The first fossil avian egg from Brazil

Marsola, J.C.A., Grellet-Tinner, G., Montefeltro, F.C., Sayão, J.M., Hsiou, A.S. & Langer, M.C., 2014. The first fossil avian egg from Brazil. Alcheringa 38, 563–567. ISSN 0311-5518.

In contrast to the rich record of eggs from non-avian dinosaurs, complete eggs attributable to Mesozoic birds are relatively scarce. Nevertheless, several well-preserved specimens have been discovered over the last three decades revealing functional and phylogenetic characters that shed light on the breeding strategies of extinct birds. Here we report the first fossil avian egg from Brazil, which was discovered in Upper Cretaceous strata of São Paulo in the southeastern part of the country. The taxonomic identity and structural features of the biomineralized tissues were determined using a combination of Scanning Electron Microscopy, Wave Dispersion Energy analyses and Computed Tomography. These show that the 125.5-μm-thick shell of the 31.4?×?19.5?mm egg incorporates three structural layers of similar thickness with both prismatic and aprismatic boundaries. Close similarity between the Brazilian bird egg and those of enantiornithines from the Upper Cretaceous Bajo de la Carpa Formation (Río Colorado Subgroup) of Argentina advocates affinity with basal Ornithothoraces. Furthermore, coherency of their depositional contexts might imply a compatible preference for breeding and nesting environments.

Júlio Cesar de A. Marsola [juliomarsola@gmail.com], Annie Schmaltz Hsiou [anniehsiou@ffclrp.usp.br] and Max C. Langer [mclanger@ffclrp.usp.br], Laboratório de Paleontologia de Ribeirão Preto, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, São Paulo state, 14040-901, Brazil. Gerald Grellet-Tinner [locarnolugano@gmail.com], Centro Regional de Investigaciones La Rioja—Consejo Nacional de Investigaciones Científicas y Técnicas, Entre Ríos y Mendoza s/n, 5301 Anillaco, Argentina; Orcas Island Museum, PO Box 134, 181 North Beach Road, Eastsound, WA 98245. Felipe C. Montefeltro [felipecmontefeltro@gmail.com], Departamento de Zoologia, Universidade Estadual Paulista, Avenida 24A 1515, Rio Claro, São Paulo State, 13506-900, Brazil. Juliana M. Sayão [jmsayao@gmail.com], Laboratório de Diversidade do Nordeste, Núcleo de Biologia, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Rua do Alto do Reservatório s/n, Bela Vista, Vitória de Santo Antão, Pernambuco state, 52050-480, Brazil. Received 18.12.2013; revised 30.4.2014; accepted 18.5.2014.     

New dinosaur remains from the Late Triassic of southern Brazil (Candelária Sequence,Hyperodapedon Assemblage Zone)

Pretto, F.A., Schultz, C.L., Langer, M.C. 4.02.2015. New dinosaur remains from the Late Triassic of southern Brazil (Candelária Sequence, Hyperodapedon Assemblage Zone). Alcheringa 39, xxx–xxx. ISSN 0311-5518

The oldest unequivocal dinosaurian records come from Upper Triassic strata, mostly from Argentina and Brazil. Recent fieldwork in the Brazilian deposits of Ischigualastian age (late Carnian–earliest Norian) have resulted in the collection of a new specimen (UFRGS-PV-1240-T) identified as dinosaurian by the presence of a concave emargination on the ventral surface of the femoral head and a well-developed deltopectoral crest on the humerus, which extends for ca 40% of its estimated proximodistal length. Although fragmentary, the material increases the dinosaurian record from the Late Triassic of Brazil, which is still modest when compared with coeval Argentine strata. Additionally, UFRGS-PV-1240-T augments the dinosaurian diversity at the ‘Sítio Janner’ site, which was until now restricted to the sauropodomorph Pampadromaeus barberenai. The new specimen is larger than most early dinosaurians (except for herrerasaurids), implying that members of the group were already occupying niches otherwise explored by other larger-bodied taxa in the ‘Sítio Janner’ palaeofauna, and Late Triassic palaeoenvironments in general.

Flávio A. Pretto [flavio_pretto@yahoo.com.br] and Cesar L. Schultz [cesar.schultz@ufrgs.br] Universidade Federal do Rio Grande do Sul, Instituto de Geociências, Setor de Paleovertebrados, Av. Bento Gonçalves, 9500—Bloco J, Prédio 43127, Campus do Vale, Agronomia?Porto Alegre, Rio Grande do Sul, Brazil, CEP 91540-000; Max C. Langer [mclanger@ffclrp.usp.br] Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Departamento de Biologia, Av. Bandeirantes, 3900, CEP 14040-901, Ribeirão Preto, São Paulo, Brazil.     

Physical Properties of Cement-Based Paste and Mortar With Dehydrated Cacti Additions

This article presents results for the physical characterization of mortar cubes fabricated with botanical (green) dehydrated additions such as nopal (Opuntia ficus indica) and aloe vera. A total of 84 mortar cubes were fabricated with and without these natural additions and tested for a period up to 900 days. Mortar without such additions served as controls. The natural dehydrated additions, nopal and aloe vera, were mixed with CPO cement (the name used in Mexico for type I Portland cement) at different percent replacements (0%, 1%, 2%, and 4%). To characterize physical properties of such mixtures, four tests were performed at ?900 days: total void content, compressive strength, ultrasound wave propagation, and wet electrical resistivity. Marginal improvements were observed within the dehydrated aloe vera replacement mixtures. Dehydrated nopal additions did increase the physical performance of the mortar with time.     

A Simplified Model to Evaluate the Dynamic Rocking Behavior of Irregular Free-Standing Rigid Bodies Calibrated with Experimental Shaking-Table Tests

A simplified model to evaluate the dynamic rocking behavior of free-standing irregular rigid bodies under earthquake-induced forces is proposed. The model analyzes the response of a three-dimensional irregular rigid body using a numerical approach that considers a critical section and two equivalent rectangular rigid blocks. Experimental shaking-table tests were carried out on modular prototypes, which allow the replication of representative mass distributions, sizes, and/or slenderness ratios for typical objects. The tests were used to calibrate the numerical model. It was found that the dynamic behavior under irregular conditions (asymmetrical shape and/or non-uniform mass distribution) can be estimated with the appropriate geometric and density considerations.     

The lower jaw and dentition of the traversodontid Exaeretodon riograndensis Abdala,Barberena & Dornelles,from the Brazilian Triassic (Santa Maria 2 Sequence,Hyperodapedon Assemblage Zone)

Exaeretodon riograndensis Abdala, Barberena, & Dornelles, 2002 Abdala, F., Barberena, M.C. and Dornelles, J.E.F. 2002. A new species of the traversodontid cynodont Exaeretodon from the Santa Maria Formation (Middle/Late Triassic) of Southern Brazil. Journal of Vertebrate Paleontology, 22: 313–325. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar] is the most abundant traversodontid preserved in the basal Santa Maria 2 Sequence (Hyperodapedon Assemblage Zone), southern Brazil and is closely related to Exaeretodon argentinus Cabrera, 1943 Cabrera, A. 1943. El primer hallazgo de terápsidos en la Argentina. Notas del Museo de La Plata, Paleontología, 8: 317–331.  [Google Scholar] from the Ischigualasto Formation, Argentina. Previous anatomical studies of E. riograndensis have focused mainly on cranial material and little is known about the morphology of its lower dentition or postdentary bones. We describe the first fairly complete postdentary series of the mandible of E. riograndensis and provide additional information on its lower dentition. The postdentary bones of E. riograndensis include a complex coronoid, an angular with a delicate reflected lamina and a stout retroarticular process of the articular, contrasting with the morphology reconstructed for Argentinean specimens, which possess a small retroarticular process. Apart from that, the postdentary bones do not differ significantly from those known for E. argentinus, a fact expected due to the great similarity between other skeletal features of these species. Furthermore, the lower postcanines of E. riograndensis have virtually the same structure as those of E. argentinus, with an approximate quadrangular shape in occlusal view. Moreover, the transverse cusp row is placed anteriorly and comprises a lingual and a buccal cusp, and the occlusal basin delimited by the four main cusps is relatively deep. The new material does not add any taxonomically diagnostic features to E. riograndensis. However, the fossils greatly improve our understanding of the anatomy of the Brazilian species.     

Influence of Frequency Content and Peak Intensities in the Rocking Seismic Response of Rigid Bodies

The rocking response of a family of bodies given by its width and height due to synthetic and recorded strong ground motions is presented; this allow us to identify the main parameters that govern their response: peak acceleration and velocity, dominant frequency, and acceleration time-history. Recorded strong ground motions were scaled to the same peak acceleration and also to the same peak velocity to analyze the effect of both parameters in the response of rigid bodies. These three parameters were used to build an equation to obtain the height/width overturning plots. The proposed equation was tested for many well-known strong ground motions and the results were compared to other methods shown to be more accurate. This parametric equation does not need iterations or numerical approximations to be solved and can provide engineers, in a very practical way, minimum design requirements or particular specifications to protect non structural elements.