72 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
scope with Everhart-Thomley detector (SEl) under lOkV accelerating voltage and 30 pm aperture 
size at Optibeam mode. All specimens were sputter-coated with gold/palladium using a Denton 
Vacuum Desk II sputter coater prior to imaging. 
Other abbreviations used in the text are: CASIZ (California Academy of Sciences, Invertebrate 
Zoology), and WoRMS (World Register of Marine Species). Photographs are by the first author 
(GCW) unless otheiwise indicated. Scanning electron micrographs are by the second author 
(J-YC). 
Key to the shallow-water genera of Gorgonians and 
Pennatulaceans of the Verde Island Passage 
(An asterisk indicates genera that contain some or all zooxanthellate species) 
la. Unbranched octocorals composed of a sterile stalk and a polyp-bearing rachis, imbedded in 
unconsolidated sediment by a muscular peduncle. Calcified central axis of variable length or 
absent with varying amounts of proteinaceous material. Sclerites are smooth three-flanged 
rods, ovals, plates, or needles (pennatulaceans ).2 
lb. Mostly branching octocorals, sometimes whiplike, encmsting, or lobate, attached to hard sub¬ 
strata by basal holdfast. Axial material highly variable, composed of a purple medullar zone, 
consolidated sclerites, hard protein, or predominantly ealcareous material. Sclerites are most¬ 
ly conspicuously tubercated, highly variable in shape (gorgonians).6 
2a. Polyps arise directly from the surface of the rachis.3 
2b. Polyps arise from polyp leaves that emanate laterally from the rachis.4 
3a. Sclerites are smooth spindles, rods, or ovals, sometimes with bilobed ends. 
. "^Cavernulina, Figs. 36A, 40A 
3b. Sclerites are tmncated plates either with smooth, uneven, or denticulated ends. 
. Veretilium, Fig. 37 
4a. Polyps united basally to form thin polyp leaves, peduncle slender.5 
4b. Polyps are contained on large thick polyp leaves, peduncle thick... Pteroeides, Figs. 39, 40C 
5a. Sclerites absent in rachis and polyp leaves. ^Virgularia, Fig. 38 
5b. Sclerites present in rachis and polyp leaves. Scytalium, Figs. 36B, 40B 
6a. Colony fonn highly vainable — membranous and encrusting, knobby to tall lobate, or form 
masses of tangled hollow branches. Axis not highly developed — eomposed of two layers, an 
outer cortex and inner medulla. Medullar sclerites often deep magenta in color. 
. "^Briareum, Figs. 3, 4 
6b. Colony form arborescent, upright and branching, rarely filiform. Axial material composed of 
consolidated sclerites, hard proteinaceous and/or calcareous material.7 
7a. Axial material composed of consolidated sclerites.8 
7b. Axial material composed of hard proteinaceous and/or calcareous material.12 
8a. Axis segmented, composed of alternating swollen, rounded nodes and straight, elongate intem- 
odes. Branching occurs at the nodes. Axial sclerites smooth.9 
8b. Axial material uniform throughout, nomsegmented.10 
9a. Sclerites include capstans often modified as birotulates (double discs) and club-like forms .. 
. Melithaea, Figs. lOA, B, 12 
9b. Sclerites are mostly spindles, often modified or curved. Acabaria, Figs. IOC, 11 
10a. Most branches are hollow, tubular, or openly channeled (interior open to the outside). 
. Solenocaulon, Figs. 5C, 6 
.11 
Annella, Figs. 7, 8 
10b. Branches are solid, not hollow. 
11a. Branching is densely reticulated (netlike), forming closed cells 
