Spawning of Cassis tuberosa is recorded and described for the first time, based on observations carried out in the Tamandaré reefs, north-eastern Brazil. The specimen was laying over gravel substrate surrounded by macroalgae at a depth of 2 m. Cassis tuberosa uses an algal frond of the genus Padina to lay its eggs. The oothecae consists of approximately 200 vasiform capsules, orange in colour. The spawn of Cassis tuberosa is quite similar to that produced by its congener, Cassis madagascariensis; however, Cassis tuberosa spawns in the soft substrate provided by algal fronds while Cassis madagascariensis utilizes coarse, carbonate sand. Considering that Cassis tuberosa is the target of multiple commercial purposes, to expand our knowledge about its biology could contribute towards protecting the essential habitat of reproductively active individuals.
