Plexauridae, Gray, 1859

Devictor, Susan T. & Morton, Steve L., 2010, Identification guide to the shallow water (0 - 200 m) octocorals of the South Atlantic Bight 2599, Zootaxa 2599 (1), pp. 1-62 : 21

Key to species of Plexauridae in the South Atlantic Bight

1. Sclerites of colonies include warty stellate plates with a central knob ( Figure 20a,b ) as well as cup-shaped rosettes ( Figure 20c ) in outer coenenchyme, with concavity of cup facing away from axis ................................................... 2

- Sclerites of colonies include spindles ( Figure 21 a-c), rods or thorn-scales ( Figure 21d,e ) but no cup-shaped rosettes in outer coenenchyme ................................................................................................................................................... 3

2. Colony stout and branching, with branches and stems up to 3 mm thick; polyps closely set and numerous ............... ................................................................................................................................. Bebryce cinerea Deichmann, 1936

- Colony slender, unbranched or sparsely branched; stem diameter not exceeding 1 mm; polyps widely set apart and sparse .............................................................................................................. Bebryce parastellata Deichmann, 1936

3. Sclerites of colonies include calicular thorn-scales ........................................................................... Paramuricea sp.

- Thorn-scales absent...................................................................................................................................................... 4

4. Colonies with prominent conical calyces along two sides of branches, with large spindles (up to 3 mm) in coenenchyme and smaller spindles towards rim of calyces ...... Scleracis guadalupensis ( Duchassaing & Michelotti, 1860)

- Colonies with crowded shelf- or dome-like calyces scattered on all sides of branches, largest sclerites not reaching 3 mm ............................................................................................................................................................................... 5

5. Calyces appearing spiny or shelf-like ( Figure 12l ); calyx with large (often> 1 mm) orange spindles extending beyond its edge and very apparent when polyp is retracted. Coenenchyme containing spindles only ......................... ...................................................................................................................................... Muricea pendula Verrill, 1864

- Calyces domelike with no large sclerites. Coenenchyme with small colorless spindles, double heads, double cones (but see exception in Remarks on species) .................................................................. Thesea nivea Deichmann 1936

Figures

FIGURE 12. a) Scleracis guadalupensis spindle; b) Thesea nivea spindle and c) double head; d) Bebryce parastellata cup-shaped sclerite and e) knobbed plate; f) Bebryce cinerea knobbed plate; g, h) Paramuricea sp. thornscales; i) crosssection of plexaurid branch, loculi within axis indicated; j) Scleracis guadalupensis conical calyces; k) Bebryce parastellata cylindrical calyces; l) Muricea pendula shelf-like calyx. Illustrations d and e modified from images by S. Cairns/ Smithsonian Institution; illustration i modified from image in Fabricus and Alderslade, 2001; illustration l modified from image by FM Bayer/Smithsonian Institution.

FIGURE 20. a) Bebryce cinerea knobbed plate; Bebryce parastellata b) knobbed star and c) cup-shaped rosette (b and c modified from images by S. Cairns/Smithsonian Institution).

FIGURE 21. a) Scleracis guadalupensis spindle; b) Thesea nivea spindle; c) Muricea pendula spindle; d, e) Paramuricea sp. thornscales.