Chromoplexaura marki ( Kuekenthal , 1913)

Williams, Gary C., 2013, New taxa and revisionary systematics of alcyonacean octocorals from the Pacific coast of North America (Cnidaria, Anthozoa), ZooKeys 283, pp. 15-42 : 31-34

Chromoplexaura marki ( Kuekenthal, 1913) Figures 12-17

Synonymy.

Euplexaura marki Kükenthal 1913: 266; Kükenthal 1924: 93-94; Ofwegen 2012a.

Material examined.

CAS 096746, California, Monterey Carmel Bay off San Jose Creek Beach (Monastery Beach), 38 m depth, 20 May 1962, coll. Dennis Sullivan, five whole colonies. CAS 173222, California, Monterey Bay, Carmel Bay (Monterey Bay Marine Sanctuary), 32 m depth, 22 September 2010, coll. Karen Grimmer, two whole colonies. CAS 168895, California, (Gulf of the Farallones National Marine Sanctuary, Rittenburg Bank), 85 m depth, 8 October 2012, coll. National Oceanic and Atmospheric Administration, one whole colony.

Description.

Colonial morphology (Figures 12-13): The predominantly proteinaceous central axis has a hollow core. The main stem above the holdfast varies from 50-120 mm in length. The ultimate branches measure 10-115 mm in length by 2.5 -4.0 mm wide. The distal extremities are acute to rounded and often slightly swollen compared to the uniform width of the rest of the branches.

Polyps (Figures 12-13). Most of the polyps are fully retractile and form low rounded to hemispherical protuberances that are distributed on all sides of the branches. Some polyps are partially exserted and are <1.0 mm in width. Autozooid walls with eight longitudinal rows of densely-set, more-or-less en chevron sclerites that give rise to narrow points in the middle of each tentacle.

Sclerites (Figures 14-17). The coenenchymal sclerites are radiates, robust spindles, and ovoid forms with highly variable tuberculation, 0.06-0.24 mm in length (Figures 14, 15, 17 A–E, G–J). Some are robust and subspherical to ellipsoid with numerous and less well-pronounced tubercles. The sclerites of the polyp wall and points are heavily tuberculated spindles and rods, 0.04 mm– 0.09 mm in length (Figures 16; 17F, K, L, M).

Color (Figures 12-13). The color of the colonies is similar in life or preserved, the coenenchyme is uniformly- colored orange-red to vivid red, while the exsert polyps are white (Figure 11E). The coenenchymal sclerites are red-orange, while the polyp wall and points sclerites are colorless.

Distribution (Figure 19): Central Oregon to southern California; 9 to at least 90 m depth.

Biology and associated species. Several of the colonies in lot 096746, have enlargements on the branches that resemble gall-like growths, which contain epizoic barnacles of the genus Conopea (pers. comm., R. Van Syoc, California Academy of Sciences).