Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher

Zapala, Argentina

Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher

Zapala, Argentina
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Filippi L.S.,Museo Municipal Argentino Urquiza | Mendez A.H.,CONICET | Gianechini F.A.,National University of San Luis | Juarez Valieri R.D.,Secretaria de Cultura de la Provincia de Rio Negro | Garrido A.C.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher
Cretaceous Research | Year: 2017

The complete osteology of the abelisaurid Viavenator exxoni, from the Bajo de la Carpa Formation (Santonian, Upper Cretaceous) is described. Viavenator is characterized by a series of autapomorphies, including: transversely compressed parietal depressions on both sides of the supraoccipital crest; ventral edges of the paraoccipital processes located above the level of the dorsal edge of the occipital condyle; basioccipital-opisthotic complex about two and a half times the width and almost twice the height of the occipital condyle, in posterior view; well-developed crest below the occipital condyle, diverging ventrally and defining the subcondylar recess; deeply excavated and sub-circular basisphenoidal recess, with its major axis transversely oriented; basipterygoid processes horizontally placed with respect to the cranial roof and located slightly dorsally to the basal tubera; mid and posterior cervical centra with slightly convex lateral and ventral surfaces; hyposphene-hypanthrum articular complex present from dorsal 2 onward; presence of an interspinous accessory articular system in middle and posterior dorsal vertebrae; presence of a pair of pneumatic foramina within the prespinal fossa in anterior caudal vertebrae; distal end of the scapular blade posteriorly curved. Particularly, Viavenator shows plesiomorphic cranial characters, i.e. flat frontals lacking domes or horns, combined with derived postcranial characters, e.g. the interspinous accessory joint system of dorsal vertebrae. This combination between plesiomorphic and derived traits suggests that Viavenator is a transitional form, which is an idea supported by its intermediate stratigraphic and phylogenetic placement between the basal and older (e.g. Skorpiovenator, Ilokelesia) and derived and younger members of the clade (e.g. Aucasaurus, Carnotaurus). © 2017 Elsevier Ltd.

Marynowski L.,University of Silesia | Scott A.C.,Royal Holloway, University of London | Zaton M.,University of Silesia | Parent H.,National University of Rosario | Garrido A.C.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2011

Wildfires play a crucial role in recent and ancient ecosystem modeling but their detailed history on the Earth is still not well recorded or understood. The co-occurrence of charcoal and pyrolytic polycyclic aromatic hydrocarbons (PAHs) is used for the recognition of wildfires in geological record that may have implications for the analysis of the terrestrial environment, ecosystems, climate and the level of atmospheric oxygen. Here we present the first multi-proxy evidence of wildfires on the Gondwana continent during the Jurassic, based on the occurrence of charcoal and pyrolytic PAHs in the Middle Jurassic of the Neuquén Basin, Argentina. This is the first evidence of wildfire in the Aalenian, the lowest stage of the Middle Jurassic, and one of the few records of wildfires in the Bathonian. Temperature interpretations, derived from charcoal reflectance data, show that charcoals formed in low temperature surface fires that only sporadically reached the higher temperatures, possibly related to crown fires. The occurrence of charcoals in the Middle Jurassic deposits confirms recent results that the atmospheric oxygen level reached at least 15% during the Middle Jurassic times. © 2010 Elsevier B.V.

Filippi L.S.,Museo Municipal Argentino Urquiza | Canudo J.I.,University of Zaragoza | Salgado J.L.,National University of Comahue | Garrido A.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher | And 3 more authors.
Geologica Acta | Year: 2011

This paper presents a new titanosaur sauropod, collected from levels of reddish clays assigned to the Plottier Formation (Coniacian-Santonian). The holotype of Petrobrasaurus puestohernandezi gen. et. sp. nov. is a disarticulated specimen, from which teeth, cervical, dorsal and caudal vertebrae, sternal plates, metacarpals, femora, tibia, a fragment of ilium, pubis, haemal arches, and cervical and dorsal ribs have been preserved. This period is of particular interest because it saw the definitive isolation of the vertebrate faunas of Patagonia, with the separation of South America from the rest of Gondwana, a process that had begun during the Early Cretaceous. Although some of the characters observed in Petrobrasaurus gen. nov. suggest a relationship with the South American clade Lognkosauria, this new sauropod is regarded as Titanosauria incertae sedis until a more profound analysis of the Titanosauria that in which it is included is undertaken.

Salgado L.,National University of Comahue | Canudo J.I.,University of Zaragoza | Garrido A.C.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher | Carballido J.L.,CONICET
Journal of Vertebrate Paleontology | Year: 2012

For the first time an association of adult and juvenile rebbachisaurid sauropods is described. The material comes from the Early Cretaceous locality of Agrio del Medio (Neuquén, Argentina). The three specimens apparently formed a single group, and their death seems to have been almost simultaneous. The two juvenile specimens are represented by axial and appendicular bones. They show a close relationship with Zapalasaurus bonapartei, which comes from a different sector of the same basin, but which is approximately the same age. The discovery at Agrio del Medio suggests that rebbachisaurid sauropods displayed gregarious behavior. The paleoenvironments in which rebbachisaurids are normally recorded implies a greater tolerance toward extremely arid environments than that shown by macronarian sauropods. © 2012 Copyright Taylor and Francis Group, LLC.

Garrido A.C.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher | Garrido A.C.,National University of Comahue | Salgado L.,National University of Rio Negro
Journal of South American Earth Sciences | Year: 2015

The Puesto Díaz Quarry (Lohan Cura Formation, Lower Cretaceous of Neuquén Basin, Argentina) consists of a monospecific dinosaur bone assemblage that includes 126 specimens from, at least, three individuals of the rebbachisaurid sauropod Comahuesaurus windhauseni. The bonebed was originated as a debris flow of an ephemeral-river bed, in distal areas of low relief. Bones are disarticulated, three-dimensionally distributed through the host facies, showing a normal grading arrangement, which can be correlated with the size, shape and hydraulic behavior inferred for each specimen. Taphonomic evidence suggests that the bones did not experience a prolonged transport, and that these were quickly buried by the debris flow event. The fact that there are more than one individual of the same species suggests a mass mortality by a catastrophic event. Scattered skeletal elements would indicate that the corpses must have been subaerially exposed, long enough to allow disarticulation by scavenging, decay, and defleshing. © 2015 Elsevier Ltd.

Filippi L.S.,Museo Municipal Argentino Urquiza | Cerda I.A.,National University of Comahue | Garrido A.C.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher
Ameghiniana | Year: 2013

Osteoderms of a new crocodyliform specimen recovered from the Puesto Hernández locality are described here, found in sediments of the Plottier Formation (late Coniacian), near Rincón de los Sauces city, Neuquén Province. The studied osteoderms, that are part of the associated material, include: dorso-sacral region, appendicular osteoderms associated to the right femur, proximoventral region of articulated caudal osteoderms, and isolated osteoderms. The histology of the osteoderms allowed determining they have a compact cortex that surrounds a more cancellous internal region. It was possible to recognize growth marks (annuli) in the entire compact tissue, indicating a minimum age of 18 years for the studied specimen. The osteoderms have characters that allow preliminarily assigning the specimen MAU-Pv-PH-437 to Mesoeucrocodylia closely related to Peirosauridae.

Parent H.,National University of Rosario | Garrido A.C.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher | Schweigert G.,Staatliches Museum fur Naturkunde | Scherzinger A.,Lammerhalde 3
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen | Year: 2013

The stratigraphy and the ammonite fauna of the Vaca Muerta and Picun Leufu formations outcropping along the transect Portada Covunco-Cerrito Caracoles (south-central Neuquen Basin) were studied by means of two representative sections. The detailed study of the lithological succession of the two sections has allowed to complete the formal subdivision of the Vaca Muerta Formation by the introduction of two new members: the Portada Covunco Member (nov.) at the base, and the Pichi Moncol Member (nov.) at the top; the middle part of the formation is currently known as the Los Catutos Member. The ammonite fauna is mainly composed by species already recorded in other localities of the basin. There are six new species, but they remain to be formally described based on better and more abundant material: Choicensisphinctes cf./aff. platyconus, Catutosphinctes aff. rafaeli, Catutosphinctes n. spp. A & B, Steueria aff. alternans, and Sutneria n. sp. A. The lowermost Tithonian (lower Picunleufuense Zone) is well represented in the section P. Covunco by the guide assemblage (Lithacoceras picunleufuense, Choicensisphinctes platyconus and Catutosphinctes guenenakenensis) at the base of the P. Covunco Mb. The Zitteli Zone (which seems to overlap the Mendozanus Zone) and the Proximus Zone occur in the middle and upper parts of the P. Covunco Mb, as recongnized by their characteristic ammonite assemblages. The upper part of the Middle Tithonian, the Internispinosum Zone, corresponds to the Los Catutos Mb and, apparently, the upper part of the Vaca Muerta Fm (Pichi Moncol Mb), although it is fossiliferous only in its lower part. The lower Upper Tithonian Alternans Zone is well documented by ammonites, whereas the upper Upper Tithonian yielded only scarce fossils which could even represent the lower Berriasian Noduliferum Zone. © 2013 E. Schweizerbart'Sche Verlagsbuchhandlung, Stuttgart, Germany.

Parent H.,National University of Rosario | Garrido A.C.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher | Schweigert G.,Staatliches Museum fur Naturkunde | Scherzinger A.,Lammerhalde 3
Revue de Paleobiologie | Year: 2011

A Tithonian section of the Vaca Muerta Formation (362 m in thickness) in Picún Leufú (southern Neuquén Basin, Argentina) was measured and sampled for ammonites. There were recognized seven different lithofacies which represent at least five different episodes of sedimentation. The ammonite fauna is dominated by perisphinctids belonging to three genera of the Ataxioceratidae. The classification proposed for the Andean lower-middle Tithonian Ataxioceratidae includes three genera: two phyletic lineages, Choicensisphinctes Leanza (Lithacoceratinae) and Catutosphinctes Leanza & Zeiss (Torquatisphinctinae), and "Lithacoceras" Hyatt represented by apparently two species in the lower Tithonian. Each one of these three genera is rather well characterized by its different ontogeny of sculpture, shell shape and coiling and, moreover, their sexual dimorphism is different, especially by the morphology of the microconchs. Both phyletic lineages include several Andean ammonites described in the literature as unrelated species but showing progressive differentiation with independent evolutionary trends. The ammonite fauna includes accessory elements (in terms of abundance) which belong to the following genera: Physodoceras (macro- and microconchs, Sutneria), Pseudolissoceras, Cieneguiticeras and Pasottia. The Picunleufuense (Standard Chronostratigraphic) Zone for the Andean Tithonian is introduced, including two horizons: the picunleufuense ? horizon (standard base of the Picunleufuense Zone) and the picunleufuense ? horizon. Upper in the section, within the biozone, or biostratigraphic range, of Pseudolissoceras zitteli, is introduced the perlaevis horizon.

The clade Aeolosaurini is represented by several specimens found, so far, only in Argentina and Brazil. The material reported here corresponds to a sauropod titanosaur consisting of four incomplete anterior caudal vertebrae, from the Narambuena Paleontological Site, Rincón de los Sauces, Neuquén Province, Argentina. The specimen comes from the Plottier Formation (late Coniacian-lower Santonian, Upper Cretaceous), Neuquén Group. The specimen has a combination of features that includes it into the clade Aeolosaurini: anterior caudal centra with anterodorsal margin bent forward; prezygapophyses elongated in anterior caudal, in correlation with the extreme displacement of the neural arch forward; and anteroposteriorly elongated articular facets of prezygapophyses, at least in the anterior caudals. However, it differs from other Aeolosaurini by having postzygapophysis with anteroposteriorly short articular facets, not as elongated in the prezygapophyses. This specimen corresponds not only to the first discovery of an Aeolosaurini in the north of the Neuquén Basin (because Rinconsaurus caudamirus Calvo & Gonzalez Riga has been included in another clade, Rinconsauria), but also the oldest record of the group. © 2013 by the Sociedade Brasileira de Paleontologia.

Parent H.,National University of Rosario | Garrido A.C.,Museo Provincial de Ciencias Naturales Prof. Dr. Juan Olsacher
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen | Year: 2015

A well exposed section of the La Manga Formation in the locality Vega de la Veranada (north of the Neuquén Province, Argentina), sampled bed-by-bed, has provided a diverse ammonite fauna. This fauna indicates an age range comprising the Lamberti to Cordatum zones, older than concluded in previous studies by different authors. There have been identified 20 species belonging to 14 genera (Hecticoceras, Choffatia, Collotia, Rehmannia, Araucanites, Euaspidoceras, "Perisphinctes", Vinalesphinctes, Peltoceratoides, Neoprionoceras, Lissoceratoides, Veranadaites n. gen., Subvinalesphinctes, and Cubasphinctes). It is introduced Veranadaites n. gen. (Type species: Veranadaites palmicostatus n. gen. et n. sp.) for small Early Oxfordian sphaeroceratids closely related to the Late Callovian-Early Oxfordian Araucanites. Choffatia schilleri n. sp. (Upper Callovian), as part of the guide assemblage, is taken as the index of the schilleri Horizon (new). Peltoceratoides pressulus leanza (Lower Oxfordian), as part of the guide assemblage, is taken as the index species of the pressulus Horizon (new). A chronostratigraphic zonation for the Callovian-Oxfordian interval in the Andean Neuquén and Tarapacá basins is proposed based on the two existing quasi-independent scales. After revision of the age of the guide ammonites, the Primus, Dimorphosus, and Eugenii zones are inserted between the Patagoniensis and Pressulus zones. The Pressulus Zone is standardized by designation of the pressulus Horizon as its base. © 2015 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.

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