SHARK (NEOSELACHII) VERTEBRAL CENTRA FROM THE QUATERNARY OF SOUTHERN BRAZIL

- In the southern coast of Brazil, shark fossil remains are commonly found along the current beach line. Most of these fossils are represented by fossilized teeth, while fossilized vertebral centra are less frequently found. In the present study, 26 fossilized vertebral centra of sharks (Neoselachii) from the Quaternary period were analyzed and described. The vertebral centra collected ex situ in the Coastal Plain of Rio Grande do Sul (CPRS) were analyzed using X-ray to observe internal structures. Two morphotypes based on their morphological structure were identified: the first was Lamnoid, identified in 17 vertebral centra, and the second was Carcharhinoid, identified in eight centra. The analyzed materials represented the first records of fossil vertebral centra of Neoselachii found in the region. The morphotypes are characterized based on the morphological structure of the vertebral centrum, allowing for differentiation and correlation with the genera of sharks in which a morphotype occurs. The study showed a direct correlation between the identified morphotypes and the lineages that make up the faunal diversity of Neoselachii occurring in the CPRS, both in the fossil record and currently. The Lamnoid morphotype occurs within Lamniformes sharks, such as the species Carcharias taurus, , Carcharodon carcharias,Isurus , Isurus oxyrinchus, , among others. The Carcharhinoid morphotype, on the other hand, is characteristic of Carcharhiniformes sharks, such as Carcharhinus leucas, , C. brachyurus, , Galeocerdo cuvier, , Galeorhinus galeus, , and others.