Appearance and biology
Metacrinus rotundus continues growing throughout its lifetime and is able to regrow its arms and stalk if they are damaged. The stalk can be as long as 40cm in adults.
Diagnostic description of Metacrinus rotundus
Isocrinid with 4 or more primibrachials.
Size
M. rotundus possesses a fan-like crown of arms supported by a stalk.
In adults:
- crown length is 10-21cm
- stalk length is 30-40cm
Growth
M. rotundus grows:
- continuously throughout its lifetime
- 36-54cm/year
Like many crinoids, it possesses the ability to:
- re-grow its arms (Oji and Okamoto, 1994)
- and even the entire stalk (Nakano et al 2004)
Disembodied stalks are known to survive many months after the crown has detached (Oji and Amemiya, 1998).
Life expectancy
M. rotundus probably lives for over 10 years (Oji, 1989).
Dispersal
Dispersal occurs via a zooplanktonic larval stage. Adults are capable of limited mobility within their habitat.
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Reproduction and lifecycle
Metacrinus rotundus occurs as both male and female individuals. Learn how and when reproduction takes place and about the various developmental stages of this stalked crinoid.