Bathyceramaster sp. 2

Mah, Christopher L., 2024, Two New Taxa of Goniasteridae (Asteroidea, Echinodermata) and Noteworthy Observations of Deep-Sea Asteroidea by the NOAA Ship Okeanos Explorer in the North and Tropical Atlantic, Zootaxa 5432 (4), pp. 461-508 : 480

Bathyceramaster sp. 2

FIGURE 7C

Description

Body thick, pentagonal to weakly stellate (R/r=1.6), interradial arcs weakly curved.Abactinal plates appear tabulate, rounded all homogeneous in size, shape and densely arranged. Surface of each plate were indistinct but appear densely granulated or spinulose (i.e. accessories dense). Superomarginal plates 18 per interradius, each plate strongly convex in cross-section. Granules evenly cover superomarginal plate surface. Distalmost 2 to 3 superomarginal plate pairs abutted over midline with proximal most in contact only on partial upper corner. Actinal surface not visible.

Color was white to light tan or orange.

Comments

Based on Fig. 7C , this species was determined to most likely be undescribed. Other species of Bathyceramaster , aside from B. kelliottae , have not been reported from the Atlantic and the individual shown is dissimilar from any of the known Pacific species.

Numerous other potential species were not compatible with characters observed. Ceramaster granularis (Retzius, 1893) possesses distinct bald patches on each superomarginal plate surface, displays more angular superomarginals with a more flattened abactinal surface, shows a dissimilar abactinal surface texture, and is a much different color. This species lacks the secondary plates which characterize Peltaster placenta , although superomarginal plates are similar. Superomarginal plates in Plinthaster are not as wide and the abactinal plates are flat without any of the apparent granulation or plate surface convexity observed on the specimen. Bathyceramaster sp. 2 ( Fig. 7C ) also showed a more pentagonal shape with shorter arms than Bathyceramaster sp. 1 shown in Fig. 7A–B .

Ecological Comments

The observed individual in Figure 7C was perched on what appeared to be a sponge, upon which it was likely feeding. This would be consistent with other observations of Bathyceramaster spp. feeding on sponges in deep-sea settings (e.g. Mah 2016, 2020).

Image Observed

Yakutat Shallow seamount, North Atlantic, 36.300863 -51.351242, 2096 m. EX2104_IMG_20210709T190138Z_ROVHD.jpg

Figures

FIGURE 7. Bathyceramaster spp. in situ. (Goniasteridae) A. and B. Same individual.Bathyceramaster sp. 1. B shows different angle highlighting abactinal surface. Sp. 1. feeding on cladorhizid sponge, North Bermuda Tritop, 2578 m. C. Sp. 2. feeding on encrusting organism, Yakutat seamount, 2096 m.