Morphometric reduction in Australocoelia palmata associated with the Devonian marine transgression

Author(s)

Ribeiro, Victor Rodrigues ; Nogueira, Caio Santos ; Sedorko, Daniel ; Sousa, Felipe Nascimento ; Caminha, Silane Aparecida Ferreira da Silva ; Ghilardi, Renato Pirani

• Document type: Journal article
• Source: Journal of South American Earth Sciences; v. 141, p. 9-pg., 2024-05-20.

Abstract

During the Devonian, the Gondwana occupied areas close to the South Pole and hosted many epicontinental seas, with a benthic fauna dominated by brachiopods. Due to the limited preservation of chronostratigraphic markers (e.g. conodonts and graptolites) on this paleocontinent, the study of ichnology and palynology has helped to track Devonian events in the South American and African continents. In the Parana<acute accent> Basin, there are records of several transgressive and regressive cycles that occurred throughout the Devonian. Thus, this study considers changes in the size and shape of the brachiopod (Australocoelia palmata Morris and Sharpe, 1846) in the LowerMiddle Devonian Chapada Group (Early Pragian-Eifelian) in the state of Mato Grosso, Brazil as a proxy for paleoenvironmental change. Morphometric analysis (length, width and length x width) shows that fossils collected in transgressive strata (Lower Unit 2, Chapada Group) had the most diverse sizes. However, fossils from a regressive context (Upper 2 Unit, Chapada Group) tend to be 25% smaller in length and width. This case of dwarfism in Australocoelia palmata may be related to changes in the composition of marine waters, resulting from an anoxic moment, driven by sea-level fluctuations. (AU)

• FAPESP's process: 20/12409-4 - Paleobiogeography and migratory routes of devonian paleoinvertebrates from Brazilian Intracratonic Basins of Paraná, Parecis, Parnaíba and Alto Tapajós
• Grantee: Renato Pirani Ghilardi
• Support Opportunities: Regular Research Grants
• FAPESP's process: 23/01445-8 - Ultrastructure of spermatozoa of the caridean shrimps of Brazil: a modern taxonomic approach through morphological and phylogenetic integration
• Grantee: Caio dos Santos Nogueira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral