Quasiaulacera, a new Hirnantian (Late Ordovician) aulaceratid stromatoporoid genus from Anticosti Island, Canada

Researchers have discovered Quasiaulacera, a new genus of aulaceratid stromatoporoids from the Hirnantian (Late Ordovician) period on Anticosti Island, Canada. This genus, characterized by its large, columnar form and unique structural features, includes two species: Q. stellata and Q. occidua. The study reveals that Quasiaulacera thrived during a period of global cooling linked to the Hirnantian glaciation but faced extinction at the Ordovician-Silurian (O/S) boundary. This finding supports evidence that the Hirnantian era was marked by both innovation and migration in tropical latitudes, despite significant generic loss. The research combines detailed morphological analysis with stratigraphic data from the Ellis Bay Formation to elucidate the evolutionary dynamics of stromatoporoids during this critical period.

Copper, P., Stock, C. W., & Jin, J. (2013). Quasiaulacera, a new Hirnantian (Late Ordovician) aulaceratid stromatoporoid genus from Anticosti Island, Canada. Journal of Paleontology, 87(4), 664–676. https://doi.org/10.1666/12-150