Preview
Family
Plexauridae
Common Name(s)
Giant slit-pore sea rod, Nodding plexaurella
Colony Form
Colonies usually tall with few long branches in multiple planes; to 1.5 m tall.
Axis
Extensively mineralized by calcite, up to 85% mineral aggregate at branch tips; aggregates up to 5 mm in length and embedded longitudinally in the gorgonin (Lewis et al. 1992).
Branches
Sparse, dichotomous; terminal branches 10-15 mm across and up to 1 m long; tips usually somewhat enlarged or bulbous.
Apertures
Distinctly slit-shaped apertures; calices form widely separated hemispherical mounds.
Mucus
None
Color
Tan, light brown to mauve; putty-gray or light brown in alcohol.
Sclerites
Polyp armature: strong; blunt rods to 0.3 mm long. Axial layer: spindles, crosses and capstans, the latter often with two longer rays, 0.15-0.25 mm long. Middle layer: large, slender spindles, triradiates, 4-radiates, to 0.45 mm across. Surface layer: capstans usually with two longer rays, 0.075-0.2 mm across.
Habitat
Inshore patch reefs to outer slope and fore reefs, from 4 to >30 m depth.
Distribution
South Florida, Bermuda and throughout the Caribbean Sea.
Similar Species
Date Taken
4-11-2016
Notes
Grows taller than either P. dichotoma or P. grisea, and with more widely spaced apertures that are always elevated. Distinguished by large quadriradiate sclerites (to 0.5 mm across) with slender arms in the middle layer. Polyps are armed more heavily than any otherPlexaurella with stout rods (0.3 mm long) (Bayer 1961). Preyed upon by the generalist octocoral predatory snail Cyphoma gibbosum, but also by Cyphoma signatum, a specialist predator on Plexaurellaspp. (Ruesink and Harvell 1990).