First report of a precocious form of strobilation in a jellyfish, the South American Pacific sea nettle Chrysaora plocamia

Abstract

Scyphozoans display a high level of developmental plasticity, including asexual reproductive strategies in their polyps. Irrespective of the alternating medusa-polyp life cycle, life stages or even complete generations can be omitted, occasionally or consistently, in some species. For example, ephyrae can be produced directly by planulae, leaving out the polyp generation, and polyps can produce free-swimming planula-like propagules, thus bypassing the medusa generation. Here, we raised Chrysaora plocamia polyps under unusually high, naturally occurring temperatures, which resulted in these polyps being unable to strobilate but able to form podocysts. Early excysts that hatched from these podocysts produced ephyrae in a premature type of strobilation. This developmental shortcut, previously unknown in scyphozoan life cycles, is described in the present report.