New observations on two umbraculid molluscs: Tylodina perversa (Umbraculida: Tylodinidae) and Umbraculum umbraculum (Umbraculida, Umbraculidae) along the central‑eastern coast of Sicily

The present note aims to provide detailed information on the biology and ecology of two marine heterobranch species belonging order Umbraculida: Umbraculum umbraculum Tylodina perversa . observations were carried out through scuba dives from 2017 May 2022 in 5 sites located along central-eastern coast Sicily. For each species, morphology, abundance, bathymetric range, substrates habitats, seasonality, further remarks here provided. Through this research, it was noted that Sicily, T. has never been found sponges genus Aplysina , its prey so far documented, but always algal substrates. Regarding U. observed counts among diet also poriferan C. crambe Moreover, study, documented for first time breeding activity reported detail.