First Major Appearance of Brachiopod-Dominated Benthic Shelly Communities in the Reef Ecosystem during the Early Silurian

Author

Cale A.C. Gushulak, The University of Western OntarioFollow

Degree

Master of Science

Program

Geology

Supervisor

Dr. Jisuo Jin

2nd Supervisor

Dr. Rong-yu Li

Joint Supervisor

Abstract

The early Silurian reefs of the Attawapiskat Formation in the Hudson Bay Basin preserved the oldest record of major invasion of the coral-stromatoporoid skeletal reefs by brachiopods and other marine shelly benthos, providing an excellent opportunity for studying the early evolution, functional morphology, and community organization of the rich and diverse reef-dwelling brachiopods. Biometric and multivariate analysis demonstrate that the reef-dwelling Pentameroides septentrionalis evolved from the level-bottom-dwelling Pentameroides subrectus to develop a larger and more globular shell. The reef-dwelling brachiopods in the paleoequatorial Hudson Bay Basin were more diverse than contemporaneous higher latitude reef-dwelling brachiopod faunas, with ten distinct community associations recognized in the Attawapiskat Formation. The absence or paucity of hurricane-grade storms in the paleoequatorial Hudson Bay Basin is interpreted as a major factor in the evolutionary success of the reef-dwelling brachiopods in the Attawapiskat Formation.

Recommended Citation

Gushulak, Cale A.C., "First Major Appearance of Brachiopod-Dominated Benthic Shelly Communities in the Reef Ecosystem during the Early Silurian" (2016). Electronic Thesis and Dissertation Repository. 3972.
https://ir.lib.uwo.ca/etd/3972