Life History Traits
Reproduction
Crinoids go through sexual reproduction and are gonochoric, meaning an individual is either male or female, with the gonads (ovaries or testes) stored within the pinnules or arms (Ruppert et al 2004). The gonads are rarely found within the arms and aren’t found within all pinnules, only within the pinnules that lie closest to the central disc (Ruppert et al 2004). The gonads contain a genital tube, called rachis, which is encapsulated in a blood cavity called a hemal sinus, which is then surrounded by a genital coelom (Ruppert et al 2004).When the eggs or sperm reach maturity within the gonads they rupture the pinnule walls and are released into the water column in a spawning event (Ruppert et al 2004). Most comatulid crinoids have their reproductive seasons extended throughout the season but spawning events seem to occur when the temperature and plankton availability within the environment goes through a considerable season variation, usually during late spring and early summer when plankton is at its highest abundance (Alender et al 1966).
Crinoids don’t seem to undergo clonal reproduction or intentional asexual reproduction (Alender et al 1966, Ruppert et al 2004). Although crinoids have the ability to regenerate body parts that have been cast off or removed it does not appear to be spontaneous or induced division of the body to produce two individuals from one as seen in asexual reproduction (Alender et al 1966, Ruppert et al 2004).
Development
Crinoid comatulid development involves an early gastrula stage similar to that seen in other echinoderm groups where the embryo elongates during the formation of the coelomic sacs into a vitellaria or free-swimming larval form called doliolaria. This non-feeding doliolaria has a barrel-shape with an anterial, apical tuft, with bilateral symmetry and four to five hoop-like ciliated bands (Ruppert et al 2004). Doliolaria settles to the bottom after a period of time in the water column and attaches to the substrate using an adhesive pit (glandular midventral depression) located near the apical tuft (Ruppert et al 2004). The larva then undergoes metamorphosis into a sessile, stalked crinoid called the pentacrinoid that resembles a small sea lily (Ruppert et al 2004). After a period of time the pentaramous crown with its newly developed cirri, breaks free from the stalk and the individual then adopts its free living adult stage (Ruppert et al 2004).
No studies have been completed in regards to the reproduction and development of C. glebosus but as most comatulid crinoids undergo the same stages of reproduction and development it can be assumed the C. glebosus undergo similar processes.
Age of Maturity and Life Span
There have been no studies examining the age of maturity or life span of C. glebosus but previous studies have found that although age of maturity varies between species, most species reach maturity the summer following the one in which it was born and has a life span of two to three years (Alender et al 1966).
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