Preview
Family
Plexauridae
Common Name(s)
Delicate spiny sea rod
Colony Form
Bushy; laterally branched but usually not in one plane, to ~30 cm tall.
Axis
Present
Branches
Usually long and flexible, sometimes short relative to colony height.
Apertures
Narrow, with pointed lower lip bearing sharp spine, directed upward toward branch tip.
Mucus
None
Color
Whitish, bluish-white or gray; dries dries white, yellowish-brown or tan.
Sclerites
Outer layer and calices: spindles stout; calice spindles to >3 mm long, with smooth strong terminal spike. Inner layer: small 8-rayed capstans (double stars) ~0.1 mm long; some more elongated and rod-like, to 0.15 mm long, with two whorls of spines.
Habitat
Moderate to deep environments; sloping rocky substrates and patch reefs, 18-128 m.
Distribution
Florida Gulf Coast, West Palm Beach through the Florida Keys, Bahamas and Caribbean Sea.
Similar Species
Date Taken
4-11-2016
Notes
Similar to M. elongata, but with thinner branches, more projecting calices and deeper habitat. M. laxa spindles have single terminal spine, whereas those of M. elongata have multiple stout flattened spines along one side.