A growth model for the highly abundant Ediacaran tubular organism <i>Funisia dorothea</i>

Abstract Funisia dorothea Droser in Droser and Gehling, 2008 is an inferred metazoan-grade tubular organism, endemic to the Ediacara Member, Rawnsley Quartzite, of South Australia (~555–550 Myr), which is characterized by a hollow, elongate body constructed of uniserially repeating modular elements and is one of the most abundantly reported members of the Ediacara biota. Thus, Funisia Droser in Droser and Gehling, 2008 has broad significance for developing understanding of the Ediacara biota and provides a large dataset for testing hypotheses on the biological traits of Ediacaran tubular organisms. This study investigates size changes in Funisia ’s modular elements to provide further insight into the paleobiology of this organism through the development of a holistic growth model. Results demonstrate that growth in Funisia was highly regulated to maintain uniform modular element width along the length of an individual and, thereby, an overall cylindrical form despite increasing module width throughout ontogeny. The growth model proposed here is compared with the pre-established growth model for another modular Ediacaran tubular organism, Wutubus annularis Chen et al., 2014, demonstrating that the two taxa had distinct growth patterns and disparate autecological strategies, despite a shared constructional morphology.