Seccao de Paleontologia

Porto Alegre, Brazil

Seccao de Paleontologia

Porto Alegre, Brazil
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Ferigolo J.,Seccao de Paleontologia | Ribeiro A.M.,Seccao de Paleontologia | Velozo P.,Seccao de Paleontologia
Comptes Rendus - Palevol | Year: 2015

The Sanga do Cabral Formation of southern Brazil has a rich fossil tetrapod assemblage and is suggested to have an Early Triassic age mainly based on the presence of the parareptile Procolophon trigoniceps. However, a Permo-Triassic age can be also suggested for this unit taking into account the presence of putative Permian taxa and some previous stratigraphic assessments. We describe here several large vertebrae from the Sanga do Cabral Formation that display a distinctive morphology that includes the presence of a transverse distance across postzygapophyses more than twice the transverse width of the centrum, and accessory articulation structures in the neural arch that remind the hyposphene and hypantrum present in some basal parareptiles and diadectomorphs. Vertebrae with a similar large size and morphology had been previously reported from the same locality as belonging to the genus Procolophon based on their parareptile appearance (mainly the presence of a swollen neural arch) and the fact that the vertebrae were collected at the same locality where a large fragmentary skull assigned to this taxon was found. However, these vertebrae lack a comparable consistent morphology with those of Procolophon and basic statistical analyses demonstrate that these vertebrae are significantly larger than those expected in the largest known Procolophon skulls of South Africa. The morphology of these vertebra is consistent with that present in seymouriamorphs, pareiasaurs and diadectomorphs, but the absence of exclusive diagnostic characters precludes an assure assignation to either of these taxa. According to their current stratigraphic range, seymouriamorphs are the most plausible postulation, as their younger representatives are known from Late Permian deposits of Russia, but the other candidates cannot be excluded. The presence of any representative of those groups in the Sanga do Cabral Formation would be important because: (1) they would represent the first and only known record of seymouriamorphs or diadectomorphs in Gondwana, regarding the characters that the described vertebrae share with these groups; (2) they would suggest a survivorship for pareisaurs up to the Latest Permian or through the Permian-Triassic boundary, according to geochronological data currently available for this unit; (3) they might also suggest a Late Permian age for at least part of the Sanga do Cabral Formation if the intraformational conglomerates that yielded the vertebrae resulted from the rejuvenation of older levels of the same unit, and they do not include reworking of stratigraphically older strata. © 2015 Académie des sciences.

Ferigolo J.,Seccao de Paleontologia | Meneghel M.,Institute Ecologia y Ciencias Ambientales | Laurin M.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments
Historical Biology | Year: 2012

The earliest undisputed crown-group amniotes date back to the Late Carboniferous, but the fossil record of amniotic eggs and embryos is very sparse, with the oldest described examples being from the Triassic. Here, we report exceptional, well-preserved amniotic mesosaur embryos from the Early Permian of Uruguay and Brazil. These embryos provide the earliest direct evidence of reproductive biology in Paleozoic amniotes. The absence of a recognisable eggshell and the occurrence of a partially articulated, but well-preserved embryo within an adult individual suggest that mesosaurs were viviparous or that they laid eggs in advanced stages of development. Our finds represent the only known documentation of amniotic embryos in the Paleozoic and the earliest known case of viviparity, thus extending the record of these reproductive strategies by 90 and 60 Ma, respectively. © 2012 Copyright Taylor and Francis Group, LLC.

Ferigolo J.,Seccao de Paleontologia | Laurin M.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments
Comptes Rendus - Palevol | Year: 2012

The Early Permian mesosaurids are the oldest known aquatic amniotes with an exclusively Gondwanan distribution. Although several hundred of complete skeletons have been discovered and intensively studied, the anatomy and taxonomic composition of the group, as well as its phylogenetic relationships remain controversial. Several well-preserved mesosaurid specimens found in Uruguay justify a new anatomical reconstruction of the skull of Mesosaurus tenuidens, differing from earlier ones especially in the presence of a lower temporal fenestra. The significance of this structure for the evolution of temporal fenestration in amniotes is evaluated according to the two most recent phylogenetic hypotheses, in which mesosaurids are basalmost sauropsids or basalmost parareptiles. A synapsid-like fenestration may be the primitive condition for Amniota, and it may be also a basal condition for parareptiles, because recent phylogenies suggest a basal position for mesosaurids and lanthanosuchoids within that group, and both possess a lower temporal fenestra. Our results also give a moderately strengthened support for diapsid affinities of turtles. © 2012 Académie des sciences.

Hadler P.,University of Pernambuco | Ferigolo J.,Seccao de Paleontologia | Ribeiro A.M.,Seccao de Paleontologia
Acta Chiropterologica | Year: 2010

The Chiroptera do not have an extensive fossil record. To date, for the Quaternary of Brazil, only material from Minas Gerais, So Paulo, Bahia and Gois States are known. For Rio Grande do Sul State, in contrast to the studies about the Pleistocene megafauna, little is known about Holocene small mammals, this being the first contribution about the Chiroptera of this age found in Rio Grande do Sul. The material was excavated from two archaeological sites, dating from ± 9,400 yrs BP to ± 4,250 yrs BP. The taxa recorded were: Chrotopterus auritus, Pygoderma bilabiatum (Phyllostomidae); Eptesicus brasiliensis, E. fuscus, Myotis cf. Myotis ruber, Vespertilionidae aff. Lasiurus (Vespertilionidae); Tadarida brasiliensis, and Molossus molossus (Molossidae). The presence of E. fuscus extends its Holocene distribution far southwards into the south temperate zone; its previous Quaternary occurrences were in Bahia State, Brazil, as well as in Venezuela, Mexico and the USA. © Museum and Institute of Zoology PAS.

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