Nymphon australe has a brooding, lecithotrophic larval protonymphon stage that limits dispersal and is not
eurybathic. Thus, we are uncertain whether long-distance genetic connectivity is due to glacial activity, the ACC, other currents, the ability to raft on other organisms, or other unknown methods of mobility (Moon et al, 2017).
Early stages of embryology and larval development have been reported for a number of bathyal and abyssal invertebrates (Prouho, 1888; Mortensen, 1921; Young and Cameron, 1989; Young and Tyler, 1993; Young et al., 1996b, c), but the complete larval development has been described for only a single
eurybathic echinoid, Cidaris cidaris (Prouho, 1888).