Doliolaria

Doliolaria is a developmental larval stage of crinoids, a class of marine echinoderms that includes sea lilies and feather stars. As part of the crinoid life cycle, fertilized eggs develop into free-swimming larvae, of which the doliolaria form is one early pelagic stage. The term is used to describe a distinct, ciliated larval morphology observed in many crinoid species.

Morphology and biology of the doliolaria stage are variable among crinoids, but these larvae are generally motile and adapted to planktonic life. They possess ciliated bands that drive swimming and feeding, and they present a simple body plan with oral and aboral surfaces and projections or appendages that aid in locomotion and capture of microalgae or other suspended food particles. The precise appearance can differ between taxa, reflecting the diversity of crinoid lineages.

Development and metamorphosis proceed from the doliolaria to a juvenile crinoid, which then settles to the substrate or remains free-living depending on the lineage. This transition marks the shift from pelagic larval life to the benthic or sessile juvenile stage that characterizes many crinoids. The doliolaria stage is of interest to researchers studying echinoderm development, evolutionary biology, and the interpretation of crinoid fossil records.

See also Crinoidea, Echinodermata, Larval development.