A quantitative and statistical discrimination of morphotaxa within the Ediacaran genus Palaeopascichnus

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 a...