New palaeobotanical contributions to the Jurassic of Northern Iberian Peninsulapalynostratigraphical and palaeoecological insights

Resumo

This doctoral thesis is based on new unpublished material excavated, prepared and studied by the author. The thesis is structured in seven chapters, including an introductory chapter and a final chapter with conclusions and general considerations. The main objectives of this thesis are (1) to provide new paleobotanical data from the Jurassic records of the northern Iberian Peninsula; (2) prospecting and excavation of new Jurassic deposits; (3) Study and identify the different fossils collected in the selected deposits; (4) Establish from the fossil record the reconstruction of the paleoclimatic and paleoenvironmental conditions during the Jurassic in the area; (5) develop paleoecological contextualization including the study of plant-insect interactions. The first chapter deals with the state of the art of Jurassic paleobotany and plant-insect interactions in the Iberian Peninsula and presents the bases to contextualize the following chapters. The second chapter deals with the discovery of a new flora with plant-insect interactions from the Middle Jurassic located on a volcanic island far from the mainland, called Isla Camarena. The third chapter describes the palynological association of the aforementioned Middle Jurassic (paleo) island of Camarena. This chapter identifies a new palynological assemblage, including its palynostratigraphic analyses, which improves the dating of this unique site and also attempts to reconstruct the plant communities that inhabited this oceanic island, their possible colonization strategies, and the dispersal capabilities of some palynomorphs found on the island (paleo) The fourth chapter describes a new species of liverwort: Ricciopsis asturicus sp. nov. found in the Upper Jurassic (Kimmeridgian) of the Lastres Formation in Asturias, constituting the earliest evidence of the Ricciaceae Family in the Iberian Peninsula. The taxonomy of this group is also discussed, proposing the deletion of an earlier species of Ricciopsis. In addition, the paleogeographic distribution of the genus is interpreted, as well as its paleoecological implications. The fifth chapter describes and identifies the palynomorphs found in different sections of the Asturian Coast of Dinosaurs, discussing the palynostratigraphic implications for the formation. In addition, the botanical affinities of the palynomorphs are taken into account, presenting the reconstruction of the plant communities that formed the landscape of the Coast of the Dinosaurs of Asturias during the Kimmeridgian, and showing an approximation to the paleoclimatic and paleoenvironmental conditions of this formation. The sixth chapter consists of new flora and insect remains from a Late Jurassic hydrothermal paleoenvironment (J/K boundary). This flora was found in the Aguilar Formation and grew in a unique environment of hot springs. The seventh chapter evaluates the new findings and their implications for the knowledge of the Jurassic paleobotany of the Iberian Peninsula, as well as a projection of the future lines of research opened with the new contributions.