University of São Paulo
December 06, 2022
The origin of tympanic ear in reptiles from a Paleo-Evo-Devo perspective
The tympanic middle ear is a key evolutionary trait in the tetrapods’ successful invasion of terrestrial environments. Despite the morphological similarities in different lineages, current literature indicates that this sensory structure evolved independently in major tetrapod groups. Based on an integrative approach combining data from the fossil record and the embryonic development we investigate the origin and homology of the tympanic ear in reptiles.
January 17, 2023
Usambara Mountains Archaeology and Palaeoecology Project (UMAPP)
The Usambaras, in northeastern Tanzania, are a biodiversity hotspot that host remarkably rich and diversified plants and animals that may have lived in this area for millions of years. However, we know very little about the climatic, ecological, and human history of this region as very few long-term studies have been conducted here. Additionally, and despite the biological wealth the mountains host, they are under threat from both anthropogenic climate change and the conversion of natural vegetation to agricultural plantations.
In July-August 2022, we conducted a pilot field season to survey archaeological sites and document local plant ecology and biodiversity. We visited and surveyed 22 rockshelters and 6 open-air sites across the East and West Usambara Mountains and uncovered over 400 lithic and pottery artifacts. This talk explores the survey results and future plans for archaeological and palaeoecological projects in the Usambara Mountains.
Swedish University of Agricultural Sciences, Sweden
January 24, 2023
Neglecting vegetation fires as a geochemical process could undermine the
reliability of paleoecological interpretations
Long-term paleoecological and paleofire records have been widely used to
elucidate the impact of vegetation fires on ecosystem dynamics, such as the distribution of
biomes, vegetation structure, carbon fluxes, nutrient cycles, and hydrological conditions.
However, in fire-prone biomes, the interpretation of paleoecological proxies is subjected to
uncertainties as the plant biomarkers/molecules are thermally modified, and the extent and
nature of alterations are yet to be well-constrained. To shed light on the current knowledge
gaps, we performed a series of controlled experiments in which leaf samples from C 3 (tree and
shrub) and C 4 (grass) plants and a topsoil sample were burned/heated under ambient oxygen at
temperatures between 200 °C and 500 °C. In this talk, I will discuss the effect of experimental
burns on commonly used paleoecological proxies such as total organic carbon content, bulk
carbon isotopic compositions, and concentration and isotopic composition of lipid biomarkers
(namely, n-alkanes and n-alkanoic acids). I will also discuss the inferences drawn from the
burning experiment and possible implications for paleoecological studies.
Utrecht University, Netherlands
January 31, 2023
Investigating early Eocene hydroclimate using fossils and models: wet-gets-wetter, dry-gets-drier?
Earth’s hydrological cycle is expected to intensify in response to global warming, with a
‘wet-gets-wetter, dry-gets-drier’ response anticipated. In this, the arid subtropics (~15-30°
N/S) are predicted to become drier. Yet proxy evidence from past warm climates suggests
these regions may instead have been characterised by wetter conditions. In this talk, I will
investigate this further using the early Eocene hothouse as case study, extracting
information on past rainfall patterns from both model simulations and proxy
University of Saskatchewan, Canada
February 07, 2023
Life Finds a Way: Understanding the Theatre of Terrestrialization
The colonization of subaerial and non-marine landscapes (“terrestrialization”) by animals and plants was a defining and irreversible innovation during the co-evolution of Earth and its biosphere. Our understanding of when, where, and even how the first animals gained a foothold on land, 420 million years ago, is increasingly refined, but many of the big questions surrounding the issue of terrestrialization remain unanswered. In this presentation I will discuss how the trace fossil record sheds light on different aspects of the initial colonization of land, from how pioneering organisms made subaerial excursions as early as the Cambrian, to the types of behaviours that dominated the first terrestrial ecosystems.
University College London, United Kingdom
February 14, 2023
South American climate & the Andes influence eutherian mammal diversity through time & latitude
South America has a unique geobiological history that is at heightened risk from the current climate emergency. Applying subsampling and Bayesian approaches to a comprehensive dataset of South American terrestrial eutherian mammal fossil occurrences, I find increases in diversity throughout the Paleogene, resulting from several intervals of high speciation rate. The remainder of the Cenozoic is characterized by greater variability, including a diversity peak in the late Miocene and pulses of heightened extinction rate in the Plio-Pleistocene. These results suggest that the present-day latitudinal biodiversity gradient first appeared in South America in the Plio-Pleistocene, at a similar time as proposed for North American mammals. This appears to have been driven by a decline in mean annual temperatures at higher latitudes in South America, in tandem with an increase in precipitation at lower latitudes that might have been accentuated by Andean uplift.
12 noon UTC!
Physical Research Laboratory, India
February 21, 2023
History of the forest fire in the western Himalaya and its linkage to
climate and human
Understanding of the past climate-human-vegetation-fire interactions is critical for
understanding modern fire dynamics associated with climate change and anthropogenic
perturbation. Because fire has played an important role in human evolution and
diversification across continents, studying past fire events provides insight into civilizational
imprints in the past, which can be implicated in present and future forest fires for mitigation
and policy making. In this talk, I will discuss about forest fire history of fire prone
mountainous region, i.e., western Himalaya using the sedimentary black carbon as a fire
University of California
Berkeley, United States
February 28, 2023
Exploring the stratigraphic expression of extinction events: A case study
of the Late Ordovician mass extinction
The structure of the stratigraphic record controls the expression of extinction events in
the fossil record, causing last occurrences of taxa to predictably cluster below facies
shifts and major stratigraphic surfaces. These stratigraphically-generated clusters of last
occurrences can easily be mistaken for pulses of extinction, leading to
misinterpretations of the pattern and drivers of an extinction event. In this talk, I will
showcase the first published method for identifying and removing these
stratigraphically-generated clusters of last occurrences from basinwide analyses of the
fossil record to determine the underlying pattern of an extinction event. Critically, this
method provides a road map for future field-based studies of mass extinction events. I
will then highlight recent advances in applying this approach to the fossil record on
Anticosti Island (Québec, Canada), combining stratigraphic, paleobiological, and
geochemical data to develop an integrative perspective of Earth System change and the
Late Ordovician mass extinction.