Appearance and biology

Diagnostic description of Metacrinus rotundus

Isocrinid with 4 or more primibrachials.


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


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 occurs via a zooplanktonic larval stage. Adults are capable of limited mobility within their habitat.


  • A stalked crinoid on a seamount
    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.