Ecology and systematics of a new exceptionally preserved paracrinoid (Echinodermata) from the Neuville Formation of Québec, Canada

Abstract New paracrinoid echinoderm specimens are described from the Late Ordovician, Neuville Formation of Québec, Canada. These new specimens share key features with the unusually preserved and poorly known Amygdalocystites? gorgo . Based on the new specimens, this taxon is distinctive from Amygdalocystites and requires establishing a new genus. Quebecocystites gorgo new genus new combination, is exceptionally preserved, displaying fine details of the feeding structures, stalk, and holdfast, which are rarely preserved within paracrinoids. This new taxon has a combination of characteristics including an amygdaloidal body with two long ambulacra, a theca composed of numerous, unorganized, and unornamented plates lacking respiratory structures, thin and reduced floor plates, and long thin brachioles. The inclusion of this new taxon into a previously published phylogenetic analysis indicates a close relationship with the Platycystitidae and suggests that respiratory structures evolved independently four times within paracrinoids. Finally, the exceptional preservation of Q. gorgo new combination provides new insights into the paleoecology of paracrinoids including direct comparisons with other suspension-feeding echinoderms allowing for the assessment of potential competition, regeneration of brachioles, and galls and pits suggesting parasitism. UUID: http://zoobank.org/1da4f244-b5bf-4b57-bfed-e35a08a5194a