Corinne Soucy
Université de Montréal
M.Sc. candidate
Supervisor: Christopher Cameron
Start: 2021-06-01
End: 2024-10-11
M.Sc. candidate
Supervisor: Christopher Cameron
Start: 2021-06-01
End: 2024-10-11
Project
Modeling the paleoecological trophic network of the Lower Ordovician Fezouata Shale (Morocco) fossil faunaThe Fezouata Shale is a fossil site with exceptional preservation discovered in the early 2000s in Morocco. The fossils found there date back to the Early Ordovician, a period between the Cambrian Explosion and the Great Ordovician Biodiversification Event (GOBE). These two events having led to a complexification of ecosystems and their trophic networks, this project aimed to further our understanding of the evolution of marine communities. To do so, a list of all species found in Fezouata, the most comprehensive published to date, was compiled. It was used to reconstruct Fezouata’s empirical trophic network, of which 15 properties were calculated and subsequently compared to a model of the trophic structure of the Fezouata network, using the niche model, known for accurately representing modern trophic networks. The Fezouata network was quite similar to modern trophic networks, but nonetheless possessed a slightly higher proportion of top (without predators) and herbivore species. This network was also compared to two others from the Cambrian : those of the Chengjiang and Burgess Shales. The Ordovician network was rather similar to that of Burgess but had a higher proportion of basal species and a lower mean trophic level than that of Chengjiang. This is logical for the Early Ordovician, when filter-feeders proliferate following a diversification in plankton. However, the other 13 properties of all three trophic networks remained similar, but many did show a progressive increase or decrease through time, from the Chengjiang Shale to the Burgess Shale, to finally the Fezouata Shale. These results support the idea that the GOBE is not as independent from the Cambrian Explosion as previously thought and that both events would instead represent two parts of one single long-lasting diversification event.
