Projeto raia de fogo: ecologia e filogeografia de Dasyatis marianae Gomes, Rosa & Gadig 2000

Abstract

A large number of sharks and rays inhabit tropical coastal áreas. Unlike pelagic environments in the open sea, coastal areas are more subject to variations, both by human actions, continental influence, geographic or climatic, resulting in a wide variety of habitats. Some species may have close relationship with certain habitats as to be possible to distinguish specific standards for different locations. Dasyatis marianae is an endemic stingray of northeastern Brazil, occurring from Maranhão to the south of Bahia, exclusively on the continental shelf. With a restricted distribution, this stingray showed stenotopic, with low amplitude tolerance to environmental conditions, especially temperature, salinity and depth. Consequently, D. marianae showed morphological differences, ecological and molecular intraspecific over their geographical distribution. The stingrays most southerly distribution are larger and have a distinct morphometric standard against the rays of the northernmost locations. In general, D. marianae is divided into two populations genetically structures, a large population connecting the extremes of the distribution and a more restricted population located in Salvador coast. Local environmental characteristics insulate this population, even without a physical barrier easy to identify. The pattern of population structure of D. marianae suggests an isolation by environment (IBE), where the interaction between the species and the habitat build their spatial variation, regardless of distance. This work, based on an integrative approach (morphology, feeding, niche modeling and phylogeographical) certainly generates grants for management actions and conservation of this species, according to Ordinance MMA n° 43/2014, is a priority for research on your conservation state.