Once the competent brachiolaria
stage was attained, the larvae initiated their attachment-settlement phase and could no longer be sampled randomly because of interindividual variability in their swimming-attachment behavior.
During the life cycle, sea stars can develop either one (brachiolaria
or bipinnaria) or two types of larva (bipinnaria plus brachiolaria
) (Byrne, 2006).
Here we document the distribution of synaptotagmin immunoreactive cells and the organization and morphology of the NS in the brachiolaria
and juveniles of asterinids with different modes of development.
From the tip of the longest arm to the posterior end of the larval body, early brachiolaria
larvae have a length of about 600 [micro]m (615 [+ or -] 62 [micro]m; n = 9), which increases up to about 950 [micro]m for late brachiolariae (944 [+ or -] 111 [micro]m; n = 13).
On removal from the gonad, blastulae floated at the air-water interface and continued development through the brachiolaria
larval stage, metamorphosing into juveniles in 3 weeks.
Embryos removed from the gonad at the early blastula stage developed independently of the parent through the wrinkled blastula and gastrula stages into a planktonic highly buoyant brachiolaria
. The developing brachia appeared as three bulges (Fig.
ochraceus because this species possesses both bipinnaria and brachiolaria
larvae of the sea star Distolasterias brucei have been reported to undergo cloning in laboratory cultures (Kitazawa and Komatsu, 2000) in a manner identical to that described in previous reports (budding and autotomy).
This species has planktotrophic development through bipinnaria and brachiolaria
feeding stages (Byrne and Barker, 1991).
For example, Astropecten latespinosus (300 [[micro]meter]) has an abbreviated lecithotrophic development, lacks both a bipinnaria and a brachiolaria
stage, and is in the plankton for only about 4 days (36).
In Asterina gibbosa (abbreviated development), hatching occurs 85 to 96 h after fertilization and produces a thoroughly transformed brachiolaria
that rapidly adheres to the substratum (Marthy, 1980).
regularis shows what is considered to be the ancestral pattern for asteroids (Strathmann, 1978), developing through planktotrophic bipinnaria and brachiolaria
larvae (Byrne and Barker, 1991).