Troncos fósseis da Bacia de Maniamba: descrição anatómica e correlação paleobiogeográfica, com base em lâminas delgadas

Abstract

During the PaleoMoz project expeditions, fossil trunks were collected from the Ksb, K6, K5, K4, and K3 formations with the aim of describing their anatomy and classifying them taxonomically. To achieve this objective, several resources were utilised, including bibliographic research, software tools, and the use of the OLYMPUS BX43 petrographic microscope for the analysis of thin sections from ten specimens: PPM2018-106N, PPM2018- 10Z, PPM2018-24R, PPM2018-25R, PPM2018-41R, PPM2019-35R, PPM2019-55R, PPM2019-59NN, PPM2019-68NN and PPM2019-71NN. Anatomical description and identification were possible based on specific features such as growth rings, pit structures in tracheid walls, and cross-field pitting. The results of this analysis showed that two specimens belong to the Agathoxylon africanum taxon (PPM2018-106N and PPM2018-25R), two specimens (PPM2018-10Z and PPM2019- 59NN) belong to Agathoxylon karooensis, two specimens (PPM2019-35R and PPM2019-55R) belong to the Australoxylon teixeirae taxon, and one specimen (PPM2019-68NN) belongs to the Cupressinoxylon cf. sp. nov., representing a new species in the Metangula Graben. Unfortunately, it was not possible to assign a taxon to three specimens (PPM2018-24R, PPM2018-41R, and PPM2019-71NN) due to their preservation state. The genera Agathoxylon and Australoxylon are widespread throughout the Karoo sequence and have been found in the Ecca Group. The genus Cupressinoxylon is distributed across both hemispheres but, in this project, represents a new taxon in the Metangula Graben and was first recorded in the Matine Formation (Upper Permian). In Gondwana, the Glossopteris flora indicates a predominantly warm and humid climate, with climatic variations between wet and arid conditions, especially in regions such as the Maniamba Basin, characterized by fluvio-lacustrine environments.