Work

Thecate medusozoan polyp from the Upper Ordovician of Québec

Year: 2026

Type: article

Abstract: The fossil record of medusozoan cnidarians is relatively sparse and, in some cases, contentious. Here, we describe a new genus and species of a well-preserved, soft-bodied, tubicolous polyp, Paleocanna tentaculum n. gen. n. sp., from the Upper Ordovician (Katian) Neuville Formation in Québec. These fossils, preserved as carbonaceous compressions, were found in association with typical shelly assemblages. Fifteen slabs of shaly limestone containing ~ 135 specimens of Paleocanna tentaculum n. gen. n. sp. were examined. Individual polyps occupied upright tubes, which occur either solitarily or in clusters. Some tubes exhibit a striated periderm near their base. The polyp is elongated, with a rounded aboral end and a consistent ring of tentacles protruding distally from the tube. A phylogenetic analysis of 69 taxa and 236 discrete morphological characters indicated that the species is more closely related to the crown clade including Staurozoa, Cubozoa, Scyphozoa than to other fossil medusozoans, e.g., conulariids and carinachitids. The uniform orientation of specimens on single slabs suggests rapid burial. Paleocanna tentaculum n. gen. n. sp. represents an exceptionally preserved member of an Ordovician deposit exhibiting Burgess Shale-type soft-tissue preservation. UUID: http://zoobank.org/12d03d82-1925-4578-873e-2e9c23db635f

Source: Journal of Paleontology

DOI: 10.1017/jpa.2025.10211

Authors: Greta Ramirez-Guerrero, Huda Alghaled, Louis-Philippe Bateman, Mario Cournoyer, Christopher B. Cameron

Institutions: Université de Montréal, McGill University

Language: English

Topic: Paleontology and Stratigraphy of Fossils

Subfield: Paleontology

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,550

Funders: Natural Sciences and Engineering Research Council of Canada, Fonds de recherche du Québec – Nature et technologies