Clonal Growth Patterns in Colonial Anthozoan Corals

Corals are modular organisms that use asexual reproduction (i.e., budding) to increase the size of the colony by adding new polyps. Clonal modularity offers several advantages, such as the ability to sustain partial mortality, redistribute resources internally, replace or repair single mod‑ules, and delay senescence, potentially supporting millenary growth. Despite the global importance of coral reefs, little is known about clonal growth rules in anthozoan corals. Coral clonal growth was reviewed to synthetise current understandings and identify gaps driving future research efforts. Despite corals present high plasticity, their growth is dictated by strong intrinsic regularities at dif‑ferent life stages and modularity levels. For example, a six‑polyps crown with fixed distances among polyps is typically formed in the early development stages of Stylophora pistillata larvae. Similarly, specific developmental regularities are observed in the budding of azooxanthellate Dendrophylliidae polyps, which are consistently maintained across generations and species. In Octocorallia, colony shape is preserved by maintaining a constant ratio between the total number of branches and mother branches. Concurrently, environmental factors (i.e., light and hydrodynamics) play a fundamental role in shaping the final morphology of the colony, driving the architectural design at different levels of modularity. Some species revealed higher plasticity at the branching level in contrast with the predetermined shape assumed by the colony. Several models have been proposed to describe the environmental modulation of coral growth, mostly in branching forms. However, a holistic, universal model applicable to a broader range of coral taxa is still lacking. Understanding the fundamental rules underpinning coral clonal growth is essential to improving predictions of coral reef recovery, inferring stress on coral colonies and guiding restoration efforts.