292-3 Paleoenvironmental reconstruction based on phenotypic variation of the coral Lublinophyllum sp. in the Mississippian Bangor Limestone (Alabama)

Session: Life and Environments Through Time and Space: Multi-Record Approaches to Stratigraphic Paleobiology, Part II

Presenting Author:

Authors:

Abstract:

Paleozoic corals can provide valuable paleoenvironmental data, yet their potential remains underutilized due to limited studies distinguishing environmental influences from genetic variability. Lublinophyllum flaccidum (Easton, 1943), a widespread rugose coral from the Bangor Limestone (Mississippian, Serpukhovian) in the Black Warrior Basin (BWB), thrived during late Serpukhovian global cooling. During this time, the BWB was part of a southwestward-prograding carbonate ramp with facies spanning lagoonal inner shelf, ooid shoals, and fore-reef buildups.  L. flaccidum from two contrasting settings of the Bangor Limestone, a fore-reef/open shelf and a lagoonal patch reef environment, is used to identify differences in morphological, reproductive, and habitat characteristics. Field data of coral density served as an indicator of habitat suitability.

Specimens from two sites were analyzed for linear growth (tabulae spacing), reproductive structures, and lonsdaleoid dissepiment development. Results reveal that fore-reef colonies exhibited faster linear growth, more abundant lonsdaleoid dissepiments, and higher density, suggesting adaptations to a favorable condition in a high-energy environment. In contrast, lagoonal colonies displayed slower growth, fewer lonsdaleoid dissepiments, and lower density, reflecting the less favorable growth conditions in a lower-energy setting.

Evidence suggests both corals shared similar reproductive strategies, combining asexual reproduction and planula settlement. Damage-recovery features were seen only in the fore-reef specimens, indicating episodic high-energy disturbances.  Phenotypic differences between sites could represent ecophenotypic variation within a single species or a divergence between closely related species adapted to different environments.  In either case, the morphological evidence supports geological interpretation of the depositional settings.   These findings underscore the value of integrating phenotypic and sedimentological evidence to refine palaeoecological interpretations. These data also contribute to the understanding of possible climate variability, coral resilience, and community level responses to environmental stress.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7224

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