16 Paleontology of North America

Added from Discipline submissions.

Monday, 9 March 2026
1:30 PM - 4:30 PM
RCC, 106

Taphonomy, taxonomy, and ecology of new and old paracrinoid specimens from the Neuville Formation of Québec, Canada.

Paper number: 16-7
Program: Technical Sessions
Time: 3:15 PM – 3:30 PM

Authors

Abstract

New paracrinoid echinoderm specimens were recently discovered from the Late Ordovician, Neuville Formation of Québec, Canada. Previously, a single specimen of paracrinoid had been reported from this locality in 1948, which showed unusual preservation as a glauconitic film. The specimen was briefly described, noting the poor preservation and distortion in its thecal outline.  However, this specimen had long, thin feeding appendages, which are unique within paracrinoids, such that it was given a species name and tentatively placed within the genus Amygdalocystites. Based on the preservation, the original author expressed doubt that more stereotypically preserved specimens could be confidently linked to species and the specimen was still in his personal collection at time of publication. Examinations of this specimen, along with the newly discovered specimens, show that they share key features and are distinct from Amygdalocystites, which requires establishing a new and separate genus. The new specimens are exceptionally preserved displaying fine details of the feeding structures, stalk, and holdfast, features rarely preserved within paracrinoids. This new taxon has a combination of characteristics including an amygaldaloidal 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.The exceptional preservation of these new specimens 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.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411743

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