Banca de DEFESA: LIVIA PACIFICO SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LIVIA PACIFICO SILVA
DATE: 29/05/2026
TIME: 14:30
LOCAL: Videoconferência (Google meet)
TITLE:

FOSSIL DECAPOD CRUSTACEANS FROM THE JANDAÍRA FORMATION (POTIGUAR BASIN), NORTHEASTERN BRAZIL: STRATIGRAPHIC CONTEXT, DIVERSITY, PALEOENVIRONMENTAL AND PALEOECOLOGICAL SIGNIFICANCE

KEY WORDS:

Brachyura; Morphometrics; Chelipeds; Sedimentology

PAGES: 62
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The opening of the South Atlantic during the Cretaceous reorganized coastal ecosystems along the equatorial margin of Brazil and promoted the expansion of shallow marine habitats occupied by diverse benthic groups, including decapod crustaceans. Here, we report new occurrences of fossil decapods from the Jandaíra Formation (Potiguar Basin, northeastern Brazil), based on material collected at the Canudos outcrop, for which a detailed sedimentological and stratigraphic framework is also presented. A total of 39 specimens assigned to Decapoda were analyzed, most represented by isolated dactyli and other cheliped fragments. Morphometric analysis of the best-preserved specimens allowed the recognition of at least five morphotypes, revealing morphological variation within the assemblage. This variability likely reflects a combination of taxonomic diversity and intraspecific factors, such as ontogeny, sexual dimorphism, and heterochely, while differences in cheliped morphology point to distinct trophic strategies. The sedimentological and paleontological data indicate deposition in an inner carbonate ramp system, characterized by alternating subtidal, lagoonal, and peritidal conditions driven by high-frequency fluctuations in relative sea level. The decapod remains are associated with proximal lagoonal facies, and their predominance as isolated chelipeds suggests pre-burial exposure, disarticulation, transport, and some hydrodynamic sorting. Although the fragmentary nature of the material precludes refined taxonomic identification, these fossils expand the record of decapods in the Potiguar Basin and constitute the first documented occurrence of the group in the Jandaíra Formation, contributing to a better understanding of the structure and dynamics of benthic communities in shallow carbonate systems of the Upper Cretaceous equatorial South Atlantic.

 

COMMITTEE MEMBERS:
Externo à Instituição - FELIPE AUGUSTO CORREIA MONTEIRO - IFCE
Presidente - 1283832 - ALINE MARCELE GHILARDI
Externa à Instituição - LUDMILA ALVES CADEIRA DO PRADO - URCA