Sensory anatomy of the most aquatic of carnivorans: the Antarctic Ross seal, and convergences with other mammals

Transitions to and from aquatic life involve transformations in sensory systems. The Ross seal, Ommatophoca rossii, offers the chance to investigate the cranio-sensory anatomy in the most aquatic of all seals. The use of non-invasive computed tomography on specimens of this rare animal reveals, relative to other species of phocids, a reduction in the diameters of the semicircular canals and the parafloccular volume. These features are independent of size effects. These transformations parallel those recorded in cetaceans, but these do not extend to other morphological features such as the reduction in eye muscles and the length of the neck, emphasizing the independence of some traits in convergent evolution to aquatic life.Facultad de Ciencias Naturales y Muse

Morfología de los dientes deciduos de algunos tremactinos (Ursida: Tremarctinae)

Se describe y compara la morfología de algunos dientes deciduos de Arctotherium tarijense Ameghino and A. angustidens Gervais and Ameghino (Ursidae, Tremarctinae) por primera vez. La morfología del dP4 y dp4 es muy similar a la del M1 y m1. La morfología general de los dP/dp4 en A. tarijense y Ursinae es similar, aunque la morfología de sus dientes definitivos es muy diferente. Los dP/dp4 de A. tarijense parecen poseer un conjunto de caracteres generalizados (en relación con el contorno de la corona, el protocono y el parastilo del dP4, el metacónido y el hipocónido del dp4). Desgraciadamente no es posible comparar esas piezas con sus homólogas en otros tremarctinos, por lo que no es posible incluir estos caracteres en el análisis filogenético de la subfamilia Tremarctinae con el fin de saber si sus relaciones filogenéticas se ven afectadas o no. Es importante remarcar que si esos carcateres estuviesen presentes en los M/m1 de A. tarijense, al menos algunos de ellos podrían ser interpretados como plesiomorfías. En este sentido, ¿la morfología de los dientes deciduos es más conservadora que la de los definitivos?.The morphology of some deciduous teeth of Arctotherium tarijense Ameghino and A. angustidens Gervais and Ameghino (Ursidae: Tremarctinae) is here described and compared for the first time. The crown morphology of dP4 and dp4 is similar to that of M1 and m1. The general morphology of dP/dp4 in A. tarijense and Ursinae is similar, but their permanent dentition morphology is different. The dP/dp4 of A. tarijense seem to bear a generalized set of characters (i.e. crown outline, the protocone and parastyle of dP4, the metaconid and hypoconid of dp4); unfortunately these teeth cannot be compared with their homologues in other tremarctines. Consequently, we are unable to include these characters in the phylogenetic analysis of the Tremarctinae subfamily in order to know whether the phylogenetic relationships are affected or not. It is interesting to note, that had these characters been present in M/m1 of A. tarijense, at least, some of them could be undoubtedly regarded as plesiomorphic features. In this respect, is the deciduous teeth morphology more conservative than that of permanent teeth?.Museo de La Plat

A new Megatheriinae skull (Xenarthra, Tardigrada) from the pliocene of northern venezuela – Implications for a giant sloth dispersal to central and North America

A skull of a ground sloth from the Pliocene San Gregorio Formation documents a northern neotropical occurrence of a megatheriine that addresses issues on intraspecific variation and biogeography. The new specimen is broadly similar in size and morphology to that of Proeremotherium eljebe from the underlying Codore Formation in the Urumaco Sequence, differing in several features such as a longer basicranial area and a more posteriorly projected basioccipital between the condyles. The living sloths species of Bradypus and Choloepus do not have unequivocal anatomical features that indicate sexual dimorphism. Nevertheless, fossil sloths may have shown such dimorphism, and speculations on this subject are part of the considerations that can be made when allocating fragmentary fossils (e.g., in the new skull the presence of a long sagittal crest could indicate a male individual and the absence of an extended crest in Proeremotherium eljebe a female one). We speculate that as early as the late middle Miocene, two main lines of Megatheriinae had clearly separated in two geographic areas, one in the rising Andean area and one at low latitudes on the lowlands of central and northern South America.Fil: Carlini, Alfredo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; ArgentinaFil: 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; ArgentinaFil: Sánchez, Rodolfo. Museo Paleontológico de la Alcaldia de Urumaco; VenezuelaFil: Sánchez Villagra, Marcelo R.. Universitat Zurich; Suiz

Chaetophractus vellerosus (Cingulata: Dasypodidae)

Chaetophractus vellerosus (Gray, 1865) is commonly called Piche llorón or screaming hairy armadillo. Chaetophractus has 3 living species: C. nationi, C. vellerosus, and C. villosus of Neotropical distribution in the Bolivian, Paraguayan, and Argentinean Chaco and the southeastern portion of Buenos Aires Province. C. vellerosus prefers xeric areas, in high and low latitudes, with sandy soils, but is able to exist in areas that receive more than twice the annual rainfall found in the main part of its distribution. It is common in rangeland pasture and agricultural areas. C. vellerosus is currently listed as "Least Concern" by the International Union for Conservation of Nature and Natural Resources and is hunted for its meat and persecuted as an agricultural pest; however, the supposed damage to agricultural-farming lands could be less than the beneficial effects of its predation on certain species of damaging insects.Facultad de Ciencias Naturales y Muse

A new species of Neosclerocalyptus Paula Couto, 1957 (Xenarthra, Glyptodontidae, Hoplophorinae) from the middle Pleistocene of the Pampean region, Argentina

A new species of the genus Neosclerocalyptus Paula Couto, 1957 (= SclerocalyptusAmeghino, 1891), N. gouldi n. sp. (Cingulata, Glyptodontidae, Hoplophorini) is described. Th is new taxon, comes from the Bonaerian Stage (middle Pleistocene; c. 0.4-0.13 Ma) of San Andrés de Giles, Buenos Aires province, Argentina. Th e type consists mainly of an associated skull, mandible and cephalic shield in an excellent state of preservation. Morphological characters that distinguish the species include: a) lesser pneumatization and lateral expansion of fronto-nasal sinuses compared to N. paskoensis; b) descending processes of maxillaries and zygomatic arches very robust and with marked ridges; c) lower third of descending processes markedly inclined toward the sagittal plane; d) inclination of the parieto-occipital skull region inter-mediate between those of Ensenadan and Lujanian forms; e) infraorbital fora mina larger than in N. paskoensis, similar in size to those of N. ornatus; and f ) occipital area less expanded laterally than in N. paskoensis. Th is new taxon completes the chronological distribution of genus Neosclerocalyptus which, until now, included two well-characterized species for the Ensenadan (early Pleistocene: N. pseudornatus and N. ornatus) and one Lujanian (late Pleistocene-early Holocene: N. paskoensis). Th e Bonaerian species, N. migoyanus, recognized by Ameghino, should be considered as a nomen dubium,due to the lack of diagnostic characters.Une nouvelle espèce de Neosclerocalyptus Paula Couto, 1957 (Xenarthra, Glyptodon-tidae, Hoplophorinae) du Pléistocène moyen de la région pampéenne d’Argentine.Une nouvelle espèce du genre Neosclerocalyptus Paula Couto, 1957 (= Sclero-calyptus Ameghino, 1891), N. gouldi n. sp. (Cingulata, Glyptodontidae, Hoplo-phorini), est décrit. Ce taxon nouveau vient de l’Étage Bonaériéen (Pleistocène moyen ; c. 0.4-0.13 Ma) de San Andrés de Giles, province de Buenos Aires, Argentine. Le spécimen est représenté par un crâne, une mandibule et un bou-clier céphalique associés, excellent état de préservation. Les caractéristiques morphologiques qui distinguent l’espèce incluent : a) une pneumatisation et une expansion latérale des sinus fronto-nasaux moindres par rapport à N. pasko-ensis ; b) des processus descendants des arches maxillaires et zygomatiques très robustes et avec des dorsales marquées ; c) le tiers inférieur des processus des-cendants incliné de manière marquée vers le plan sagittal ; d) une inclinaison de la région crânienne pariéto-occipitale intermédiaire entre celles des formes ensénadéennes et lujanéennes ; e) des foramens infraorbitaux plus grands que chez N. paskoensis, de même longueur que ceux de N. ornatus ; et f ) une région occipitale moins développée latéralement que chez N. paskoensis. Ce nouveau taxon complète la distribution chronologique du genre Neosclerocalyptus, qui, jusqu’à présent, incluait deux espèces bien caractérisées propres à l’Ensénadéen (Pleistocène inférieur : N. pseudornatus et N. ornatus) et une autre limitée au Lujanéen (Pleistocène supérieur-Holocène inférieur : N. paskoensis). L’espèce bonaériéenne, N. migoyanus, reconnue par Ameghino doit être considérée comme un nomen dubium, par son manque de caractères diagnostiquesFacultad de Ciencias Naturales y Muse

A new species of Neosclerocalyptus Paula Couto, 1957 (Xenarthra, Glyptodontidae, Hoplophorinae) from the middle Pleistocene of the Pampean region, Argentina

A new species of the genus Neosclerocalyptus Paula Couto, 1957 (= SclerocalyptusAmeghino, 1891), N. gouldi n. sp. (Cingulata, Glyptodontidae, Hoplophorini) is described. Th is new taxon, comes from the Bonaerian Stage (middle Pleistocene; c. 0.4-0.13 Ma) of San Andrés de Giles, Buenos Aires province, Argentina. Th e type consists mainly of an associated skull, mandible and cephalic shield in an excellent state of preservation. Morphological characters that distinguish the species include: a) lesser pneumatization and lateral expansion of fronto-nasal sinuses compared to N. paskoensis; b) descending processes of maxillaries and zygomatic arches very robust and with marked ridges; c) lower third of descending processes markedly inclined toward the sagittal plane; d) inclination of the parieto-occipital skull region inter-mediate between those of Ensenadan and Lujanian forms; e) infraorbital fora mina larger than in N. paskoensis, similar in size to those of N. ornatus; and f ) occipital area less expanded laterally than in N. paskoensis. Th is new taxon completes the chronological distribution of genus Neosclerocalyptus which, until now, included two well-characterized species for the Ensenadan (early Pleistocene: N. pseudornatus and N. ornatus) and one Lujanian (late Pleistocene-early Holocene: N. paskoensis). Th e Bonaerian species, N. migoyanus, recognized by Ameghino, should be considered as a nomen dubium,due to the lack of diagnostic characters.Une nouvelle espèce de Neosclerocalyptus Paula Couto, 1957 (Xenarthra, Glyptodon-tidae, Hoplophorinae) du Pléistocène moyen de la région pampéenne d’Argentine.Une nouvelle espèce du genre Neosclerocalyptus Paula Couto, 1957 (= Sclero-calyptus Ameghino, 1891), N. gouldi n. sp. (Cingulata, Glyptodontidae, Hoplo-phorini), est décrit. Ce taxon nouveau vient de l’Étage Bonaériéen (Pleistocène moyen ; c. 0.4-0.13 Ma) de San Andrés de Giles, province de Buenos Aires, Argentine. Le spécimen est représenté par un crâne, une mandibule et un bou-clier céphalique associés, excellent état de préservation. Les caractéristiques morphologiques qui distinguent l’espèce incluent : a) une pneumatisation et une expansion latérale des sinus fronto-nasaux moindres par rapport à N. pasko-ensis ; b) des processus descendants des arches maxillaires et zygomatiques très robustes et avec des dorsales marquées ; c) le tiers inférieur des processus des-cendants incliné de manière marquée vers le plan sagittal ; d) une inclinaison de la région crânienne pariéto-occipitale intermédiaire entre celles des formes ensénadéennes et lujanéennes ; e) des foramens infraorbitaux plus grands que chez N. paskoensis, de même longueur que ceux de N. ornatus ; et f ) une région occipitale moins développée latéralement que chez N. paskoensis. Ce nouveau taxon complète la distribution chronologique du genre Neosclerocalyptus, qui, jusqu’à présent, incluait deux espèces bien caractérisées propres à l’Ensénadéen (Pleistocène inférieur : N. pseudornatus et N. ornatus) et une autre limitée au Lujanéen (Pleistocène supérieur-Holocène inférieur : N. paskoensis). L’espèce bonaériéenne, N. migoyanus, reconnue par Ameghino doit être considérée comme un nomen dubium, par son manque de caractères diagnostiquesFacultad de Ciencias Naturales y Muse

Astrapotheres from Cañadón Vaca, middle Eocene of central Patagonia: New insights on diversity, anatomy, and early evolution of Astrapotheria

Astrapotheria is one of the most emblematic groups of endemic South American ungulate-like extinct mammals, traditionally compared with modern tapirs and rhinos. Oldest astrapotheres are known from the early Eocene Itaboraian fauna (Brazil), but the earliest diverse astrapothere assemblage is known from the middle Eocene Cañadón Vaca Member of the Sarmiento Formation exposed at Cañadón Vaca (Vacan subage of the Casamayoran Land Mammal Age), in central Patagonia, Argentina. Previous reports of astrapotheres from Cañadón Vaca included Trigonostylops, Tetragonostylops, Albertogaudrya, and Scaglia, but only the record of the latter was unequivocal. New materials from Cañadón Vaca described herein confirms the occurrence of Trigonostylops (T. wortmani) and of Tetragonostylops (likely represented by a species different from the nominal species from Itaboraí). Additionally, two other taxa are identified: The former, described as cf. Scaglia cf. kraglievichorum, is represented by a partial skull with an unusual combination of cranial characters, and could correspond to an adult of Scaglia kraglievichorum (known by a juvenile skull); the other taxon is represented by a partial mandible with distinctive osteological and dental features, but the possibility of its belonging to Scaglia cannot be discarded. The occurrence of Albertogaudrya in Cañadón Vaca could not be confirmed by the examination of the new and previous collections. Astrapotheres from Cañadón Vaca show a wide morphological disparity of cranial designs, but all consistently share long, unreduced nasals, thus the presumed possession of a short tapir-like proboscis only typifies the post-Casamayoran astrapotheres.Fil: Kramarz, Alejandro Gustavo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Bond, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; ArgentinaFil: Carlini, Alfredo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentin

A review of the Miocene record of Pampatheriidae (Mammalia, Xenarthra) from Uruguay

The Pampatheriidae represents an extinct group of cingulates whose remains are mostly known from Quaternary sediments. Contrary, the Mio-Pliocene record of the group is infrequent and largely based on fragmentary materials. In Uruguay, Miocene Pampatheriidae has been described almost exclusively on the basis of isolated osteoderms assigned to Kraglievichia paranense (Ameghino). A few communications also refer to the possible occurrence of the genus Vassallia Castellanos. In this contribution we review the taxonomic status of those past mentions and present three sets of unpublished materials deposited in the collections of the Museo Nacional de Historia Natural (MNHN), and the Paleontological Museum of the Real de San Carlos (AC). MNHN 2528 includes two fixed osteoderms associated with a nearly complete skull preserving the full dental series except for both M1 and the right M2, and the apex of the rostrum (part of the premaxilla and the nasal regions). MNHN 1482 includes numerous osteoderms, partially complete mandibular rami, the right ulna, the left astragalus and a fragment of the pelvis, all belonging to one specimen. Both fossils were exhumed from the Balneario Arazatí (San José Department) in sediments of the Camacho Formation (late Miocene, Huayquerian SALMA), and are provisionally assigned to Vassallia sp. AC 1050 is an almost completely articulated carapace which contains part of the skull, several isolated osteoderms and some vertebrae, collected in the marine facies of the San Pedro Member of the Camacho Formation, in Colonia Department. This material has a particular set of morphological features (i.e., configuration of the teeth, patterns of ornamentation in the osteoderms) which demands to be cautious on its taxonomical allocation. The finding of these associated cranial and exoskeletal remains becomes an important element for the current review of the taxonomy of the Mio-Pliocene South American Pampatheriidae.Sesiones libresFacultad de Ciencias Naturales y Muse

A new genus and species of Planopinae (Xenarthra: Tardigrada) from the Miocene of Santa Cruz Province, Argentina

Prepoplanops boleadorensis, a new genus and species of Planopinae (Xenarthra, Tardigrada), is described herein. The new taxon is based on a nearly complete specimen recovered from the Cerro Boleadoras Formation (Miocene, Río Zeballos Group), in northwestern Santa Cruz Province, Argentina. The shape and length of the predentary region of the skull and the length of the diastema of Prepoplanops boleadorensis differ from those present in the species of Planops. The posterolateral opening of the mandibular canal and the position of the posterior margin of the mandibular symphysis differ from those of species of Prepotherium. In addition, Prepoplanops boleadorensis differs from Planops martini in the size of the humeral tuberosities, the development of the deltoid crest, the position of the distal margin of the humeral trochlea, the shape and position of the olecranon, the development of the femoral epicondyles, and the shape of the medial margins of the patellar trochlea and medial condyle. On the other hand, it differs from Prepotherium potens in the shape of the medial margin of the medial condyle. The recognition of Prepoplanops boleadorensis increases the diversity of Planopinae for the Miocene of Patagonia, Argentina.Fil: Carlini, Alfredo Armando. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: 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; ArgentinaFil: Dal Molin, Carlos N.. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; Argentin

North American Glyptodontines (Xenarthra, Mammalia) in the Upper Pleistocene of northern South America

The Glyptodontidae is one of the most conspicuous groups in the Pleistocene megafauna of the Americas. The Glyptodontinae were involved in the Great American Biotic Interchange (GABI) and their earliest records in North America are about 3.9 Ma, suggesting an earlier formation of the Panamanian landbridge. Taxonomically it is possible to recognize two Pleistocene genera of Glyptodontinae:Glyptodon (ca. 1.8 – 0.008 Ma), restricted to South America, andGlyptotherium (ca. 2.6 – 0.009 Ma), including records in both North and Central America. Here we present the first report of the genusGlyptotherium in South America, from the Late Pleistocene of several fossil localities in Falcon State, northwestern Venezuela. A comparative analysis of the material, represented by cranial and postcranial parts, including the dorsal carapace and caudal rings, suggests a close affinity withGlyptotherium cylindricum (Late Pleistocene of Central Mexico). This occurrence in the latest Pleistocene of the northernmost region of South America Supports the bidirectional faunal migration during the GABI and the repeated re-immigration from North America of South American clades, as has been reported in other members of the Cingulata (e.g., Pampatheriidae).Facultad de Ciencias Naturales y Muse