First record of Amorphinopsis atlantica (Porifera: Demospongiae: Halicondriidae) in the Paraguau River estuary: Is its presence an invasion or an adaptation to changing environmental conditions?

Herein, we describe the first-ever identification of Amorphinopsis atlantica in the Iguape Bay (Bahia, Brazil). The bay, where fish and shellfish harvesting has been practiced for centuries, is part of the Paraguau River estuary, the main tributary of Todos-os-Santos Bay. Massive encrusting specimens of sponge species growing on three different types of substrates were collected manually in the intertidal zone of a mangrove in an estuary; despite being initially described in Brazilian subtropical coastal waters. There are records for A. atlantica in the southeastern states of Rio de Janeiro, So Paulo, and northeastern states of Pernambuco, Paraba (Brazil), Falcn (Venezuela), Campeche and Vera Cruz (Mexico), in the department of Crdoba (Colombia), in the Hidden Creek district (Belize) and the Atlantic coast of Costa Rica. In the collection area, the construction of a dam in the tidal river and the subsequent hydroelectric power have changed the estuary dynamics to a threshold condition expected to be tolerated by new colonizers organisms. In this unpredictable scenario, Amorphinopsis atlantica has found a new habitat for more than 15 years. Local people have alleged that the sponge may cause recurring skin rashes, but this has not yet been confirmed. Monitoring and study on the distribution and abundance of the species and a medical survey may clarify the role of the sponge on the skin dermatitis complained by the local population.