The Z stack of a vestibula larva of the sea urchin Heliocidaris erythrogramma recorded by confocal laser scanning microscopy

Abstract

The Z stack in this archive is representative of a vestibula larva of H. erythrogramma at an early stage in the development of the hydrocoele recorded in an Olympus FluoView 1000 laser scanning system. It is from a study of an echinoid with abbreviated larval development that shows the morphogenesis of the adult coeloms. The development is asymmetric with a larger left coelom forming on the larval-left side and a smaller right coelom forming on the larval-right side. The hydrocoele forms from the anterior part of the left coelom. The five lobes of the hydrocoele from which the pentamery of the adult derives take shape on the outer distal wall of the anterior part of the left coelom. The hydrocoele separates from the more posterior part of the left coelom, which becomes the left posterior coelom. Both larval and adult polarities are evident in this larva, supporting an origin from a single ancestral polarity.