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Proboscideans are megamammals widely recorded in South America Quaternary deposits, especially in Brazil, where many specimens were found in tanks and caves. In tank deposits, the fossil remains are usually recognized as adult individuals, although highly and usually fragmented. The records of immature proboscideans are rare, consisting of isolated teeth and jaw fragments, especially from tank deposits. Here we describe a new and rare occurrence of an immature proboscidean — a second upper left deciduous premolar (DP2) of Notiomastodon cf. platensis — from Pernambuco state, Brazil. This record increases the number of immature individuals known for Notiomastodon in Brazil, contributes to the understanding of the frequency of immature individuals in tank deposits, and increases Notiomastodon geographic distribution in South America. Keywords: South America, Quaternary, Notiomastodon platensis, immature, tank deposit.

The Pediomyiodea has been largely regarded as a Late Cretaceous North American metatherian lineage; however, some studies have suggested that a few South American taxa could be related to this family. Herein, Austropediomys marshalli gen. et sp. nov. from the Itaborai Basin, Brazil (lower Eocene – Itaboraian SALMA), is described. Austropediomys gen. nov. represents the first report of a pediomyoid metatherian in the Paleogene of South America backed by a phylogenetic analysis. Several derived features in the upper molars support its belonging to the Pediomyoidea: presence of accessory ‘conular-like’ structures (here named conuloids) lingual to the conules; supernumerary stylar cusps; asymmetric stylar shelf, with parastylar shelf reduced to a narrow rim in M1; straight centrocrista; short and obliquely oriented prepacrista, which contacts StA in M2–3. The presence of ‘conular-like’ structures lingual to the paraconule and metaconule is identified in Austropediomys gen. nov. and in Late Cretaceous pediomyoids as well, and results in the phylogenetic analysis as a synapomorphy of the Pediomyoidea. Austropediomys gen. nov. is autapomorphyc in the presence of enlarged conuloids on protocristae. The record of a pediomyoid in the Paleogene of South America increases the temporal and biogeographical range of this lineage. Also, our results support the hypothesis that several non-related metatherian lineages dispersed from North to South America via the Caribbean Plate, most probably during the latest Cretaceous, in an island-hopping or sweepstakes model.

In Brazil, Glyptotherium findings occur mainly in the Northeastern region. In the northeast, Brazilian Intertropical Region (BIR), there are records of Glyptotherium of the Upper Pleistocene, mainly in the State of Pernambuco. This work reports new findings of Glyptotherium in a tank deposit from the Upper Pleistocene of Pernambuco, corresponding to isolated osteoderms and an astragalus which approaches in detail to North American forms. This record expands both the distribution of Glyptotherium to the BIR, and the data regarding the paleobiogeographic relations among the faunas of megamammals of the North of South America, Central America, and the South of North America during the Late Pleistocene.

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.

Intertropical Pleistocene taxa of dasypodids and pampatheriids are reported for the Lagoon-Barrier III System (Arroio Chui locality) and for the Touro Passo Formation (Ponte Velha I locality), both from Rio Grande do Sul State, southern Brazil. The record of pampatheriids includes new specimens that confirm the presence of Pampatherium humboldti in the Arroio Chui assemblage. Material previously assigned to Holmesina majus is identified as H. paulacoutoi. The record of dasypodids includes a large-sized specimen of the genus Dasypus, represented by an isolated pelvic buckler osteoderm, closely related to Dasypus (Hyperoambon) kappleri, and of Propraopus sulcatus, represented by isolated moveable and fixed osteoderms. This southernmost Brazilian record of P. sulcatus extends their distribution by about 2200 km from Lagoa Santa (Minas Gerais State, Brazil). The first record of P. sulcatus also includes specimens previously referred to as Propraopus cf. grandis from the Touro Passo Formation. Propraopus sulcatus differs from P. punctatus and P. grandis in having: osteoderms with wrinkled external surface, with wide and relatively deep sulci; principal figure plane, ranging from subcircular to hexagonal in fixed osteoderms; and moveable osteoderms with principal sulci forming a lageniform figure, and with four to five larger foramina distributed on the posterior half of these sulci. The late Pleistocene mammals of the coastal province and western Rio Grande do Sul were previously considered closely related to those of the Pampean region of Argentina. However, the presence of intertropical mammals in southern Brazil (Arroio Chui locality and Touro Passo Formation) mixed with Pampean representatives, corroborates the proposal of a close paleobiogeographic relation with assemblages of northern Uruguay and Argentine Mesopotamia.

We describe a new metatherian of the genus Gaylordia Paula Couto, from the early Eocene Itaboraí Basin, Brazil. This new species (estimated body mass ~60-90.9 g) is based on lower and upper dentition elements and is characterized by a more plesiomorphic dental morphology with respect to G. macrocynodonta Paula Couto (with a larger body mass, estimated in ~74-103 g for large individuals or males). The species G. doelloi Marshall, represented by small individuals or females, is regarded a junior synonym of G. macrocynodonta. A phylogenetic analysis as well as details of the occlusal surface of its upper and lower molars suggests that Gaylordia is closely related to the Pucadelphyidae, a non-marsupial “ameridelphian” group previously recorded at the early Paleocene locality of Tiupampa, Bolivia., Descreve-se um novo marsupial basal do gênero Gaylordia Paula Couto, do Eoceno inicial da bacia de Itaboraí, Brasil. Esta nova espécie (massa corporal estimada ~60-90.9 g) está baseada na dentição superior e inferior, e é caracterizada por uma morfologia dentária mais plesiomórfi ca em relação a G. macrocynodonta Paula Couto (cuja maior massa corporal é estimada em ~74-103 g para grandes indivíduos ou machos). A espécie G. doelloi Marshall, representada por indíviduos pequenos ou fêmeas, é considerada um sinônimo junior de G. macrocynodonta. Uma análise fi logenética, bem como detalhes da superfície oclusal de seus molares superiores e inferiores sugerem uma relação próxima de Gaylordia aos Pucadelphyidae, um grupo de ameridélfi os não marsupiais previamente registrados no Paleoceno inicial da localidade de Tiupampa, Bolivia., Facultad de Ciencias Naturales y Museo