Search

The Alianca Formation, within the Brazilian Reconcavo–Tucano–Jatoba Rift System, is a succession of Late Jurassic sedimentary rocks that record the maximum flooding surface of shallow Capianga Lake in the Afro-Brazilian Depression, Gondwana. Several aulacogens and drift-marginal Mesozoic basins of eastern Brazil and western Africa recorded the great extensional event that occurred during the early stage of Gondwana break-up. Lithologic, petrographic, micropaleontological and geochemical analyses of lacustrine carbonates collected near the city of Ibimirim, Pernambuco State, were carried out to establish the paleolimnological evolution of a marginal area of Capianga Lake, in the Jatoba Basin. The ostracode fauna, obtained from grainstone and calcareous quartzarenite, is constituted by Theriosynoecum pricei, Theriosynoecum uninodosa, Theriosynoecum quadrinodosum, Reconcavona? jatobaensis and Alicenula? spp. Carbon and oxygen stable isotopes in bulk rock, Theriosynoecum pricei and Alicenula? spp. were measured. Theriosynoecum pricei displays the most negative δ13C values, between − 2.1 and − 1.3‰. The δ13C values obtained from Alicenula? spp. and bulk rock were also negative. The δ18O values for Theriosynoecum pricei range from − 10.1 to + 4.1‰. Alicenula? spp. show δ18O values between − 4.6 and + 5.8‰. The bioclastic character of the carbonates and the presence of cross-bedding and ripple marks suggest deposition in a low-energy, low-gradient, ramp-type littoral zone of a shallow, balanced-fill lake. The ostracode association, characteristic of permanent, alkaline, freshwater bodies, corresponds to the Theriosynoecum pricei ostracode biozone, which is of Tithonian age. The lithofacies, along with covariation of δ13C and δ18O, and large δ18O fluctuations, suggest that this marginal area of Capianga Lake was characterized by stable hydrological conditions in a closed basin. The δ13C values display a slightly narrower range, suggesting oligotrophic to slightly mesotrophic conditions, and holomixis in this marginal area of Capianga Lake.

The fossil mammals that lived in the Brazilian Intertropical Region during the Quaternary are found in different types of deposits (e.g. natural tanks, ponds, caves, rockshelter, and riverbeds) throughout the Brazilian territory. The state of Bahia, located on northeastern Brazil, stands out for the presence of large and important caves, which are characterized by the natural deposition of sediments and fossils. The study aims to identify the fauna found in the Borboletas Cave, and to provide the first paleoecological inferences for the environment during the Late Pleistocene-Holocene. Here we present the first record of Palaeolama major, Hippidion principale and Smilodon populator in Paripiranga, Bahia. Coendou sp., Mazama gouazoubira, and Toxodon platensis, already known to the region, were also collected and identified. Based on the chronological and geographical distribution of the taxa, it is suggested that the faunal content found lived during the Late Pleistocene – Holocene. The presence of the taxa found indicate an open paleoenvironment, similar to savanna, with areas covered with grasses associated with areas with forest cover. This study demonstrates that the Borboletas Cave is the richest paleontological site carrying the mammals in this region.

Occurrences of gomphotheres in northeastern Brazil there are in tank deposits, caves and lagoons and many of these records are from the Pleistocene tank deposits, formed by physical and chemical erosion in crystalline rock. These deposits are common in northwestern of State of Ceara and correspond to the most Pleistocene fossil findings. This paper presents the description of two specimens of gomphotheres identified as Gomphotheriidae constituting an unprecedented record for the City of Iraucuba, Ceara, located 150 km from Fortaleza. In the same place, Xenarthra, Liptoterna, Notoungulata and Perissodactyla were also found.

Pleistocene sites with mammals in Brazil are commonly recorded from limestone or dolomite caves, outcrops at rivers and creeks, coastal plain lagoon deposits, rock shelters, and natural tanks. This work presents a new late Pleistocene site containing bones and footprints of mammals. The footprints are assigned to llama (Lamaichnum), cervid (Pecoripeda), horse (Hippipeda), and at least one megamammal (?Toxodon), constituting the northernmost record for the late Pleistocene of South America and the first record from Brazil. Mammals are related to fluvial environments along with treeless vegetation during a sub-humid climate, in a region currently dominated by a semiarid biome.

Zeusdelphys complicatus is one of the most enigmatic metatherians from the Itaboraí Basin. The type and only known specimen was previously regarded as the upper dentition of Eobrasilia; an M4 of a new taxon; an M3 of a Kollpaniidae (now regarded as a group of “condylarths”); a probable M1 of an incertae sedis taxon; and as an M1 of a Protodidelphidae. Herein, we present a morphological review of the dental structures of Zeusdelphys complicatus, presenting new interpretations and comparing it with other North and South American taxa. We also perform a phylogenetic analysis in order to test the affinities of Zeusdelphys and the validity of most studied characters. The results recovered Zeusdelphys complicatus as more closely related to Hatcheritherium alpha than to any other metatherian. Glasbiidae were recovered as the sister lineage of Protodidelphidae within Didelphimorphia, as true marsupials. Ectocentrocristus was recovered as the sister taxon of Zeusdelphys + Hatcheritherium, as a Hatcheriformes. The analysis recovered this suborder as an independent lineage from Polydolopimorphia, being more closely related to “Alphadontidae”. The affinities with Protodidelphidae are a result of convergent evolution, as Zeusdelphys is more closely related to Hatcheritherium alpha from the Late Cretaceous of North America. The results support a North American origin for Hatcheriformes. The presence of strong sea-level lowstands and islands in the Caribbean Plate during the Late Cretaceous provide valid data to support a faunal interchange between Americas during the latest Late Cretaceous. Based on the results, Zeusdelphys represents a South American early Eocene surviving Hatcheriformes.

Quaternary mammals from Touro Passo Formation (southern Brazil, Rio Grande do Sul State) were studied in the 1970s and assigned to the Pleistocene/Holocene transition, approximately between 13,000 and 3500 BP. Subsequent dating by thermoluminescence indicated that the sediments of this formation are older, between 42 and 15 ka BP, and ages obtained by AMS in mollusks and 14C of charcoal ranged from 16 to 10 ka BP. However, none of these ages were obtained directly from vertebrates. In this work, four teeth samples of Artiodactyla indet., Gomphoteriidae indet. (2 samples, called G1 and G2) and Toxodon sp., from Ponte Velha I locality, Touro Passo Creek were dated by Electron Spin Resonance (ESR). The results are 34 ± 6 ka for Artiodactyla, 23 ± 5 ka for G1, 28 ± 3 ka for G2 and 19 ± 3 ka for Toxodon sp. The variation in the ages of the materials corroborates the hypothesis that the fossils of Ponte Velha I locality have been reworked. The dating contributes to the chronology of the Brazilian Pleistocene mammals and corroborates the previous interpretations on the timing of deposition of Touro Passo Formation during the late Pleistocene.

A new Ar/Ar date on the Las Flores Tuff (Río Chico Group, Las Flores Fm., central Patagonia, Argentina) yielded an age of 49.512±0.019Ma. This tuff, which stratigraphically overlies the mammal-bearing deposits that produced the Las Flores fauna, helps constrain the age of the Itaboraian SALMA [South American Land Mammal Age] to which that fauna is referred. The new data also have implications for the age of succeeding mammal biochrons, such as the Riochican and "Sapoan" which are revised to being somewhat younger than previously interpreted. Although closer in age than formerly interpreted, they still are biotically distinct. Concomitant evaluations suggest that the Itaboraian SALMA is perhaps more contemporary with the EECO (Early Eocene Climatic Optimum) than previously considered. The Riochican may be interpreted as post-EECO, with its cooler climate consistent in that regard. A recent reconsideration of the chronology of elements of the Salamanca Formation resulted in the downward revision of the ages of the Peligran SALMA and the Carodnia Zone biochrons. These operations, together with our results, reflect a 9 m.y. gap in the late Paleocene and early Eocene land mammal record in South America. Fil: Woodburne, Michael O.. Museum of Northern Arizona; Estados Unidos Fil: Goin, Francisco Javier. 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; Argentina Fil: Raigemborn, María Sol. 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 Fil: Heizler, Matt. New Mexico Geochronological Research Laboratory; Estados Unidos Fil: Gelfo, Javier Nicolás. 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; Argentina Fil: Oliveira, Édison V.. Universidade Federal de Pernambuco; Brasil

Os mamíferos pleistocênicos são encontrados com frequência em toda a região Nordeste do Brasil. Os fósseis em geral ocorrem em tanques, lagoas, terraços fluviais, cavernas e ravinas. No estado de Pernambuco são registradas ocorrências de mamíferos pleistocênicos em 38 municípios. Neste trabalho, foram estudados aspectos taxonômicos e tafonômicos de paleofauna, preservada em lagoas da bacia do riacho Caboclo, tributário do rio São Francisco, em Afrânio, Pernambuco, Brasil. A pesquisa envolveu levantamento bibliográfico, cartográfico, trabalhos de campo e laboratoriais. Mais de 1.250 ossos, dentes e osteodermos foram estudados. A associação fossilífera é monotípica, poliespecífica, com os graus de fragmentação e desgaste variando em quatro classes. Os ossos foram preservados por conservação da composição química original, permineralização e substituição por calcita e por calcita magnesiana. Foi identificada uma diversificada fauna distribuída em cinco ordens (Tardigrada, Cingulata, Notoungulata, Proboscidea e Perissodactyla), sete famílias (Megatheriidae, Mylodontidae, Dasypodidae, Glyptodontidae, Toxodontidae, Gomphotheriidae e Equidae) com os taxa: Eremotherium laurillardi, Mylodonopsis ibseni, Panochthus greslebini, Holmesina paulacoutoi, Hoplophorus euphractus, Stegomastodon waringi, Toxodon platensis, equídeo e gliptodontideo indeterminados. Foram registrados pela primeira vez em Pernambuco os gêneros Hoplophorus e Mylodonopsis. A paleofauna é predominantemente herbívora, de um paleoambiente de savana ou cerrado. Através da datação por Luminescência Opticamente Estimulada (LOE) de sedimentos depositados em camadas acima dos fósseis, estimou-se uma idade mais antiga do que 11.300±2.000 anos para a última fase de ocupação da megafauna na região.