THE BIOSTRATIGRAFICAL SIGNIFICANCE OF Limipecten GIRTY, 1904, AND Heteropecten KEGEL & COSTA, 1951 IN THE ITARARÉ GROUP

NEVES JACQUELINE; SIMOES MARCELLO; TABOADA, ARTURO CÉSAR

Crato

Congreso; XXIV Congresso Brasileiro de Paleontologia; 2015

Within the Late Paleozoic succession of the Paraná Basin, Brazil, bivalve are the most diverse and abundant benthic macroinvertebrates recorded in the fossil assemblages of the Itararé, Guatá and Passa Dois groups. Assemblages of the Itararé Group are mainly dominated by pectinids, particularly members of the family Heteropectinidae Beurlen, 1954. These occur in various marine assemblages and, in some cases, can form thin pectinid-rich shell pavements (e.g., Rio da Areia sandstone, Taciba Formation, Teixeira Soares, PR). Heteropecten paranaensis Neves et al., 2014 is the most common and abundant heteropectinid in the Taciba Formation. This is a key species since it is a good indicator of regional and interbasinal biocorrelations with other faunas, such as those recorded at Bela Vista do Sul (Butiá quarry), near Mafra, SC, and the famous Argentinean Eurydesma fauna of the Bonete Formation, Sauce Grande-Colorado Basin. Limipectinids are also recorded in the Itararé succession and is represented by Limipecten (formally Aviculopecten capivariensis Mendes, 1952), as pointed out by A.C. Rocha-Campos in his Full Professor-Thesis, in 1969. Until now Limipecten was only recorded in the Capivari Formation, in the central-eastern portion of the state of São Paulo. Limipectinids are characterized by a distinct ornamentation and can be easily distinguished of heteropectinids. The ongoing taxonomic study of the Rio da Areia bivalve assemblage in the uppermost portion of the Taciba Formation, Teixeira Soares region, indicates that not only heteropectinids are recorded in this molluscan fauna, but also limipectinids. These are represented by rare dorsal valves of Limipecten Girty, 1904. Despite of that, the record of this genus in the Taciba Formation is relevant for the following reasons: first, it adds a new taxa to the already diverse bivalve assemblage of the Taciba Formation in Teixeira Soares, PR (the most diverse bivalve fauna of the entire Gondwana succession of the Paraná Basin); second, suggests biocorrelations of this fauna with those of the Capivari Formation, third, a variety of distinct pectinid genera thrived in the glacial and post-glacial succession of the Paraná Basin and the taxonomic studied of those poorly explored marine faunas of the Itararé Group must be viewed from this perspective. [FAPESP 2009/17555-0]