Meeting Abstract
Thecosome pteropods are specialized pelagic mollusks that produce calcium carbonate shells of aragonite. Because pteropods may serve as sentinel species in regards to the effects of ocean acidification (OA) and other stressors, it is important to have a baseline understanding of their distribution, developmental timing and life history so that changes due to anthropogenic forcing can be recognized. Relatively little is known regarding the morphology and timing of progression through early developmental stages in the genus Limacina. In this study, we characterized the generation time, developmental timing and early shell formation in Limacina retroversa, an abundant and ecologically important thecosome species in the North Atlantic. Wild-caught adult L. retroversa typically laid gelatinous ribbons containing 10 – >100 eggs within 2 days of capture. When reared at 8°C, embryos advanced to the 16-cell stage by 11 hours post spawning (HPS) and to a mixture of blastula and early gastrula stages by 16 HPS. Free-swimming trochophore larvae hatched from the egg capsule after 3 days, and shelled veliger larvae were observed after 6-7 days. Calcein staining enabled visualization of early calcification within the round shell gland of trochophore larvae and assessments of incremental growth in juvenile pteropods. Eggs laid in captivity reached reproductive maturity after ~3 months, and adults continued laying eggs for the rest of their lives (approximately 6 months). This study provides a baseline and framework for future studies of the effects of environmental conditions on Limacina development.
