Embryonic Velar Structure and Function of Two Sibling Species of Crepidula with Different Modes of Development

• Published in: The Biological bulletin (Lancaster) Vol. 203; no. 1; pp. 80 - 86
• Main Authors: Chaparro, O. R., Charpentier, J. L., Collin, R.
• Format: Journal Article
• Language: English
• Published: United States Marine Biological Laboratory 01.08.2002; University of Chicago Press
• Subjects: Animals; Body Constitution; Body Patterning - physiology; Cilia; Crepidula dilatata; Crepidula fecunda; Development and Reproduction; Eggs; Embryo, Nonmammalian - physiology; Embryo, Nonmammalian - ultrastructure; Embryos; Evaluation; Evolution; Evolution (Biology); Fecundity; Invertebrates; Larvae; Larval development; Marine; Marine biology; Marine invertebrates; Microscopy, Electron, Scanning; Mollusca - classification; Mollusca - embryology; Morphology; Morphology (Biology); Nurses; Physiological aspects; Swimming; Velar consonants; United States
• ISSN: 0006-3185; 1939-8697
• DOI: 10.2307/1543460

The structure and function of the embryonic velum of two closely related species of Crepidula with different modes of development are examined. The velum of C. dilatata, a direct developer whose embryos feed on nurse eggs, does not differ substantially from the velum of C. fecunda, a species with planktotrophic larvae. Although velar ciliation develops earlier in embryos of C. dilatata, embryos of both species were able to feed on small particles, using the opposed-band ciliary mechanism. However, the embryos of C. dilatata lose this ability as they grow. The embryos of C. dilatata were not able to swim, whereas those of C. fecunda swam consistently in vials of seawater. This difference in swimming ability is probably due to differences in velum-body size allometry between the two species.