Ecological tiering and the evolution of a stem: the oldest stemmed frond from the Ediacaran of Newfoundland, Canada

Research at Mistaken Point, Newfoundland, reveals the oldest known stemmed frond from the Ediacaran period, Culmofrons plumosa. This discovery underscores a significant evolutionary adaptation where rangeomorphs developed sturdy stems to elevate above lower-tier feeding guilds, likely in response to competitive nutrient acquisition. The cylindrical macroscopic stem of C. plumosa, found in the Briscal Formation, marks a departure from typical modular branching patterns and highlights the role of ecological tiering in early ecosystem engineering. The study suggests that competition for dissolved organic nutrients drove this morphological innovation, expanding the functional morphospace available to Ediacaran organisms.

Laflamme, M., Flude, L. I., & Narbonne, G. M. (2012). Ecological tiering and the evolution of a stem: the oldest stemmed frond from the Ediacaran of Newfoundland, Canada. Journal of Paleontology, 86(2), 193–200. https://doi.org/10.1666/11-044.1