A New Species of Neoglyptatelus (Mammalia, Xenarthra, Cingulata) from the Late Miocene of Uruguay Provides New Insights on the Evolution of the Dorsal Armor in Cingulates

The genus Neoglyptatelus Carlini, Vizcaíno and Scillato-Yané has been considered a member of Glyptatelinae, a group encompassing the purportedly basal-most glyptodonts. It is up to now represented by two species from Colombia: Neoglyptatelus originalis Carlini, Vizcaíno and Scillato-Yané, from the middle Miocene (a carapace fragment, isolated osteoderms and postcranial bones), and Neoglyptatelus sincelejanus Villarroel and Clavijo, from the middle or late Miocene (a partial carapace and a caudal armor). More scarce material assigned to this genus was recovered from the late Miocene of Uruguay and Brazil. In this article, we describe a new species, Neoglyptatelus uruguayensis, from the late Miocene Camacho Formation, Uruguay, based on an almost complete carapace and several postcranial bones. We conducted a phylogenetic analysis based on 167 morphological characters (23 new ones and 144 from previous analysis) scored for 19 taxa, encompassing some of the best known glyptodontid genera, one pampathere and four armadillos (including the enigmatic genus Pachyarmatherium Downing and White). In the most parsimonious tree that was obtained, Neoglyptatelus forms a clade with Pachyarmatherium (Pachyarmatheriidae), which is the sister group of the glyptodonts + pampatheres clade; consequently, it is not a glyptodont, as previously believed. This result, together with the known stratigraphic and geographic distribution of Neoglyptatelus and Pachyarmatherium, suggests that this new cingulate clade originated in South America and that Pachyarmatherium reached North America during the Plio--Pleistocene. The carapace of Neoglyptatelus and Pachyarmatherium comprises pelvic and scapular shields overlapping each other without separate intervening transverse mobile bands, an arrangement that differentiates both genera from the remaining cingulates.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; ArgentinaFil: Rinderknecht, Andrés. Museo Nacional de Historia Natural; UruguayFil: Jones, Washington. Museo Nacional de Historia Natural; UruguayFil: Vizcaíno, Sergio Fabián. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Porpino, Kleberson de Oliveira. Universidade Do Estado Do Rio Grande Do Norte; Brasi

The first cranial remains of the Pleistocene proterotheriid Neolicaphrium Frenguelli, 1921 (Mammalia, Litopterna): A comparative approach

The first cranial and upper dental remains of a proterotheriid referred to Neolicaphrium cf. N. recens Frenguelli, 1921, are described from the late Pleistocene of northern Uruguay (Sopas Formation). An isolated molariform from the Pleistocene of northeastern Pampean Argentina is considered as Neolicaphrium sp. It is the last surviving Pleistocene Proterotheriidae. An expanded diagnosis of this genusbased until now only on mandibular charactersis provided. The following combination of characters distinguish it from other genera of proterotheriids for which characters of the skull have been described: dorsal surface of skull almost parallel to the occlusal surface of the cheek teeth series; relatively large orbits and diastema; very large caniniform upper incisors; upper premolars and molars relatively low crowned; P2 nearly quadrangular; molariforms (at least P4 and M1-3) with anterolingual cingulae; anteroposteriorly short upper molar series; M1-3 with metaconule reduced to a small transverse crest connecting the hypocone to the metacone; hypocone reduced (or nearly absent), particularly in M3; M3 located below the orbit. A principal component analysis places it near the smallest species of proterotheriids, which were separated very well along the second component, usually related to shape.Fil: Ubilla, Martin. Facultad de Ciencias; UruguayFil: Perea, Daniel. Facultad de Ciencias; UruguayFil: Bond, Mariano. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Rinderknecht, Andrés. Museo Nacional de Historia Natural; Urugua

A new genus and species of a giant Dinomyidae (Rodentia, Caviomorpha) from the late Miocene of Uruguay

The Dinomyidae composed a family of "giant" rodents, restricted to South America. Nowadays this family includes only the "pacarana", a medium size caviomorph mostly distributed through the Amazonian Basin. Nevertheless, the past diversity of the group was notable with more than 60 described species currently grouped into five extinct subfamilies. Eumegamyinae is one of these subfamilies, characterized by hosting medium to big size forms including the largest known rodents. In this communication we describe the remains of a new giant Eumegamyinae exhumed from the coast of San José Department (southern Uruguay), in sediments of the Camacho Formation, assigned to the late Miocene Huayquerian SALMA. The remains include the posterior region of the skull, the occipital condyles, and the entire right auditory region of a unique animal. In connection with the crania we recovered the atlas and the almost complete dental series. The premolo-molar series are characterized by having the P4, M1 and M2 composed by five transverse lophs of which the first two (anterior ones) remain free, while the three posterior ones are joined together by the lingual (internal) side. The M3 is composed by three anterior free lophs and two posterior ones, joined at the lingual side. The auditive region has a short meatus acusticus externus with the foramen stylomastoideum located below them, and a well developed ectotympanic cavity. Based on the state of development of the foramen stylomastoideum and the presence or absence of the ectotympanic cavity, we describe two morphologies for the Eumegamyinae auditory region. The taxonomic and systematic relevance of the dental series versus the auditory region in Dinomyidae is discussed.Sesiones libresFacultad de Ciencias Naturales y Muse

First record of Tetrastylus Ameghino, 1886 (RODENTIA; DINOMYIDAE) from the upper miocene of Uruguay

The first record for Uruguay of the dinomyid rodent Tetrastylus Ameghino, an almost complete right mandible from the upper Miocene Camacho Formation, is described. According to the p4 and m3 morphology it is inferred a juvenile-subadult ontogenetic stage for this specime

First record of the genus Nopachtus (Xenarthra: Cingulata: Glyptodontidae) in Uruguay

Nopachtus Ameghino is a poorly known genus of glyptodontid. The genus includes 2 species recorded in Argentina: Nopachthus coagmentatus Ameghino, from Brochero Formation (Montehermosian-Chapadmalalian, Early Pliocene-Late Pliocene) of Sierras de Córdoba/El Polvorín Formation (Upper Chapadmalalian, Pliocene) of Sierras Bayas de Olavarría, Buenos Aires province, and Nopachthus cabrerai Zamorano, Scillato-Yané, González-Ruiz and Zurita, from Monte Hermoso Formation (Montehermosian, Early Pliocene) from SO of Buenos Aires province. The knowledge about the presence of Nopachtus outside Argentina, is due to Toriño y Rinderknecht (2005), who mention one osteoderm which possesses similar characters to those of Nopachtus and Panochthus intermedius Lydekker. Later, Toriño y Perea (2008) resume this consideration. In this paper, the materials referred to Nopachtus in Uruguay are studied. There are 2 isolated osteoderms corresponding to the dorsal carapace: FC-CVF 1825 and CF-CVF 2759, both from Camacho Formation (Late Miocene) or Raigón Formation (Late Miocene-Middle Pleistocene) of the coast cliffs of San José Departament, Uruguay. Due to the great similarity of these osteoderms to those of Nopachtus, and according to the comparative analysis conducted, both are assigned to the present genus, thus expanding the geographic distribution of this taxon to Uruguay.Nopachtus Ameghino es un género de gliptodóntido poco conocido. Cuenta con 2 especies registradas para Argentina: Nopachtus coagmentatus Ameghino, de la formación Brochero (Montehermosense-Chapadmalalense, Plioceno Temprano-Plioceno Tardío) de las sierras de Córdoba/formación El Polvorín (Chapadmalalense Superior, Plioceno) de las sierras Bayas de Olavarría, provincia de Buenos Aires; y Nopachtus cabrerai Zamorano, Scillato-Yané, González-Ruiz y Zurita, de la formación Monte Hermoso (Montehermosense, Plioceno Temprano) del SO de la provincia de Buenos Aires. El conocimiento sobre la presencia de Nopachtus fuera de Argentina se debe a la mención de Torino˜ y Rinderknecht (2005) de un osteodermo que posee características semejantes a Nopachtus y a Panochthus intermedius Lydekker; posteriormente, Torino˜ y Perea (2008) retoman esta consideración. En la presente contribución se realiza un estudio de materiales referidos a Nopachtus en Uruguay. Se trata de 2 osteodermos aislados correspondientes a la coraza dorsal: FC-CVF 1825 y FC-CVF 2759, ambos proceden de la formación Camacho (Mioceno Tardío) o formación Raigón (Mioceno Tardío-Pleistoceno Medio) de las barrancas costeras del departamento de San José, Uruguay. Dada la notoria semejanza de estos osteodermos con los de Nopachtus, y por comparaciones realizadas, se asignan al citado género, ampliándose así la distribución geográfica del taxón a Uruguay.Facultad de Ciencias Naturales y Muse

The state of knowledge of the jaguar Panthera onca (Linnaeus, 1758) (Carnivora, Felidae) during the Quaternary in Uruguay

Felids are the top predators in the environments they inhabit. They entered South America at the Pliocene-Pleistocene boundary, but their fossil record in Uruguay, although informative, is scarce. In the present contribution, three new materials (two hemimandibles and an isolated first lower molar) assigned to Panthera onca (Linnaeus, 1758) are described. This material came from Quaternary sediments (Sopas, Dolores, and Libertad Formations) from several localities in Uruguay. Based on this material, different aspects of the paleobiology and paleoecology of jaguars are discussed. Remains of these felids were previously listed but never described; thus, the material analyzed here is the first fossil records reliably determined for P. onca in Uruguay. These felids would have shared an ecological niche with other large carnivores during the late Pleistocene in Uruguay, such as saber-toothed cats (Smilodon populator Lund, 1842; S. fatalis Leidy, 1868), Puma concolor Linnaeus, 1771, and short face bears Arctotherium Burmeister, 1879; and they would have fed upon medium-sized herbivores, principally in vegetated environments.L’état des connaissances du jaguar Panthera onca (Linnaeus, 1758) (Carnivora, Felidae) au Quaternaire de l’Uruguay. Les félidés sont les principaux prédateurs des environnements qu’ils habitent. Ceux-ci sont arrivés en Amérique du Sud dans la limite Pliocène-Pléistocène, mais leur registre fossile pour l’Uruguay, bien qu’informative, est rare. Dans la présente contribution, trois nouveaux matériaux attribués à Panthera onca (Linnaeus, 1758) (deux hémimandibles et une première molaire inférieure isolée) sont décrits. Ce matériel provient de sédiments quaternaires (formations Sopas, Dolores et Libertad) de divers sites en Uruguay. Sur la base de ce matériel, différents aspects de la paléobiologie et de la paléoécologie desjaguars sont discutés. Les restes de ces félidés ont été précédemment répertoriés, mais jamais décrits, donc le matériiel analysé ici est le premier enregistrement fossile de P. onca clairement déterminé pour l’Uruguay. Ce félidé aurait pu partager une niche écologique avec d’autres grands carnivores du Pléistocène supérieur de l’Uruguay, tels que les tigres à dents de sabre (Smilodon populator Lund, 1842; S. fatalis Leidy, 1868), Puma concolor Linnaeus, 1771, et les ours à face courte Arctotherium Burmeister, 1879, se nourrissant principalement d’herbivores moyens dans des environnements de jungl

A mitogenomic timetree for Darwin’s enigmatic South American mammal Macrauchenia patachonica

The unusual mix of morphological traits displayed by extinct South American native ungulates (SANUs) confounded both Charles Darwin, who first discovered them, and Richard Owen, who tried to resolve their relationships. Here we report an almost complete mitochondrial genome for the litoptern Macrauchenia. Our dated phylogenetic tree places Macrauchenia as sister to Perissodactyla, but close to the radiation of major lineages within Laurasiatheria. This position is consistent with a divergence estimate of B66Ma (95% credibility interval, 56.64–77.83 Ma) obtained for the split between Macrauchenia and other Panperissodactyla. Combined with their morphological distinctiveness, this evidence supports the positioning of Litopterna (possibly in company with other SANU groups) as a separate order within Laurasiatheria. We also show that, when using strict criteria, extinct taxa marked by deep divergence times and a lack of close living relatives may still be amenable to palaeogenomic analysis through iterative mapping against more distant relatives.Facultad de Ciencias Naturales y Muse

A mitogenomic timetree for Darwin’s enigmatic South American mammal Macrauchenia patachonica

The unusual mix of morphological traits displayed by extinct South American native ungulates (SANUs) confounded both Charles Darwin, who first discovered them, and Richard Owen, who tried to resolve their relationships. Here we report an almost complete mitochondrial genome for the litoptern Macrauchenia. Our dated phylogenetic tree places Macrauchenia as sister to Perissodactyla, but close to the radiation of major lineages within Laurasiatheria. This position is consistent with a divergence estimate of B66Ma (95% credibility interval, 56.64–77.83 Ma) obtained for the split between Macrauchenia and other Panperissodactyla. Combined with their morphological distinctiveness, this evidence supports the positioning of Litopterna (possibly in company with other SANU groups) as a separate order within Laurasiatheria. We also show that, when using strict criteria, extinct taxa marked by deep divergence times and a lack of close living relatives may still be amenable to palaeogenomic analysis through iterative mapping against more distant relatives.Facultad de Ciencias Naturales y Muse

Estudios sobre los roedores gigantes del Uruguay, departamento de San José (Mioceno tardío-plioceno) y sus implicancias para la sistemática y taxonomía de la familia Dinomyidae (mammalia, rodentia)

Tribunal: Daniel Perea, Enrique Lessa y Peter Sprechmann.Orientador: Martín Ubilla.Co-orientador: R. Ernesto Blanco