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Evolutionary Rates Of Basal Iguanodontians Around Jurassic-Cretaceous Transition In Europe
Publication . Rotatori, Filippo; Moreno-Azanza, Miguel
Iguanodontian dinosaurs are among the very first members to have been discovered, and since then, several new remains have been discovered all around the globe. These herbivores are especially diverse and abundant in the Early Cretaceous of Europe, North America and Asia. Comparatively, very little is known about Late Jurassic species and several specimens have been overlooked during the years, due also to lower preservation potential. In the present work, we aim to review and describe Late Jurassic Iguanodontian remains recovered mainly from Lourinhã Formation (Portugal) and update with a new set of observations phylogenetic matrices, in order to elucidate systematic relationships and macroevolutionary patterns within the clade.
This work reports several undescribed specimens which indicated a hidden taxonomic diversity for the clade. This initial observation was corroborated not just by the reappraisal of type material of taxa already known, but also from the report and description of two species.
The species richness of Iguanodontian dinosaurs in the Upper Jurassic beds of Lourinhã Formation is doubled, and the recovery of individuals of different ontogenetic stages indicate the presence of thriving populations.
Furthermore, the new data acquired in Portugal, Europe and North America and compiled into the phylogenetic data matrix that was the main novel result of this doctoral project, were analysed with Maximum Parsimony and Bayesian Inference. We recovered a new systematic relationship, and we formally erected a new clade of high-sailed Iguanodontian dinosaurs. Furthermore, tip dated phylogenies indicate that most of the clade of Iguanodontians appeared, diversified and dispersed by the Late Jurassic. The Cretaceous assemblages are the result of extinction events that affected different Iguanodontian lineages. Body size increased by Late Jurassic, and in Early Cretaceous different clades evolved toward different optima, resulting in niche segregation.
This thesis remarked on the pivotal role of Western Europe, and in particular Portugal and Iberia, for Iguanodontian dinosaurs' macroevolution.
Dental microwear texture analysis reveals behavioural, ecological and habitat signals in Late Jurassic sauropod dinosaur faunas
Publication . Winkler, Daniela E.; Tschopp, Emanuel; Saleiro, André; Wiesinger, Ria; Kaiser, Thomas M.; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Nature Publishing Group
Most faunas from the Mesozoic era were dominated by sauropod dinosaurs, the largest terrestrial animals to ever exist. These megaherbivores were remarkably diverse and widely distributed. Here we study three Late Jurassic faunas from the USA, Portugal and Tanzania, each approximately 150 million years old, which are known for their extreme sauropod diversity. Whereas general taxonomic composition was similar in these three faunas, the major clades differed in relative abundance. Moreover, their depositional strata record distinct climatic regimes. Using dental microwear texture analysis, we investigated the impact of these climate regimes and the resulting food availability on the different sauropod taxa. Wear patterns in camarasaurid macronarians show minimal variation across different climate regimes, supporting previous studies suggesting that these animals migrated to follow their preferred climate niche and food source. North American camarasaurids show similar wear patterns to those of Portuguese turiasaurs, another broad-crowned taxon, which did not exist in the Jurassic of North America. By contrast, where camarasaurids and turiasaurs co-occurred in Portugal, their microwear patterns are distinct, suggesting niche differentiation to avoid ecological competition between these two clades. Flagellicaudatan diplodocoids display highly variable wear patterns, indicating limited migration (and therefore seasonal variation in diet), which aligns with observed biogeography patterns in the USA. Early-branching titanosauriforms show highly distinct wear patterns between different climate regimes, which can probably be attributed to different abrasive loads in the respective habitats. Our results demonstrate that dental microwear texture analysis not only records dietary preferences but also reveals behaviour such as competition and migration related to dietary niches in past ecosystems.
Future Palaeontologists Will Detect Current Mammal Latitudinal Biodiversity Gradient
Publication . Galván, Sofía; Gamboa, Sara; Chiarenza, Alfio Alessandro; Rotatori, Filippo Maria; Oliver, Adriana; Varela, Sara; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Faculdade de Ciências e Tecnologia (FCT); Wiley-Blackwell
Aim: Fossil data provide crucial insights into past biogeographic and macroecological patterns. However, geological, biological, and sampling biases can potentially compromise genuine biodiversity inferences. Here, we tested whether fossil biases may hinder the accurate retrieval of the Latitudinal Biodiversity Gradient (LBG). Location: Global. Time Period: Contemporary. Major Taxa Studied: Mammals. Methods: We implemented a filtering process to current mammal distribution maps, simulating one geological, two biological, and three sampling sources of bias. Namely, distribution maps were downgraded to regions with sediments, species preservation was modulated by their range size and body size, and sampling was applied to locations with a fossil record. We applied the filters sequentially to mimic a process of progressive fossilisation, considering three preservation rates and removing up to 98.8% of the original species. We also applied filters independently to assess their individual effect. Lastly, we quantified the richness loss, the change in the slope between latitude and richness, and the change in richness maxima throughout the filters. Results: Results indicate that the applied filters collectively and distinctly influence the detection and robustness of the LBG signal. However, although the slope of the richness gradient diminishes progressively (especially for filters affecting species by their body size or taxonomic group), a LBG signal is detected across all the filters. Equally, despite the critical species loss, richness maxima remain around the equator. Main Conclusions: We demonstrated that strongly incomplete or biased samples can still recover accurate large-scale biogeographic patterns such as the LBG. Our results show an optimistic scenario in which, although the LBG intensity is sensitive to the uneven loss of information in biodiversity data, a detectable signal can be retrieved for all scenarios.
Revisiting the choristodere and stem-lepidosaur specimens of the Guimarota Beds (Kimmeridgian, Portugal)
Publication . Guillaume, Alexandre R.D.; Puértolas-Pascual, Eduardo; Moreno-Azanza, Miguel; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; Faculdade de Ciências e Tecnologia (FCT); DCT - Departamento de Ciências da Terra; Institute of Paleobiology, Polish Academy of Sciences
The Guimarota beds (Kimmeridgian, Portugal) constitute one of the richest microvertebrate assemblages for the Upper Jurassic, which include a diverse fauna of small reptiles. Among others, was described a new species of a small choristodere, “Cteniogenys reedi”. The genus, also known from the Morrison Formation (Upper Jurassic, USA) and the Kirtlington Mammal Bed (Middle Jurassic, UK), constitutes one of the oldest and most basal forms of this aquatic reptile lineage considered to be ecologically similar to crocodylomorphs. However, later works considered this species to be a junior synonym, and challenged the assignment of some of this material, ascribing them to the aquatic stem-lepidosaur Marmoretta. Here, we provided a revision of the published material from the Guimarota beds assigned to Cteniogenys, together with unreported and mislabelled specimens. We confirmed that the Portuguese specimens are probably non-conspecific with the taxa described in the Upper Jurassic of North America and in the Middle Jurassic of England. Unfortunately, the lack of diagnostic features from the only valid species prevented to confirm the original description as a distinct new species. Therefore, we only referred it to Cteniogenys aff. C. antiquus. We further supported the presence of Marmoretta in the Upper Jurassic of Portugal, and erected a new species, Marmoretta drescherae. Those occurrences support original palaeoenvironmental interpretations of the Guimarota beds as a wetland, probably close to mangrove-like, with important freshwater inputs. The presence of Cteniogenys in Portugal further supports faunal interchanges between North America, Europe, and potentially Northwestern Africa during the Jurassic/Cretaceous transition, if later occurrences are to be confirmed. The presence of Marmoretta also extend the temporal range of this relict reptile lineage at a time where squamates were radiating. However, its absence in other contemporary Jurassic localities, notably in the Lourinhã and Morrison formations, could hint towards ecological differences between those assemblages.
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Concurso de Projetos IC&DT em Todos os Domínios Científicos
Número da atribuição
PTDC/CTA-PAL/2217/2021