72 research outputs found
On the anatomy of wood showing affinities with the genus vertebraria royle, from the irati formation, state of São Paulo, Brazil
Results of research on permineralized wood samples from the Irati Formation (middle to upper Permian) in the State of São Paulo, Brazil add to our understanding of several questionable problems concerning samples showing affinities with the vertebrarian types of axes. A new xylic structural plan including even roots and stems would have been characterized throughout Gondwanaland from post-glacial time through the Late Permian. Until now a number of samples had been described as a single taxonomic unit under the designation of Vertebraria indica Royle 1939. Presumably this taxon does not include only a single generic group, but rather it represents a complex of forms distributed throughout Gondwanaland that are grouped together on the basis of important and similar features, such as: 1) wedge-shaped stelic configuration resembling that of the vertebrarian stelic plan; 2) wavy grouwth rings and asymmetric growth of the vascular cilynder resulting from the cambial activity of ray cells and parenchyma cells in the rings; 3) a frequent and peculiar pitting arrangement on the radial walls of the tracheids which now appears to be also a common feature among glossopteridean shoots and vertebrarian axes. It was possible to identify some samples as independent and definite genera on the basis of their well-preserved leaf and root traces, their nodal structures and also their very characteristic manner of issuing adventitious branches. Eventhough they are not classified in the genus Vertebraria, they are closely comparable in many aspects to axes of this genus. A discussion is presented here of the genus Vertebraria and it is concluded that the related genus Tordoxylon Krãusel 1956 is a valid taxon that can be distinguished within the vertebrarian complex on the basis of its characteristic xylic plan. Some problems concerning taxonomic names are also discussed. A preliminary account of the paleoecological significance of these anatomical structures is presented in view of their rapid rise and extinction during geologic time.Os resultados das pesquisas em lignispécimes permineralizados da formação Irati (Permiano médio a superior), Estado de São Paulo, Brasil, fornecem novos subsídios para o entendimento de diversas questões ainda pendentes, quanto às estruturas xílicas anatomicamente afins aos órgãos vasculares do tipo "Vertebrada". Plano xilico novo, que incluia raízes e caules deveria ter existido em todo ò Gondwana, a partir do tempos pós glaciais, ao final do Permiano. Até o presente, bom número de amostras foi descrito sob unidade taxonômica, única, designada Vertebraria indica Royle 1939. Presumivelmente esse taxon não inclui, somente, um gênero, mas, preferencialmente, representa um complexo de gêneros distribuidos através do Gondwana. Os mesmos podem ser grupados com base em importantes características, bastante semelhantes, como: 1) configuração estélica, em cunhas, assemelhando-se ao plano estélico de "Vertebraria 2) anéis de crescimento ondulantes associados a crescimento assimétrico do cilindro vascular, como resultado da atividade cambial das células dos raios e das células de parênquima presentes nos anéis; 3) arranjo das pontuações, sobre as paredes radiais dos traqueídeos, bastante peculiar; esse arranjo parece ter sido comum, tanto em ápices caulinares de glossopterídeas, quanto em órgãos vasculares designados como "Vertebraria". Na presente pesquisa foi possível identificar gêneros independentes e definidos com base em estruturas bem preservadas, relativas a traços foliares e a traços de raízes adventícias; tornou-se possível a identificação de estrutura nodal típica e um modo bastante característico de emitir ramos, em algumas das amostras. Embora todas as formas, aqui estudadas, não tenham sido classificadas no gênero Vertebraria, são compatíveis em muitos aspectos ao referido gênero. Portanto, oferecemos uma discussão a respeito do complexo Vertebraria e concluímos que Tordoxylon Kràusel 1956 é um gênero válido, o qual pode ser reconhecido em meio ao referido complexo, levando-se em consideração o seu plano xilico, muito peculiar. Alguns problemas relativos à nomenclatura dos espécimes são também discutidos no presente trabalho. Apreciação preliminar, sobre o significado paleoecológico, das estruturas anatômicas, foi aqui situada, tendo em vista o rápido surgimento e desaparecimento dessas formas gondwanicas
Histological and framboidal textures in diagenetic pyrite from the gondwana coal beds,Brazil
Nas camadas de carvão do Grupo Tubarão, depositadas na Bacia do Paraná, no sul do Brasil, ocorre pirita. As piritas do carvão da região de Cambui, na Bacia do Rio do Peixe, estudadas em seção polida, apresentam texturas framboidal e histológicas que são interpretadas como evidências de piritas 'singenéticas, depositadas durante a diagênese. Marcassita subordinada, que ocorre como veios e em bandas concêntricas de textura coloforme, indicaria formação num meio localmente acidificado. As estruturas anatômicas observadas nas seções polidas de pirita correspondem a partes de sistema vascular complexo de plantas fósseis, que sugerem a revisão da idéia corrente de possíveis afinidades de formas do Hemisfério Sul com as do Hemisfério Norte.Pyrite occurs in the Gondwana coal measures of the Tubarão Group, in the Paraná sedimentary basin, Southern Brazil. Polished sections of pyrite from the Carnbui area show framboidal and histological textures which are interpreted as evidence for the syngenetic origin of the pyrite, deposited during diagenesis. Subordinate marcasite, which occurs as secondary veins and concentric bands with colloform textures, would indicate formation in a locally acid environment. The anatomical structures observed in polished sections of pyrite show parts of a complex vascular system which suggests that current opinion concerning the affinities of the forms of the Southern Hemisphere with those of the Northern Hemisphere should be revised
Brasilestiloxylon e solenobrasilioxylon, dois novos gêneros gondwânicos na formação Irati, Estado de São Paulo, Brasil
Wood samples showing peculiar features in the initial part of the gymnospermous wood body and in the pith are here described. The genus Brasilestiloxylon n.g. shows the conservative nature of its ealier vascular elements of the intermediate phase (Chaveau, 1911) which usually has been described as centripetal elements or mesarch xylem. The genus Solenohrasilioxylon is closely comparable to the genus Solenoxylon Krausel 1956, but in contrast it has in the central part of the pith, secretory canals also
Nova forma do complexo Vertebraria nos argilitos carbonosos da Formação Rio Bonito, Santa Catarina, Brasil
Available evidence presented here supports the approach by MUSSA (1978) that Vertebraria ROYLE really comprises a complex of forms. Schopficaulia n. g. is a distinct new unit which presents external morphological characters similar to Vertebraria, but whose anatomical plan clearly represents aerial vascular organs, such as branching woody axes showing adventitious rootlet traces and undifferentiated branch or foliar traces. The pith is unquestionably indicative of plants of the runner, climbing or shrub type adapted to a swampy environment. The fact that vertebrarian-type axes are restricted to Gondwanic coal fields is consistent with the environmental interpretation inferred from the pith plan. All indications substantiate the viewpoint that the plants lived at the very site where they were later fossilized
Maxillo-Facial Morphology in Beckwith-Wiedemann Syndrome: A Preliminary Study on (epi)Genotype-Phenotype Association in Caucasians
Beckwith–Wiedemann syndrome (BWS) is a congenital overgrowth disorder caused by various (epi)genetic alterations affecting the expression of genes on chromosome 11p15. Cardinal features include abdominal wall defects, macroglossia, and cancer predisposition. Several (epi)genotype–phenotype associations were described so far, but specific studies on the evolution over time of maxillo-facial phenotype in the molecular subtypes still are scanty. The aim of this cross-sectional study was to associate maxillo-facial morphology and growth pattern with genoype in 25 Caucasian children with BWS and macroglossia. Twelve patients experienced a loss of metilation at imprinting center 2 (IC2-LoM), five had mosaic paternal uniparental isodisomy of chromosome 11 (UPD(11)pat), and eight were negative. A more marked tongue enlargement was detected in patients with IC2-LoM and negative genotype, while UPD(11)pat children showed mild macroglossia (p = 0.048). A cluster analysis did not demonstrate any specific relationship between (epi)genotype and maxillo-facial phenotype, but separated BWS patients based on their cephalometric characteristics. Children with IC2-LoM or negative genotype displayed hyperdivergence values > 30°, clockwise growth tendency, and skeletal class II into the same cluster. They had a negative prognostic score. These preliminary data suggest the need for developing individualized protocols for early monitoring of the craniofacial growth in such patients
O significado estratigráfico do Complexo Solenoide no Permiano do Gondwana
The Solenoid Complex comprises a fossil wood assemblage with stratigraphic distribution restricted to the middle-late Kungurian, present in Western (Irati Formation, Paraná Basin, Brazil) and Eastern (Upper Barakar Interval of the Indian basins) Gondwana. Its occurrence seems to be related to the adaptation of certain plant groups to paleoenvironmental stress in lowland niches of coastal areas subject to salinity variation. The disappearance of these forms in the latest Kungurian is probably linked to the cessation of these conditions, which is confirmed by the sedimentary record. The here designated "Solenoid Complex Zone" correlates with the acme in diversification of striate and taeniate patterns especially in bisacatte pollen grains, but also in monosacatte ones, reflecting important tectonically and climatically driven changes in the vegetational pattern. The waning icehouse stage during the Permian was an important factor to the development of similar vegetation patterns in Western and Eastern Gondwana in the latitudinal belt of 40° - 55°.O Complexo Solenoide compreende um conjunto de lenhos fósseis com distribuição estratigráfica restrita ao Kunguriano médio-superior, presente no Gondwana Ocidental (Formação Irati, Bacia do Paraná, Brasil) e Oriental (Intervalo Barakar Superior de bacias da Índia). A sua ocorrência parece estar relacionada à adaptação de determinados grupos vegetais ao estresse paleoambiental em terras baixas de áreas costeiras sujeitas a variações de salinidade. O desaparecimento dessas formas no topo do Kunguriano está provavelmente relacionado à cessação de tais condições, o que é confirmado pelo registro sedimentar. A "Zona do Complexo Solenoide" aqui designada correlaciona-se com o clímax na diversificação de padrões estriados e teniados principalmente em polens bissacados, mas também em monossacados, refletindo importantes modificações no padrão vegetacional relacionadas à evolução climática e a processos tectônicos. O declínio do estágio icehouse durante o Permiano foi um fator importante para o desenvolvimento de padrões florísticos similares no leste e oeste do Gondwana em uma faixa latitudinal entre 40° - 55°
Medula do tipo artisia na formação Iratí (Permiano), estado de São Paulo, Brasil
This paper records the first ocurrence of a pith cast resembling Artisia in Brazil, from near Porongaba, São Paulo. This pith cast may be related to the genus Solenoxylon Kräusel, first registred in southwest Africa, but also known in the Permian of Brazil
Estudo estratigráfico e paleoecológico em ocorrências fossiliferas da formação Iratí, estado de São Paulo, Brasil
Longitudinal monitoring of alpha-fetoprotein by dried blood spot for hepatoblastoma screening in beckwith-wiedemann syndrome
Correspondence on “Clinical spectrum of MTOR-related hypomelanosis of Ito with neurodevelopmental abnormalities,” by Carmignac et al
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