189 Paleontology, Paleoecology/Taphonomy (Posters)

Tuesday, 21 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Environmental Controls on Niche Space Occupation and Feeding Ecology of Late Ordovician (Katian) Crinoid Communities

Paper number: 189-2
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Understanding the role of environmental variables in ecological strategies and niche space occupation is critical for disentangling drivers of community assembly and evolution over time. Communities of species all showing similar traits can indicate a dominant process of habitat filtering where specific traits are required for survival. In contrast, high levels of trait variation within a community indicate competition plays a stronger role. Crinoids are incredible paleoecological model specimens: their skeletons preserve ecomorphological traits reflective of their filter-feeding life mode, and rapid post-mortem disarticulation of crinoid skeletons means death assemblages containing well-preserved specimens represent ecological snapshots of their paleocommunities. Crinoids are also well-represented through time, allowing for the potential to track their shifting ecologies during radiations, extinctions, and in between. The Katian Stage of the Late Ordovician (453.0-445.2 Ma) was a time of high taxonomic, ecological, and morphological diversity for crinoids resulting in elevated community complexity. Crinoid generic diversity reached its Ordovician peak during the Katian, making it an ideal time interval to investigate the ecological strategies of crinoids in different sedimentary environments.

 

To determine how crinoid feeding strategies co-vary with environmental variables, we compared the feeding ecology and niche space occupation of multiple Katian crinoid communities from different environments. Here, we present results from an analysis of the feeding ecology of crinoids from an exceptionally well-preserved Katian fauna from the Neuville Formation (Upper Trenton Group, Quebec, Canada). A principal coordinates analysis (PCO) was conducted to model the ecomorphospace occupation of the Neuville crinoid fauna based on ecomorphological traits collected from fossil specimens. Traits associated with the primary axes of differentiation within ecomorphospace included calyx size and filtration fan density. To investigate how environmental differences may affect crinoid feeding ecology, we compared the Neuville and Brechin (Ontario, Canada) crinoid faunas. The Neuville fauna represents a low-energy, deep-water marine environment, whereas the Brechin represents a shallow marine shelf setting near in age and location to the Neuville. Additional comparisons with crinoids sampled across environmental gradients from the Cincinnatian Series provide further data for investigating relationships between feeding ecology and environmental variables. Understanding how crinoid niche space occupation and ecological strategies vary environmentally will allow for more effective comparison between temporally distant crinoid communities and establish the drivers of community assembly and evolution over time.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412513

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