Sycetta papillata sp. nov. (Porifera, Calcarea): the first record of Sycetta to the Southwestern Atlantic Ocean.

Sycetta is a poorly known genus of calcareous sponges, primarily distinguished by the presence of tubes (the choanocyte chambers) radially organized around the atrial cavity and completely separated from each other. These tubes, referred to as conical diverticula or more aptly as papillae, impart a distinctive appearance to the external morphology of the sponges. Herein, we present the description of Sycetta papillata sp.