The Palaeopascichnida are a relatively understudied component of the Ediacaran biota. The eponymous Palaeopascichnus delicatus is comprised of serially arranged, mm-scale allantoid chambers that have variously been interpreted as evidence of movement, feeding traces, and body fossils of various affinities. Palaeopascichnus has most recently been compared to the deep-marine Xenophyophora, an extant group of large benthic protists that is characterized by large size and possession of stercomata within their cells. The construction and growth of the palaeopascichnids, and its implications for their phylogenetic affinity, are assessed using material from the Avalon Peninsula of Newfoundland, Canada. The application of quantitative morphological analysis to the study of over ninety well-preserved specimens of Palaeopascichnus demonstrates considerable variation in chamber shape and size, and in behaviour along the chamber series. The combination of morphometric and multivariate statistical analysis allows the recognition of natural groups within the dataset, thereby demonstrating variability within and between morphospecies. Morphological comparisons of fossil palaeopascichnids with extant protistan taxa support the proposed protistan affinity of Palaeopascichnus, allowing further resolution regarding the diversity and disparity within this prominent element of the later Ediacaran biotas of Gondwana and Baltica.