Arinosaster patriciae gen. nov. et sp. nov. A–C Details of the sponge colonies encrusting the sinkhole rock wall crevices, from the whitish initial borders to the grayish tubular projections surmounting the fine deposited sediments D One tubular projection of A. patriciae photographed in alcohol. Photos A–C by Patricia Arrais Rodrigues da Silva. Photo D by Alexandre Cunha Ribeiro.