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Porto Alegre, Brazil

Hsiou A.S.,Secao de Paleontologia | Albino A.M.,University of the Sea
Alcheringa | Year: 2011

We describe an incomplete trunk vertebra of a snake attributable to the Viperidae, collected from a conglomerate facies in upper Pleistocene sediments at the Mississippi locality, Upper Juruá River, southwestern Brazilian Amazonia. It represents the first fossil snake record from the Pleistocene of this region. This specimen extends the fossil distribution of the Viperidae, representing the northernmost record of a snake in the Brazilian Pleistocene. © 2011 Association of Australasian Palaeontologists.

Hsiou A.S.,Secao de Paleontologia | Albino A.M.,CONICET
Herpetological Journal | Year: 2010

We report new snake vertebral remains originating from the late Miocene of south western Brazilian Amazonia (Solimões Formation) and the middle-late Miocene of Venezuela (Socorro and Urumaco Formations). The Brazilian material was attributed to Boidae (aff. Epicrates sp. and Waincophis sp.) and to two probably undetermined "Colubridae". The new snake vertebrae from Venezuela are referred to the extant boid Eunectes sp. Known specimens from the middle Miocene of Venezuela (Socorro Formation) are re-evaluated as cf. Eunectes. Until now, South American late Miocene squamate records have been reported only from Argentina and Venezuela. We present the first record in the Neogene of Brazil, considerably increasing our knowledge of the South American herpetofauna.

The genus Cavia includes four species for Brazil, C. aperea (at least two subspecies, C. a. aperea and C. a. pamparum), C. magna, C. intermedia and C. fulgida. Aiming to contribute to the anatomy and to distinction of these species the syncranium (skull and mandible) of C. a. pamparum from Rio Grande do Sul State is described and compared with C. magna from Rio Grande do Sul and Santa Catarina States, C. intermedia from Moleques do Sul island on Santa Catarina's coast, and C. fulgida from Minas Gerais and Paraná States. Cavia aperea skull is lower and longer, with laterally compressed rostrum; marked interorbital constriction; elliptical orbit with broad communication with temporal fossa; broad and depressed infraorbital foramen; longer and lower mandible, with angular process not reflected laterally; dental formula 1I.0C.1P.3M; hypselodont teeth; molariforms formed for two prisms, the anterior laminar and the posterior cordiform. Cavia aperea distinguishes from C. magna by a less developed rostrum and ventral root of zygomatic process of maxilla; infraorbital foramen more depressed; posterior portion of dorsal surface of frontals and parietals less convex laterolaterally; paraoccipital apophysis shorter and more bent anteriorly; superior incisors narrower and generally opistodonts (proodonts in C. magna); external tertiary notch (fte) deeper with a thicker cement; anterior prolongation to fte more developed; and a constriction at the bottom of posterior prolongation. Cavia intermedia is distinguished by a shorter jugal; reduced/absent jugal fossa; more prominent depression in the interorbital region; larger sagittal crest; less marked lateral constriction in basisphenoid; wider magnum foramen; lower supraoccipital; fte less marked and its anterior prolongation little developed; the anterior prism of p4 as large as the posterior; anterior prism of m3 larger than posterior; shallow internal secondary notch in m3. Cavia fulgida differentiates by the smaller dimensions and a deeper fte. However southern Brazil specimens with these characters, but not typical coloration of C. fulgida, should belong to C. aperea. More studies are needed to clarify this issue.

Lopes R.P.,Federal University of Rio Grande do Sul | Ferigolo J.,Secao de Paleontologia
Revista Brasileira de Paleontologia | Year: 2015

Here are described post mortem modifications (pseudopaleopathologies) in 762 specimens of extinct mammals from three middle to late Pleistocene assemblages (Campanha, Chuí Creek and continental shelf) of the state of Rio Grande do Sul, southern Brazil. These assemblages include mostly large-sized herbivores preserved in fluvial facies, although the assemblage from the shelf consist of remains that were reworked several times by sea-level oscillations. Although some patterns of modification are similar between the assemblages (e.g. post-fossilization plain fractures), others such as the grade of abrasion or weathering varies according to the depositional setting. The scarcity of modifications that could be attributed to predators or scavengers indicate that carnivory was not a major process driving the formation of the assemblages. Most of the fossils from the Campanha are complete, but a relatively high proportion of them exhibits advanced stage of weathering, whereas those from Chuí Creek and the continental shelf are mostly unweathered. Most of the remains from the Campanha and Chuí Creek are unabraded, whereas all fossils from the shelf were subject to abrasion. Few fossils exhibit signs of modification by organisms such as plants and insects. Fossils from the continental shelf have crusts of beach rock, and some specimens from the Campanha and Chuí Creek have crusts of calcium carbonate or iron oxide. Besides the abrasion, the main difference between fossils from the continental and marine assemblages is the dark color and higher mechanical resistance of the latter. This difference is related to post depositional geochemical processes in the marine environment. The chemical composition of fossils from Chuí Creek and continental shelf was qualitatively analyzed using energy dispersive X-ray spectrometry (EDX) and compared with recent bones. The results show the presence in the fossils of several elements not found in recent bones, incorporated through diagenetic processes controlled by specific conditions of each depositional environment. © 2015 by the Sociedade Brasileira de Paleontologia.

Holanda E.C.,Federal University of Rio Grande do Sul | Ferigolo J.,Secao de Paleontologia | Ribeiro A.M.,Secao de Paleontologia
Journal of Mammalogy | Year: 2011

A new species of Tapirus (Perissodactyla: Tapiridae) is described from the upper Pleistocene of the Rio Madeira Formation in Araras, Nova Mamoré Municipality, Rondonia State, Brazil. Tapirus rondoniensis sp. nov. is represented by a nearly complete skull with a unique combination of characters that differ from those of extant and fossil species of Tapirus described from South America. It is diagnosed mainly by its broad frontals that bear a pneumatization extending to the frontoparietal suture, a high sagittal crest, a weakly molarized P2 lacking a protoloph, and a metaloph that merely reaches the base of the ectoloph. T. rondoniensis sp. nov. is similar in some respects to T. terrestris, but it retains some primitive dental and cranial character states in common with T. pinchaque, such as broad frontals and a weakly molarized P2. © 2011 American Society of Mammalogists.

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