RESULTADOS E DISCUSSÃO

Os resultados serão expostos e discutidos nos três manuscritos que se seguem. No primeiro manuscrito, intitulado “Permian wood with primary body preserved from Southeast of Brazil (Irati Formation, Paraná Basin)”, são descritos três taxa com base em caracteres do corpo primário: Solenopitys rusticana, Abietopitys sp. e Atlanticoxylon bortoluzzii comb. nov. Além da combinação nova, é também sugerida uma emenda ao morfogênero Atlanticoxylon. Nestes lenhos são observados falsos anéis de crescimento, características interpretadas como xeromórficas e que podem se relacionar às condições secas do ambiente deposicional da Formação Irati.

Figura 16. Campanha de campo em Conchas, onde foram coletados oito fragmentos de lenhos de camadas da Fm. Teresina, dos quais foram selecionados para o estudo os espécimes CP1/269 (que pode ser observada em C) e CP1/280. E-F. Campanha em Piracicaba onde se coletaram as amostras CP1/266, CP1/271 e CP1/272 (nas imagens E e F).

No segundo manuscrito, intitulado “Madeiras permianas das formações Irati e Teresina, Bacia do Paraná, sul do Brasil: taxonomia quantitativa e presença de fungos” são descritos cinco taxa: Agathoxylon, Brachyoxylon, Protobrachyoxylon sp.1, Protobrachyoxylon sp. 2 e Protobrachyoxylon sp. 3. Observa-se que os lenhos descritos (e que outros da literatura) são correlacionáveis a lenhos do Grupo Ecca (Permiano da Bacia do Karoo, sul da África), principalmente pela presença de espessamentos espiralados e de pontoações mistas. Discute-se que a presença de hifas fossilizadas (em alguns dos espécimes identificados como Protobrachyoxylon sp. 3) e de interrupções do crescimento (em quase todos os lenhos classficados como Protobrachyoxylon sp. 2 e Protobrachyoxylon sp. 3) indicam uma desestabilização dos ecossistemas naquele momento.

Por fim, os dados apresentados no terceiro manuscrito, “Fenologia foliar de madeiras permianas das Formações Irati e Teresina, Bacia do Paraná, sul do Brasil”, apontam a presença de espécies perenes à decíduas com tempo de longevidade foliar de cerca de três anos na Formação Irati e de um quase predomínio de espécies perenes na Formação Teresina. Propõe-se que tal predomínio de espécies perenes na Formação Teresina em comparação à Formação Irati é relacionado a uma transição entre um ambiente deposicional mais afetado por sazonalidade, na Formação Irati, para um ambiente menos sazonal, na Formação Teresina.

6.1. Manuscrito I

Permian wood with preserved primary body components from the southeast of Brazil (Irati Formation, Paraná Basin).

Rafael S. Faria1, Fresia Ricardi-Branco1, Rosemarie Rohn2, Marcelo Adorna Fernandes3 and Isabel C. Christiano de Souza1.

1. Departament of Geology and Natural Resources, State University of Campinas, João Pandiá Calógeras Street, 51, Campinas, SP, Brazil, [email protected]

2. Departament of Applied Geology, University of the State of São Paulo – UNESP - Rio Claro, Av. 24A, 1515, Rio Claro, SP, Brazil.

3. Departament of Ecology and Evolutive Biology, Federal University of São Carlos, Washington Luiz Highway, 235, São Carlos, SP, Brazil.

Abstract

Here we describe fossil wood with preserved pith and primary xylem from strata of the Irati Formation (Artinskian of the Paraná Basin). The three specimens studied are all related to the Coniferales and include the following taxa: Solenopitys rusticana Mussa, Abietopitys Kräusel (Merlotti) sp. and Atlanticoxylon bortoluzzii (Guerra) comb. nov. Solenopitys rusticana represents a morphospecies with a solid, heterocellular pith with a peripheral secretory canal system. Abietopitys sp. has a solid, lobed, homocellular pith associated to a secondary xylem containing cross-fields with non-contiguous pits. Atlanticoxylon bortoluzzii (Guerra) comb. nov. has a lacunose, heterocellular pith with “nests” of sclereids, with a central secretory canal and a pheripheral system of canals. An emended diagnosis of the morphogenus Atlanticoxylon is suggested to account for the possibility of the existence of the pheripheral secretory system. The false growth rings observed in those specimens are xeromorphic adaptations that may be related

to the depositional environment of the Irati Formation. The exact factor that controlled the xeromorphy cannot yet be determined, but the present study corroborates clearly the sedimentary evidences of dry conditions of the Irati Formation.

Key-words: Fossil wood; Permian; Irati Formation; Paraná Basin.

1. Introduction

In the Permian, the floristic elements of Gondwanaland were typically characterized by the glossopterids and other spermatophytes, as well as by lycopsids and monilophytes (ferns and sphenophytes). Among the spermatophytes, the conifers are mainly represented by allocthonous fossil wood (leaf organs are less frequent). In western Gondwanaland, the Permian deposits occur over an extensive area of South America and in Brazil. Numerous fossil wood morphogenera and morphospecies have been described from the Permian strata of the Paraná Basin, in the Irati Formation. They lived at a time when the global climate was becoming more arid and the Irati Gulf was isolated from the Panthalassa Sea (Milani, 2007).

The first fossil wood to be registered from the Irati Formation was Dadoxylon whitei, found in the district of Assistência, in the municipality of Rio Claro, in the state of São Paulo, in southern Brazil (Maniero 1944). This fossil was later transferred to the morphogenus Polysolenoxylon in a revaluation of the specimen (Kräusel and Dolianiti 1958). New samples from the same location led to the description of the morphogenera Parataxopitys (Mussa 1974) and Protopodocarpitys (Maniero 1951). Further discoveries in the state of Rio Grande do Sul (southern Brazil) led to the description of two new morphospecies of Polysolenoxylon (Guerra 1975) and a new morphospecies of Bakaroxylon (Schrage 1976). Later, two new morphogenera

were also found in the state of São Paulo: Brasilostiloxylon and Solenobrasilioxylon (Mussa 1978).

Mussa (1982) was responsible for one of the major contributions to the growing body of knowledge of gondwanan lignophytes with her unpublished PhD thesis, a small atlas of fossil wood from the Irati Formation. In this atlas, she described three new morphospecies of Polysolenoxylon, a new morphospecies of Taxopitys, a new morphospecies of Protopodocarpitys, two new morphospecies of Brasiloestiloxylon, a new morphospecies of Taenopitys, a new morphospecies of Kaokoxylon, a new morphospecies of Krauselpitys and two new morphospecies of Solenopitys, as well as the new morphogenera Atlanticoxylon (with five morphospecies), Petalopitys (with two morphospecies), Paranaseptoxylon (with two morphospecies), Torosoxylon (with two morphospecies), Paulistoxylon (with one morphospecies), Austroscleromedulloxylon (with one morphospecies) and Antarticoxylon (with one morphospecies).

The Irati Formation stands out in relation to the great diversity of fossil wood in contrast to other Brazilian and gondwanan formations as well as to the high number of specimens with lacunose pith and/or with secretory canals (Mussa 1982). Here, three new specimens related to the Coniferales, collected in strata of the Irati Formation at two locations in the state of São Paulo are described. The main objective of this paper is the systematic analysis of these specimens, as well as the interpretation of their environmental adaptations related to the conditions in which occurred the deposition of the Irati Formation.