“…The species of this genus occur from shallow to deep waters, being most abundant in environments rich in organic matter, as well as in sunken bones and in reducing environments (Paavo et al, 2000;Dahlgren et al, 2001;Rouse & Pleijel, 2001;Paxton & Morineaux, 2009;Wiklund et al, 2012;Taboada et al, 2013;Salvo et al, 2014). Many species are used as models for embryological, behavioral, evolutionary and bioassay studies due to their easy maintenance in the laboratory (Åkesson, 1970;Brown & Ahsanullah, 1971;Pfannenstiel, 1977;Hooftman & Vink, 1980;Sella, 1985Sella, , 1991Sella et al, 1997;Paavo et al, 2000;Sella & Lorenzi, 2000;Paxton, 2004;Prevedelli et al, 2006;Schleicherova et al, 2010).…”