GONIASTERIDAE, Forbes, 1841

Mah, Christopher L., 2021, The East Pacific / South Pacific Boundary: New taxa and occurrences from Rapa Nui (Easter Island), New Caledonia and adjacent regions, Zootaxa 4980 (3), pp. 401-450 : 418

GONIASTERIDAE sp. C

Comments. As indicated in Mecho et al. (2019) Goniasteridae sp. C suggests Ceramaster australis , previously known only from Macquarie Ridge and New Caledonian waters (H.E.S. Clark & McKnight 2001). This species was observed off Rapa Nui between 160– 280 m. Mecho et al. (2019: Fig. 14C ) and Fig. 6E (herein) displays strongly convex superomarginal plates with curved edges, which are darker in color, and in contact laterally between plates, as is seen in C. australis ( Fig. 6E ). Images of “ Goniasteridae sp. C” Strongly suggest Ceramaster australis but image quality is imperfect and characters such as the elongate superomarginal plate shape and body color appear to differ from descriptions of C. australis .

Feeding observation. A further observation of “ Goniasteridae C” from Rapa Nui ( Fig. 6E ) shows it on what appears to be a fallen stalk of a “black coral” or antipatharian. Polyps on the stalk are fully extended on one side of the star but absent on the other side with the star showing an upward curvature around the stalk. This appears to be feeding by the goniasterid on the polyps of the antipatharian. Bo et al. (2018) has reported on a similar Atlantic species, Peltaster placenta , feeding on an antipatharian.

Occurrence. Macquarie Ridge and New Caledonia, Rapa Nui? 148–590 m.

Material examined. MNHN IE-2009-2126 . Banc Éponge, 24°55′24.0024″S, 168°21′30.0132″E, 525–560 m, Coll. N / O Alis, SMIB 4 DW 39. 1 dry spec .

Figures

FIGURE 6. Anthenoides epixanthus and Goniasteridae “C” (Rapa Nui): A. Abactinal surface. Scale bar equals 0.5 cm. B. Abactinal surface interradial paired plates. Scale bar equals 0. 25 cm. C. Actinal surface. Scale bar equals 0.5 cm. D. Actinal surface close-up, oral region. Scale bar equals 0.2 cm. E. Rapa Nui Goniasteridae “C” (similar to Ceramaster australis) feeding on fallen antipatharian. Image Courtesy A. Mecho.

FIGURE 14. Ophidiaster agassizi USNM E46260 (Juan Fernandez Islands, Chile): A. Abactinal view. Scale bar equals 1.5 cm. B. Abactinal surface close-up. Scale bar equals 0.4 cm. C. Actinal surface. Scale bar equals 1.5 cm. Inset scale bar equals 1.0 mm. D. Actinal surface showing furrow spination. Scale bar equals 0.4 cm.