40 research outputs found
Descrição morfológica do crânio e mandíbula de Stratiotosuchus maxhechti (Crocodylomorpha, Cretáceo Superior do Brasil) e seu posicionamento filogenético
A detailed description of the skull and mandible of the crocodylomorph Stratiotosuchus maxhechti Campos, Suarez, Riff & Kellner, 2001 is presented here. This specimen (DGM 1477-R; housed at the Museu de Ciências da Terra, DNPM, Rio de Janeiro) was collected in 1988 at outcrops of the Adamantina Formation (Upper Cretaceous) in the western part of the São Paulo State. The laterally compressed rostrum, the presence of a huge, strongly grooved and flexed jugal, and the presence of only five maxillary theropodomorph teeth supports the allocation of Stratiotosuchus maxhechti to the Baurusuchidae. lt differs from other species of this clade by the marked depression of the posterodorsal surface of the frontals and the inflated lateral edges of the maxillae. Since the skull of Stratiotosuchus maxhechti is the most complete Baurusuchidae known to date, it presents several new cranial data for a member of this group, particularly details of the occipital and palatal region which are described here for the first time. This material also allowed the identification of an individualized parasphenoid, that has never been reported in an adult crocodylornorph before. Several aspects of cranial morphology, like the occipital ornamentation, the Eustachian morphology, and the dentition, supports the general idea that Stratiotosuchus (and perhaps all baurusuchids) have had terrestrial habits.Na década de 1980, foi coletado um esqueleto praticamente completo e articulado de um crocodilomorfo inicialmente relacionado ao gênero Baurusuchus. Este material provém de afloramentos da Formação Adamantina, de idade cretácica, situados no oeste do Estado de São Paulo e foi depositado no Departamento Nacional de Produção Mineral (DNPM) no Rio de Janeiro. Este material foi posteriormente descrito como Stratiotosuchus maxhechti Campos, Suarez, Riff & Kellner, 2001. Neste trabalho, é apresentada uma descrição detalhada do crânio e mandíbula de S. maxhechti após sua preparação completa. A feição alta e comprimida do rostro, a presença de um grande jugal fortemente sulcado e flexionado em sua porção anterior, apenas cinco dentes maxilares teropodomorfos, dentre outras características, reforçam a idéia prévia de este táxon tratar-se de um Baurusuchidae. Este táxon difere dos demais Baurusuchidae pela presença de uma marcada depressão na superfície posterodorsal do frontal e margens laterais das maxilas infladas. Uma vez que o Stratiotosuchus maxhechti é o mais completo Baurusuchidae conhecido atualmente, apresenta várias novas características cranianas para o grupo, particularmente detalhes das regiões occipital e palatal, que são descritas aqui pela primeira vez. Esse material permitiu também a identificação de um parasfenóide individualizado, elemento jamais reconhecido num crocodilomorfo adulto. Esta descrição fornece uma base de dados que será de grande utilidade na elucidação das relações filogenéticas dos Mesoeucrocodylia basais, comunidade esta que compunha uma diversificada fauna no Gondwana (especialmente na América do Sul) durante o Cretáceo. Além disso, vários aspectos da morfologia craniana, como ornamentação occipital, a morfologia do sistema de Eustachio e a dentição indicam que este táxon (e talvez todos os baurusuquídeos) possuíam hábitos terrestres
The austral components of the Neogene South American crocodylian fauna: the northeast Miocene-Pliocene Argentinean record
During the last years the knowledge about derived eusuchian crocodiles has been increased. Anatomical and phylogenetic approaches as well as new fossil records have lighted the evolutive and biogeographic history of several groups. In this way, paleontological research on Miocene-Pliocene South American taxa have provided new information that allowed supporting taxonomical and biogeographical hypotheses, many of them erected since the end of XIX century. The richest and more explored regions concerning Mio-Pliocene crocodylians in South America correspond to basins that surround the areas of Urumaco (Venezuela), La Venta (Colombia), Acre (Brazil), and Paraná (Northeast Argentina). Late Miocene-Pliocene fossils from Paraná were recovered from the "Conglomerado Osífero" (Ituzaingó Formation) and assigned to several taxa of Caimaninae (Alligatoroidea) and one Gavialoidea. Recent research has allowed exploring the taxonomical diversity of this fauna, including a descriptive revision and phylogenetic reanalysis of bizarre forms as Mourasuchus species. The Miocene-Pliocene "fauna" of crocodiles recorded in Northeastern Argentina differs from coeval ones of Northern South America by the absence of sebecids, crocodyloids, some alligatorid genera (as Purussaurus, Melanosuchus, and Paleosuchus), and by the rarity of gavialoid species. Giant forms, conspicuous in the Northern South American deposits, are virtually rare in the southern latitudes. Despite it, the austral South American crocodilian fauna exhibits strong affinities with that from the Northern Mio-Pliocene, sharing taxa at generic and even at specific levels (Gryposuchus neogaeus (Rusconi), Mourasuchus nativus (Gasparini), and Caiman latirostris (Daudin) [= C. cf. lutescens]). Such aquatic forms might indicate partial connections of drainage basins through swampy areas on their boundaries. These fresh water habits would have permitted migration of some of the crocodiles, but would have been an effective barrier for the migration of other taxa (e.g., cryptodirans turtles) as well as preclude the assumption of an intracontinental seaway link, as already proposed by some authors. Nevertheless, the historical factors that determinate the geographic patterns of distribution of crocodyles in South America should de evaluated in a biogeographical context.Simposio VII: Paleontología y
biocronología del Terciario tardío de la
MesopotamiaFacultad de Ciencias Naturales y Muse
Discussões sobre a presença do gênero aeolosaurus powell 1987 (dinosauria, titanosauria) no cretáceo superior do Brasil
The records of Cretaceous Brazilian titanosaurs assigned to the Patagonian genus Aeolosaurus Powell (Dinosauria, Sauropoda, Titanosauria) are discussed. The fragmentary and isolated nature of many of the specimens and the incomplete knowledge of the diversity and phylogenetic relationships of Brazilian titanosaurs generate uncertainty regarding the taxonomic assignments. Revision of the Brazilian specimens attributed to Aeolosaurus suggests that there are no characters indicating the presence of this Patagonian genus in the Late Cretaceous of Brazil. The conclusion that the relationships of these specimens were incorrectly recognized, points out that better taxonomic procedures, using consistent data, such as the presence of well-defined apomorphies, are needed for correct taxonomic designations, paleogeographic and paleobiostratigraphic inferences and the proposal of biochrons.Key words: Titanosauria, Aeolosaurini, Aeolosaurus, Late Cretaceous, Bauru Group, Brazil.O registro de titanossauros no Cretáceo do Brasil, associado ao gênero patagônico Aeolosaurus Powell (Dinosauria, Sauropoda, Titanosauria), é discutido. A natureza fragmentária e isolada de muitos dos materiais estudados e o conhecimento ainda incipiente da real diversidade e das relações filogenéticas dos titanossauros brasileiros tem gerado incertezas nas afinidades taxonômicas propostas. A revisão dos espécimes brasileiros atribuídos a Aeolosaurus sugere que não há caracteres para sustentar a ocorrência deste gênero patagônico no Cretáceo do Brasil. A constatação de que estes materiais isolados e fragmentários foram inadequadamente reconhecidos em suas relações alerta para a necessidade de procedimentos taxonômicos mais adequados. Para tanto, identificações bem fundamentadas, por exemplo, na presença de apomorfias, é indispensável para a correta designação taxonômica, e as consequentes inferências paleobiogeográficas, paleobiostratigráficas e no estabelecimento de biócronos.Palavras-chave: Titanosauria, Aeolosaurini, Aeolosaurus, Cretáceo Superior, Grupo Bauru, Brasil
First description of scleractinian corals from the Santa Marta and Snow Hill Island (Gamma Member) formations, Upper Cretaceous, James Ross Island, Antarctica
Antarctic corals are known from the Upper Cretaceous Santa Marta Formation (Santonian–early Campanian) and Gamma Member (late Campanian) of Snow Hill Island Formation (late Campanian–early Maastrichtian) but they have not so far been taxonomically described. We describe three corals taxa based on 29 specimens collected in 2007 and 2016 on James Ross Island (northeast of the Antarctic Peninsula). They represent the first formal record of scleractinian corals from the Santa Marta Formation, identified as Caryophylliidae indet. and Gamma Member of Snow Hill Island Formation, identified as ?Astreopora sp. and Fungiacyathus deltoidophorus. The family Caryophylliidae and the genus Astreopora were not restricted to the Weddellian Biogeographic Province but the species Fungiacyathus deltoidophorus was endemic to Antarctica during the Cretaceous. The genus Fungiacyathus and the family Caryophylliidae thrive in Antarctica until the present day. Fungiacyathus occurred in shallower environments during the late Campanian than today. No specimens related to Astreopora have yet to be found in Antarctica after the late Campanian. This can be explained by the capacity of Fungiacyathus and Caryophyllidae to endure cold waters, since they are asymbiotic corals. The symbiotic ?Astreopora sp., due to its sensitivity to low temperatures, became extinct in this continent as soon as the Antarctic waters began to cool, around the Campanian/Maastrichtian. The presence of ?Astreopora sp. in Gamma Member of Snow Hill Island Formation may represents the first occurrence of this genus in Antarctica and the oldest record of this genus in the Southern Hemisphere
Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine
[This corrects the article DOI: 10.1186/s13054-016-1208-6.]
Late Miocene crocodylians from northeast Argentina: New approaches about the austral components of the Neogene South American crocodylian fauna
The richest and more explored regions concerning Miocene crocodylians in South America are the basins surrounding the areas of Urumaco (Venezuela), La Venta (Colombia), Acre (Northwest Brazil) and Paraná (Northeast Argentina). Fossils from the late Miocene in the Paraná area were recovered from the Conglomerado Osífero (Ituzaingó Formation) and assigned to several taxa of Caimaninae (Alligatoroidea) and to a taxon of Gavialoidea. The late Miocene fauna of crocodylians recorded in northeast Argentina differs from coeval ones of northern South America by the absence of crocodyloids, some alligatorid genera (such as Purussaurus, Melanosuchus, and Paleosuchus) and by the scarce gavialoid species. Giant forms, conspicuous in the northern South American deposits, are also absent in southern latitudes. Despite this, the austral South American crocodylian fauna exhibits strong affinities with the northern, contemporary forms, sharing taxa at generic (i.e. Caiman and Gryposuchus) and even specific levels (i.e. Mourasuchus nativus). The sharing of such freshwater taxa in the Miocene indicates partial connections of drainage basins through swamp areas on their boundaries, and is evidence against the assumption of an intracontinental coeval seaway link in this continent proposed by several authors.Fil: Bona, Paula. 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: Riff Goncalves, Douglas. Universidade Federal de Uberlândia; BrasilFil: Brandoni, Zulma Nelida. 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 new Mourasuchus (Alligatoroidea, Caimaninae) from the late Miocene of Venezuela, the phylogeny of Caimaninae and considerations on the feeding habits of Mourasuchus
Mourasuchus (Alligatoroidea, Caimaninae) is one of the most peculiar crocodyliforms due to the skull morphology consisting of a long, wide, dorsoventrally flat rostrum with long, slender mandibular rami. Despite these peculiarities, the systematics, phylogeny and feeding habits of this taxon have not been properly studied. In this paper, we describe a new species of the genus, Mourasuchus pattersoni sp. nov., from the late Miocene of the Urumaco Formation of Venezuela. The new species differs from the other Mourasuchus species in having a lateromedially wide, dorsoventrally high jugal bone and a circular incisive foramen, which both represent autapomorphies of the new taxon. Phylogenetically, M. pattersoni sp. nov. is more closely related to M. amazonensis and the specimen UFAC-1424 (formely attributed to M. nativus) than to M. arendsi or M. atopus, whilst Mourasuchus is recovered once more as a monophyletic group. Furthermore, the cladistic analysis performed in this contribution offers a new phylogenetic assessment of Caimaninae, including many taxa described recently for the group. In this study, we also discuss the crocodylian diversity of the Urumaco Formation as well as how paleoenvironment may have contributed toward its evolution. In addition, we provide a discussion of the potential feeding habits of Mourasuchus. In this contribution, Mourasuchus is regarded as a taxon that likely preferred to prey on small animals. The unusual skull morphology of this group may have evolved to cover a large area with the rostrum, allowing for a more efficient prey capture, while the prey may have consisted predominantly of large amounts of small animals
Revisiting Gryposuchus jessei Gürich, 1912 (Crocodylia: Gavialoidea): specimen description and comments on the genus
Souza, Rafael Gomes De, Riff, Douglas, De Souza-Filho, Jonas P., Kellner, Alexander W. A. (2018): Revisiting Gryposuchus jessei Gürich, 1912 (Crocodylia: Gavialoidea): specimen description and comments on the genus. Zootaxa 4457 (1): 167-178, DOI: 10.11646/zootaxa.4457.1.
New lower jaw and teeth referred to Maxakalisaurus topai (Titanosauria: Aeolosaurini) and their implications for the phylogeny of titanosaurid sauropods
Sauropod dinosaurs compose a diversified, well known, and worldwide distributed clade, with a stereotyped body plan: deep trunk, elongated neck and tail, columnar limbs and very small skull. In Brazil, the group is represented by ten formally described Cretaceous species, mostly titanosaurs. This is the case of Maxakalisaurus topai, known based on an incomplete and disarticulated skeleton, unearthed from deposits of the Adamantina Formation in Minas Gerais. Here, we report a partial right dentary, including five isolated teeth, collected from the same site as the type-series of M. topai and tentatively referred to that taxon. The bone is gently curved medially, the functional teeth are set on an anterolingual position, and two replacement teeth are seen per alveoli. New morphological data gathered from that specimen was employed to conduct a comprehensive phylogenetic analysis of Titanosauria (with 42 taxa and 253 characters), based on previous studies. The Aeolosaurini clade was recovered, with Gondwanatitan and Aelosaurus as sister taxa, and Maxakalisaurus, Panamericansaurus, and Rinconsaurus forming a basal polytomy