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The goal of this work is to establish how many spieces of Arctoceras occured during the middle Smithian time (Early Triassic), a time interval which witnessed the first explosive radiation of ammonoids after the Permian-Triassic boundary mass extinction.
The steps of this work include mechanical preparation and the study of ontogeny and variation by means of classic biometry and geometric morphometry. This study is based on new and large collections from NE Nevada which lend themselves to statistical analyses.
This Master project focuses on the Smithian-Spathian boundary, which witnessed the largest -Early Triassic marine extinction ca 2Myr after the end-Permian mass extinction. In the western USA, the late Smithian coincides with a maximum onlap, but it is manifested by a marine regression in most other known sections, world-wide. This boundary is also accompanied by an abrupt cooling of sea surface temperature and global change from wet to dry climate, as indicated by palynofloras.
This MSc includes both field and lab work. The first goal of this master project is to test the global character of the temperature drop down near the Smithian-Spathian boundary by means of paleotemperature isotopic proxies. The second goal is the investigation of the depositional environments of this time interval of the Thaynes Formation and the resolution of the paradox of a local maximum onlap coincident with a worldwide regression. This includes high resolution facies and diagenesis analysis, taphonomy, paleoecology, and chemostratigraphy.
The candidate will be actively participate and interact with the research groups of H. Bucher (mass extinctions and recoveries) and H. Weissert (paleoceanography). External collaborations with A. Brayard (Dijon) and T. Vennemann (Lausanne) are also foreseen.
Following the largest mass extinction of the end-Permian, ammonoid diversity first peaked during the early Smithian, ca 1 Myr after the extinction event. The main lines of the Salt Range (Pakistan) and Spiti (Indian Himalaya) Smithian records have been recently established. However, the analysis of new samples from this critical time interval of the biotic recovery is needed for a better resolved estimation of species richness and improved understanding of the phylogenetic relationships that led this first diversity explosion. This MSc work will be conducted in conjunction with other PhDs and MScs addressing complementary aspects of the Early Triassic biotic recovery.
Genuine carbon and oxygen isotopic values are preserved in the aragonitic shells of Jurassic and Cretaceous ammonoids. The aim of this work is to (i): test for any vital effect that could influence measured values; (ii): map isotopic values on the outer shell as well as septa; (iii): characterize oceanographic/climatic variations recorded throughout growth and (iv): reconstruct how much time elapsed during growth for different morphological variants from the same sample.
The ornamentation of bivalves, which includes all external morphological features of the shell such as ribs, knots or spines, is often an adaptation to particular functions. It may support burrowing in soft or hard substratum, strengthen the rigidity of the shell in the face of high water energy, enable weight reduction, or help defending the animal against predators. Trends in the relative frequencies of different types of ornamentation over geologic times are therefore expected to reflect changes in the ecological regime (such as the evolution of competitors and predators), changes of the physical environment, or evolutionary innovations related to the occupation of new niches. The project aims at analyzing evolutionary trends in the ornamentation of bivalve shells in this context. It will consist of three main steps: (1) defining different categories of shell ornamentation; (2) documenting relative frequencies of these categories in bivalve genera from the Cambrian to the Recent, based on the Treatise on Invertebrate Paleontology and primary literature, and (3) analyzing the dataset with respect to potential driving forces. As such, the project results will add to our understanding of macroecological trends in a major class of marine invertebrates.
Mysidioptera ist eine Gattung der Feilenmuscheln (Limidae), die in der Mittel- und frühen Obertrias innerhalb relativ kurzer Zeit extrem schnell diversifizierte (über 100 beschriebene Arten), aber gegen Ende der Trias wieder ausstarb. Dieses Muster steht im Gegensatz zur etwa zeitgleich entstandenen Gattung Plagiostoma aus der gleichen Familie, die niemals eine so grosse Diversität wie Mysidioptera erreichte, dafür aber wesentlich langlebiger war und erst in die Kreide ausstarb. Die beiden nah verwandten und ökologisch vergleichbaren Gattungen stehen damit stellvertretend für zwei sehr unterschiedliche Diversitäts-Dynamiken: "boom and bust" Dynamik (Mysidioptera) versus Gleichgewichtsdynamik (Plagiostoma). In der Masterarbeit sollen die Diversitäts-Dynamiken der beiden Gattungen in der Trias auf Grundlage von Literaturstudium und Sammlungsmaterial rekonstruiert werden und Gründe für die unterschiedlichen Speziations- und Aussterbe-Dynamik erschlossen werden. Aus dieser Fallstudie werden allgemeine Erkenntnisse über die Steuerungsfaktoren von unterschiedlichen Diversitäts-Dynamiken erwartet, die sich auf andere Gruppen übertragen lassen.
Am Übergang von der Trias in den Jura fand eines der fünf grössten Massenaussterbe-Ereignisse der Erdgeschichte statt. Im Gegensatz zu anderen Massenaussterbe-Ereignissen konnte sich jedoch die benthische Lebewelt sehr schnell wieder erholen. Die post-extinction-Faunen des Unterjura sind daher deutlich diverser und ökologisch heterogener als solche nach anderen Aussterbe-Ereignissen. In dem Projekt soll erstmals eine moderne ökologische Analyse benthischer Faunengemeinschaften aus dem basalen Unterjura Mitteleuropas durchgeführt werden. Dazu sind Neuaufsammlungen geplant, die mit der Auswertung von Sammlungsmaterial kombiniert werden sollen. Im Ergebnis sollen die post-extinction Faunen des Unterjura paläo-ökologisch charakterisiert und mit ähnlichen Faunengemeinschaften aus der Zeit nach dem endpermischen Massenaussterben verglichen werden. Unterschiede zwischen diesen Faunengemeinschaften sollen herausgearbeitet werden mit dem Ziel, ein generelles konzeptionelles Verständnis für die ökologischen Prozesse zu entwickeln, die im Anschluss an globale Umweltkatastrophen wirksam sind.
Within evolutionary research, palaeontology uniquely allows for the study of (1) evolution in its ecological context (palaeo-ecology) and (2) the long-term fate of species and higher-rank taxa through geologic time (macroevolution). I am flexible in offering topics for master theses in both areas. Typically, palaeo-ecological studies will be based on own fieldwork, whereas studies in macroevolution make use of literature data and museum collections. Do not hesitate to contact me if you are interested in contributing to our understanding on how life on Earth evolved from a palaeontological perspective!
In der Arbeitsgruppe "Evolutionsmorphologie and Paläobiologie" (Prof. Sánchez, PD Dr. Scheyer und Kollegen) bieten wir verschiedene Masterarbeitsthemen an. Wir beschäftigen uns hauptsächlich mit unterschiedlichen Aspekten der Evolution und Entwicklungsbiologie der Wirbeltiere. Unsere Anlagen umfassen ein Nasslabor für Gewebelehre, Morphometrie-Untersuchungen und vergleichbare ontogenetische Studien, sowie ein Labor für Paläohistologie, in dem wir die Struktur und Entwicklung von fossilen Hartgeweben studieren.
Auf der Lab-Webseite www.msanchezlab.net finden Sie eine Liste unserer gegenwärtigen Forschungsschwerpunkte und Infos zu Themen für Masterarbeiten in unserer Gruppe. Dort erfahren Sie auch Näheres über alle Angehörigen der Arbeitsgruppe, deren Forschungsinteressen sowie Publikationen.
Bitte kontaktieren Sie Prof. Sánchez oder PD Dr. Scheyer für weitere Einzelheiten.
Methods of virtual palaeontology become increasingly important and more widely applied. For this Master-thesis, it is planned that the candidate will segment existing micro-CT image-stacks of Devonian invertebrates (arthropods, molluscs or else) in order to obtain good images of the fossils. These images will then be used to determine and describe the material and in some cases, new species can be described based on these materials. If time permits, constructional morphology as well as aspects of the animal's phylogeny can be studied as well.
Palynology is the study of microscopic resistant-walled fossils of various plants, animals and protists. It offers a wide range of interesting master's theses.
The analysis of spore and pollen associations through time allows for reconstruction of past vegetation composition and terrestrial ecosystem dynamics but also to detect evolutionary pathways in plants. Spore-pollen analyses are also used as valuable climate proxy.
Palynofacies analysis includes not only palynomorphs, such as spores and pollen grains, but also palynodebris such as wood particles, cuticles, algae, etc. thus describing the entire assemblages of particulate organic matter. Thus, palynofacies describes the depositional environment of the studied sample and is often used for basin analysis (e.g. sea-level changes, petroleum exploration).
Please do not hesitate to contact Dr. Elke Schneebeli for further information.
