuss the experimental procedure we used to characterize the DNA from the Floridian samples, focusing on challenges of working with ancient specimens from warm environments and steps taken to confirm the authenticity of the recovered sequence.

Glyptodonts are a group of extinct xenarthrans with several anatomical features that make them one of the most bizarre groups of mammals. By the late 19th century, some authors began to analyze the brain of Pleistocene glyptodonts using natural endocranial casts. These studies revealed the small size of the brain of the large Pleistocene forms. However, the evolution of the brain in glyptodonts and how it fits in a phylogenetic context has not been analyzed. In order to evaluate the evolution of the brain in this group, we described the first digital endocranial cast of the late Miocene glyptodont Pseudoplohophorus absolutus and compared it with digital endocranial casts of the Pleistocene glyptodonts Glyptodon, Doedicurus, and Panochthus and the extant armadillos Dasypus, Euphractus, Chaetophractus, and Zaedyus. The endocast morphology of P. absolutus is similar to that of Pleistocene glyptodonts: large olfactory bulbs, a small cerebrum with a single neocortical sulcus, and a large cerebellum. Ho...

The mammalian order Edentata includes the armadillos, sloths and anteaters, and the extinct glyptodonts; the mammalian order Pholidota comprises the pangolins or scaly anteaters. Keywords: armadillo; sloth; anteater; pangolin; glyptodont

The writer has assembled the principal results from the investigations of early man made in America, especially North America, from 1839 to 1939. Special attention is directed to associated vertebrate faunas and geologic conditions. A selected bibliography and index to localities in North America are given. It is concluded that man in America was contemporaneous with several vertebrate genera and species now extinct. Among extinct mammalia regarded as associated with man on the basis of more than one occurrence and on observations by more than one worker are elephant, mastodon, camel, horse, bison, sloth, armadillo, glyptodont, tapir, dire wolf, sabre-tooth tiger, peccary, beaver, deer, and cave bear. A considerable number of other extinct species of mammals, birds, and reptiles, based on observations at one or more localities, are probably to be included as associates of man. Human materials have been found in unmistakable association with these animals under varied geologic conditions such as in stream terrace, cave, loess, peat, and lake deposits. Some of the extinct animals associated with man, formerly regarded as index fossils of the Pleistocene, appear to have continued their existence into relatively late geologic time. The supposition that all species with which man is associated continued into the Recent epoch is not justified. Additional information on the time of extinction of these animals and on the age of human remains found in association with them has been obtained in recent years from a study of physiographic features, particularly stream terraces. These observations are in agreement with the conclusion derived from a study of the fossils that man reached America previous to the close of the Pleistocene period.

In the southern part of the State of Puebla, central Mexico, the town of Tepexi de Rodriguez is a well-known fossiliferous area because of the beautiful and extraordinary Early Cretaceous vertebrates recovered from the Tlayua Quarry (Applegate, 1996; Espinosa-Arrubarrena and Applegate, 1996; Reynoso-Rosales, 1996a, 1996b, 1997, among others), and a Tertiary plant locality known as “Los Ahuehuetes” (Magallon-Puebla and Cevallos-Ferriz, 1994; Velasco de Leon and Cevallos-Ferriz, 1997; Ramirez-Garduno, 1998, among others). The Axamilpa river drains this area and along its banks a sequence of Late Cenozoic sands, silts, and gravels are exposed. In these sediments scattered fossil mammalian remains had been recovered (Torres-Martinez and Agenbroad, 1991; Montellano-Ballesteros and Castro-Azuara, 1996; Fig. 1). Figure 1 —Location map of Rancho Gerardo During 1998 the “Rancho Gerardo” locality, near the Rio Axamilpa yielded skeletal elements of the gomphothere mastodon Cuvieronius along with remains of other fossil mammals. These remains included isolated teeth and a lower jaw of Equus , postcranial remains and lower molars of Mammuthus , a tooth and dermal ossicles of a mylodontid edentate, and glyptodont scutes. This faunal association indicates a Pleistocene age for the assemblage. The “Rancho Gerardo” locality is located one kilometer east of Road 455 that connects La Colorada and Tepexi de Rodriguez. On the southern bank of the Rio Axamilpa three stratigraphic units were recognized: a basal dark-brown silty sand; a middle yellowish silt and sand with lenses of rounded and elongated cobbles; and an upper dark-brown silt and sand with irregularly-shaped calcite concretions. Vertebrates have not been recovered from the lower unit. The equid and mammoth remains came from the upper unit and the mastodon and edentate material came from the middle unit. The recovery of two lower mastodon jaws indicate the presence of two individuals. …

Fossiliferous strata exposed along the northwestern flank of Dry Mountain on the 111 Ranch, 27 km southeast of Safford, Graham County, Arizona, were dated by means of isotopic methods and the magnetic-reversal time scale. A 100-m fossiliferous interval contains the later part of the Gauss Chron and the early part (pre-Olduvai) of the Matuyama Chron. Zircon fission-track ages on an ash bed just below the Gauss-Matuyama boundary support this identification. Owing to these age constraints, the fossil mammals at the 111 Ranch locality are all constrained within the later part of the Blancan Mammal Age rather than the latest Blancan and early Irvingtonian, as previously stated in the literature. They are, therefore, synchronous with certain localities (Wolf Ranch and California Inst. Technology) in the Saint David Formation of the San Pedro Valley 130 km to the southwest of Dry Mountain. The horse Nannippus persisted in the 111 Ranch locality at least until the end of the Gauss Chron, in confirmation of data from the San Pedro Valley. A diverse group of equine and asinine equids is evident in the 111 Ranch fauna, which argues for an early divergence of these major branches of horse phylogeny. The 111 Ranch fauna records the first appearance of three neotropical immigrants in the southwest, including the sloth Glossotherium , the glyptodont Glyptotherium , and the capybara Neochoerus . A palearctic immigrant, the vole Synaptomys , is also present.