Larval development and metamorphosis of the Australian diadematid sea urchin Centrostephanus rodgersii

Abstract

Summary The complete larval development through to metamorphosis of the sea urchin Centrostephanus rodgersii is described for the first time. Embryos developed from small eggs (113 μm) to large echinopluteus larvae (3250 μm arm length) over a period of approximately 4 months. Fully developed larvae are two-armed echinoplutei with densely pigmented postoral and anterolateral arms and oral hood. The posterodorsal and the preoral arms do not appear to form. The skeletal body rods form a basket-like structure posteriorally, and fenestrated skeletal rods support the postoral arms. Five primary podia emerge from the vestibule, at around 100 days old, and attach to the substrate at settlement. The larval epidermis recedes from the arm rods and collects on the aboral surface of the juvenile, and the adult rudiment emerges as the larva metamorphoses to the juvenile stage.