Embryonic and larval development of Pinctada margaritifera (Linnaeus, 1758)

We describe the developmental stages of the black-lip pearl oyster, Pinctada margaritifera (Linnaeus, 1758), larvae from fertilisation through embryonic development and larval growth in the laboratory at 28 ± 1°C. Larvae were anesthetised, fixed, critical-point dried and examined using a scanning electron microscope. We examined embryonic development (fertilisation, polar body, blastomeres, gastrula) and attributes of the larval shell (size, prodissoconch I/II, growth lines, provinculum, shell fracture) and larval velum. The first polar body formed 24 min after fertilisation and fertilised eggs had a mean diameter of 59.9 ± 1.4 μm. The earliest actively swimming trochophore appeared 8-12 h after fertilisation. The D stage was reached approximately 24 h after fertilisation and measured 79.7 ± 2.3 μm in shell length. Ten-day-old larvae had umbones that arose opposite each other above the hinge axis and 22-day-old larvae, with a mean shell length of 230.8 ± 4.9 μm, developed a pigment spot just before entering the pediveliger stage. © Malacological Society of Australia 2013