Pillsburiaster calvus Mah, 2011, n. sp.
Pillsburiaster calvus n. sp. (Figures 17 A–E) Diagnosis. Carinal series clearly distinguished, strongly convex, each plate with a periphery of ~ 20 coarse, sphaerical granules with 8–12 granules covering the plate surface (20–30 total on each plate surface). Superomarginal plates elongate with a str...
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| Format: | Other/Unknown Material |
| Language: | unknown |
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2011
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| Online Access: | https://zenodo.org/record/6184373 https://doi.org/10.5281/zenodo.6184373 |
| Summary: | Pillsburiaster calvus n. sp. (Figures 17 A–E) Diagnosis. Carinal series clearly distinguished, strongly convex, each plate with a periphery of ~ 20 coarse, sphaerical granules with 8–12 granules covering the plate surface (20–30 total on each plate surface). Superomarginal plates elongate with a strongly convex, round area free from granules, occupying 50 – 50 % of each supeormarginal plate surface. Furrow spines 2–3. Body weakly stellate (R/r= 1.74). Etymology. The species epithet “ calvus ” refers to the Latin for “bald” which refers to the prominent bald spots on the superomarginal plate surface. Distribution. Burdwood Bank in the Scotia Sea from 339– 357 m. Material examined. HOLOTYPE. USNM 1149357. Burdwood Bank. 54 ° 43 ’S; 56 ° 37 ’W to 54 ° 42 ’S; 56 ° 36 ’W. 339– 357 m. Coll. R/V Eltanin, University of Southern California, 14 March 1966.(1 dry spec., R= 4, r= 2.3). Description. Body form stellate-pentagonal (R/r= 1.74). Interadial arcs concave. Arms triangular (Fig. 17 A). Abactinal plates rounded to irregular in outline, larger proximally becoming smaller and more irregular closer to contact with superomarginal plate series. Plates flattened with fasciolar grooves absent. Carinal plate series relatively nondescript relative to other abactinal plates, and are covered with granules proximally, except at distalmost regions on arms. At approximately nine to 10 carinals away from the terminus, these plates become bare and strongly convex, irregularly round in outline. All other abactinal plates covered by granules, 15–45 in number, rounded to weakly pointed (Fig. 17 B). Granules crowded but evenly spaced and are largest centrally with smaller granules forming periphery. Boundary between central and peripheral granules weakly defined. Papulae present in radial regions where they surround abactinal plates, six to a plate. Papulae absent interradially and centrally on disk. Marginal plates 28 in each interradius (armtip to armtip), elongate in shape (Fig. 17 A). Superomarginal and inferomarginal plates with 1: ... |
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