Earthworms (Annelida: Oligochaeta) exhibit robust regenerative abilities that vary across species, body regions, and evolutionary lineages. This manuscript synthesizes classical and contemporary research on annelid regeneration—including wound closure, immune activation, blastema formation, segment reconstruction, and ventral nerve cord regrowth—and integrates these mechanisms with ecological observations from Prince Edward Island (PEI) earthworm communities. Drawing from cellular, molecular, and transcriptomic studies, we outline the processes that enable successful regeneration and contrast them with taxa that have lost regenerative capacity. We also contextualize regeneration within earthworm immunity, extracellular matrix (ECM) remodelling, and segmental patterning. Figures illustrate the regeneration sequence, coelomocyte dynamics, molecular pathways, and comparative outcomes. This synthesis provides a mechanistic foundation for interpreting regeneration in PEI earthworm species and supports future ecological and applied research.
Keywords: earthworm regeneration; blastema; neuroregeneration; fibrosis; tissue engineering