Comparative anatomy of the olfactory rosete of tiger shark, Galeocerdo cuvier (Chondrichthyes, Galeocerdonidae) and the guitarfish, Pseudobatos percellens (Chondrichthyes, Rhinobatidae) and possible ecological implications

Abstract

Anatomical studies approaching ecomorphological interpretation allow to understanding the organism-environment interactions. Elasmobranchs (sharks and rays) are pivotal vertebrates in the trophic systems of marine environments, remarkably due to their role as predators and mesopredators. The olfactory organs of elasmobranchs are important in locating their prey. The presente study intend to describe the anatomy features of the olfactory rosette of two distinct elasmobranch ecomorphotypes having different feeding habits and habitat use (the tiger Shark, Galeocerdo cuvier, and the guitarfish, Pseudobatos percellens) in order to identify the differences and its ecological implications. The specimens come from artisanal and industrial fisheries that operate on the Southeastern Brazil. For each species, a minimum of 10 specimens will be analyzed, covering both sexes and different size classes. After removing the olfactory rosette, meristic and morphometric data will be taken and the data obtained will be compared concerning ecomorphological parameters (food and habitat use).